Hair damage reducer

Abstract

To provide a material of natural origin that is effective in reducing hair damage.SOLUTION: A lactic acid bacteria-fermented product obtained by fermenting a fermentation raw material containing a milk component or the like with lactic acid bacteria is used as an active ingredient of a hair damage reducing agent. The hair damage reducing agent is effective in protecting hair from damage such as hair washing and perming. Therefore, it is suitable as a component of a hair composition or the like.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a hair damage reducing agent having the effect of protecting hair from various types of damage. [Background technology]

[0002] Various hair cosmetics have been developed to protect hair from damage caused by external stimuli such as washing with shampoo or the like, drying with a hairdryer or the like, perm treatment, hair dye treatment, ultraviolet rays when going outside, etc. Since such cosmetics are often used daily, it is desirable that the active ingredients be naturally derived materials or the like that are less irritating to the scalp and hair.

[0003] Meanwhile, the present applicant has revealed that lactic acid bacteria fermentation products obtained by fermenting fermentation raw materials containing milk components and the like with lactic acid bacteria are effective in inhibiting the production of advanced glycation end products such as pentosidine (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6326413 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the effects on hair of lactic acid bacteria fermented products obtained by fermenting fermentation raw materials containing milk components and the like with lactic acid bacteria have not been clear.

[0006] The object of the present invention is to provide a naturally derived material that has an excellent effect of reducing hair damage. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the inventors conducted extensive research and discovered that lactic acid bacteria fermentation products obtained by fermenting fermentation raw materials containing milk components and the like with lactic acid bacteria have the effect of protecting hair from damage caused by hair washing, perm treatment, etc., and thus completed the present invention.

[0008] That is, the present invention is as follows. [1] A hair damage reducing agent whose active ingredient is lactic acid bacteria fermentation product. [2] The hair damage reducing agent according to [1] above, wherein the lactic acid bacteria fermentation product is a fermentation raw material containing milk components fermented with lactic acid bacteria. [3] The hair damage reducing agent according to [1] or [2] above, wherein the lactic acid bacteria fermentation product is a low molecular weight fraction obtained by fractionating the supernatant obtained by fermenting a fermentation raw material containing milk components with lactic acid bacteria to a molecular weight of 20,000 Da or less. [4] A hair damage reducing agent according to any one of [1] to [3] above, wherein the lactic acid bacteria in the lactic acid bacteria fermentation product are lactic acid bacteria belonging to Streptococcus thermophilus. [5] The hair damage reducing agent according to [4] above, wherein the lactic acid bacterium is Streptococcus thermophilus YIT2084 strain (FERM BP-10879). [6] A hair composition containing the hair damage reducing agent according to any one of [1] to [5] above. [7] Use of the hair damage reducing agent according to any one of [1] to [5] above for preparing a hair composition. [Effects of the Invention]

[0009] According to the hair damage reducing agent of the present invention, the active ingredient is a lactic acid bacteria fermentation product obtained by fermenting a fermentation raw material containing milk components, etc. with lactic acid bacteria, and therefore it can be suitably used as a compounding ingredient in a hair composition. [Brief explanation of the drawings]

[0010] [Figure 1]1A and 1B are graphs showing the results of measuring hair gloss in Test Example 1, where FIG. 1(a) is a graph showing the results for the single test group, FIG. 1(b) is a graph showing the results for the continuous test group, and FIG. 1(c) is a graph showing the numerical data of the measurements. [Figure 2] 2A and 2B are diagrams showing the results of measuring the friction strength of hair in Test Example 1, where FIG. 2(a) is a diagram showing the results of the single test group in a graph, FIG. 2(b) is a diagram showing the results of the continuous test group in a graph, and FIG. 2(c) is a diagram showing the numerical data of the measurements. [Figure 3] 3A and 3B are graphs showing the results of measuring the tensile strength of hair in Test Example 1, where FIG. 3(a) is a graph showing the results for the single test group, FIG. 3(b) is a graph showing the results for the continuous test group, and FIG. 3(c) is a graph showing the numerical data of the measurements. [Figure 4] 4A and 4B are diagrams showing the results of measuring the contact angle when water is dropped onto the hair surface in Test Example 2, where FIG. 4A is a diagram showing the results in a graph, and FIG. 4B is a diagram showing the numerical data of the measurement. [Figure 5] 10 is a table showing an example of images acquired for each test group in Test Example 2. [Figure 6] 1 is a chart showing the results of examining the state of the cuticle on the hair surface for each test group in Test Example 3. DETAILED DESCRIPTION OF THE INVENTION

[0011] In the present invention, a lactic acid bacteria fermentation product is used as an active ingredient of a hair damage reducing agent. The lactic acid bacteria fermentation product refers to a product obtained by fermenting a fermentable fermentation raw material with lactic acid bacteria, and may or may not contain lactic acid bacteria cells. For example, it may be a supernatant obtained by removing lactic acid bacteria cells by filtration or the like after fermentation of the fermentation raw material with lactic acid bacteria.

[0012] The fermentation raw material is not particularly limited as long as it can be fermented by lactic acid bacteria, and examples thereof include animal-derived raw materials such as cow's milk, human milk, goat's milk, etc., cream, and skim milk powder, as well as plant-derived raw materials such as aloe and soy milk. Among these, it is particularly preferable to use fermentation raw materials containing milk components such as cow's milk, human milk, goat's milk, etc., cream, and skim milk powder. Furthermore, these fermentation raw materials may be subjected to pretreatment such as filtration or centrifugation, dissolution or dilution with a solvent, pulverization with a mixer or the like, enzymatic treatment with amylase, cellulase, pectinase, protease, etc., or extraction with a solvent before use in fermentation.

[0013] Furthermore, the lactic acid bacteria used for fermentation are not particularly limited, and examples thereof include Lactobacillus species such as Lactobacillus casei, Lactobacillus crispatus, Lactobacillus plantarum, Lactobacillus amylovorus, Lactobacillus brevis, Lactobacillus buchneri, Lactobacillus fermentum, Lactobacillus mali, Lactobacillus parabuchneri, Lactobacillus paracasei, Lactobacillus pentosus, Lactobacillus rhamnosus, Lactobacillus vitulinus, and Lactobacillus zeae, and lactococci such as Lactococcus lactis. Examples of lactic acid bacteria include the genus Leuconostoc, such as Leuconostoc mesenteroides, Leuconostoc carnosum, Leuconostoc citreum, Leuconostoc gelidum, and Leuconostoc lactis, the genus Pediococcus, such as Pediococcus pentosaceus, the genus Enterococcus, such as Enterococcus faecalis and Enterococcus faecium, the genus Weissella, such as Weissella confusa, Weissella paramesenteroides, and Weissella viridescens, and the genus Streptococcus, such as Streptococcus thermophilus. One or more of these lactic acid bacteria may be used.

[0014] The fermentation conditions are not particularly limited, and for example, lactic acid bacteria may be added to the fermentation raw material at a concentration of 0.01 to 10% by mass, preferably 0.1 to 5% by mass, and the fermentation may be carried out for 1 to 96 hours, preferably 3 to 96 hours, at 20 to 45° C., preferably 25 to 42° C. Other conditions, such as standing, stirring, shaking, and aeration, may also be selected appropriately according to the method suitable for fermentation.

[0015] Furthermore, during the fermentation, the fermentation raw material may contain, for example, yeast extract, chlorella extract, vitamins, protein hydrolysates, amino acids, minerals, salts, surfactants, fatty acids, metals, etc.

[0016] The lactic acid bacteria fermentation product obtained by fermenting the fermentation raw material with lactic acid bacteria as described above can be used as is, either with or without the lactic acid bacteria cells, or after the cells have been removed. However, the lactic acid bacteria fermentation product may be further subjected to known purification or separation treatments such as filtration, dialysis, precipitation, and centrifugation, or may be further subjected to extraction treatment with a solvent or heat treatment. It may also be subjected to freeze-drying or concentration to dryness.

[0017] In a preferred embodiment of the present invention, a fermentation raw material containing a milk component is used as the fermentation raw material for obtaining a lactic acid bacteria fermentation product. Among these, a supernatant obtained from fermenting a fermentation raw material containing a milk component with lactic acid bacteria is preferred, and a low molecular weight fraction of the supernatant obtained from fermenting a fermentation raw material containing a milk component with lactic acid bacteria is particularly preferred.

[0018] The lactic acid bacteria fermentation product obtained by fermenting a fermentation raw material containing milk components with lactic acid bacteria will be further described below.

[0019] Lactic acid bacteria used in the fermentation of a fermentation raw material containing milk components with lactic acid bacteria (hereinafter sometimes referred to as "lactic acid bacteria fermented product (milk component)") are preferably, for example, lactic acid bacteria of the genus Streptococcus, such as Streptococcus thermophilus, or the genus Lactobacillus, such as Lactobacillus casei or Lactobacillus plantarum. Among these lactic acid bacteria, lactic acid bacteria of the genus Streptococcus are preferred, with Streptococcus thermophilus being more preferred. Among them, Streptococcus thermophilus YIT2084 strain (FERM BP-10879, date of deposit: August 18, 2006), Streptococcus thermophilus YIT2085 strain (FERM BP-10880, date of deposit: August 18, 2006), Streptococcus thermophilus YIT2021 strain (FERM BP-7537, date of deposit: November 1, 1996), Streptococcus thermophilus YIT2059 strain (FERM BP-10878, date of deposit: August 18, 2006), Streptococcus thermophilus YIT2001 strain (FERM BP-10879, date of deposit: August 18, 2006), and Streptococcus thermophilus YIT2002 strain (FERM BP-10879, date of deposit: August 18, 2006) were also identified. BP-7538, date of deposit: January 31, 2001), and the like are preferred, and Streptococcus thermophilus YIT2084 strain (FERM BP-10879, date of deposit: August 18, 2006) is particularly preferred. One or more of these lactic acid bacteria may be used. The lactic acid bacteria strains with the above deposit numbers were deposited at the National Institute of Advanced Industrial Science and Technology (National Institute of Advanced Industrial Science and Technology, Patent Organism Depositary, Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki Prefecture, Japan (postal code 305-8566)), but since April 1, 2013, they have been transferred to the National Institute of Technology and Evaluation (National Institute of Technology and Evaluation, Patent Organism Depositary, Room 120, 2-5-8 Kazusakamatari, Kisarazu, Chiba Prefecture, Japan (postal code 292-0818)).

[0020] Fermentation of a fermentation raw material containing milk components with lactic acid bacteria can be carried out according to known general culture conditions for growth, for example, by preparing a milk component-containing medium so that the milk components are 1 to 20% by mass, inoculating this with lactic acid bacteria at 0.01 to 10% by mass, preferably 0.1 to 5% by mass, and culturing for 1 to 48 hours, preferably 4 to 30 hours, at 20° C. to 45° C., preferably 37° C. to 42° C. Furthermore, other conditions, such as standing, stirring, shaking, and aeration, can also be selected appropriately according to a method suitable for fermentation.

[0021] Furthermore, the milk component-containing medium may contain ingredients commonly used to supplement nutrient sources for lactic acid bacteria, such as yeast extract, chlorella extract, vitamins such as vitamin A, B vitamins, vitamin C, and vitamin E, protein hydrolysates including various peptides, amino acids, salts such as calcium and magnesium, surfactants such as polysorbate 80, fatty acids such as oleic acid, and metals such as calcium, magnesium, and manganese.

[0022] The lactic acid bacteria fermentation product (milk component) obtained in this manner can be subjected to known purification and separation processes such as filtration, dialysis, precipitation, and centrifugation, as well as extraction processes using solvents, heat treatment, freeze-drying, and concentration to dryness.

[0023] The lactic acid bacteria fermentation product obtained by fermenting a fermentation raw material containing a milk component with lactic acid bacteria as described above can be used as is, either with or without the lactic acid bacteria cells, or after the cells have been removed, but it may also be used after further purification or separation treatment such as known filtration, dialysis, precipitation, or centrifugation, or after extraction with a solvent or heat treatment. It may also be subjected to freeze-drying or concentration to dryness.

[0024] In addition, the supernatant obtained from fermenting a fermentation raw material containing milk components with lactic acid bacteria (hereinafter sometimes referred to as ``lactic acid bacteria fermentation product (milk component) supernatant'') can be obtained by removing solid matter from the lactic acid bacteria fermentation product (milk component) obtained as described above using conventional methods such as centrifugation and filtration.

[0025] Furthermore, the low molecular weight fraction of the supernatant obtained by fermenting a fermentation raw material containing milk components with lactic acid bacteria (hereinafter sometimes referred to as the "low molecular weight fraction of the lactic acid bacteria fermentation product (milk component) supernatant") refers to the fraction of the lactic acid bacteria fermentation product (milk component) supernatant with a molecular weight of 20,000 Da or less. The fraction with a molecular weight of 20,000 Da or less can be obtained by subjecting the lactic acid bacteria fermentation product (milk component) supernatant to treatments such as ultrafiltration, gel filtration, and dialysis.

[0026] The lactic acid bacteria fermentation product of the present invention as described above has an excellent effect of reducing hair damage. Here, "hair damage" as used herein does not have the meaning that is different from that understood by those of ordinary skill in the art, and includes hair damage caused by external stimuli such as washing with shampoo, drying with a hair dryer, perming, dyeing, and ultraviolet rays when going outside. Furthermore, the term "damage reducing agent" also means something that improves the condition of hair compared to when it is not applied, or something that restores the condition of hair to an even better state than before damage.

[0027] The lactic acid bacteria fermentation product of the present invention can be used directly to reduce hair damage, but a more desirable use is to incorporate it into a hair composition prepared in various product forms. In some embodiments, such hair products may be prepared in combination with other formulation ingredients. Examples of other formulation ingredients include water, alcohols, oils, surfactants, preservatives, fragrances, colorants, moisturizers, thickeners, antioxidants, chelating agents, pH adjusters, foaming agents, UV absorbing / scattering agents, powders, vitamins, amino acids, antibacterial agents, plant extracts, seaweed extracts, and various pharmaceuticals. In some embodiments, the lactic acid bacteria fermentation product of the present invention may be in the form of an additive ingredient used to prepare such hair products.

[0028] Specific examples of hair compositions containing the lactic acid bacteria fermentation product according to the present invention include hair products such as shampoo, rinse, treatment, hair tonic, hair liquid, hair cream, hair milk, etc. The content of the lactic acid bacteria fermentation product is not particularly limited and may be appropriately determined depending on the desired product form, etc., but the mass (dry solid content) of the lactic acid bacteria fermentation product in the product composition is preferably 0.00001 to 15 mass%, more preferably 0.00004 to 9 mass%, and even more preferably 0.0002 to 3 mass%.

[0029] In some embodiments of the present invention, the hair composition containing the lactic acid bacteria fermentation product of the present invention may be a drug, quasi-drug, or cosmetic as defined in the Act on Ensuring Quality, Efficacy, and Safety of Pharmaceuticals, Medical Devices, etc. [Example]

[0030] The present invention will be explained in more detail below with reference to examples, but these examples are not intended to limit the scope of the present invention.

[0031] [Preparation Example 1] Lactic acid bacteria fermentation products were obtained as follows.

[0032] A loopful of Streptococcus thermophilus YIT2084 (FERM BP-10879) stored at -80°C was inoculated into a 2 mL test tube of M-17 medium (Difco) containing 10 g / L lactose and cultured overnight at 40°C. This culture was then inoculated into 2 mL of 10% by weight nonfat dry milk solution (Difco) at a concentration of 1% by weight and cultured overnight at 40°C as a preculture. The preculture was then inoculated into 100 mL of the main culture medium (3% by weight nonfat dry milk solution) at a concentration of 1% by weight and cultured at 40°C for 24 hours. The cultured bacterial solution was centrifuged at 8,000 × g for 15 minutes at 4°C to remove the precipitate. The resulting precipitate-removed liquid (supernatant) was ultrafiltered at 3,000 × g for 1 hour at 4°C using a centrifugal ultrafiltration filter (product name "Centricut Mini V-20" manufactured by Kurabo Industries, Ltd.) with a molecular weight cutoff of 20,000 Da. This low-molecular-weight fraction contained 2% (20,000 μg / mL) of dry solids. The average molecular weight of the low-molecular-weight fraction in the lactic acid bacteria fermentation product (milk component) supernatant was approximately 300 Da.

[0033] The average molecular weight is a value measured by dissolving the low molecular weight fraction in a 50 mM sodium chloride solution and then performing HPLC under the following conditions.

[0034] (HPLC conditions) Equipment: Waters-600E Detector: ISIRI-980 Column: Shodex SUGARKS-804 Column temperature: 80℃ Mobile phase: 50mM NaCl Flow rate: 1mL / min Injection volume: 10μL

[0035] <Test Example 1> The effect on hair damage of the lactic acid bacteria fermentation product obtained in Preparation Example 1 was investigated. To do this, first, a hair bundle product, 100% black human hair with the roots straightened (product name "BS-B3A" manufactured by Beaulux Co., Ltd.), was used and washed for 5 minutes with warm water (tap water) adjusted to 40°C, and after washing, the hair bundle was placed between a dry towel for 60 seconds to remove excess water (towel dry), to prepare damaged hair for evaluation.

[0036] The lactic acid bacteria fermentation product or purified water was placed in a container, and hair tresses were exposed to the test solution by immersing them in the container for 10 minutes after washing. The hair was then dried for 10 minutes with a hot air dryer from a distance of approximately 15 cm. An untreated group was also set up, in which towel-dried hair tresses were dried for 10 minutes with a hot air dryer without any treatment.

[0037] Furthermore, there was a test group in which the treatment from washing hair to using a hot air dryer was performed once (hereinafter referred to as "single use"), and a test group in which the treatment was performed once a day for seven days, for a total of seven times (hereinafter referred to as "continuous use").

[0038] (1) Glossiness The glossiness of the hair was measured using a gloss meter MPA-5 (Integral Corporation). Specifically, a probe attached to the device was pressed against three locations on the hair bundle: a location near the center of the length and two nearby locations, and the reflection of the light source emitted from the probe was automatically measured. Measurements were taken three times per hair bundle, and the average value was used. A significant difference test was also performed using the Student t-test. Glossiness can be said to be an index related to the shine of hair.

[0039] (2) Friction strength The frictional strength of the hair was measured using a digital force gauge ZP-20N (IMADA Co., Ltd.). Specifically, the comb provided with the device was attached to the tip, and the hair bundle was combed from the root to the tip, and the resistance force (≒ frictional force) during this process was measured. Measurements were taken three times per hair bundle, and the average value was used. A significant difference test was also performed using the Student t-test. Frictional strength can be said to be an index related to the ease of combing hair.

[0040] (3) Tensile strength The tensile strength of the hair was measured using a digital force gauge ZP-20N (IMADA Co., Ltd.). Specifically, three random hairs were selected from a hair bundle, attached to both ends of an attachment on the device, and pulled at a speed of 0.08 cm / s with a motor, and the force (N) at which the hair broke was measured. Measurements were performed three times per hair bundle, and the average value was used. A Student's t-test was also performed to test for significance. The tensile strength can be considered an index related to hair stiffness.

[0041] FIG. 1 shows the measurement results of hair gloss.

[0042] As shown in Figure 1(a), in the single test group, treatment with purified water resulted in a measured value of 1.73, while treatment with the lactic acid bacteria fermentation product resulted in a measured value of 2.45. Also, as shown in Figure 1(b), in the continuous use test group, treatment with purified water resulted in a measured value of 1.99, while treatment with the lactic acid bacteria fermentation product resulted in a measured value of 2.86. In both single and continuous use, treatment with the lactic acid bacteria fermentation product resulted in higher hair gloss than purified water. Furthermore, treatment with the lactic acid bacteria fermentation product resulted in significantly higher hair gloss (improved shine) compared to the untreated measured value of 2.05 (single use) or 2.13 (continuous use) (p<0.01 for both the single and continuous use test groups).

[0043] FIG. 2 shows the measurement results of the friction strength of hair.

[0044] As shown in Figure 2(a), in the single-use test group, the measured value was 25.34 after treatment with purified water, compared to 13.56 after treatment with the lactic acid bacteria fermentation product. Also, as shown in Figure 2(b), in the continuous-use test group, the measured value was 25.99 after treatment with purified water, compared to 10.94 after treatment with the lactic acid bacteria fermentation product. In both single and continuous use, treatment with the lactic acid bacteria fermentation product resulted in lower hair friction strength compared to purified water. Furthermore, in both single and continuous use, treatment with purified water resulted in significantly higher hair friction strength (reduced combability) compared to the untreated group (p<0.01 for both the single and continuous use test groups). However, treatment with the lactic acid bacteria fermentation product did not show any significant difference, maintaining combability equivalent to the untreated group. Furthermore, the test group continuously used with the lactic acid bacteria fermentation product showed a tendency for hair friction strength to decrease (a tendency for combability to improve) compared to the untreated group.

[0045] FIG. 3 shows the measurement results of the tensile strength of the hair.

[0046] As shown in Figure 3(a), in the single test group, the measured value after treatment with purified water was 0.72, while the measured value after treatment with the lactic acid bacteria fermentation product was 1.10. Also, as shown in Figure 3(b), in the continuous test group, the measured value after treatment with purified water was 0.79, while the measured value after treatment with the lactic acid bacteria fermentation product was 1.31. In both single and continuous use, treatment with the lactic acid bacteria fermentation product increased the hair tensile strength compared to purified water. Furthermore, in the continuous use test group, treatment with the lactic acid bacteria fermentation product resulted in a significantly higher hair tensile strength (improved body) compared to the measured value of 1.06 in the untreated group (p<0.01 for the single use test group).

[0047] <Test Example 2> The lactic acid bacteria fermentation product obtained in Preparation Example 1 was used to investigate its effect on hair damage. To this end, a certain amount of hair bundle was prepared using black human hair (same person) (product name "BS-PGM" manufactured by Beaulux Co., Ltd.). The hair bundle was then immersed in a 0.5% aqueous solution of sodium lauryl sulfate (SLS) for 30 minutes, washed with purified water, and dried. The hair was then treated with a perm agent in the usual manner. The collected hair was thoroughly rinsed and dried with a cool air dryer, and this was used as damaged hair for evaluation.

[0048] The lactic acid bacteria fermentation product or purified water was placed in a container, and hair tresses treated with a perm agent were immersed in the container for 10 minutes to be exposed to the test solution. The tresses were then dried with a cold air dryer. An untreated group was also set up, in which the hair tresses treated with the perm agent were left untreated and dried with a cold air dryer in the same manner.

[0049] Hair was randomly selected from the hair bundles from each test group that had undergone the above treatments and fixed so that the surface was horizontal on a glass slide. 2 μL of water was dropped onto the hair surface, and the contact angle after 20 seconds was measured using a measuring device called "DropMaster DMo-501" (Kyowa Interface Science Co., Ltd.), and an image was taken. Measurements were performed three times per hair bundle, and the average value was used. The results were tested for significance using a Student's t-test.

[0050] The contact angle measurement results are shown in Figure 4. Also, Figure 5 shows an example of an image obtained for each test group.

[0051] As shown in Figures 4 and 5, the contact angle of the purified water-treated group (98.6°) decreased compared to the untreated group (103.2°), indicating a tendency for the hair surface to become more hydrophilic. On the other hand, the contact angle of the lactic acid bacteria fermentation product-treated group (110.7°) increased compared to the untreated group (103.2°), indicating a tendency for the hair surface to become more water-repellent. This is thought to be due to the recovery of damaged cuticles.

[0052] <Test Example 3> One gram of uncolored human hair was immersed in a 10% aqueous solution of sodium bicarbonate at room temperature for one hour, then washed with purified water and dried to obtain a hair sample after damage treatment. The damaged hair was also immersed in the lactic acid bacteria fermentation product obtained in Preparation Example 1 for 10 minutes, then washed with purified water and dried to obtain a hair sample after treatment with the lactic acid bacteria fermentation product.

[0053] The specimens before treatment, after damage treatment, and after treatment with the lactic acid bacteria fermentation product were each observed under a microscope to check the condition of the cuticle on the hair surface.

[0054] As a result, as shown in Figure 6, the cuticles of healthy hair were neatly aligned and closed, but those of damaged hair were white and turned up. On the other hand, treatment with the lactic acid bacteria fermentation product obtained in Preparation Example 1 showed improvement in the cuticles.

Claims

1. A hair damage reducing agent containing a lactic acid bacteria fermentation product as an active ingredient, The lactic acid bacteria fermented product is obtained by fermenting a fermentation raw material containing a milk component with lactic acid bacteria. The hair damage reducing agent uses a low molecular weight fraction obtained by fractionating the supernatant obtained by the above procedure into fractions having a molecular weight of 20,000 Da or less.

2. The hair damage reducing agent according to claim 1, wherein the hair damage reduced by the hair damage reducing agent is damage caused to hair by external stimuli selected from the group consisting of washing hair with shampoo, drying with a hair dryer, perm treatment, hair dye treatment, and ultraviolet rays when going outside.

3. The hair damage reducing agent according to claim 1 or 2, wherein the lactic acid bacteria in the lactic acid bacteria fermentation product are lactic acid bacteria belonging to the genus Streptococcus thermophilus.

4. The hair damage reducing agent according to claim 3, wherein the lactic acid bacterium is Streptococcus thermophilus YIT2084 strain (FERM BP-10879).

5. Use of the hair damage reducing agent according to any one of claims 1 to 4 for preparing a hair composition for reducing hair damage.

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