Eating too much fat can be harmful to intestinal bacteria, suggests a new Chinese study.
The study was conducted on more than 200 healthy young adults, who were assigned to a low, moderate or high-fat diet for six months. Those in the high-fat diet group have seen "adverse changes" in their levels of some intestinal bacteria and compounds that these bacteria produce, the researchers said.
Such changes could have "long-term negative consequences, such as an increased risk of metabolic diseases such as type 2 diabetes," the authors wrote in the February 19 issue of the journal Gut.
The results could be particularly relevant for the Chinese and other countries where the regimes are becoming more westernized, compared to the traditional regimes of the region. The results could also apply to people in developed countries like the United States, who are already on a diet with a high fat intake, but more research is needed to examine this issue, said the authors. [5 Ways Gut Bacteria Affect Your Health]
In addition, the study was conducted in young and healthy adults (aged 18-35). It is therefore unclear whether the results apply to other groups of people.
Intestine bacteria and fat
Previous studies have shown that people's diets can affect their intestinal bacteria and that obesity has been linked to the reduction of certain types of these bacteria. But relatively few studies have examined changes in intestinal bacteria after individuals are assigned to a particular diet.
In the new study, participants were randomly assigned to one of the following three diet groups: the low-fat group, of which 20% of daily calories are derived from fat and 66% from carbohydrates; the moderate fat group, of which 30% of daily calories comes from fat and 56% from carbohydrates; and the high-fat group, of which 40% of daily calories come from fat and 46% from carbohydrates.
The total number of calories and the amount of protein and fiber in the participants' diet were the same for all groups. Participants also gave blood and stool samples at the beginning and at the end of the study.
At the end of the six-month study, participants in the low-fat diet group found an increase in so-called good bacteria levels Blautia and Faecalibacterium compared to their levels at the beginning of the study; those in the high-fat diet group had decreased levels of these bacteria. Blautia and Faecalibacterium The bacteria help produce a fatty acid called butyrate, which is an essential source of energy for intestinal cells and has anti-inflammatory properties, the researchers said.
Indeed, when the researchers measured butyrate levels in participants' stool samples, they found that those in the low-fat group had increased levels of this compound at the end of the study, while those in the high fat group had reduced levels.
In addition, during the study, people in the high-fat diet group experienced an increase in levels of bacteria called Bacteroides and Alistipeswho have been associated with type 2 diabetes.
People in the high-fat diet group have also experienced an increase in so-called long-chain fatty acids, which are supposed to stimulate inflammation in the body. In fact, the researchers found an increase in the levels of certain markers of inflammation in the blood of participants in the lipid group.
"Compared to a low-fat diet, long-term consumption of a higher-fat diet seems to have" negative effects, at least for healthy young adults in China who are moving to a more diet Westernized, the researchers said.
The study found that participants in all three diet groups had lost weight during the study, the low fat diet group losing the most weight. It is not clear if weight loss could be related to some of the observed changes in intestinal bacteria and metabolic markers of participants, so future research is needed to clarify this, said the authors.
The research was carried out at the General Hospital of the People's Liberation Army in Beijing and at Zhejiang University in Hangzhou, China.
Originally published on Science live.