Although many studies have shown that dietary content affects the health of the host by changing the gut microbiota, researchers said very little was known about the links between habitual diets and the gut microbiota of Japanese people.
Therefore, researchers from the University of Shiga Prefecture and Sagami Women's University analysed the faecal microbiota of healthy, young Japanese women, who then filled in a dietary survey over three consecutive days.
T-RFLP pattern analysis divided the subjects into two clusters (A and B). It was then found that cluster A also had lower intakes of iron and vitamin K and higher intakes of mushrooms and snacks than cluster B.
Cluster A was then found to have a high relative abundance of Bacteroides and Clostridium cluster IV, while cluster B had a high relative abundance of Bifidobacterium and Lactobacillales.
Furthermore, analysis of Spearman rank correlations found several significant relationships between faecal microbiota and the specific intake of particular nutrients and food groups.
Food and microbiota link
It found that the relative abundance of Bifidobacterium was significantly linked to intakes of iron, magnesium and vitamin K, while the presence of Bacteroides was negatively correlated with vitamin K intake and folic acid.
In terms of Clostridium XI, the abundance was higher among those who consumed less cholesterol, vitamin B2 and biotin, while Clostridium IV was linked to higher intakes of mushroom, and negatively correlated with egg intake.
Lactobacillales abundance was higher among those who consumed fewer green vegetables.
"These results suggest that dietary habits may strongly affect Bifidobacterium, Bacteroides and Clostridium abundance in the gut microbiota of young Japanese women," wrote the researchers.
The analysis also found a high intake of fermented foods amongst the subjects, with natto and kimchi being particularly popular.
The researchers added: "This is the first study to show relationships between faecal microbiota and habitual dietary intake in Japanese people.
"Accumulation of results from similar studies will help to elucidate the relationships between dietary intake and diseases in Japanese people."
Source: Journal of Nutritional Science and Vitaminology (Japan)
"The Relationship between Habitual Dietary Intake and Gut Microbiota in Young Japanese Women"
Authors: Takahiro Seura, et al.