In vitro fermentation by gut microbiota of human subjects from three ethnic groups in Hawaii

Abstract

The gut microbiota that lives in our large intestine has a close relationship with our health and well-being. Gut microbial composition depends on both environmental factors and factors from their hosts. This pilot study investigated dietary habits and fecal short-chain fatty acid (SCFA) concentration with substrates inulin and glucose in three ethnic groups (Caucasian, Chinese, Japanese) in Hawaii (n=9). Dietary intake was recorded for 3 to 4 days prior to fecal specimen collection. An in vitro fermentation was conducted to evaluate the energy production potential of the gut microbiota obtained from human fecal specimens. Caucasians had significantly higher food weight intake than the other two ethnic groups. With substrates added, Caucasians also produced a higher concentration of butyrate, propionate and total SCFA than Japanese subjects at time point 12 and 24 hr, which Japanese had significantly lower production (P<0.05). The SCFA concentrations produced by the individual subjects were widely variable over the 24-hour study period. Higher food weight, carbohydrate intake, and dietary fiber intake were associated with higher SCFA production in vitro. This study demonstrated that Caucasians had higher propionate, butyrate, and total SCFA production than Japanese subjects in response to added inulin. Further studies are required to determine if the effects of ethnicity and dietary pattern on bowel health are sustained in the long-term.