Nutritional compositions and products

Abstract

A bite-sized nutritional composition comprising an iron source, at least one vitamin and chocolate, wherein the iron source is in the form of a microencapsulated iron. A nutritional composition suitab

Description

Field of Invention The present invention relates to nutritional compositions and products comprising iron and one or more vitamins or other micronutrients. In particular, the compositions and products are for use as health supplements and can be used for the treatment or prevention of iron deficiency. Background Iron is an essential nutrient in the mammalian diet, being a component of red blood cells and vital to oxygen transport. However, for those suffering from an iron deficiency or at risk of suffering from iron deficiency it can be difficult to increase iron intake from food alone. This may particularly be the case for vegans and vegetarians since non-heme iron in plants is not so readily absorbed by the body as heme iron that is obtained from meat and fish. Moreover, incorporating additional iron into food products and the use of nutritional supplements containing high concentrations of iron is not straightforward and can cause problems such as an unpleasant metallic taste, and gastrointestinal effects such as heartburn, nausea, constipation and diarrhoea. In particular, pregnant women, who are often in need of such iron supplements, can be more susceptible to these effects making the iron supplements hard to tolerate and decreasing the likelihood that they will take the supplements regularly. Accordingly, there is a need for improved products and methods for delivering iron, and for increasing iron absorption. Summary Accordingly, the present invention provides a nutritional composition comprising an iron source, at least one vitamin, and folic acid, wherein the iron source is in the form of a microencapsulated iron, the folic acid is comprised in a complex with buckwheat flour, the nutritional composition comprises chocolate, and the nutritional composition is in the form of a bite-sized product. Also provided herein is a nutritional composition suitable for increasing iron absorption in a subject, the nutritional composition comprising an iron source, wherein the iron source is in the form of a microencapsulated iron, and wherein the nutritional composition comprises buckwheat or is prepared from buckwheat. In a second aspect the present invention provides the nutritional composition of the invention for use in preventing the occurrence of an iron deficiency or in treating or reducing an iron deficiency in a human, optionally wherein the human is a pregnant woman. As described below the present invention uses buckwheat flour in the nutritional composition to increase the iron absorption from a microencapsulated iron comprised in the nutritional composition. In a still further aspect the present invention provides a method for the production of the nutritional composition according to invention, comprising mixing the encapsulated iron with (i) the chocolate and the at least one vitamin, and (ii) with the folic acid complexed with buckwheat to form the nutritional composition. Optionally, the method comprises: (a) melting the chocolate; (b) adding the encapsulated iron, the at least one vitamin, and the folic acid complexed with buckwheat to the melted chocolate; (c) mixing the encapsulated iron, the at least one vitamin, and the folic acid complexed with buckwheat with the melted chocolate to form a mixture; (d) pouring the mixture into a mould; and (e) cooling the mixture to form a product which is solid; (f) removing the product from the mould. The present inventors have shown that nutritional compositions comprising a combination of chocolate and microencapsulated iron in the form of bite-sized products can successfully address the problems of metallic taste and gastrointestinal issues and enhance compliance with a regime of daily supplement intake. Further vitamins and micronutrients (including those that are important during pregnancy, such as folic acid) can be incorporated into these products while retaining these key features. In particular, the advantageous properties of the product can be retained while incorporating folic acid complexed with buckwheat, which enhances absorption of the folic acid. The present inventors also surprisingly show that incorporating a buckwheat complexed micronutrient alongside the microencapsulated iron in the nutritional composition can be used to increase further the absorption of iron. Brief Description of the Drawings In relation to the present invention reference is made, by way of example only, to the accompanying Figures in which: Figure 1 provides a bar chart showing the amount of ferritin obtained from Caco-2 cells after contact with iron released by in vitro digestion from various iron-containing formulations. Figure 2 provides a bar chart showing the concentration of iron in Caco-2 cells after contact with iron released by in vitro digestion from various iron-containing formulations. Detailed Description The word “about”, when used herein to define an amount, refers to ± 10%, preferably ±5%, of the amount specified, unless otherwise indicated. It is noted that the amounts of micronutrients (iron, vitamins, and folic acid) mentioned herein are those derived from the specific micronutrient ingredients mentioned herein and do not include any micronutrients that may be contained in the chocolate. As described above, provided herein is a nutritional composition comprising an iron source and at least one vitamin, wherein the iron source is in the form of a microencapsulated iron, the nutritional composition comprises chocolate, and the nutritional composition is in the form of a bite-sized product. In particular, the nutritional composition is an individual, bite-sized, chocolate-based product, and it is intended as a dietary supplement to be taken orally (e.g. once per day). Also provided herein is a nutritional composition suitable for increasing iron absorption in a subject, the nutritional composition comprising an iron source, wherein the iron source is in the form of a microencapsulated iron, and wherein the nutritional composition comprises buckwheat or is prepared from buckwheat. Iron source The iron source in the composition is in the form of microencapsulated iron. The microencapsulation provides for controlled release of the iron in the upper intestine, such that after consumption the majority of the iron is retained within the capsule as the composition passes from the mouth of the consumer into the stomach and is only released upon reaching the intestine (in particular the duodenum) where it comes into contact with the digestive juices there and the released iron is absorbed into the blood stream. This encapsulation and controlled release help to protect against a metallic taste, and gastrointestinal side-effects. Moreover, iron salt forms are very reactive, which may cause oxidation of the other components in the composition. Accordingly, the microencapsulation protects the iron and prevents it from interacting with the external environment. Methods of microencapsulation are known in the food industry (e.g. WO 2010 / 040789 Al; Choudhury et al., Microencapsulation: An overview on concepts, methods, properties and applications in food. Food Frontiers. 2021; 2(4): 426-442). The microencapsulation may result in microcapsules ranging from 1 pm to several 100 pm in diameter, e.g. 400 pm in diameter. The microencapsulated iron may comprise a matrix and a core, wherein the matrix encapsulates at least one physiologically acceptable iron compound or iron complex in the core. The iron in the compound / complex may be in the Fe2+ or the Fe3+ oxidation state. Preferably the iron in the compound / complex is in the Fe3+ oxidation state. Preferably the physiologically acceptable iron compound is ferric saccharate (FS). In a preferred embodiment the matrix is an alginate matrix (e.g. as described in WO 2010 / 040789 Al). The alginate matrix may be a calcium alginate matrix or a sodium alginate matrix. Preferably the alginate matrix is a calcium alginate matrix. In an example of the preferred embodiment the microencapsulated iron is AB Fortis® (made by Frutarom using a patented manufacturing process) which comprises a calcium alginate matrix and a ferric saccharate (FS core). The microencapsulated ferric saccharate (MFS), which comprises 40% elemental iron is produced by ionotropic gelation of alginate with calcium entrapping ferric saccharate inside. Since calcium displays a comparatively stronger interaction with alginate, it acts as a microcapsule stabiliser preventing the release of the iron. In the intestine, the calcium alginate dissolves, releasing the iron which has a weaker interaction with alginate. A clinical trial with AB Fortis® was carried out to prove its bioavailability. Ferrous sulphate was used as a control as it has always been used as a first-line treatment due to a good bioavailability profile. Transferrin is the most effective carrier of iron and demonstrates an extremely high affinity to iron (Contreras et al., Comparative study of the oral absorption of microencapsulated ferric saccharate and ferrous sulphate in humans. European Journal of Nutrition. 2013;53(2):567-574). It was shown that transferrin saturation values of MFS were slightly higher than that of control (ferrous sulphate), however there was no significant difference between the two (p >0.05). Thus, this proved that the absorption of MFS is equivalent to that of ferrous sulphate, but with the benefits of the iron being encapsulated. The nutritional composition may comprise from 5 mg to 30 mg of iron, preferably from 10 to 20 mg of iron. In particular, where the nutritional composition is intended for consumers who are not pregnant or trying to conceive then the nutritional composition may comprise between 10 mg and 15 mg iron, or about 12 mg iron. Where the nutritional composition is intended for consumers who are pregnant or who are trying to conceive (and therefore whose requirements for iron are likely to be higher) the nutritional composition may comprise between 15 mg and 20 mg iron, or about 17 mg iron. Vitamins The nutritional composition comprises at least one vitamin. Suitable vitamins can be selected based on need and official recommendations regarding daily allowances. Preferably the at least one vitamin is at least one of vitamin C, vitamin B6, vitamin B12 and vitamin D3, each of which is described further below. Vitamin C Vitamin C is also known as ascorbic acid and is a water-soluble vitamin. The nutritional composition of the invention may comprise from 10 to 60 mg of vitamin C. Preferably where the nutritional composition is intended as a supplement for pregnant women, or women trying to conceive (and therefore may further contain folic acid) the nutritional composition may comprise from 20 to 60 mg of vitamin C, and preferably about 40 mg of vitamin C. Where the nutritional composition is not intended as a supplement for pregnant women, or women trying to conceive, the requirement for vitamin C may be lower and the vitamin C can be included to aid iron adsorption, and for this lower vitamin C levels can be used. In such cases the nutritional composition may comprise from 10 to 30 mg of vitamin C, preferably about 20 mg vitamin C. Preferably the vitamin C in the composition is comprised in a liposome as liposomal vitamin C. Liposomal vitamin C has several advantages over non-liposomal vitamin C, and in particular improves the overall absorption rate of the vitamin C. Specifically, due to its hydrophilic nature, ascorbic acid does not diffuse easily through the lipid bilayer of intestinal epithelial cells, hence limiting its bioavailability (Michels et al., Myths, artifacts, and fatal flaws: identifying limitations and opportunities in vitamin C research. Nutrients. 2013;5(12):5161-92). Ascorbic acid is innately unstable, sensitive to light, heat and high pH. It is also extremely susceptible to oxidation (Jampilek J, et al., Nanomaterials (Basel). Potential of Nanonutraceuticals in Increasing Immunity 2020; 10(11):2224). Liposomal entrapment of Vitamin C increases its stability and bioavailability (Kirby CJ et al. Stabilization of ascorbic acid by microencapsulation in liposomes. Int J Food Sci Technol. 1991;26:437-449). The liposomal membrane not only offers increased product stability, but also protects the active Vitamin C from degrading in the acidic stomach pH (Bozzuto G, et al., Liposomes as nanomedical devices. Int J Nanomedicine. 2015;10:975-99; Subramani T, et al., An overview of liposomal nano-encapsulation techniques and its applications in food and nutraceutical J Food Sci Technol. 2020;57(10):3545-3555). Structural similarity of liposomal vesicles to biological membranes facilitates intestinal absorption of active substances, thus increasing their bioavailability and, consequently, their effectiveness as proven by a randomised controlled trial (Gopi et al., Evaluation and Clinical comparison studies on liposomal and non-liposomal ascorbic acid (Vitamin C) and their enhanced bioavailability. J Liposome Res. 2021; 31(4);356-364). In the case of liposomes, delivery of active substances to the cells takes place in a controlled manner, either by fusion or by endocytosis (Aqil et al., Cancer Lett. Bioavailability of phytochemicals and its enhancement by drug delivery systems. 2013;334(l): 133-41). Liposomal encapsulation also protects the gut lining from irritation by the active Vitamin C (Aqil et al., Cancer Lett. Bioavailability of phytochemicals and its enhancement by drug delivery systems. 2013;334(l): 133-41). The benefits of liposomal Vitamin C are being reviewed in several fields including protection from ischaemic injury. Oral delivery of 4g of liposomal Vitamin C provided protection from ischaemia-reperfusion mediated oxidative stress and showed a significantly higher circulating concentration than unencapsulated Vitamin C (Davis et al., Liposomal-encapsulated Ascorbic acid: Influence on Vitamin C bioavailability and capacity to protect against ischaemia-reperfusion injury. Nutr Metab Insights. 2016 20;9 25-30). Intake of liposomal vitamin C in supra-optimal daily doses of more than 1-2 g may also significantly reduce the risk of gastrointestinal disorders in sensitive individuals (Lykkesfeldt et al., Vitamin C Adv Nutr. 2014;5(l): 16-18). Further, the liposomal vitamin C is advantageous over non-liposomal vitamin C in that it reduces the degree of tangy taste of the product to an acceptable level. Accordingly, it is preferred to use liposomal vitamin C when the nutritional composition includes higher levels of vitamin C, e.g. above 25 or 30 mg of vitamin C. A particularly preferred liposomal vitamin C is Liposovit-C® (made by BART Pharma) which comprises an external single bilayer of lecithin (phosphatidylcholine) molecule entrapping vitamin C molecules in an aqueous core phase. This product has been shown to protect vitamin C from chemical and enzymatic degradation during storage and during transit through the digestive tract, and is gentle on the lining of the gut, protecting the intestinal epithelium from irritation resulting from taking increased doses of vitamin C. In addition, it achieves a 2.5x superior bioavailability profile compared to conventional doses, enhancing the effectiveness of the vitamin C supplementation, i.e. achieve an equivalent therapeutic effect with lower doses of the active substance. The product enables slow and sustained release of vitamin C from the liposomal vesicle and is fully safe, biodegradable and biocompatible. Vitamin D3 Vitamin D3 is also known as cholecalciferol and is a type of vitamin D which is made naturally by the body on exposure of the skin to sunlight. Vitamin D3 may be taken as a dietary supplement, particularly by individuals who do not achieve regular natural exposure to sunlight. Vitamin D is a fat-soluble vitamin. It plays an important role in immune function, cell differentiation, bone growth, calcium homeostasis and reduce inflammation as well as risk of chronic diseases. Vitamin D is biologically inactive, so it needs to be metabolised to its biologically active forms. It enters the circulation from either skin or gut and is then transformed into 25-hydroxyvitamin D3 [25(OH)D or calcidiol] in the liver, and subsequently into 1,25-dihydroxy vitamin D3 [1,25(OH)2D or calcitriol] (Ponsonby et al., Vitamin D status during Pregnancy and Aspects of Offspring Health. Nutrients. 2010;2(3):389-407). The nutritional composition of the invention may comprise from 0.005 to 0.05 mg of vitamin D3 and preferably from 0.01 to 0.03 mg of vitamin D3. D3 is preferably incorporated where the nutritional composition is intended as a supplement for pregnant women, or women trying to conceive (and may therefore further contains folic acid). Unfortunately, the therapeutic effectiveness of vitamin D may be limited due to its lipophilic nature, poor solubility in gastrointestinal fluids and low bioavailability (Simoliunas E et al. Medicina (Kaunas). 2019;55(6):265). Moreover, the vitamin is easily degradable under the influence of oxygen present in air, the light and higher temperature (Simoliunas E et al. Medicina (Kaunas). 2019;55(6):265). Accordingly, preferably the vitamin D3 in the composition is comprised in a liposome as liposomal vitamin D3 (lipid encapsulated vitamin D3). Lipid encapsulated vitamin D3 confers protection against the acidic stomach environment (Kiani et al., Production of novel vitamin D3 loaded nanocapsules for milk fortification. International Journal of Food Properties 2017; 20(11):2466-2476), demonstrating higher bioavailability of the active form. Liposomal technology is quoted among the most promising solutions to improve the bioavailability of active substances which are poorly soluble in water (Simoliunas E et al. Medicina (Kaunas). 2019;55(6):265; Hsu et al., Nutrients. 2019;l 1(1):68), including vitamin D. In a clinical study by Paulina et al. liposomal vitamin D3 release profile was compared to oily vitamin D3 formulation. Liposomal vitamin D3 caused a rapid increase in plasma concentration of calcidiol, which was not observed in the oily formulation (Dalek et al., Bioavailability by design- Vitamin D3 liposomal delivery vehicles. Nanomedicine 2022 Jul; 43:102552). Patients supplemented with liposomal D3 achieved fasted compensation of calcidiol levels leading to significant improvement in the metabolic profile particularly, insulin sensitivity (Yanachkova et al., Benefits of using a microencapsulated vitamin D delivery system in women with polycystic ovary syndrome. Eur J Hosp Pharm. 2021-002967). Liposomal vitamin D3 also mimics the natural plasma membrane of animal tissue, hence boasting a higher bio-compatibility (Maurya et al., Vitamin D microencapsulation and fortification: Trends and technologies. The Journal of Steroid Biochemistry and Molecular Biology, 2020 196: 105489). Another advantage of liposomal technology is its ability to prevent chemical and / or physical degradation of active substance in storage (Shukla et al., Front Microbiol. 2017;8:2398) and as a result to ensure a longer shelf-life of the product. Vitamin B6 Apart from folic acid, intake of other B-group vitamins, especially B6 and B12 also has a huge influence in metabolic processes. Vitamin B6 (pyrioxamine) is a water-soluble vitamin and that it is a member of the vitamin B complex family (Black R, Micronutrients in pregnancy. British Journal of Nutrition. 2001 ;85(S2):S 193). It is a co-enzyme which is crucial in protein metabolism in development of the central nervous system. It is not common to be deficient in Vitamin B6 alone, it is usually associated with deficiency with other vitamin B complex family. Vitamin B6 deficiency leads to pre-eclampsia, gestational carbohydrate intolerance, hyperemesis gravidarum, and neurologic disease of infants (Salam et al., Pyridoxine (vitamin B6) supplementation during pregnancy or labour for maternal and neonatal outcomes. Cochrane Database of Systematic Reviews. 2015). Moreover, according to previous studies, vitamin B6 is an effective method in treating morning sickness by greatly improving nausea (Harker et al., Treating nausea and vomiting during pregnancy: case progression. BMJ. 2004;328(7435):337). Accordingly, the nutritional composition may comprise vitamin B6. The nutritional composition of the invention may comprise from 0.5 to 5 mg of vitamin B6 and preferably from 1 to 3 mg of vitamin B6. The vitamin B6 may preferably be in the form of pyridoxine hydrochloride (which is the form of vitamin B6 that is recommended by the FDA). Vitamin Bl 2 Vitamin B12 (cobalamin) is a member of the vitamin B complex family. It is an important nutrient for foetal development as it supports erythropoiesis (Black R, Micronutrients in pregnancy. British Journal of Nutrition. 2001 ;85(S2):S 193). Vitamin B12 is an enzyme which catalyses mitochondrial conversion of ethylmalonic acid to succinyl-CoA, which is vital for the metabolism of fat and protein as well as synthesis of haemoglobin. In addition, vitamin B12 acts as a co-factor with folic acid to generate methionine from homocysteine in the cytosol (Institute of Medicine, Food and Nutrition Board. Dietary reference intakes: thiamine, riboflavin, niacin, vitamin B6, folate, vitamin B12, pantothenic acid, biotin andcholine. Washington, DC: National Academy Press; 1998). Increasing prevalence of low plasma vitamin B12 concentration during pregnancy are observed globally, and particularly with an increased risk of vitamin B12 deficiency for pregnant women who consume a long-term, predominantly vegetarian diet (Koebnick et al., Long-Term Ovo-Lacto Vegetarian Diet Impairs Vitamin B-12 Status in Pregnant Women. The Journal of Nutrition. 2004;134(12):3319-3326). Previous studies suggested strong association between maternal and infant plasma vitamin B12 concentrations at delivery, i.e. maternal vitamin B12 status directly affects the foetal vitamin B12 status at birth. Low maternal vitamin B12 concentrations are also linked with multiple clinical symptoms and impaired foetal growth (Dror et al., Effect of vitamin B12 deficiency on neurodevelopment in infants: current knowledge and possible mechanisms. Nutrition Reviews. 2008;66(5):250-255). If serum vitamin B12 level is below 200 pg / ml then the individual is deemed to be vitamin B12 deficient (Gropper et al., Advanced nutrition and human metabolism.Wadsworth Cengage Learning, 2009). However, the US Institute of Medicine defined the lower limit as 120-180 pmol / L (170-250 pg / mL) (Institute of Medicine, Food and Nutrition Board. Dietary reference intakes: thiamine, riboflavin, niacin, vitamin B6, folate, vitamin B12, pantothenic acid, biotin andcholine. Washington, DC: National Academy Press; 1998). Low vitamin B12 level leads to decrease in methylation activity which may then cause defective DNA synthesis, megaloblastic anaemia and neurological abnormalities (Sanchez et al., Plasma Folate, Vitamin B12, and Homocyst(e)ine Concentrations in Preeclamptic and NormotensivePeruvian Women. American Journal of Epidemiology. 2001;153(5):474- 480). Accordingly, the nutritional composition may comprise vitamin B12, in particular from 0.002 to 0.010 mg of vitamin B12, and preferably from 0.004 to 0.008 mg of vitamin B12. Folic Acid Folate, also known as vitamin B9, is well known to be important in foetal development. It is normally manufactured as folic acid for inclusion in dietary supplements and is converted into folate by the body. Daily supplementation of 0.4mg of folic acid is recommended by health organisations and is considered as safe for both pregnant women and their unborn children as all the oxidised form of folic acid can be effectively converted into biologically active metabolites during absorption (Eichholzer et al., Folic acid: a public-health challenge. The Lancet. 2006;367(9519): 1352-1361). Accordingly, where the nutritional composition is intended for pregnant women or women who are trying to conceive, the composition may comprise from 0.2 to 0.6 mg of folic acid, preferably about 0.4 mg. Buckwheat complexed vitamins / folic acid The nutritional compositions of the invention comprises buckwheat flour. The flour may be present in an amount of from 200 mg to 800 mg, preferably from 300 mg to 600 mg, and more preferably from 400 mg to 500 mg. As shown in Example 3, when the folic acid is incorporated in the nutritional composition in a form that is complexed with buckwheat the absorption of the microencapsulated iron is synergistically increased. Without wishing to be bound by theory the inventors consider that the additional fibre and natural enzymes within the buckwheat flour surprisingly assist in intestinal absorption of the iron leading to improved bioavailability. Accordingly, the buckwheat flour may be utilised in the nutritional composition to enhance iron absorption in the intestine. The vitamins and micronutrients indicated above may be incorporated into the nutritional composition in a form that is complexed with buckwheat to improve their own absorption. In particular, this is for the folic acid. These buckwheat complexes are formed by germination of the buckwheat seeds in nutrient bath that includes the vitamins or folic acid. The buckwheat seeds take up the vitamins / folic acid and incorporate these. After the seeds begin to sprout the sprouting is stopped by drying and the seeds are ground into flour which can be utilised in the nutritional composition. Methods for producing these buckwheat complexes are known in the art (e.g. US 2007 / 0292541 Al; http8; / / eurochem.de / wp- In particular, it is preferred that the folic acid is incorporated into the nutritional composition in a complex with buckwheat. A particularly suitable product in this regard is Cultavit® folic acid (produced by eurochem GmbH). Cultavit® is buckwheat enriched with methyl folate. Buckwheat is used as a protective plant constituent to protect folic acid from degradation before reabsorption. It also prolongs the process of reabsorption hence improving its bioavailability. If folic acid metabolism takes place too quickly after ingestion i.e. in a short burst, then the concentration of metabolised folic acid will be greater than the transport capacity of folic acid via folate transporters. This may lead to unspecific uptake via diffusion through the intestinal lining. By incorporating buckwheat into the formulation, the release of folic acid is controlled and prolonged, maximising the transport of folic acid into the foetus via folate transporters in the maternal placenta. Therefore, absorption which delivers the ingested Folic Acid in a prolonged controlled manner rather than a “single short wave” can increase the overall bioavailability of Folic Acid (https: / / eurochem.de / wp- Controlled release of folic acid via Cultavit® also minimises the presence of any unmetabolized folic acid which could potentially have a negative impact on prenatal programming by acting as a methyl donor for the regulation of gene expression in the foetus (Folic acid fortification and public health: Report on threshold doses above which 12nmetabolized folic acid appear in serum. BMC Public Health. 2007;7(l). A clinical study has been carried out to prove the enhanced bioavailability of Cultavit® folic acid compared to the standard form h tip s : / / eurochem. de / w p - content / uploads / 2017 / 05 / CuVil 6FinalReport-160714.pdf. Powdered buckwheat and pure folic acid were used as negative and positive control respectively. This study has shown that there was no observable change in the serum level of folic acid for dried buckwheat powder. For both standard folic acid and Cultavit® folic acid, serum levels increased in the first 2 hours. The increase of Cultavit® folic acid was slightly slower than that of standard folic acid. However, at the 3rd hour after ingestion, the serum level of Cultavit® folic acid was significantly higher than that of standard folic acid (p <0.05). Area under curve was used to analyse by the authors to study their bioavailability. Standard folic acid peaked at around 1 hour after ingestion before the serum level started to decrease. On the other hand, an increase in serum level Cultavit® folic acid was comparatively slower, peaking at the 2nd hour after ingestion, however the peak was higher than that of standard folic acid. The area under curve of Cultavit® folic acid was 38% higher than that of standard folic acid, which indicated better resorption kinetics as well as a higher bioavailability. It is considered that Cultavit® folic acid significantly enhanced the bioavailability of folic acid as p <0.05. Therefore, it is preferred to use this product or similar in the nutritional composition of the invention. Chocolate As indicated above, the bite-sized nutritional product of the invention comprises chocolate. In particular, the product is chocolate-based and may comprise at least 80% by weight of chocolate, preferably at least 85% by weight of chocolate. In particular, it is considered that the relative high percentage of chocolate is important to assist in the palatability of the product and ensure compliance with the daily dosing schedule. Accordingly, better quality chocolate is preferable. The chocolate used in the nutritional composition may be made from ingredients comprising cocoa mass, cocoa butter, sugar and (whole) milk powder. Optionally the ingredients comprise one or more of emulsifier, soya lecithin and natural vanilla flavouring. The milk powder may be substituted by a vegetarian or vegan alternative in order to avoid animal products. Milk or dark chocolate may be used. The dark chocolate may comprise at least about 55% cocoa solids. The milk chocolate may comprise at least about 35% cocoa solids. Products The nutritional compositions of the invention are in the form of products that are easy for the individual to consume and are sized accordingly. In particular, the nutritional compositions of the invention would normally be in the form of products that are between 4 g and 6 g in weight, preferably between 4.5 g and 5 g, most preferably about 4.75 g. The nutritional composition of the invention is in the form of a bite-sized product, and may be in the shape of a ball, a dome (hemisphere), an ovoid or a button. In particular, “bite-sized” refers to the product being small enough to be eaten in one mouthful. The product may have a volume of from 2 ml to 10 ml, preferably between 4 ml and 6 ml, and more preferably about 5 ml. Production The nutritional composition of the invention may be made by a process comprising mixing the encapsulated iron with (i) the chocolate and the at least one vitamin, and (ii) with the folic acid complexed with buckwheat to form the nutritional composition. Optionally the method comprises: (a) melting the chocolate; (b) adding the encapsulated iron, the at least one vitamin, and the folic acid complexed with buckwheat to the melted chocolate; (c) mixing the encapsulated iron, the at least one vitamin, and the folic acid complexed with buckwheat with the melted chocolate to form a mixture; (d) pouring the mixture into a mould; and (e) cooling the mixture to form a product which is solid; (f) removing the product from the mould. In particular, the chocolate can be melted to a temperature at which it is sufficiently liquid to allow the encapsulated iron and the at least one vitamin to readily incorporated. The chocolate may be melted at about 28°C to 35°C, or at about 30°C. The melting temperature will vary depending on the ingredients in the chocolate that is being used. The mixing step is intended to disperse the micronutrients evenly through the chocolate so that the when the chocolate is poured into the moulds each bite-sized product contains the same amounts of the micronutrients. The mixture can be poured into a mould at room temperature. In particular, the mould may be a plurality of moulds to form a plurality of the bite-sized products. The mixture may be cooled and the products solidified at room temperature. Packaging and storage The nutritional compositions of the invention in the form of nutritional products may be stored in airtight containers, e.g. in an airtight box, at room temperature. The containers may be vacuum sealed. In particular, the present invention further provides a package comprising a plurality of the bite-sized products, e.g. 10, 20 or 30. The package may comprise the plurality of products in a single container or each product may be individually wrapped. Uses As indicated above the nutritional compositions of the invention are intended to be taken as oral daily supplements and can be used to treat an iron deficiency or prevent an iron deficiency in a human subject. In particular, the human subject may be a pregnant, or trying to conceive. The invention further provides the use of buckwheat, in particular buckwheat flour, in a nutritional composition to increase the absorption of iron released from a microencapsulated iron comprised in the nutritional composition when consumed by a subject. These nutritional compositions may comprise one or more of the further micronutrients or chocolate as described above. As shown in Example 3 below, when buckwheat flour is included in the nutritional composition the absorption of iron from the nutritional composition is increased. The invention will be described further with reference to the following examples. EXAMPLES Example 1 - Production of chocolate domes containing micronutrients The formulation of two examples of the nutritional composition of the invention and the process for producing examples of the bite-sized products are described. Formulation 1 - “Gio Iron” / “Gio Period” - which can be used for providing essential nutrients, and in particular increasing the iron intake of individuals at risk of iron deficiency or suffering from iron deficiency. Formulation 2 - “Gio Prenatal” - which can be used for providing essential nutrients, and in particular increasing iron intake, during pregnancy. The formulations are made from the following ingredients: Liposovit® C (Liposomal L-ascorbic acid, glycerol, maltodextrin, sunflower lecithin phospholipids); Liposovit® D3 Vegan* (Liposomal Vitamin D3, alpha tocopherol, gum arabic); Cultavit®* (Buckwheat enriched Folic Acid); AB Fortis® Microencapsulated ferric saccharate containing approx. 40% iron (Ferric saccharate, Calcium alginate, Water); Vitamin B12 (Cyanocobalamin); Vitamin B6 (Pyridoxine HC1); Chocolate (sugar; whole milk powder; cocoa butter; cocoa mass; emulsifier: soya lecithin; and natural vanilla flavouring) * Used in Formulation 2 only Allergens: milk and soy The products via the following steps: 1. Measuring - the quantities of the ingredients (i.e. the milk or dark chocolate, and the micronutrient) are weighed out according to the amounts shown in the table below. (All values must be within +10% range); 2. Mixing - all ingredients are mixed with the chocolate blend in the Stephan Mixer at 30°C, and a vacuum is used to remove any excess air bubbles, to achieve a smooth blend without any lumps or grains; 3. Depositing - the chocolate mixture is deposited into the filling tray of the praline machine; and the tray is vibrated gently to make the chocolate an evenly round shape on top, and produce hemispheres with dark / milk chocolate colour; no damage; average weight: 4.75 g + / - 10% Table 1 below provides the amount of each ingredient in each chocolate, while Table 2 provides the amount of each micronutrient present in each chocolate. Ingredient Amount of ingredient in each chocolate (+ / -10%) in g Formulation 1 “Gio Iron” / “Gio Period” Formulation 2 “Gio Prenatal” AB Fortis® Microencapsulated Iron 0.03 0.0425 Ascorbic acid or Liposovit® C 0.02 of ascorbic acid 0.191 of Liposovit® C Vitamin B6-HC1 0.00243 0.00243 Vitamin B12 0.000006 0.000006 Liposovit® D3 Not added 0.067 Cultavit® (containing folic acid) Not added 0.445 Chocolate Amount to make up to total weight of 4.75 (+ / - 10%) Amount to make up to total weight of 4.75 (+ / - 10%) Table 1. Amounts of ingredients in each chocolate Nutrient Amount (mg) per individual bite-sized product* Chocolate made from Formulation 1 “Gio Iron” / “Gio Period” Chocolate made from Formulation 2 “Gio Prenatal” Iron 12 17 Vitamin C 20 40 Vitamin B6 2 2 Vitamin B12 0.006 0.006 Vitamin D3 Not added 0.02 Folic Acid Not added 0.4 * amounts do not include any nutrients from the chocolate ingredient. Table 2. Amounts of micronutrients in each chocolate The individual chocolates produced are hemispherical / dome shaped and can be packaged in airtight containers and stored at room temperature. The chocolates can be taken at the recommended daily dose of one per day and can be taken at any time during the day. Example 2 - Sensory Study This example describes a sensory study that was conducted to show how the product was received by consumers. Study with Formulation 1 - “Gio Iron” - with each individual chocolate having formulation 1 as per Example 1. Number of participants: 25 Studies were performed just after manufacture (TO) followed by 14 weeks after date of manufacture (Tl). The chocolates were stored in an airtight container at room temperature. 19 participants were women, 6 were men All participants were between the age of 18 and 60 years Participants were asked to taste the product and then rate its visual appeal, smell, taste, texture, and palatability. They were also asked to comment on whether the product causes a metallic aftertaste and to provide general remarks on the product. The results are shown below in Tables 3 and 4 (for TO) and Tables 5 and 6 (for Tl). Aspect Rating Parameters Key Remarks Made Exceptional Good Satisfactory Poor Very Poor Visual appeal 1 23 1 0 0 Organic looking Smell 2 22 1 0 0 Smells of cocoa Taste 24 1 0 0 0 Divine; can’t stop at 1 Texture 23 2 0 0 0 So smooth Palatability 21 4 0 0 0 Melts in mouth Table 3. Results from sensory study of product with formulation 1 at TO Aspect Metallic No metallic aftertaste Key Remarks Made Aftertaste 0 25 There was a tangy aftertaste (N.B. this is due to the Vitamin C) Table 4. Results of aftertaste analysis of product with formulation 1 at TO Aspect Rating Parameters Key Remarks Made Exceptional Good Satisfactory Poor Very Poor Visual appeal 1 22 2 0 0 Organic looking Smell 1 24 0 0 0 Smells of fresh cocoa Taste 23 2 0 0 0 Best vitamin supplement I have ever tasted Texture 24 0 1 0 0 Smooth and silky Palatability 20 3 2 0 0 Melts in mouth Table 5. Results from sensory study of product with formulation 1 at Tl Metallic No metallic aftertaste Key Remarks Made Aftertaste 0 25 There was a tangy aftertaste (N.B. this is due to the Vitamin C) Table 6. Results of aftertaste analysis of product with formulation 1 at T1 Study with Formulation 2 - “Gio Prenatal” - with each individual chocolate having formulation 2 as per Example 1 Number of participants: 25 The study was performed 4 weeks after manufacture, the chocolates having been stored in an airtight container at room temperature. All 25 participants were females; among the participants 3 participants were pregnant at the time of the study, 2 participants were breastfeeding, 16 participants have been pregnant, and 3 participants plan to get pregnant in the next year Participants were asked to taste the product and then rate its visual appeal, smell, taste, texture, and palatability. They were also asked to comment on whether the product causes a metallic aftertaste and to provide general remarks on the product. The results are shown below in Tables 7 and 8. Aspect Rating Parameters / Numbers Key Remarks Made Exceptional Good Satisfactory Poor Very Poor Visual appeal 5 19 1 0 0 Doesn’t look “industrial”; has “hand crafted” element Smell 3 21 1 0 0 Smells of cocoa Taste 24 1 0 0 0 Best prenatal supplement I have tasted Texture 15 8 2 0 0 Slightly grainy; velvety smooth Palatability 21 4 0 0 0 Melts in mouth; velvety Table 7. Results from sensory study of product with formulation 2 Metallic No metallic aftertaste Key Remarks Made Aftertaste 0 25 There was a tangy aftertaste. N.B. this was due to the Vitamin C Table 8. Resu Its of aftertaste ana ysis of product with formulation 2 As shown by the results in Tables 3 to 8 above, the chocolate products were well-received by the tasters in the studies, and the presence of the nutrients in the chocolates does not negatively affect the appearance, taste and consistency of the products. In particular, none of the participants detected any metallic aftertaste and none reported any nausea or stomach issues arising from eating the product. Rather, as shown by the remarks recorded in the tables above, the tasters enjoyed the product, indicating that the product will be more eagerly taken by consumers. The results show that when mixed together as a chocolate blend, the ingredients are stable and have an outstanding taste profile. There is no metallic taste detected from the iron, which the inventors consider is due to the combination of the microencapsulation of the iron and the taste masking effects of the cocoa. Due to the taste profile, the chocolate products would ensure a high compliance rate with daily supplement intake. In particular for the “Gio Prenatal” product this would lead to prevention of complications in pregnancy such as iron deficiency anaemia, folate deficiency, and Vitamin D deficiency. Example 4 - Iron Absorption Testing This example describes testing that was carried out to determine the absorption profile of iron from the products having Formulation 2 (“Gio Prenatal”) as compared to other prenatal supplements on the market. Iron absorption normally takes place in the duodenum region of the small intestine therefore the human intestinal cell line Caco-2 cells was chosen as a model for investigating the in-vitro iron absorption as it has been well-characterised by numerous previous studies (Fairweather et al., The Usefulness of in vitro Models to Predict the Bioavailability of Iron and Zinc: A Consensus Statement From the HarvestPlus Expert Consultation. International Journal for Vitamin and Nutrition Research. 2005;75(6):371-374). Caco-2 cells exhibit the morphological characteristics of mature enterocytes and express the majority of the receptors involved in iron absorption, such as DMT-1, DcytB and Iregl (ferroportin), IREI and IRE2. Ferritin concentration was measured as an estimation of iron absorption in Caco-2 cells; this method demonstrates good correlation with human absorption data at the corresponding time point (Yun et al., An In Vitro Digestion / Caco-2 Cell Culture System Accurately Predicts the Effects of Ascorbic Acid and Polyphenolic Compounds on Iron Bioavailability in Humans. The Journal of Nutrition. 2004;134(10):2717-2721). Caco-2 cells synthesise ferritin according to their corresponding iron status as well as the iron levels in the surrounding environment (Sharp et al., Methods and Options for Estimating Iron and Zinc Bioavailability Using Caco-2 Cell Models: Benefits and Limitations. International Journal for Vitamin and Nutrition Research. 2005;75(6):413-421). Ferritin is an iron storage protein which is regarded as a marker for iron absorption (Andrews N. Disorders of Iron Metabolism. New England Journal of Medicine. 1999;341(26): 1986-1995). The in vitro methodology used in the present Example follows that set out in Yun et al., (An In Vitro Digestion / Caco-2 Cell Culture System Accurately Predicts the Effects of Ascorbic Acid and Polyphenolic Compounds on Iron Bioavailability in Humans. The Journal of Nutrition. 2004;134(10):2717-2721). The test formulations in the table below were subjected to simulated digestion in vitro, and the caco-2 cells were exposed to the digests such that iron from the digests became accessible for uptake by the caco-2 cells. Ferritin formation by the caco-2 cells, a marker for cell Fe uptake, was then used as the indicator of Fe bioavailability. Table 9 below shows the content of the test formulations. Test Formulation No. and Name Test Formulation Content 1. Fe-FA-MV* Iron sulphate (85 mg); conventional folic acid (FA) (0.4 mg); MV* 2. ABF-FA-MV* AB Fortis® (42.5 mg), conventional Folic Acid (0.4 mg), MV* 3. Fe-CuFA-MV* Iron sulphate (85 mg), Cultavit® (445 mg), MV* 4. ABF-CuFA- MV* AB Fortis® (42.5 mg), Cultavit® (445 mg), MV* 5. FeSO4 and FA Iron sulphate (85 mg) and conventional Folic acid (0.4 mg) 6. Pregnacare® Pregnacare® Liquid formulation (5 mL) 7. Ferrous sulphate (FeSO4) Iron sulphate (85 mg) *MV: Multivitamins and micronutrients consisting of Vitamin C, Vitamin B6 in the form of B6 HC1, Vitamin B12, Vitamin D3, calcium in the form of calcium carbonate, and choline in the form of choline bitartrate. Mass used in mg 70, 2.43, 0.006, 0.02, 500 and 1094, respectively. Table 9. Test formulations All formulations were dissolved in 5 ml water, except for Pregnacare® as this is already in liquid form. Caco-2 cells were obtained at passage 56 and used experimentally between passages 57 to 60. Stock cultures were maintained in 75 cm3 tissue culture flasks in complete medium [Dulbecco’s modified Eagle’s media (DMEM) - Glutamax® (pH 7.4) supplemented with 10% FCS, 1% antibiotic / antimycotic solution and 25 mM HEPES]. The cells were cultured in an incubator at 37°C in an atmosphere of 95% air and 5% CO2 at constant humidity. Besides, the cells were fed every two days. Cells were seeded onto 6-well plates at an initial seeding density of 1.5 x 105 cells / cm3 for the dissolution absorption experiment. Parallel 6-well plates were also seeded similarly for the assessment of cell viability prior to the commencement of the uptake experiment and following completion. Caco-2 cells were differentiated to a fully matured gastrointestinal (GI) tract phenotype at day 14-15 post-seeding, at which time iron uptake experiments were commenced. On day 13 post-seeding cells were prepared for experiment by aspirating growth media and washing Caco-2 cell monolayers three times with wash solution (140 mM NaCl, 5 mM KC1, 10 mM PIPES buffer, pH 6.7, 37°C) and then incubated in serum-free MEM for 24 h. On day 14 test media was prepared by titrating MEM with 0.1 M HC1 or 0.1 M NaOH to pH 5.8, which represents the physiological pH in the duodenum. Test media was then sterile filtered using a 0.2pm filter unit, buffered with 2-(N-Morpholino) ethanesulfonic acid (MES, 10 mM) and aliquoted into individual falcon tubes. Samples from the test preparations were added to the test media to achieve a final concentration of 20pM elemental iron for each. Caco-2 cells in test plates were then incubated with iron enriched test media (six wells per condition) for 2 h at 37°C in a plate incubator rocking gently at 15 rpm. After incubation period test media was aspirated and cells washed twice with wash solution and finally with a removal solution (wash solution plus 5 pm Na hydrosulphite and 1pm bathophenanthro-line disulfonate) to remove any surface bound iron, as described previously (Zhu L, Glahn R, Yeung C, Miller D. Iron Uptake by Caco-2 Cells from NaFeEDTA and FeSO4: Effects of Ascorbic Acid, pH, and a Fe(II) Chelating Agent. Journal of Agricultural and Food Chemistry. 2006;54(20):7924-7928). Caco-2 cells were then incubated with fresh MEM for a further 24 h in a cell culture incubator (37°C, 95% air and 5% CO2). After 24 hours of incubation, media was aspirated. Cells were harvested by addition of 350 pl lysis buffer (50 mM NaOH supplemented with 1 pg / ml protease inhibitor cocktail) per well for 40 min while rocking gently on a plate shaker (6 rpm). Cells were then scraped, and the resultant lysate was pipetted into 0.5 ml microcentrifuge tubes and stored immediately at -20°C for further analysis. Protein Content by Bicinchoninic Acid Assay (BCA) BCA protein assay kit (Thermo Fisher Scientific (Northumberland, UK) was used to determine total protein content of Caco-2 cell lysates. Samples were assayed in duplicate following manufacturer’s protocol using bovine serum albumin (BSA) stock (2 mg / ml) as a standard. Absorbance was measured at 562 nm using a microplate reader (VersaMax, Molecular devices, USA). The results obtained from BCA were used to standardize both the results of immunoassay (ELISA) and ferrozine assay. Determination of Ferritin by Immunoassay (ELISA) Iron absorption was determined by measuring total ferritin protein concentration in cell lysates using a spectrophotometric ELISA kit as described previously (Zariwala M. Comparison Study of Oral Iron Preparations Using a Human Intestinal Model. Scientia Pharmaceutica. 2013;81(4): 1123-1139). A standard curve was generated using the standards provided (0, 6, 20, 60, 200 ng standard / ml). Samples and standards (30 pl each) were loaded in duplicates onto a 96-well plate and the incubation steps were carried out as described in previous studies (Zariwala M. Comparison Study of Oral Iron Preparations Using a Human Intestinal Model. Scientia Pharmaceutica. 2013;81(4): 1123-1139). Absorbance was determined at 490 and 630 nm using a microplate reader (VersaMax, Molecular devices, USA). Ferritin concentration was then standardised against total protein concentration (ng ferritin / mg protein) and considered a marker of iron absorption. Test F ormulation No. and Name Test Formulation Content Measured Ferritin (ng / mg cell protein) 1. Fe-FA-MV* Iron sulphate; conventional folic acid (FA); MV* 46.684 2. ABF-FA-MV* AB Fortis®, conventional Folic Acid, MV* 40.870 3. Fe-CuFA-MV* Ferrous sulphate, Cultavit®, MV* 47.639 4. ABF-CuFA-MV* AB Fortis®, Cultavit®, MV* 252.787 5. FeSO4 and FA Iron sulphate and conventional Folic acid 42.390 6. Pregnacare® Pregnacare® Liquid formulation 19.173 7. Ferrous sulphate (FeSO4) Ferrous sulphate 31.571 *MV: Multivitamins as in Table 9 Table 10. Test formulations and amounts of ferritin measured. The concentration of ferritin obtained from the test formulations is shown in Table 10 and also in Figure 1. The fourth formulation in Table 10 (ABF-CuFA-MV), which consists of AB Fortis® and Cultavit®, and multivitamins, gave the best iron absorption; its iron absorption was significantly higher, i.e. 13-fold, than that of Pregnacare®, which is currently #1 UK brand for prenatal supplementation (p <0.05). It is noted that both the AB Fortis® and the Cultavit®FA are in prolonged delivery forms, which are aimed at releasing the majority of the iron and folic acid directly in the intestine. Without wishing to be bound by theory the inventors consider that the excipients in Cultavit® (i.e. primarily the fibres but potentially also the natural enzymes), act to aid absorption of the iron released from the AB Fortis®. Based on this work the inventors consider that the AB Fortis® and Cultavit® ingredients have a synergistic effect promoting higher iron absorption alongside proven superior bioavailability profiles of the individual vitamins. Iron Quantification by Ferrozine Assay In a further study, a comparison of total intracellular iron concentration of the test formulations shown in Table 10 as well as controls were conducted. 200 pl of cell lysates, produced from the caco-2 cells treated as described above, were placed in Eppendorf tubes and mixed with 100 pl of 0. IM HC1, and 100 pl of the iron-releasing reagent (a freshly mixed solution of equal volumes of 1.4M HC1 and 4.5% (w / v) KMnO4 in H2O). These mixtures were incubated for 2 hours at 60°C within a fume hood, since chlorine gas was produced during the reaction (Fish W.W. Rapid Colorimetric Micromethod for the quantitation of complexed iron in biological samples. Methods Enzymol. 1988;158:357-364). The HCl / KMnO4 pretreatment is sufficient to release iron quantitatively from proteins, including the iron-storage protein ferritin (May et al., The UV and visible spectral properties of ferritin. Archives of Biochemistry and Biophysics. 1978;190(2):720-725) and heme proteins such as hemoglobin (Panter S.S. Release of Iron from Haemoglobin. Methods Enzymol. 1994;231:502-514).The HCl / KMnO4-mediated digestion of iron-containing proteins is essential for iron quantitation of heme proteins because Fe2+-ferrozine complex would not be recovered by treatment of hemoglobin with ferrozine if the protein has not been pretreated with acidic permanganate solution (Panter S.S. Release of Iron from Haemoglobin. Methods Enzymol. 1994;231:502-514). After the mixtures had cooled to room temperature, 60 pl of the iron-detection reagent (6.5mM ferrozine, 2.5M ammonium acetate, and IM ascorbic acid dissolved in water) was added to each tube. After 30min, 200 pl of the solution in each tube was transferred into a well of a 96-well plate and the absorbance was measured at 550nm on a microplate reader. The iron content of the sample was calculated by comparing its absorbance to that of a range of standard concentrations of equal volume that had been prepared in a way similar to that of the sample (mixture of 200 L of FeSO4 standards in 200 pl 50 mM NaOH, 200 pl iron-releasing reagent, and 60 pl iron- detection reagent). The intracellular iron concentration determined for each well of a cell culture was standardised against the protein content of that well. Ferrozine reacts with ferrous iron in the sample, thus forming a purple complex that strongly absorbs light at 550 nm, with a colour intensity directly proportional to the concentration of iron in the formulation (Fish W.W. Rapid Colorimetric Micromethod for the quantitation of complexed iron in biological samples. Methods Enzymol. 1988;158:357-364). The absorbance at 550 nm rapidly increases to maximal values within 10 minutes and remains stable for at least 1 hour. It is important to include ascorbic acid because it reduces ferric iron in samples to ferrous iron (Davis et al., A modified ferrozine method for the measurement of enzyme-bound iron. Journal of Biochemical and Biophysical Methods. 1986; 13(1):39-45). The ascorbic acid is usually fortified with a strong acid to prevent the reduced state of the former acid. Moreover, it is also essential to incubate the cell lysates with HCl / KMnO4 solution for 2 hours at 60°C as it produces the maximal detection of iron in the samples, reduced incubation temperature or time may lower the total concentration of iron detected in the samples. The results are shown in Table 11 and Figure 2. Test Formulation No. and Name Concentration of Iron (mcm) 1. Fe-FA-MV* 15.780 2. ABF-FA-MV* 14.228 3. Fe-CuFA-MV* 9.731 4. ABF-CuFA-MV* 20.404 5. FeSO4 and FA 14.271 6. Pregnacare® 10.967 7. Ferrous sulphate (FeSO4) 12.003 Minimum Essential Media (MEM) 5.492 Table 11. Test formulations and iron concentration measured. As shown in Figure 2, it was determined that Test formulation 4 (ABF-CuFA-MV) had the highest total intracellular iron concentrations, followed by Test Formulation 1 (Fe-FA-MV). The results obtained from ferrozine assay were consistent with the trend of the results obtained from immunoassay detecting ferritin as described above, except for Test Formulation 3 (Fe-CuFA-MV). Test Formulation 3 showed a lower total intracellular iron concentration but a higher absorption rate than Test Formulation 1. The inventors consider that this is likely the effect of Cultavit® as it contains enzymes which are believed to promote absorption (laniro et al., Digestive Enzyme Supplementation in Gastrointestinal Diseases. Current Drug Metabolism. 2016; 17(2): 187- 193). STATEMENTS OF INVENTION The invention includes the following items: 1. A nutritional composition comprising an iron source, at least one vitamin, and folic acid, wherein the iron source is in the form of a microencapsulated iron, the folic acid is comprised in a complex with buckwheat flour, the nutritional composition comprises chocolate, and the nutritional composition is in the form of a bite-sized product. 2. The nutritional composition of item 1, wherein the microencapsulated iron comprises an alginate matrix. 3. The nutritional composition of item 2 wherein the alginate matrix comprises sodium alginate. 4. The nutritional composition of item 2 wherein the alginate matrix comprises calcium alginate. 5. The nutritional composition of any preceding item, wherein the microencapsulated iron comprises a core comprising at least one physiologically acceptable iron compound or iron complex. 6. The nutritional composition of item 5, wherein the at least one physiologically acceptable iron compound or iron complex is ferric saccharate. 7. The nutritional composition of any preceding item, comprising from 5 mg to 30 mg of iron. 8. The nutritional composition of item 7, comprising from 10 mg to 20 mg of iron. 9. The nutritional composition of item 8, comprising from 10 to 15 mg iron. 10. The nutritional composition of item 9, comprising about 12 mg iron. 11. The nutritional composition of item 8, comprising from 15 to 20 mg iron. 12. The nutritional composition of item 11, comprising about 17 mg iron. 13. The nutritional composition of any preceding item, wherein the at least one vitamin is vitamin C. 14. The nutritional composition of item 13, comprising from 10 mg to 60 mg vitamin C. 15. The nutritional composition of item 14, comprising from 20 mg to 60 mg vitamin C. 16. The nutritional composition of item 15, comprising about 40 mg vitamin C. 17. The nutritional composition of item 15, comprising from 10 mg to 30 mg vitamin C. 18. The nutritional composition of item 17, comprising about 20 mg vitamin C. 19. The nutritional composition of any preceding item, comprising vitamin D3. 20. The nutritional composition of item 19, comprising from 0.005 to 0.05 mg vitamin D3. 21. The nutritional composition of item 20, comprising from 0.01 to 0.03 mg vitamin D3. 22. The nutritional composition of item 21, comprising about 0.02 mg vitamin D3. 23. The nutritional composition of any preceding item, comprising vitamin B6. 24. The nutritional composition of item 19, comprising from 0.5 to 5 mg vitamin B6. 25. The nutritional composition of item 20, comprising from 1 to 3 mg vitamin B6. 26. The nutritional composition of item 21, comprising about 2 mg vitamin B6. 27. The nutritional composition of any preceding item, comprising vitamin B12. 28. The nutritional composition of item 27, comprising from 0.002 to 0.010 mg vitamin B12. 29. The nutritional composition of item 28, comprising from 0.004 to 0.008 mg vitamin B12. 30. The nutritional composition of item 29, comprising about 0.006 mg vitamin B12. 31. The nutritional composition of any preceding item, wherein the vitamin C is liposomal vitamin C, and / or wherein the vitamin D3 is liposomal vitamin D3. 32. The nutritional composition of any preceding item, comprising from 0.2 to 0.6 mg of folic acid. 33. The nutritional composition of item 32, comprising from 0.3 to 0.5 mg of folic acid. 34. The nutritional composition of item 33, comprising about 0.4 mg of folic acid. 35. The nutritional composition of any preceding item, wherein the chocolate is made from ingredients comprising cocoa mass, cocoa butter, sugar and (whole) milk powder. 36. The nutritional composition of item 35, wherein the ingredients further comprise one or more of an emulsifier, soya lecithin and natural vanilla flavouring. 37. The nutritional composition of any preceding item, which comprises at least 80% by weight chocolate. 38. The nutritional composition of item 37, which comprises at least 85% by weight chocolate. 39. The nutritional composition of any preceding item, which is in the form of a ball or a dome. 40. The nutritional composition of any preceding item, which is in the form of a bite-sized product which weighs between 4 g and 6 g. 41. The nutritional composition of item 40, wherein the bite-sized product weighs between 4.5 g and 5 g. 42. The nutritional composition of item 41, wherein the bite-sized product weighs about 4.75 g. 43. The nutritional composition of any preceding item, which has a volume of from 2 ml to 10 ml. 44. The nutritional composition of item 43, which has a volume of from 4 ml to 6 ml. 45. The nutritional composition of item 44, which has a volume of about 5 ml. 46. A nutritional composition for use in preventing the occurrence of an iron deficiency or in treating or reducing an iron deficiency in a human, wherein the nutritional composition is as defined in any preceding item. 47. The nutritional composition for use according to item 52, wherein the human is pregnant or trying to conceive. 48. A method of treating, preventing or reducing an iron deficiency in a subject, comprising orally administering a nutritional composition as defined in any of items 1 to 51. 49. A process for the production of the nutritional composition according to any of items 1 to 45, comprising mixing the encapsulated iron with (i) the chocolate and the at least one vitamin, and (ii) with the folic acid complexed with buckwheat to form the nutritional composition, optionally wherein the method comprises: (a) melting the chocolate; (b) adding the encapsulated iron, the at least one vitamin, and the folic acid complexed with buckwheat to the melted chocolate; (c) mixing the encapsulated iron, the at least one vitamin, and the folic acid complexed with buckwheat with the melted chocolate to form a mixture; (d) pouring the mixture into a mould; and (e) cooling the mixture to form a product which is solid; (f) removing the product from the mould. 50. A package comprising a plurality of the nutritional compositions according to any of items 1 to 45. All publications, patents, and patent applications mentioned herein are hereby incorporated by reference in their entirety. In cases where the present specification and a document incorporated by reference include conflicting and / or inconsistent disclosure, the present specification shall control.

Claims

1. A nutritional composition comprising an iron source, at least one vitamin, and folic acid, wherein the iron source is in the form of a microencapsulated iron, the folic acid is comprised in a complex with buckwheat flour, the nutritional composition comprises chocolate, and the nutritional composition is in the form of a bite-sized product.

2. The nutritional composition of claim 1, wherein the microencapsulated iron comprises an alginate matrix, preferably where the alginate matrix comprises sodium alginate or calcium alginate.

3. The nutritional composition of claim 1 or claim 2, wherein the microencapsulated iron comprises a core comprising at least one physiologically acceptable iron compound or iron complex.

4. The nutritional composition of claim 3, wherein the at least one physiologically acceptable iron compound or iron complex is ferric saccharate.

5. The nutritional composition of any preceding claim, comprising from 5 mg to 30 mg of iron, preferably from 10 mg to 20 mg of iron.

6. The nutritional composition of any preceding claim, wherein the at least one vitamin is vitamin C, vitamin B6, vitamin B12 or vitamin D3.

7. The nutritional composition of claim 6, wherein the vitamin C is liposomal vitamin C,and / or wherein the vitamin D3 is liposomal vitamin D3.

8. The nutritional composition of any preceding claim, comprising from 0.2 to 0.6 mg of folic acid, preferably from 0.3 to 0.5 mg of folic acid.

9. The nutritional composition of any preceding claim, wherein the chocolate is made from ingredients comprising cocoa mass, cocoa butter, sugar and (whole) milk powder, optionally wherein the ingredients comprise one or more of emulsifier, soya lecithin and natural vanilla flavouring.

10. The nutritional composition of any preceding claim, which comprises at least 80% by weight chocolate, preferably at least 85% by weight chocolate.

11. The nutritional composition of any preceding claim, which is in the form of a ball or a dome.

12. The nutritional composition of any preceding claim, which is in the form of a bitesized product which (i) weighs between 4 g and 6 g, preferably between 4.5 g and 5 g; and / or (ii) has a volume of from 2 ml to 10 ml, preferably between 4 ml to 6 ml.

13. A nutritional composition for use in preventing the occurrence of an iron deficiency or in reducing an iron deficiency in a human, wherein the nutritional composition is as defined in any preceding claim.

14. The nutritional composition for use according to claim 13, wherein the human is pregnant or trying to conceive.

15. A process for the production of the nutritional composition according to any of claims 1 to 12, comprising mixing the encapsulated iron with (i) the chocolate and the at least one vitamin, and (ii) with the folic acid complexed with buckwheat to form the nutritional composition.

16. The process according to claim 15, wherein the method comprises:(a) melting the chocolate;(b) adding the encapsulated iron, the at least one vitamin, and the folic acid complexed with buckwheat to the melted chocolate;(c) mixing the encapsulated iron, the at least one vitamin, and the folic acid complexed with buckwheat with the melted chocolate to form a mixture;(d) pouring the mixture into a mould; and(e) cooling the mixture to form a product which is solid;(f) removing the product from the mould.

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