JP2020158439A - Intestinal bacterial flora improver and secondary bile acid generation inhibitor - Google Patents

Abstract

To provide a new use of soybean isoflavone as a food material.SOLUTION: The present invention provides, as an intestinal bacterial flora improver, and as a secondary bile acid generation inhibitor, a composition containing soybean isoflavone as an active ingredient.SELECTED DRAWING: None

Description

The present invention relates to a new use of soy isoflavone as a food material.

It is widely believed that abnormalities in the intestinal flora (disbiosis) are important factors in the development of conditions such as obesity, type 2 diabetes, colorectal cancer, and inflammatory bowel disease. For example, one of the causes of obesity is a change in the composition of the intestinal flora. Specifically, in obese humans, the abundance ratio of Firmicutes bacteria tends to be high, and the abundance ratio of Bacteroidetes bacteria tends to be low. On the other hand, in the case of normal or lean humans, the tendency is opposite to that of the obese type, the abundance ratio of Bacteroidetes phylum bacteria is high, and the abundance ratio of Firmicutes phylum bacteria is low (Non-Patent Document 1). .. For this reason, it has been proposed to change the composition of the intestinal flora from obese to normal or lean by ingesting health foods. For example, by using an extract of a Salacia plant as an active ingredient, It has been reported that the abundance ratio of Bacteroidetes increases and the abundance ratio of Firmicutes decreases (Patent Document 1). In addition, in many patients with ulcerative colitis, the abundance ratio of butyric acid-producing bacteria is lower than that in healthy subjects, which is one of the causes of inflammatory bowel disease (ulcerative colitis, Crohn's disease). One is that the concentration of butyric acid in the intestine is reduced due to the decrease in butyric acid-producing bacteria in the intestine (Non-Patent Document 2).

In addition, bile acids have been reported as a flora regulator of the intestinal flora, and it has been reported that bile acids increased by ingesting a high-fat diet affect changes in the intestinal flora. Bile acids are the main component of bile involved in the absorption of lipids, and their main role is to promote the formation of micelles in the digestive tract when fat is ingested, making it easier to absorb fat. Bile acids consist of primary bile acids and secondary bile acids. Primary bile acids are synthesized in the liver from cholesterol as conjugated bile acids conjugated to glycine or taurine and secreted into the intestine. Conjugate bile acids that have finished their role in the intestine are reabsorbed in the small intestine and returned to the liver. However, some conjugated bile acids go to the colon, where glycine or taurine is released by intestinal bacteria (deconjugation), and the deconjugated primary bile acids (such as cholic acid and chenodeoxycholic acid) are further deoxycholic acid and It is converted to secondary bile acids such as lithocholic acid. When converted to secondary bile acids, the hydrophobicity of the molecule increases and it exhibits strong bactericidal activity. For example, deoxycholic acid (DCA), which is a secondary bile acid, is known to exhibit 10 times more bactericidal activity than cholic acid (CA), which is a primary bile acid (see Non-Patent Document 3).

From these facts, as a mechanism of bacterial flora change in the intestine, the intestinal bacteria in the intestine increase the concentration of deoxycholic acid (DCA) as a result of excessive secretion of bile acid by ingestion of a high-fat diet. The "bile acid hypothesis" that it is a selective pressure has been proposed (see Non-Patent Document 4). In addition, deoxycholic acid (DCA) is known to have a colorectal cancer promoting effect (Non-Patent Document 5). Furthermore, according to the description in Patent Document 2, the reason why colorectal cancer has increased in Japan in recent years is that the increase in lipid intake due to westernization of diet and the accompanying increase in intestinal bile acid amount are related. Some literature points out. Furthermore, Non-Patent Document 6 describes intestinal bacteria (deoxycholic acid-producing bacteria) that convert primary bile acids (such as cholic acid) that help digestion and absorption of lipids into secondary bile acids (such as deoxycholic acid) when they become obese. ) Is significantly increased, which causes hepatic stellate cells in the liver to undergo cell aging due to the effect of secondary bile acids increased in the body, and secretes inflammatory cytokines, thereby promoting carcinogenesis of surrounding hepatocytes. It is stated that a similar mechanism is involved in the development of liver cancer associated with human obesity, and suppressing the growth of deoxycholic acid-producing bacteria may lead to the prevention of the development of liver cancer. It has been suggested.

As described above, various secondary bile acid lowering agents (secondary) have been conventionally used as a method for improving or preventing the onset of diseases (colon disease, liver disease) caused by secondary bile acids and their symptoms. (Secondary bile acid production inhibitor) has been proposed. For example, a secondary bile acid lowering agent containing a plant-derived polyphenol such as curcumin as an active ingredient (Patent Document 3), and a secondary bile acid production inhibitor containing an α-linked galactose-containing oligosaccharide as an active ingredient (Patent Document 3). 4), Extract of Reishi component Secondary bile acid inhibitor as an active ingredient (Patent Document 5), Deoxycholic acid reduction using cells of lactic acid bacteria belonging to Lactobacillus gasseri and / or a culture thereof as an active ingredient Agents (Patent Document 2) and the like have been proposed. In particular, according to the lactic acid bacterium, suppressing the change from primary bile acid to secondary bile acid suppresses the production of secondary bile acid without reducing the amount of useful primary bile acid, that is, selectively. It is said to be excellent in that it can reduce the amount of secondary bile acids.

Japanese Unexamined Patent Publication No. 2015-127340 JP-A-2017-66086 Japanese Unexamined Patent Publication No. 2009-227609 Japanese Unexamined Patent Publication No. 2004-244365 Japanese Unexamined Patent Publication No. 2018-43955

Ley R.E., et al., Nature, 2006, Vol.444, No.7122. Pp.1022-1023 Machiels K., et al., Gut, 2014, Vol.63, No.8, pp.1275-1283 Kurdi et al., J Bacteriol., 188 (5), 1979-1986 (2006) Yokota et al., Gut Microbes., 3 (5): 455-459 (2012) H. Bernstein et al., Mutat. Res., Vol. 589, pp. 47-65, 2005 Japan Science and Technology Agency Homepage "Japanese Foundation for Cancer Research, Japan Science and Technology Agency (JST) June 27, 2013" Joint announcement: Changes in intestinal bacteria associated with obesity are vital Promotes the onset of obesity "(http://www.jst.go.jp/pr/announce/20130627-2/)

An object of the present invention is to provide a new use of soy isoflavone as a food material. Specifically, it is an object to provide a new functional use as a food material based on a useful bioregulatory function (tertiary function) exerted on a living body when soy isoflavone is ingested.

As a result of diligent studies to solve the above problems, the present inventors have made a deterioration of the intestinal flora (intestine) caused in mice by ingesting a diet imitating a high-fat diet (primary bile acid-added diet). (Changes in the composition of the internal bacterial flora) can be significantly improved by ingesting soy isoflavone at the same time, and equol-producing bacteria, butyrate-producing bacteria and other short-chain fatty acid-producing bacteria, which are considered to be useful intestinal bacteria, or / And it was found that the decrease of lactic acid bacteria was suppressed and further increased.

We also found that ingestion of soy isoflavone significantly reduced the increase in the amount of secondary bile acid produced by ingestion of a primary bile acid-added diet, while that of primary bile acids useful for fat absorption. It was confirmed that the amount did not decrease, but rather increased.

The present invention has been completed based on such findings, and includes the following embodiments.
(I) Intestinal flora improving agent (I-1) An intestinal flora improving agent containing soy isoflavone as an active ingredient.
(I-2) The agent for improving the intestinal flora according to (I-1), which exerts at least one action and effect selected from the group consisting of the following (a) to (e):
(A) Increase in Shannon index,
(B) Decrease in the ratio of "Pharmicutes / Bacteroidetes" in the intestinal bacteria,
(C) Increase in the abundance of equol-producing bacteria (Adlercreutzia) in the intestinal bacteria (d) Increase in the abundance of short-chain fatty acid-producing bacteria in the intestinal bacteria,
(E) Increase in the abundance rate of lactic acid bacteria (Lactobacillus) in intestinal bacteria

(II) Secondary bile acid production inhibitor (II-1) A secondary bile acid production inhibitor containing soy isoflavone as an active ingredient.
(II-2) The secondary bile acid production inhibitor according to (II-1), which is characterized by increasing the amount of primary bile acid produced.

(III) Additive for intestinal flora improving agent, additive for secondary bile acid production inhibitor (III-1) For intestinal flora improving agent or secondary bile acid production inhibitor containing soy isoflavone as an active ingredient Additives for agents.

(IV) How to use soy isoflavone (IV-1) Soy isoflavone or the additive described in (III-1) is blended into an oral composition, and the oral composition has an effect of improving the intestinal flora, secondary. A method of using soy isoflavone for imparting at least one action selected from the group consisting of a bile acid production inhibitory action and a primary bile acid production increasing action.

According to the present invention, it is possible to provide an intestinal flora improving agent containing soy isoflavone as an active ingredient. According to the intestinal flora improving agent of the present invention, (a) an increase in the Shannon index, (b) a decrease in the ratio of "Pharmicutes / Bacteroidetes" in the intestinal bacteria, and (c) an intestinal bacterium. Increased abundance of equol-producing bacteria (Adlercreutzia), (d) increased abundance of short-chain fatty acid-producing bacteria in gut flora, and (e) abundance of lactic acid bacteria (Lactobacillus) in gut flora At least one effect selected from the group consisting of increases can be exerted. From the action and effect of (a), the intestinal flora improving agent of the present invention can improve the diversity of the intestinal flora reduced by ingestion of a high-fat diet. Moreover, according to the action effect of (b), it is possible to change the constitution from the obese type to the normal type or the lean type by changing the composition of the intestinal flora. According to the action effect of (c), equol having an estrogen-like action is produced in the body, so that it becomes possible to supplement female hormones that tend to be deficient with aging. According to the action and effect of (d), it becomes possible to prevent or ameliorate diseases and pathological conditions caused by a decrease in short-chain fatty acids in the intestine, such as inflammatory bowel disease. In addition, according to the action effect of (e), it is possible to prevent or improve autoimmune diseases and common colds caused by lactic acid bacteria, and to improve intestinal regulation, diarrhea, stool, etc. by increasing good bacteria and suppressing bad bacteria. ..

Further, according to the present invention, it is possible to provide a secondary bile acid production inhibitor containing soy isoflavone as an active ingredient. The agent for suppressing the production of secondary bile acids of the present invention is excellent in the action of reducing the amount of secondary bile acids in the intestine. Therefore, it can be usefully used for preventing or ameliorating the onset of diseases and pathological conditions (for example, colon disease and liver disease) caused by secondary bile acids. Further, according to the secondary bile acid production inhibitor of the present invention, the amount of primary bile acid produced, which is important for lipid absorption, can be reduced by suppressing the production of secondary bile acid from the primary bile acid in the intestine. Rather than decreasing, it can be increased to selectively reduce the amount of secondary bile acid produced.

Furthermore, since the secondary bile acid production inhibitor of the present invention contains soy isoflavone, whose food safety has been confirmed, as an active ingredient, there is no concern about side effects, and it should be taken reasonably by incorporating it into daily eating habits. And can enjoy the above-mentioned effects.

Furthermore, according to the additive for the intestinal flora improving agent of the present invention, the additive for the production inhibitor of secondary bile acids, or the method of using the soy isoflavone of the present invention, a food composition targeting the same, etc. By adding and blending with, the above-mentioned intestinal flora improving agent of the present invention and / and the secondary bile acid production inhibitor can be easily prepared and provided.

Shannon index (mean ± SEM (n = 6), Tukey-HSD test) by "intestinal flora analysis in cecal contents" in the experimental example was used in the control group, CA group (coruic acid administration group), and CA + 3% raffinose. The results of comparison between the group, CA + 0.5% curcumin group, and CA + 0.8% isoflavone group are shown. Different letters in each graph indicate that there is a significant difference between the groups (p <0.05). In the "analysis of the intestinal flora in the contents of the cecum" in the experimental example, (A) the composition of the intestinal flora at the portal level (n = 6) was determined in the control group, CA group (colic acid administration group), and CA + 3. The results of comparison between the% raffinose group, the CA + 0.5% curcumin group, and the CA + 0.8% isoflavone group are shown. (B) The ratio of Firmicutes to Bacteroidetes (Firmicutes / Bacteroidetes ratio) is shown in each group. It is a figure which compared the abundance ratio (%) of equol-producing bacteria (genus Adlercreutzia) in the cecal contents for each group among the results obtained by "analysis of the intestinal flora in the cecal contents" in the experimental example. .. Average value ± standard error (n = 6) (hereinafter, the same applies to FIGS. 4 to 7). Different letters in each graph indicate significant differences between groups (Tukey-HSD test, p <0.05). It is a figure which compared the abundance ratio (%) of lactic acid bacteria (genus Lactobacillus) in the cecal contents for each group among the results obtained by "analysis of the intestinal flora in the cecal contents" in the experimental example. Among the results obtained by "analysis of intestinal flora in the contents of the cecum" in the experimental example, the abundance ratio (%) of various short-chain fatty acid-producing bacteria present in the contents of the cecum was compared for each group. Is. A is a diagram comparing the abundance ratio (%) of butyric acid-producing bacteria (genus Coprococcus) in the cecal contents for each group; B is a butyric acid / propionic acid / isovaleric acid-producing bacteria in the cecal contents for each group. Figure comparing the abundance ratio (%) of (Prevotella genus); C is a figure comparing the abundance ratio (%) of succinic acid-producing bacteria (Parabacteroides genus) in the contents of the cecum for each group; D is each group It is a figure which compared the abundance ratio (%) of acetic acid / lactic acid-producing bacteria (genus Blautia) in the contents of the cecum. It is a figure which compared the abundance ratio (%) of the bacteria belonging to Firmicutes phylum present in the cecal contents for each group among the results obtained by "analysis of the intestinal flora in the cecal contents" in the experimental example. .. A shows the abundance ratio (%) of bacteria in the genus Turicibacter and B in the genus Dorea. In Fig. A, different letters in each graph indicate that there is a significant difference between the groups (Tukey-HSD test, p <0.05). * In Fig. B shows that there is a significant difference compared to the CA group by Welch's test (p <0.05). Among the results obtained by "analysis of intestinal flora in the contents of the cecum" in the experimental example, the abundance ratio (%) of bacteria of the phylum Proteobacteria (Desulfovibrionaceae) in the contents of the cecum was compared for each group. is there. Different letters in each graph indicate that there is a significant difference between the groups (Tukey-HSD test, p <0.05).

(I) Intestinal flora improving agent The intestinal flora improving agent of the present invention (hereinafter, also simply referred to as “the present bacterial flora improving agent”) is characterized by containing soy isoflavone as an active ingredient.

Soy isoflavone is a type of flavonoid that is mainly contained in soybean germ, and is a general term for compounds whose basic skeleton is the compound represented by the following formula:

Known soy isoflavones include compounds having the above basic skeleton (soy isoflavone aglycone), glycosides to which sugars are bound (soy isoflavone glycosides), acetylated products of the glycosides, and malonylated products. ing. The term "soy isoflavone" in the present invention includes these soy isoflavone aglycones, soy isoflavone glycosides, and acetylated products thereof, and malonylated products without distinction. Specifically, examples of soy isoflavone aglycone include genistein, daidzein, and glycitein. Examples of soy isoflavone glycosides include genistin, daidzin, and glycitin. Examples of the acetylated form of the soy isoflavone glycoside include acetylgenistin, acetyldaidzin, and acetylglycitin, and examples of the malonylated form include malonylgenistin, malonyldaidzin, and malonylglycitin. These soy isoflavones may be used alone or in combination of two or more. Further, in the present invention, the soybean isoflavone may be purified from soybean, but may be a crude product, for example, one extracted from soybean (extract), crushed or shredded soybean, and the like. You may use any of. Methods for purifying or extracting isoflavones from soybeans are known, and in the present invention, purified or extracts of soybean isoflavones obtained according to known methods can be used. Commercially available soy isoflavones can also be used.

The present bacterial flora improving agent may be in any form as long as it is orally administered. In addition, as long as it has a form of oral administration (oral ingestion), it is classified according to its use (pharmaceutical products, non-pharmaceutical products, foods and drinks [foods for specified health use, foods with functional claims, foods with nutritional function, etc. And supplements]) are not particularly limited. Foods and drinks are preferable, and foods for specified health use or foods with functional claims that can claim their actions and effects are more preferable.

Orally administered forms, specifically prepared in the form of liquids (including extract forms and syrups) or jelly agents; powders, fine granules, or granules formulated in powder or granular form by a conventional method; Capsules (hard capsules, soft capsules) in which liquids, powders or granules are filled in capsules; or powders or granules further tableted into tablets (solid preparations) can be mentioned.

The present bacterial flora improving agent can also be prepared in various dosage forms (oral administration form) by combining the above soy isoflavone with conventionally known edible carriers, excipients and the like that are pharmaceutically or food-acceptable.

When the present bacterial flora improving agent is in the form of a liquid preparation, it may be cryopreserved, or it may be preserved after removing water by freeze-drying or the like. Freeze-dried preparations, dry syrups, etc. are used by adding sterilized water or the like at the time of use and dissolving them again.

When the present bacterial flora improving agent is in the form of a solid agent, for example, in the case of tablets, conventionally known carriers in the art can be widely used. Examples of such carriers include excipients such as lactose, sucrose, sodium chloride, glucose, urea, starch, calcium carbonate, kaolin, and stearic acid; water, ethanol, propanol, simple syrup, glucose solution, starch solution, gelatin. Binders such as solutions, carboxymethyl cellulose, cellac, methyl cellulose, potassium phosphate, polyvinylpyrrolidone, crystalline cellulose, hydroxypropyl cellulose, hypromellose, sodium alginate; dried starch, canten powder, laminaran powder, sodium hydrogen carbonate, polyoxyethylene sorbitan fatty acid Disintegrants such as esters, sodium lauryl sulfate, stearic acid monoglyceride, starch, crospovidone, povidone, low-substituted hydroxypropyl cellulose; disintegration inhibitors such as stear, cocoa butter, hydrogenated oil; quaternary ammonium salts, lauryl Absorption enhancer such as sodium sulfate; Moisturizer such as glycerin; Adsorbent such as starch, lactose, kaolin, bentonite, colloidal silicic acid; Lubricating agent such as purified talc, stearic acid, boric acid powder, polyethylene glycol, etc. Can be used. Further, the tablet may be a tablet coated with a normal skin, for example, a sugar-coated tablet, a gelatin-encapsulated tablet, an enteric-coated tablet, a film-coated tablet or a double tablet, or a multi-layer tablet, if necessary. Further, the composition containing the active ingredient can be filled into a conventionally known capsule made of gelatin, pullulan, starch, gum arabic, hydroxypropylmethyl cellulose (HPMC) or the like as a capsule to obtain a capsule.

Further, in the form of a pill, a carrier conventionally known in the art can be widely used. Examples thereof include excipients such as glucose, lactose, starch, cacao butter, hardened vegetable oil, kaolin and talc, binders such as gum arabic powder, tragant powder, gelatin and ethanol, and disintegrants such as laminarin and canten. Can be used.

In addition to the above, as additives, for example, surfactants, absorption promoters, adsorbents, fillers, preservatives, stabilizers, emulsifiers, solubilizers, etc. may be appropriately selected and used according to the form of the preparation. it can.

All of these forms can be prepared by using ordinary methods in the art. For example, tablets are well mixed and dispersed by appropriately adding the above active ingredients and other excipients necessary for obtaining tablets. It can be obtained by locking. Further, the powder can be obtained by appropriately adding the above active ingredient and other excipients necessary for obtaining the powder, and mixing and powdering by a suitable method.

The present bacterial flora improving agent may have a normal food or drink form in addition to the above-mentioned formulation form. The food or drink can be produced by adding an additive containing the soy isoflavone described above or the soy isoflavone described later to various foods and drinks. The food or drink may be in a form that can be orally ingested, such as a solution, suspension, emulsion, jelly (gel), sol, powder, or solid molded product, and is not particularly limited. Specifically, for example, instant noodles, retort foods, canned foods, microwave foods, instant soups / miso juices, freeze-dried foods and other instant foods; soft drinks, fruit juice drinks, vegetable drinks, soy milk drinks, coffee drinks, tea. Beverages, powdered beverages, concentrated beverages, nutritional beverages, alcoholic beverages and other beverages; bread, pasta, noodles, cake mixes, fried flour, bread flour and other wheat flour products; candy, caramel, chewing gum, chocolate, cookies, biscuits, cakes , Pies, snacks, crackers, Japanese sweets, desserts and other sweets; Sauces, tomato processed seasonings, flavored seasonings, cooking mixes, sauces, dressings, soups, curry and stew ingredients; Fats and oils such as processed fats and oils, butter, margarine, and mayonnaise; dairy beverages, yogurts, cheese, fermented milk, lactic acid bacteria beverages, ice creams, creams and other dairy products; processed egg products such as pudding and mayonnaise; fish ham Processed marine products such as sausages and pastes of marine products; Processed livestock products such as meat ham and sausage; Processed agricultural products such as canned agricultural products, jams and marmalades, pickles, boiled beans, cereals; frozen foods, nutritional foods, etc. ..

(Action of intestinal flora improving agent)
The target of this microbiota improving agent is human or non-human animals. It is preferably human. Examples of non-human animals include pets (pets), laboratory animals, and animals kept in zoos and aquariums. By administering (ingesting) this bacterial flora improving agent to humans or non-human animals, it is possible to adjust the composition of the intestinal flora of the human or non-human animals, and in particular, ingest a high-fat diet. It is possible to improve the resulting changes in the composition of the gut flora and return it to a state before or close to that of a high-fat diet, or even better. For example, ingestion of this bacterial flora improving agent induces the following changes in the intestinal flora.

(A) Increase in Shannon index By ingesting this microbiota improving agent by humans or non-human animals, the Shannon index decreased by ingesting a high-fat diet can be increased (increase in Shanon index). The Shannon index is an index in which the frequency of each bacterial species is added to the number of bacterial species, and is used as an index for judging the diversity of the intestinal flora. In other words, ingestion of this flora improver by humans or non-human animals improves the diversity of the intestinal flora that was reduced by ingesting a high-fat diet, and is normal before ingesting a high-fat diet. It is possible to return to a state (diversity of intestinal flora) or close to it.

(B) Changes in the composition of the intestinal flora at the phylum level When humans or non-human animals ingest this bacterial flora improver, Firmicutes against the Bacteroidetes phylum bacteria present in the intestine The proportion of phylum bacteria (“Pharmicutes phylum / Bacteroidetes phylum Bacteria” ratio) decreases. This decrease in abundance ratio may be caused by an increase in the ratio of Bacteroidetes to the ratio of Firmicutes, or by an increase in the ratio of Firmicutes to the ratio of Bacteroidetes. It may be caused by a decrease in the proportion of Firmicutes phylum bacteria and an increase in the proportion of Bacteroidetes phylum bacteria. As described in Non-Patent Document 1, the “Pharmicutes / Bacteroidetes” ratio tends to be high in obese or obese subjects and low in normal or lean subjects. As shown in the experimental examples described later, the composition of the intestinal flora can be changed from the obese type to the normal or lean type (non-obese type) by ingesting this bacterial flora improving agent. According to the flora improving agent, it is considered possible to reduce obesity, prevent obesity, or maintain a non-obesity state. In other words, according to this bacterial flora improving agent, diet effects such as suppression of weight gain and weight loss can be expected.

(C) Increase in the abundance of bacteria that are beneficial to the living body (1) Increase in the abundance of equol-producing bacteria (Adlercreutzia) in the intestinal bacteria When humans or non-human animals ingest this flora improver, the intestines It is possible to increase the proportion of Adlercreutzia, which is an equol-producing bacterium present in the body. This bacterium has the effect of converting isoflavones ingested into the body into equol, which has higher estrogen-like activity. In other words, this bacterial flora improving agent containing soy isoflavone as an active ingredient increases the proportion of equol-producing bacteria (Adlercreutzia) present in the intestine by being taken into the body, thereby metabolizing and activating isoflavones by itself. Produces equol by promoting. Therefore, this bacterial flora improver enhances the production of equol from isoflavones by improving the human intestinal flora (adjusting the composition of the intestinal flora), and exerts equol-based action and effect. Becomes possible. The effects based on equol are not limited, but alleviate the symptoms of menopausal disorders (such as swelling / burning, headache, dizziness, autonomic imbalance-like symptoms, tachycardia, and blood pressure fluctuations); Suppression; Suppression of excess sebum secretion (prevention or improvement of acne and breakouts); Prevention of cancer (breast cancer, uterine body cancer, prostate cancer, stomach cancer, etc.); Type II diabetes (fasting blood glucose level, insulin resistance) Prevention or improvement of lifestyle-related diseases (diabetes, hyperlipidemia, arteriosclerosis, high cholesterol, etc.); prevention or improvement of osteoporosis, increase in bone density, increase in bone mineral concentration; skin aging ( Prevention or improvement of skin firmness and elasticity, spots, wrinkles, sagging; improvement of blood flow (prevention or improvement of coldness, stiff shoulders, tension headache, dullness and dryness of skin); prevention or improvement of male hair loss At least one action and effect selected from improvement and the like can be expected.

(2) Increase in the abundance ratio of short-chain fatty acid-producing bacteria in the intestinal bacteria When humans or non-human animals ingest this bacterial flora improving agent, the proportion of short-chain fatty acid-producing bacteria present in the intestine is increased. be able to. Specifically, as short-chain fatty acid-producing bacteria, bacteria of the genus Coprococccus that produce butyric acid, bacteria of the genus Parabacteroides that produce succinic acid, bacteria of the genus Prevotella that produce butyric acid, propionic acid, and isovaleric acid, acetic acid, Bacteria of the genus Blautia that produce lactic acid can be mentioned. According to these short-chain fatty acid-producing bacteria, the abundance of short-chain fatty acids that exert useful functions in the intestine can be increased.
The role of short-chain fatty acids in the intestine and their relationship to health are explained below.

a. Strengthening the barrier function from harmful substances Acetic acid is said to have the function of enhancing the barrier function of the large intestine. Butyric acid is also said to have the effect of promoting the secretion of mucin, a mucosal substance, and protecting the large intestine by activating the MUC2 gene in intestinal cells.

b. Prevention of carcinogenesis Short-chain fatty acids are said to help prevent colorectal cancer because they make the intestines weakly acidic, making it difficult to produce harmful secondary bile acids. Butyric acid is said to suppress the onset of colorectal cancer by suppressing the abnormal proliferation of colorectal cells, promoting apoptosis, and suppressing the lesions of colorectal cells. There is a research report that propionic acid acts on short-chain fatty acid receptors in liver cancer cells to suppress the growth of liver cancer cells.

c. Prevention of obesity Short-chain fatty acids act on short-chain fatty acid receptors in adipocytes to suppress the uptake of energy into adipocytes and prevent adipocyte hypertrophy. It also acts on short-chain fatty acid receptors in nerve cells and promotes energy consumption via the sympathetic nervous system, and has the function of adjusting the energy balance.

d. Prevention of diabetes Butyric acid acts on L cells in the intestinal tract to promote the secretion of the intestinal hormone GLP-1. GLP-1 has the effect of preventing and ameliorating diabetes, suppressing the decrease in the number of pancreatic β cells that secrete insulin, and promoting insulin secretion.

e. Suppression of appetite Butyric acid and propionic acid secrete GLP-1 as well as intestinal hormones such as PYY from L cells in the intestinal tract. GLP-1 and PYY are known to act on the brain to suppress appetite, maintain a feeling of fullness, and prevent overeating.

f. Regulation of immune function Approximately 60% of the immune cells of the whole body are concentrated in the intestine, and it is said that the imbalance of the intestine (especially excessive immune reaction) affects the whole body. Butyric acid has the effect of increasing immune cells called Treg cells, which suppress the excessive immune response, and it is known that butyric acid promotes the acetylation of histones in colonic epithelial cells. Butyric acid is also said to be useful for inflammatory bowel disease, which is an immune disease of the intestine.

(3) Increase in the abundance ratio of lactic acid bacteria in the intestinal bacteria By ingesting this bacterial flora improving agent by humans or non-human animals, the proportion of lactic acid bacteria present in the intestine can be increased. The increase in lactic acid bacteria can be expected to prevent or improve autoimmune diseases and common colds caused by lactic acid bacteria, and improve intestinal regulation, diarrhea, stools, etc. by increasing good bacteria and suppressing bad bacteria.

The subject to whom this bacterial flora improving agent is applied may be any person who needs to enjoy the above-mentioned effects, and is not particularly limited as long as it is a factor that changes the composition of the intestinal flora. It can be widely targeted at those who consume a fat diet. Those who prefer to consume a high-fat diet are preferable, and those who are obese or prone to obesity are more preferable. A fat diet is a diet containing a large amount of fat and is not strictly defined, but a diet in which fat accounts for approximately 30 to 40% or more of the total energy intake (fat energy ratio) is mentioned. be able to. For example, meat such as beef rose, beef loin, ground beef, con beef (cow), pork rose, pork loin, bacon (pork), sausage (pork); seafood such as anki, sushi toro, eel margarine, sanma, buri etc. Kind: Egg yolk, fresh cream (milky fat), and eggs and dairy products such as Camambale cheese; Grains such as croissant, Denish pestry, corn snack, potato chips; Macademian nuts, peanuts, almonds, cashew nuts, etc. Nuts; Diets rich in fat-containing ingredients such as fried pork, pork flour, mayonnaise, French dressing, olive oil, sesame oil, salted butter, and margarine tend to be high-fat foods. Obesity is judged based on BMI (Body Mass Index: weight [kg] / height [m] squared), and a BMI of 30 or more is evaluated as obesity, and 25 or more and less than 30 is evaluated as obese (slightly obese). Can be done.

Whether or not the intestinal flora is improved by taking (administrating and ingesting) this bacterial flora improving agent can be evaluated and confirmed by analyzing the intestinal bacteria contained in feces.

In addition, soy isoflavone, which is the active ingredient of this bacterial flora improving agent, can be added by changing the composition of the intestinal flora and / or increasing the abundance of useful intestinal bacteria, as shown in the experimental examples described later. .. It is thought that it suppresses the production of primary bile acids into secondary bile acids in the intestine. As a result, according to this bacterial flora improver, the production of primary bile acids useful for lipid absorption does not decrease, but rather increases, and the production of secondary bile acids that cause colorectal cancer and liver cancer. The production can be significantly suppressed and the abundance in the intestine can be reduced.

The dose (intake) of this bacterial flora improving agent can be appropriately changed depending on the condition of the subject and the degree of symptoms, but the daily dose (intake) for one adult (body weight 50 kg) is the present bacterial flora. The amount of soy isoflavone (dry amount) contained in the improving agent is usually about 10 to 150 mg. It is usually used in the form of oral administration once a day or divided into 2 to 3 times a day. The time of administration is not particularly limited, and for example, any one or more time zones of morning, noon, and evening meals can be exemplified. Further, although not limited, it is preferably within 30 minutes with meals or before or after meals because it affects the absorption of lipids contained in food.

(II) Secondary Bile Acid Production Inhibitor The secondary bile acid production inhibitor of the present invention (hereinafter, also simply referred to as “the present production inhibitor”) is characterized by containing soy isoflavone as an active ingredient.

The production inhibitor is not particularly limited as long as it is in the form of oral administration, similarly to the above-mentioned agent for improving the bacterial flora. In addition, as long as it has a form of oral administration (oral ingestion), it is classified according to its use (pharmaceutical products, non-pharmaceutical products, foods and drinks [foods for specified health use, foods with functional claims, foods with nutritional function, etc. And supplements]) are not particularly limited. Foods and drinks are preferable, and foods for specified health use or foods with functional claims that can claim their actions and effects are more preferable.

The production inhibitor may have a form of ordinary food or drink in addition to various formulations. The food or drink can be produced by adding an additive containing the soy isoflavone described above or the soy isoflavone described later to various foods and drinks.

The dose (intake) of the production inhibitor can be appropriately changed depending on the condition of the subject and the degree of symptoms, but the daily dose (intake) for one adult (body weight 50 kg) is the production inhibitor. It is usually about 10 to 150 mg in terms of the amount of soy isoflavone (dry amount) contained in. It is usually used in the form of oral administration once a day or divided into 2 to 3 times a day. The time of administration is not particularly limited, and for example, any one or more time zones of morning, noon, and evening meals can be exemplified. Further, although not limited, it is preferably within 30 minutes with meals or before or after meals because it affects the absorption of lipids contained in food.

The target person of this production inhibitor may be a person who needs to reduce the amount of secondary bile acid produced, and is not particularly limited as long as it is a factor that increases the amount of secondary bile acid produced. It can be widely targeted at those who consume a fat diet. Those who prefer to consume a high-fat diet are preferable, and those who are obese or prone to obesity are more preferable.

Whether or not the production of secondary bile acids is suppressed and the amount of production decreases by taking (administration, ingestion) of this production inhibitor is evaluated and confirmed by analyzing and measuring the amount of bile acids in feces. be able to. It is considered that this production inhibitor suppresses the production of primary bile acid to secondary bile acid in the intestine. As a result, as shown in the experimental examples described later, according to this production inhibitor, the production of primary bile acids useful for lipid absorption is not decreased, but rather increased, and the production of colorectal cancer and liver cancer is increased. The production of the causative secondary bile acid can be significantly suppressed and the abundance in the intestine can be reduced.

(III) Additive for improving the intestinal flora or an additive for suppressing the production of secondary bile acids The additive of the present invention is characterized by containing soy isoflavone, preferably edible soy isoflavone, as an active ingredient. To do.

The additive of the present invention is an additive used to impart an intestinal flora improving action to a target oral composition based on the intestinal flora improving action of soy isoflavone, which is an active ingredient thereof. Is. The additive of the present invention can also be used to further enhance the action of an oral composition having an action of improving the intestinal flora.

The additive of the present invention is used to impart a secondary bile acid production inhibitory effect to a target oral composition based on the secondary bile acid production inhibitory effect of soy isoflavone, which is an active ingredient thereof. It can also be an additive to be used. The additive of the present invention can also be used to further enhance the action of an oral composition having an action of suppressing the production of secondary bile acids. In addition, the additive of the present invention increases the amount of primary bile acid produced and decreases the amount of secondary bile acid produced in the target oral composition based on the action of soy isoflavone, which is the active ingredient thereof. It is also an additive used to impart the action of The additives of the present invention can also be used to further enhance their actions on oral compositions having these actions.

Here, the oral composition targeted by the present invention includes a composition to be orally administered to a person or a composition to be ingested by a person, specifically, an oral drug, an oral quasi-drug, and a food or drink. Is included. Food and drink are preferable.

The type of soybean isoflavone used as a raw material for the additive of the present invention, the method for preparing the soy isoflavone, and the like are as described in (I) above, and can be incorporated in this column (III).

The additive of the present invention may be soy isoflavone itself, or is prepared by combining soy isoflavone with a conventionally known edible carrier, excipient, etc. that are pharmaceutically acceptable as foods. There may be. The additive of the present invention is added and blended with the above-mentioned oral drug, quasi-drug, and / or food and drink to prepare the above-mentioned secondary bile acid production inhibitor. Therefore, as long as it is not particularly limited, even if it has the form of a liquid agent (including extract form or syrup) or jelly agent, the liquid agent is formulated into powder or granules by a conventional method. Powders, fine granules, granules; capsules filled with liquids, powders or granules (hard capsules, soft capsules), or powders or granules further tableted into tablets. May (solid preparation).

The amount of the additive of the present invention used by adding and blending to oral medicines, quasi-drugs, and / or foods and drinks is an intestinal flora improving agent prepared by blending the additive of the present invention. The ratio of the daily administration (ingestion) of the secondary bile acid production inhibitor to the amount of soy isoflavone (dry amount) is usually about 10 to 150 mg.

The additive of the present invention is used as one of the raw materials together with other raw materials in the step of preparing the above-mentioned oral composition (oral drug, quasi-drug, and / or food and drink), or orally. When the composition is taken (administered or ingested), it can be blended with the oral composition at the time of use.

(IV) Method of Using Soy Isoflavone The present invention also provides a method of using soy isoflavone. The method has an effect of improving the intestinal flora, an effect of suppressing the production of secondary bile acids, and / or an effect of increasing the amount of primary bile acid produced and decreasing the amount of secondary bile acid produced in the oral composition. It is a method of using soy isoflavone for imparting, and the method can be carried out by blending soy isoflavone with a target oral composition. In addition, instead of soy isoflavone, the above-mentioned additive containing soy isoflavone as an active ingredient can also be used.

Details of the target oral composition and the method of using soy isoflavone are as described above.

Hereinafter, in the present specification, the terms "including" and "containing" include the meanings of "consisting of" and "consisting of substantially".

Hereinafter, the present invention will be described with reference to experimental examples in order to help understanding the structure and effects of the present invention. However, the present invention is not limited by these experimental examples. The following experiments were performed under room temperature (25 ± 5 ° C.) and atmospheric pressure conditions, unless otherwise noted.

Experimental example Bile acid intake test A test animal (mouse) was fed with soy isoflavone in addition to primary bile acid (cholic acid), and the body weight, food intake, bile acid content weight, and bile acid content in the bile acid content ( The amount of primary bile acid, the amount of secondary bile acid, and the total amount of bile acid) were measured. In addition, genomic DNA was extracted from the contents of the cecum and analyzed for intestinal flora.

(1) Test animal Animal: Male C57BL / 6J mouse 8 weeks old (purchased from Japan SLC)
Breeding period: After the animals were brought in, they were divided into the following test groups so that the average body weight of each group would be equal after a 2-week acclimation period with normal food solid samples.
Breeding environment: Room temperature 25 ° C, humidity 55%, fluorescent lights in the room were turned on every 12 hours from 7:00 am to 7:00 pm.

Test area:
After the acclimatization period, the test animals were grouped into the following test groups (n = 6 or 7 in each group), and 0.3% (w / v) call was applied to the bile acid-administered groups (b) to (e). The acid (CA) aqueous solution was drunk, and the feed containing each ingredient in the control diet was freely ingested for 2 weeks.
(A) Control group: Control diet (normal diet solid sample D12450J: Research Diet) + drinking water (distilled water, the same applies hereinafter) (b) Bile acid administration group (CA group): Control diet + 0.3% Ingestion of drinking water containing cholic acid (c) 3% raffinose + bile acid administration group (CA + 3% raffinose group): Control diet + 3% rafffinose + 0.3% intake of drinking water containing cholic acid (d) 0.5% curcumin + bile acid Administration group (CA + 0.5% curcumin group): Control diet + 0.5% curcumin + 0.3% cholic acid-added drinking water (e) 0.8% soy isoflavone + bile acid administration group (CA + 0.8% isoflavone group): Control diet + 0.8% soy isoflavone + 0.3% distilled water with bile acid added In addition, isoflavone P40 (manufactured by Fujicco Co., Ltd.) was used as soy isoflavone. Isoflavone P40 contains 37% by mass or more of isoflavone. Of all isoflavones, the proportion of glycosides of the three isoflavones, genistein, daidzein, and glycitein, is about 85% by mass or more, and aglycone is contained in a ratio of about 15% by mass. The above "0.8%" is an amount converted into the isoflavone content contained in isoflavone P40.

(2) Test method and its results 1. Body weight, cecal content, and cecal content For the test animals in each test group, body weight, cecal content, and daily food intake (g / day / mice) were measured after a 2-week administration period. The results are shown in Table 1 as the mean value + standard error (n = 6 to 7) of each group.

As shown in Table 1 above, although the amount of food intake did not change significantly, a significant decrease in body weight was observed in the (e) CA + 0.8% isoflavone group as compared with the control group and the CA group. It was. In contrast, neither the (c) CA + 3% raffinose group nor the (d) CA + 0.5% curcumin group showed significant weight loss. Compared with the control group and CA group, (c) CA + 3% raffinose group and (e) CA + 0.8% isoflavone group showed an increasing tendency of cecal contents, especially in (e) CA + 0.8% isoflavone group. It showed a significant increase.

3. 3. Amount of bile acid in the contents of the cecum The amount of bile acid in the contents of the cecum was quantified. Bile acid analysis in various biological samples using ultra performance liquid chromatography / electrospray ionization-mass spectrometry (UPLC / ESI-) was published by Hagio et al. (Hagio, M., M. Matsumoto, and S. Ishizuka. A sample for LC-MS was prepared from the contents of the cecum according to the method described in MS). Methods Mol. Biol. 708: 119-129.), And the bile acid component was analyzed and quantified using LC-MS.

The table shows the results of comparing the amounts of primary and secondary bile acids and total bile acids in the control group, CA group, CA + 3% raffinose group, CA + 0.5% curcumin group, and CA + 0.8% isoflavone group. Describe in 2. Table 2 also shows the results of the Tukey HSD test. The letters on the upper right shoulder of each number indicate that different letters are significantly different between groups (p <0.05), and there is no significant difference if the same letters are included.

As shown in Table 2, the CA group ingested cholic acid had a lower amount of primary bile acid and a significantly higher amount of secondary bile acid containing highly toxic deoxycholic acid (DCA) than the control group. It was increasing. On the other hand, in the CA + 0.8% isoflavone group in which soybean isoflavone was ingested in addition to cholic acid, the amount of primary bile acid was significantly increased and deoxy was significantly increased as compared with both the control group and the CA group. The amount of deoxycholic acid (DCA) was also significantly reduced with both of the amounts of secondary bile acids compared to the CA group with increased amounts of cholic acid (DCA) and secondary bile acids.

According to the above-mentioned bile acid administration test, soy isoflavone has an action of suppressing an increase in secondary bile acid caused by ingestion of CA, in other words, a high-fat diet, that is, a secondary bile acid reducing effect (secondary bile acid). Production suppression effect) was confirmed. On the other hand, in the CA + 0.8% isoflavone group, the amount of primary bile acids such as cholic acid (CA) and taurocholic acid (TCA) increased, so that soy isoflavone has an effect of primary bile acids (for example). It has the effect of suppressing the production and increase of secondary bile acids and reducing the amount of secondary bile acids produced without impairing (rather, enhancing) the emulsification of fat, excretion of cholesterol, etc. confirmed.

As shown in Table 1, the amount of cecal content was increased in the CA + 0.8% isoflavone group, but it is known that the increase in the cecal content is associated with the increase in short-chain fatty acids that have beneficial effects on the host. Has been done. From this, in the CA + 0.8% isoflavone group, metabolites of short-chain fatty acid-producing bacteria, which are specific useful bacteria, increase, the intestinal pH decreases, and / or the diversity of the intestinal flora is improved. As a result, it is considered that the primary bile acid production is increased and the secondary bile acid production is decreased. In addition, as shown in Table 1, since weight loss was observed in the CA + 2% isoflavone group, its anti-obesity effect is considered to be related to changes in the intestinal flora due to soy isoflavone intake.

Recently, it has been reported that an antioxidant called Tempole suppresses obesity due to high-fat diet intake, reduces Firmicutes phylum, which is increased by high-fat diet, and increases Bacteroideets phylum, which is decreased by high-fat diet. (Li et al., Microbiome remodeling leads to inhibition of intestinal farnesoid X receptor signalling and decreased obesity. Nat Commun., 4: 2384. Doi: 10.1038 / ncomms3384 (2013)). Administration of Tempole increases the amount of conjugated bile acid called tauro-β-muricholic acid (TβMCA), which acts as an antagonist against the nuclear receptor farnesoid X receptor (FXR) in the gastrointestinal tract, and inhibits the activation of FXR. It has been suggested that obesity is suppressed in. Although the mechanism of anti-obesity due to isoflavone intake is not clear, the primary bile acid tauro-β-muricholic acid (TβMCA) was significantly increased in this study. Obesity suppression may occur through increased production.

3. 3. Composition of intestinal flora in the contents of the cecum For the test animals in each test group, DNA was extracted from the contents of the cecum collected after a 2-week administration period according to a conventional method, and the 16S rRNA gene V3 was requested to Biological Research Institute Co., Ltd. The -V4 region was amplified and meta 16S flora analysis was performed with Illumina MiSeq. A total of 1,511,039 reads (50,368 leads on average) of the obtained 30 samples were analyzed for flora using QIIME (Quantitave Insights Into Microbial Ecology).

From the results of the flora analysis, the Shannon index (an index in which the frequency of each bacterial species was added to the number of bacterial species), the flora composition at the phylum level, and the flora composition at the family / genus level were obtained. The Shanon index is used as an index to judge bacterial flora diversity.

[Shanon index]
The results of the Shanon index (mean ± SEM (n = 6), Tukey-HSD test) are shown in Fig. 1. As shown in FIG. 1, a significant decrease in Shannon index (decrease in flora diversity) was observed in the CA group compared with the control group, but a significant improvement (decrease in flora diversity) was observed in the CA + 0.8% isoflavone group. Improvement) was observed.

[Gate-level flora composition]
The phylum-level gut flora composition (n = 6) in the cecal contents is shown in FIG. 2A. As shown in FIG. 2A, administration of CA increased the phylum Proteobacteria and decreased the phylum Bacteroidetes. The ratio of Firmicutes to Bacteroidetes (Firmicutes / Bacteroidetes ratio) is shown in FIG. 2B. As shown in FIGS. 2A and 2B, especially in the CA + 0.8% Iso group, a decreasing tendency of the Firmicutes / Bacteroidetes ratio was observed as the number of Bacteroidetes phylums increased. As described in Non-Patent Document 1, it is known that in the obese human intestinal flora, the composition ratio of bacteria belonging to the phylum Bacteroidetes is low and the composition ratio belonging to the phylum Firmicutes is high. On the other hand, as the body weight decreases, that is, as it becomes normal or lean, the composition ratio of bacteria belonging to the phylum Bacteroidetes increases, and the composition ratio belonging to the phylum Firmicutes decreases. Since the results in FIG. 2B were correlated with the weight loss in the CA + 0.8% Iso group shown in Table 1, ingestion of soy isoflavone changed the composition of the intestinal flora and changed to a lean constitution. It was confirmed that.

[Family / genus level flora composition]
The family / genus level gut flora composition (n = 6) in the cecal contents is shown in FIGS. 3, 4, 5A to D, and 6 to 8. As shown in FIG. 3, it was confirmed that the genus Adlercreutzia, which is an equol-producing bacterium decreased by the administration of CA, was significantly increased by the administration of isoflavone. As shown in FIG. 4, it was confirmed that the genus Lactobacillus, which is a lactic acid bacterium decreased by the administration of CA, was increased by the administration of isoflavone. Further, as shown in FIGS. 5A to 5D, short-chain fatty acid-producing bacteria, Coprococcus (butyric acid-producing bacteria) (Fig. 5A) and Prevotella (butyric acid, propionic acid, isoflavone-producing bacteria), which were reduced by CA administration, were produced. ) (Fig. 5B) was also confirmed to be significantly increased by administration of isoflavone. In particular, the genus Prevotella is known to be a bacterium of the phylum Bacteroidetes that is sensitive to bile acids. Furthermore, as shown in FIGS. 5C and 5D, it was confirmed that the genus Parabacteroides (succinic acid-producing bacterium) and the genus Blautia (acetic acid, lactic acid-producing bacterium), which are short-chain fatty acid-producing bacteria, were also increased by the administration of isoflavone. In addition, as shown in FIGS. 6 and 7, the Firmicutes phylum (Turicibacter genus, Dorea genus) (FIGS. 6A and B) and the Proteobacteria phylum (Desulfovibrionaceae family) (Fig. 7), which were increased by CA administration, were both increased by soy isoflavone administration. It was confirmed that it decreased.

4. Discussion It is generally known that high-fat diet intake causes an increase in the Firmicutes phylum and a decrease in the Bacteroidetes phylum with an increase in secondary bile acids, which lead to the development of obesity and metabolic syndrome. In addition, it has been pointed out that the increase in secondary bile acids due to high-fat diet intake is associated with colorectal diseases and liver diseases (Non-Patent Document 2). In this study, it was confirmed that the secondary bile acid increased by the administration of CA was decreased by the administration of soy isoflavone. Furthermore, the diversity of the intestinal flora decreased by CA administration was improved by administration of soy isoflavone (for example, the Bacteroidetes phylum decreased by CA administration was increased by soy isoflavone administration, and the Firmicutes phylum increased by CA administration. (Turicibacter, Dorea) and Proteobacteria (Desulfovibrionaceae) are all reduced by soy isoflavone administration, and the ratio of Firmicutes to Bacteroidetes (Firmicutes / Bacteroidetes ratio) is reduced), and soy isoflavone. It was confirmed that administration increased useful bacteria such as various short-chain fatty acid-producing bacteria such as butyric acid-producing bacteria (Coprococcus genus), equol-producing bacteria (Adlercreutzia genus), and lactic acid bacteria (Lactobacillus genus) in the intestine.

The details of the relationship between these gut flora and bile acids are unknown, but as a result of the improvement of the diversity of the intestinal flora reduced by the administration of CA by the administration of soy isoflavone, the suppression of secondary bile acid production, And it is considered that an increase in primary bile acids has occurred. Thus, through the intestinal flora improving effect and / or the secondary bile acid reducing effect (secondary bile acid production suppressing effect) obtained by ingesting soy isoflavone, obesity, metabolic rodome, colon disease, It is considered to exert an effect of improving and preventing other diseases and pathological conditions such as liver disease.

Claims (6)

An agent for improving the intestinal flora containing soy isoflavone as an active ingredient. The agent for improving the intestinal flora according to claim 1, which exhibits at least one action and effect selected from the group consisting of the following (a) to (e):
(A) Increase in Shannon index,
(B) Decrease in the ratio of "Pharmicutes / Bacteroidetes" in the intestinal bacteria,
(C) Increase in the abundance of equol-producing bacteria (Adlercreutzia) in the intestinal bacteria (d) Increase in the abundance of short-chain fatty acid-producing bacteria in the intestinal bacteria,
(E) Increase in the abundance rate of lactic acid bacteria (Lactobacillus) in intestinal bacteria A secondary bile acid production inhibitor containing soy isoflavone as an active ingredient. The secondary bile acid production inhibitor according to claim 3, wherein it exerts an action effect of increasing the amount of primary bile acid produced and decreasing the amount of secondary bile acid produced. Additive for intestinal flora improving agent or secondary bile acid production inhibitor containing soy isoflavone as an active ingredient. Soy isoflavone or the additive according to claim 5 is blended into an oral composition, and the oral composition has an effect of improving the intestinal flora, an effect of suppressing secondary bile acid production, and an effect of increasing the amount of primary bile acid. A method of using soy isoflavones to impart at least one action selected from the group.