High-fat diet linked to unfavorable gut microbiota changes
Eating a diet high in fat and low in carbohydrates can lead to changes in the gut at the microbiome level that could lead to the development of metabolic disorders, according to study results published in Gut.
Duo Li, PhD, of the Institute of Nutrition and Health at Qingdao University in China, and colleagues wrote that their findings could be important in countries where diets are becoming more westernized.
“Western-type diet has a strong effect on the genetic composition and metabolic activity of gut microbiota,” they wrote. “Evidence has shown that in humans gut microbiota diversity and richness are reduced when comparing such high-fat diets with more traditional diets with relatively higher proportions of carbohydrate. Such diet-induced ‘dysbiosis’ in gut-associated microbial communities has been postulated as a major trigger of metabolic impairments associated with obesity.”
Researchers conducted a 6-month randomized controlled-feeding trial comprising 217 healthy young adults (aged 18-25 years; 52% women; BMI <28 kg/m²). They randomly assigned patients to go on one of three isocaloric diets (lower-fat [fat 20% energy], moderate-fat [fat 30% energy] and higher-fat [fat 40% energy]) and assessed the effects of the dietary interventions on the gut microbiota and inflammatory triggers in blood and fecal samples taken at baseline and after 6 months.
Investigators found that the lower-fat diet was associated with increased alpha-diversity assessed by the Shannon index (P = .03), as well as increased abundance of Blautia (P = .007) and Faecalibacterium (P = .04). The higher-fat diet was associated with increased levels of Alistipes (P = .04) and Bacteroides (P < .001) with decreased levels of Faecalibacterium.
Li and colleagues found that the higher-fat diet was associated with changes to long-chain fatty acid metabolism, which resulted in higher levels of chemicals that could potentially trigger inflammation.
“Compared with a lower fat diet, long-term consumption of a higher fat diet appears to be undesirable ... for young healthy adults whose diet is in transition from the traditionally consumed lower fat, higher carbohydrate diet to one characterized by an appreciably higher fat content,” they wrote. “These findings might also have relevance in developed countries in which fat intake is already high.” – by Alex Young
Disclosures: The authors report no relevant financial disclosures.