Health Benefits

Anti-Fatigue Effect

According to the study, “Ingredients, Functionality, and Safety of the Japanese Traditional Sweet Drink Amazake” by Atsushi Kurahashi, Koji amazake intake improved QOL(quality of life) based on all investigated terms, such as fatigue. The authors concluded that B vitamins and amino acids, especially branched chain amino acids (BCAAs), contained in Koji amazake, might be functional substances. Koji amazake has also been reported to have remarkable physical fatigue recovery effects on pain in long-distance runners. (1)

Support Good Intestinal Environment

According to Kurahashi, “the Koji amazake intake ... showed a significant improvement in the frequency of bowl movements and constipation”.
Furthermore, it is reported “the effects of Koji amazake on defecation status in healthy volunteers with relatively low stool frequency and the Koji amazake intake group (five males, nine females) had an improved defecation frequency compared to that before intake”. (1) Kurahashi also pointed out on the other research paper, “Intake of Koji Amazake Improves Defecation Frequency in Healthy Adults”, that the findings of this study showed that the intake of Koji amazake including metabolites produced by A. Oryzae ... was beneficial for increasing the defecation frequency and faecal weight in healthy adults and also for changing the relative abundances of the genera Blautia and Bacteroides in the faecal microbiota.(4)

Maintain Healthy Hair and Skin

According to the scientific study “Amazake made from sake cake and rice koji suppresses sebum content in differentiated hamster sebocytes and improves skin properties in humans” by Hiroko Maruki-Uchida, “continuous ingestion of amazake may ... improve(d) the glossiness of hair and increased L* values(skin colour parameters) under the eyes” (3). “Glossy hair changes ... was significantly improved between the placebo group and the amazake group. Statistically difference in dark circles under the eyes, glossy hair, and waking up well were only seen in the amazake group” (3). Regarding the glossiness of hair, hair is reported to reflect amino acid ingestion. The consumption of rich nutrients including amino acids may be related to hair gloss (2) (3).
The rice Koji is known to contain soluble B vitamins such as thiamin (B1), niacin (B3), pantothenic acid (B5) and B6 (2), which is considered to help cell regeneration on the skin cells, hair cells, brain cells, and can balance the immune and nervous system.

References

(1)Ingredients, Functionality, and Safety of the Japanese Traditional Sweet Drink Amazake
(2)Metabolite profile of koji amazake and its lactic acid fermentation product by Lactobacillus sakei UONUMA
(3)Amazake made from sake cake and rice koji suppresses sebum content in differentiated hamster sebocytes and improves skin properties in humans
(4)Intake of Koji Amazake Improves Defecation Frequency in Healthy Adults