2019 Volume 25 Issue 3 Pages 435-442
Multi-grain koji (MGK), an enzyme-rich food, is produced by solid-state fermentation of a mixture of seven types of grains. In this study, we aimed to assess the effects of MGK on body composition in rats fed a high fat diet, and in young women. Twenty human participants had a body fat percentage >28 %. These participants were blindly divided into test and placebo groups, with 0.5 g/day of MGK and autoclaved (inactivated) MGK consumed, respectively. The weights of liver and visceral fat were lower in rats fed a high-fat diet supplemented with MGK than those provided the autoclaved MGK. After 3 months, body weight and body mass index, and the percentage of body fat (in test group only) were significantly reduced compared to the values recorded before MGK intake. Thus, we demonstrate that MGK supplementation is effective in decreasing body fat in women.
In the Japanese National Health and Nutrition Survey of 2016, the percentages of obese adults, represented by a body mass index (BMI) >25 kg/m2, were 31.1 % and 19.0 %, in men and women, respectively (i). WHO reports that overweight and obesity is one of the major risk factors for noncommunicable diseases such as cardiovascular diseases, type 2 diabetes, musculoskeletal disorders, and some types of cancers (ii). Thus, improving overweight and obesity in patients is very important for a healthy life span. Recently, foods with a lipolysis-promoting function have attracted much attention, and capsinoid (Snitker, 2009) and quercetin glycosides (Nakamura, 2015) serve as examples of ingredients in food with the promoting function. Furthermore, Lactobacillus amylovorus CP1563-supplemented beverage was shown to reduce body fat in obese class I participants (Nakamura et al., 2016). Lactobacillus gasseri SBT2055 showed effects lowering abdominal adiposity and body weight (Kadooka et al., 2010). Therefore, we used bacteria to investigate the anti-obesity efficacy of food.
Millets such as the Japanese barnyard millet, foxtail millet, and proso millet, contain more vitamins and minerals than polished rice and wheat flour (iii). Whole grains have been associated with a decrease in body fat in obese humans (Kirwan et al., 2016). Multi-grain koji (MGK), an enzyme-rich food, is produced by the solid-state fermentation of a mixture of seven types of grains (namely barley, foxtail millet, Japanese barnyard millet, proso millet, sorghum, purple-black rice, and rice powder) by Aspergillus oryzae. MGK has a higher content of acid proteases and neutral proteases than individual cereals fermented with Aspergillus oryzae (Inoue et al., 2007). A previous study determined that supplementation with fermented burdock improved the intestinal tract environment and decreased the weight of adipose tissues in rats (Okazaki et al., 2013). Mice fed an MGK-supplemented diet had lower levels of serum triglyceride compared to those fed a non-supplemented diet (Inoue et al., 2007). However, it remains unknown whether the intake of MGK affects body composition, and induces a decrease in body fat. Therefore, we conducted two studies to investigate whether: 1) supplementation with MGK inhibits the accumulation of fat in rats fed a high fat diet, and 2) the daily consumption of MGK decreases body fat percentages in mildly obese young women.
Materials MGK and autoclaved MGK were provided by YAEGAKI Bio-Industry, Inc. (Himeji, Hyogo, Japan). Ingredients of multi-grain koji (MGK) are mixture of seven types of grains (namely barley, foxtail millet, Japanese barnyard millet, proso millet, sorghum, purple-black rice, and rice powder). MGK is produced by the solid-state fermentation of a by Aspergillus oryzae. Macro nutrients of MGK were protein (12.0 %), total fat (3.5 %), ash (2.2 %), dietary fiber (10.5 %), carbohydrate (63.3 %), water (8.5 %) by analytical manual for standard tables of food composition in japan (iv). Autoclaved MGK was prepared by autoclaving the MGK at 121 °C for 20 min to deactivate an enzyme. The activities of the digestive enzyme, α-amylase, and acid protease and neutral protease were 2,492, 41,035, and 44,788 units/g of MGK, respectively (v). Organic acids were analyzed by LC of organic analytical system (vi). In the autoclaved MGK, enzymes were deactivated.
Dietary study in rats This study was approved by the Ethics Committee of YAEGAKI Bio-Industry, Inc. The experiments were performed following the Guidelines for the Care and use of experimental animals set by the Japanese Association for laboratory animal science.
Twenty-one Sprague Dawley male rats (SD rat) were purchased from Clea Japan, Inc. (Tokyo, Japan) at six weeks old, and were housed individually in plastic cages. The rats were divided into three groups (control, autoclaved MGK and MGK groups; 7 rats per group) so that the average weight of each group was equal. The control group was fed a high-fat, high-sucrose diet; the diet composition is described in Table 1. The autoclaved MGK and MGK groups were fed a control diet supplemented with 3 % (w/w) autoclaved MGK and MGK, respectively. Each diet was administered to the rats in the two groups for 21 days. Food intake was limited to ensure each of the three groups consumed the same average amount of food by weight. Feces were collected during the last three days of the dietary intervention period, and the amount of cholesterol and triglyceride per gram of feces were measured. After the dietary intervention, rats were sacrificed and the following features weighed: body, liver, gastrocnemius muscle, adipose tissue (around the mesentery, kidney, and testes) and cecal digesta. We also measured the levels of two liver enzymes involved in fatty acid beta-oxidation: carnitine palmitoyl transferase (CPT) and peroxisomal Acyl-CoA oxidase (ACO). The cecum contents were collected and used to measure the levels of organic acid by HPLC (Shimazu LC-10A) using the ion exchange column with p-toluenesulfonic acid solution (vi). Following the collection of each peak, the quantity of the organic acids was measured using biSioux TRIS buffer.
| Control | Autoclaved MGK | MGK | |
|---|---|---|---|
| Milk casein | 200.00 | 196.40 | 196.40 |
| Beef tallow | 300.00 | 298.95 | 298.95 |
| Mineral Mix | 35.00 | 34.34 | 34.34 |
| Vitamin Mix | 10.00 | 10.00 | 10.00 |
| L-cystine | 3.00 | 3.00 | 3.00 |
| Cellulose | 50.00 | 46.85 | 46.85 |
| Sucrose | 200.00 | 200.00 | 200.00 |
| Corn starch | 199.50 | 177.96 | 177.96 |
| Choline bitartrate | 2.50 | 2.50 | 2.50 |
| Multi-grain koji (MGK) | - | - | 30.00 |
| Autoclaved MGK1 | - | 30.00 | - |
| Total (g) | 1000.00 | 1000.00 | 1000.00 |
Single-blind, placebo-controlled human dietary intervention study The protocol for this study was approved by the Ethics Committee of Mukogawa Women's University (Permit Number: 14-10). At the briefing session with the interested participants, we explained the purpose of the study, how the dietary compliance would be enforced, the potential risks and benefits of participating in the study, and the ability of participants to withdraw from the study. Only the attendees who agreed to all study conditions were deemed eligible to participate. Written informed consent was obtained from all study enrollees. The study was performed from July – September. And the diet contents of the intervention period did not set a limit.
Healthy women >20 years old were recruited at Mukogawa Women's University, from which we selected 20 women (mean ±SD; 20.2 ±0.41 years) with a body fat percentage >28 %. Fig. 1 shows the protocol used for this single-blind intervention trial in this single-center. Subjects were randomly assigned to the test diet group or placebo diet group, and were divided such that no significant difference in body fat was present between the groups. For 98 days, subjects in the test group consumed 3 g/day containing 0.5 g MGK and 2.5 g autoclaved MGK, while subjects in the placebo group consumed 3 g/day autoclaved MGK. Body composition was measured before dietary intervention and at 1, 2, and 3 months after the intervention. Body weight, body fat amount, muscle mass, and body fat percentage were measured with an InBody 270 (InBody Japan Inc., Tokyo, Japan). The feces were obtained before and after intervention and were saved for the freezing. The intestinal microbiota present in feces were analyzed by Techno Suruga Laboratory Co., Ltd. (Shimizu, Shizuoka, Japan). Subjects were advised to retain their daily physical activities or dietary patterns.
Experimental design of the single-blind placebo-controlled human dietary intervention study.
The placebo group (n =10) was supplemented with 3 g/day of Autoclaved MGK, and the test group (n =10) supplemented with 3 g/day of MGK. The dietary intervention lasted for 3 months, and measurement of body composition was carried out at four points (before intervention, and 1 month, 2 months and 3 months after start of intervention). Fecal sampling and analysis of intestinal microbiota in feces were carried out before intervention and at 3 months.
1BMI: body mass index
2MGK: multi-grain koji
Statistical analysis In the rat experiment, all data are presented as mean ± standard error (SE) (Cumming et al., 2007). The statistical differences were obtained using one-way analysis of variance (ANOVA) followed by Tukey's multiple-comparison test. In the human study, data are presented as mean ± standard deviation (SD). Statistically significant differences were determined using repeated two-way ANOVA followed by Bonferroni's multiple comparison test. For both studies, differences are considered to be statistically significant when the p values were < 0.05. GraphPad Prism version 5.0 (GraphPad Software, San Diego, CA, USA) was used for all the analyses.
Preliminary Dietary study in rats At the end of the 21-day dietary intervention, no significant difference in body weight and total food intake was found among the three groups (Table 2). The liver weights in the MGK group were significantly lower when compared those of the control and autoclaved-MGK groups (Table 2). Moreover, the weight of adipose tissues around the mesentery, kidney, and testis in the MGK group was significantly lower than that of the control and autoclaved-MGK groups (Table 2). No significant difference in the weight of the gastrocnemius muscle among the three groups was found. Based on these results, the 21-day MGK diet did not result in weight loss. However, a decrease in the weight of the adipose tissue appeared to occur without a subsequent decrease in the muscle amount. This suggests that MGK inhibited the accumulation of fat induced by the high-fat diet administered to rats. Furthermore, it was thought that the major difference was not found in the weight and muscle weight for a decrease in body fat, and this was this was similar the increase of the cecum digest.
| Control | Autoclaved MGK | MGK | P value3 | |
|---|---|---|---|---|
| Body weight gain (g/21days) | 175±3 | 176±2 | 180±4 | N.S. |
| Total food intake (g/21days) | 445±1.1 | 446±0.5 | 446±0.5 | N.S. |
| Liver weight (g/100g of body weight) | 4.36±0.08 a | 4.36±0.08 a | 3.89±0.14 b | 0.006 |
| Adipose tissue weight2 (g/100g of body weight) | 6.25±0.42 a | 6.23±0.36 a | 4.65±0.23 b | 0.006 |
| Gastrocnemius muscle (g/100g of body weight) | 0.60±0.01 | 0.59±0.01 | 0.59±0.01 | N.S. |
| Cecal digesta (g) | 1.83±0.23b | 1.84±0.24 b | 2.90±0.25 a | 0.007 |
| Organic acids(ug/g of cecal digesta) | ||||
| Phosphate | 1337±135 ab | 1967±228 a | 1103±154 b | 0.008 |
| Succinate | 1657±297 a | 893±228 ab | 771±185 b | 0.037 |
| Lactate | 175±80 b | 247±80 ab | 3790±1449 a | 0.016 |
| Acetate | 2929±189 | 2524±119 | 2323±289 | N.S. |
| Propionate | 821±51 b | 1150±87 a | 807±119 b | 0.024 |
| Butyrate | 867±109 | 665±100 | 757±162 | N.S. |
Generally, the mean serum concertation of triglyceride in the 11 weeks olds SD rats fed a commercial diet (CFR-1, Oriental Yeast Co., Ltd, Tokyo, Japan) are about 20 mg/dL (vii). It was reported that the liver concentration of triglyceride in the 12 weeks old SD rats fed a 7 % fat diet was approximately 13 mg/g of liver (Hirahata et al., 2012). The concentrations of total cholesterol and triglyceride in the serum and liver were comparable among the three groups (Table 3). Furthermore, the serum and liver concertation of triglyceride in the control and MGK groups (Table 3) were about 8-10 folds and 3 folds higher than that of the above concentrations (vii, Hirahata et al., 2012). Moreover, the levels of the enzymes involved in fatty acid beta-oxidation (CPT and ACO) in the liver were comparable among the three groups (Table 3). A previous study by Inoue M. et al. (2007) reported that serum triglycerides in ICR mice fed an MGK-supplemented commercial diet (CE-2, Clea Japan) for 28 days, showed a tendency to decrease when compared to mice fed the same diet without MGK {Control; 161±11 mg/dL (Mean±SE, n=10), MGK; 127±13 mg/dL (Mean±SE, n=10)}. The mean fat percentages of CE-2 in their study was approximately 4.6 %. However, the fat percentage of diet in our study was approximately 30 %. Thus, it was inferred that the supplementation of MGK could not protect the excess increase in triglyceride in the serum and the liver induced by high fat diet.
| Control | Autoclaved MGK | MGK | P value2 | |
|---|---|---|---|---|
| Serum | ||||
| Triglyceride (mg/dL) | 204±36 | 158±35 | 164±40 | N.S. |
| Total cholesterol (mg/dL) | 72.6±3.9 | 79.0±2.8 | 75.4±5.8 | N.S. |
| Liver | ||||
| Triglyceride (mg/g of Liver) | 29.5±1.3 | 30.6±1.9 | 31.6±3.2 | N.S. |
| Total cholesterol (mg/g of Liver) | 4.4±0.2 | 4.8±0.4 | 4.8±0.4 | N.S. |
| CPT (mU / mg protein in Liver) | 3.29±0.12 | 3.25±0.14 | 3.71±0.29 | N.S. |
| ACO (mU / mg protein in Liver) | 2.71±0.07 | 2.76±0.06 | 2.99±0.13 | N.S. |
MGK intervention in young students Before and during the intervention periods (before, 1 month, 2 mo, 3 mo), we measured body weight, BMI, percent of body fat, and amount of body muscle each month; the results are shown in Table 4. Overall, the body mass index (BMI) and body fat for subjects before intervention ranged from 20.6 to 27.6 kg/m2, and 28.3 % to 37.8 %, respectively. Body weight and BMI in both groups significantly decreased in 2 and 3 months when compared to the values before the dietary intervention period (Table 4). In the test group, body fat percentages significantly decreased in 2 and 3 months when compared to the values before the intervention period (Table 4). The corresponding decrease in the placebo group was not significant (Table 4). The rate of decline in body fat percentage in the test group approximately doubled that of the placebo group (Table 4). No significant changes were found in the weight of the body muscle of either group (Table 4). With respect to the diet of the subjects during the study period, a major difference was not found between the test group and placebo group (data not shown). Hayashida et al. (2014) reported that supplementation in the form of beverages containing fermented plant extract, resulted in body weight and body fat reduction in women. Moreover, supplementation with fermented burdock decreased the weight of the adipose tissue in rats than when a non-fermented burdock was administered (Okazaki et al., 2013). MGK is therefore suggested to reduce body fat in adult humans. Therefore, it seemed that the decrease of body weight on test group depended 2 % decrease of body fat. The body weight of placebo group decreased 0.7 kg significantly, but decrease of body fat wasn't admitted. The decreased of placebo group was regarded as decrease of the moisture content.
| Placebo (Autoclaved MGK) | Test (MGK) | P value2 | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Before | 1 mo | 2 mo | 3 mo | Before | 1 mo | 2 mo | 3 mo | G | T | G×T | |
| Body weight (kg) | 56.5±5.9a | 56.5±5.9a | 55.8±6.5b | 55.8±6.1b | 56.7±6.4A | 56.3±6.2AB | 55.8±6.7BC | 55.6±6.7C | N.S. | <0.001 | N.S. |
| Δ Body weight (kg) | - | −0.1±0.7 | −0.8±1.1 | −0.8±1.1 | - | −0.4±0.7 | −0.9±1.0 | −1.1±0.7 | - | - | - |
| BMI (kg/m2) | 22.8±1.7a | 22.7±1.8a | 22.4±2.0b | 22.4±1.9b | 22.5±1.9A | 22.3±1.9AB | 22.1±2.0BC | 22.1±2.0C | N.S. | <0.001 | N.S. |
| Δ BMI (kg/m2) | - | −0.1±0.4 | −0.4±0.5 | −0.4±0.5 | - | −0.2±0.3 | −0.4±0.4 | −0.4±0.3 | - | - | - |
| Body fat (%) | 32.4±2.9 | 32.2±3.4 | 31.9±3.3 | 31.6±3.6 | 32.2±2.3A | 31.5±2.2AB | 31.8±2.2BC | 30.3±2.4C | N.S. | <0.001 | N.S. |
| Δ Body fat (%) | - | −0.1±1.2 | −0.4±1.3 | −0.8±1.5 | - | −0.8±0.9 | −1.1±0.9 | −1.9±1.4 | - | - | - |
| Body muscle (kg) | 35.9±2.8 | 35.9±2.9 | 35.6±3.2 | 35.8±2.9 | 36.1±4.4 | 36.3±4.1 | 36.2±4.5 | 36.4±4.3 | N.S. | N.S. | N.S. |
| Δ Body muscle (kg) | - | 0.0±0.4 | −0.3±0.6 | −0.1±0.5 | - | 0.2±0.7 | 0.0±0.9 | 0.3±0.7 | - | - | - |
Relationship of MGK and microflora In this animal experiment, we examined the levels of organic acid in the cecum. The weight of cecal digesta was heavier in the MGK group than in the control and autoclaved-MGK groups (Table 2). Moreover, the concentration of lactate in the MGK group was obviously higher than that of the control and autoclaved-MGK groups (Table 2). These results are partially consistent with the previous report, where fermented burdock (Okazaki et al., 2013) was used. Lactobacillus and Bifidobacterium produce lactate by metabolism. Thus, in this intervention study, we investigated the intestinal microbiota in feces, as Kawadu et al., (1994) reported that the microflora within feces was similar to that of cecum. Only Clostridium cluster IX (operational taxonomic unit [OTU] 110) of the test group significantly decreased when compared to the dietary values before intervention (Table 5). Bifidobacterium (OTU 124), Lactobacillales (OTU 332), and Lactobacillales (OTU 657) showed a tendency to increase after intervention began; however, the differences were not significant (Table 5). It was reported that the supplementation with Lactobacillus reduced body fat in humans (Nakamura et al., 2016 and Kadooka et al., 2010). The primary mechanism of improvement of fat metabolism by probiotics such as Lactobacillus and Bifidobacterium are that these bacteria combine with cholesterol and bile acids, and then are excreted in feces (Kondo and Shimizu., 2010). The excretion of bile acids is promoted by deconjugated enzymes of Lactobacillus and Bifidobacterium (Kondo and Shimizu. 2010). In this animal experiment, mean fecal triglyceride excretion (mg/day) in the MGK group was higher than that of the autoclaved-MGK group although not significant {MGK vs autoclaved-MGK; 9.0 ± 1.0 vs 5.6 ± 1.5, p = 0.084 (unpaired t test)}. Whereas, the fecal total cholesterol was comparable between the MGK and autoclaved-MGK groups (data not shown). From this rat experiment results of cecal digesta weights, cecum concentrations of lactate and a fecal triglyceride excretions and the previous reports, MGK may be indirectly related to the absorption of fat in the gut via the change of intestinal flora.
| Placebo | Test | P value2 | ||||||
|---|---|---|---|---|---|---|---|---|
| (Autoclaved MGK) | (MGK) | |||||||
| OTU | Before | 3 mo | Before | 3 mo | G | T | G×T | |
| 106 | Clostridium subcluster XIVa | 0.0±0.2 | 0.1±0.2 | 0.3±0.8 | 0.5±1.3 | N.S. | N.S. | N.S. |
| 110 | Clostridium cluster IX | 1.9±3.8 | 1.0±1.7 | 4.4±5.0A | 1.3±12B | N.S. | 0.021 | N.S. |
| 124 | Bifidobacterium | 27.1±12.9 | 23.1±10.8 | 17.2±11.8 | 22.3±11.7 | N.S. | N.S. | N.S. |
| 137 | Prevotella | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | - | - | - |
| 168 | Clostridium cluster IV | 0.3±0.5 | 9.1±13.2 | 0.5±1.4 | 0.8±2.3 | N.S. | N.S. | N.S. |
| 317 | Prevotella | 0.0±0.0 | 0.0±0.0 | 0.7±2.1 | 0.0±0.0 | N.S. | N.S. | N.S. |
| 332 | Lactobacillales | 7.3±7.3 | 9.1±13.2 | 3.9±7.8 | 5.4±9.3 | N.S. | N.S. | N.S. |
| 338 | Clostridium cluster XI | 3.6±5.2 | 2.4±2.1 | 1.7±2.7 | 0.8±1.3 | N.S. | N.S. | N.S. |
| 366 | Bacteroides | 1.2±0.9 | 0.9±0.4 | 1.9±2.1 | 1.4±1.1 | N.S. | N.S. | N.S. |
| 369 | Clostridium cluster IV | 0.0±0.0 | 0.0±0.0 | 0.1±0.3 | 0.2±0.5 | N.S. | N.S. | N.S. |
| 423 | Clostridium cluster XVIII | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | - | - | - |
| 443 | None | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | - | - | - |
| 469 | Bacteroides | 7.1±7.4 | 3.5±4.9 | 9.7±7.1 | 4.7±10.1 | N.S. | 0.045 | N.S. |
| 494 | Clostridium subcluster XIVa | 6.9±4.7 | 11.1±5.7 | 11.1±52 | 12.8±6.4 | N.S. | 0.026 | N.S. |
| 505 | Clostridium subcluster XIVa | 0.0±0.0 | 0.0±0.2 | 0.1±0.2 | 0.8±2.4 | N.S. | N.S. | N.S. |
| 517 | Clostridium subcluster XIVa | 0.1±0.3 | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | N.S. | N.S. | N.S. |
| 520 | Lactobacillales | 0.1±0.3 | 0.1±0.2 | 0.2±0.5 | 0.1±0.2 | N.S. | N.S. | N.S. |
| 643 | None | 0.0±0.0 | 0.0±0.0 | 1.5±3.1 | 1.6±3.4 | N.S. | N.S. | N.S. |
| 650 | Clostridium cluster XVIII | 1.6±3.1 | 2.3±3.9 | 0.4±0.7 | 0.2±0.4 | N.S. | N.S. | N.S. |
| 657 | Lactobacillales | 6.1 ±4.3 | 8.0±7.9 | 4.4±3.4 | 7.1±4.0 | N.S. | N.S. | N.S. |
| 749 | Clostridium cluster IV | 2.9±3.6 | 3.0±3.2 | 7.0±4.4 | 3.6±4.9 | N.S. | N.S. | N.S. |
| 754 | Clostridium subcluster XIVa | 2.5±1.9 | 3.4±3.5 | 2.5±2.0 | 3.0±2.8 | N.S. | N.S. | N.S. |
| 770 | None | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | - | - | - |
| 853 | Bacteroides | 0.1±0.3 | 0.1±0.2 | 0.1±0.3 | 0.1±0.3 | N.S. | N.S. | N.S. |
| 919 | Clostridium cluster XI | 3.1±4.7 | 1.7±0.9 | 1.7±1.2 | 1.3±0.7 | N.S. | N.S. | N.S. |
| 940 | Clostridium subcluster XIVa | 10.7±7.8 | 10.3±8.5 | 9.3±12.8 | 7.9±3.8 | N.S. | N.S. | N.S. |
| 955 | Clostridium subcluster XIVa | 11.0±6.3 | 12.4±3.9 | 14.7±6.6 | 17.5±12.2 | N.S. | N.S. | N.S. |
| 968 | None | 0.8±0.7 | 1.1±1.0 | 0.8±0.9 | 1.0±0.6 | N.S. | N.S. | N.S. |
| 990 | Clostridium subcluster XIVa | 5.7±6.5 | 5.5±3.2 | 5.9±3.6 | 5.4±3.2 | N.S. | N.S. | N.S. |
In both the animal and human experiments conducted in this study, the negative control group was administered the autoclaved MGK. Thus, it is estimated that the efficacy of MGK resulted in the components exhibiting sensitivity to heat. MGK is an enzyme-rich food containing acid and neutral proteases. Acid protease from rice koji was active within the pH range of 2.5–4.0. This acid protease was inactivated by heat (60 °C) for 1 h (Nunokawa et al., 1962). In addition, MGK was shown to digest casein in artificial gastric juice in vitro (Inoue et al., 2007). It was reported that cecal Bifidobacterium significantly elevated in rats fed a high-fat diet supplemented with Aspergillus-derived protease (194 fold); a similar result was not obtained when orientase was supplemented (Yang et al., 2015). Moreover, the occupation ratio of Bifidobacterium in the cecum was higher in mice fed a high-fat diet and supplemented with fermented burdock than those that were not administered this supplement (Okazaki et al., 2013). Matsumoto et al. (2014) found that supplementation with beverages containing plant enzymes significantly increased Bifidobacterium and reduced Clostridium cluster IV in human feces, when compared to placebo beverages. Therefore it was suggested that effects of MGK on body weight reduction may be mediated via intestinal bacteria although the underlying mechanism is unclear.
Our intervention study had some limitations. To begin, our total number of human participants was small. In addition, we did not perform a detail recording of the diets of these participants. Finally, our results may not be applicable to adults of all ages as our analysis was performed with only young women.
We found that an MGK-supplemented diet decreased body fat accumulation in rats fed a high-fat diet and body fat percentage in young women. The efficacy of this supplementation has been suggested to be a result of the enzymes of MGK, through their improvements of the microflora. However, the detailed mechanism of body fat reduction could not be defined. Future studies are required to reveal the influence and body changes associated with MGK intake.
Acknowledgments We gratefully acknowledge the participation of the subjects in the human dietary intervention study. We would also like to thank Editage for English language editing.
