Diets containing fish, poultry, or both without red meat are associated with a lower risk of type 2 diabetes, new data from the United Kingdom reveals.
The reduced risk is partly due to lower obesity and abdominal fat rates in participants with such dietary patterns.
The study, “Types of Diet, Obesity, and Incident Type 2 Diabetes: Findings from the UK Biobank Prospective Cohort Study,” was published in Diabetes, Obesity and Metabolism.
An unhealthy diet, including a high intake of red meat, processed meats, sugar-sweetened beverages, and refined grains, is a risk factor for type 2 diabetes. Conversely, diets rich in whole grains, dairy, vegetables, fruits, legumes, fish and poultry are associated with a lower risk of the condition.
There is conflicting evidence in the literature on the association between vegetarian, fish, poultry, and meat-based diets and type 2 diabetes. While some studies show a protective role for fish, poultry and vegetarian diets, others either show no protective role for vegetarian diets after considering BMI or a raised risk of type 2 diabetes for meat, fish and poultry-based diets.
Now, a team of scientists in the UK used data from the UK Biobank to investigate the associations between vegetarian fish, poultry, meat diets and varied diets and the incidence of type 2 diabetes. They also studied if obesity plays a role in the incidence of type 2 diabetes.
The study included 203,790 participants without diabetes at baseline. All participants completed questionnaires about their medical history, BMI, and diets. The participants’ diets were grouped into four categories: vegetarian, fish-only eaters, fish and poultry eaters, and meat consumers (fish, poultry, and red meat). A group of participants reported eating a varied diet and were assessed separately.
The participants (55% women) were mainly meat eaters (87.3%). A total of 7.8% reported eating a varied diet, 2.2% ate fish only, 1.6% were vegetarians, and 1.1% ate fish and poultry only. After a median follow-up of 5.4 years, 5,0627 (2.5%) participants were diagnosed with type 2 diabetes.
Compared to meat-eaters, fish and poultry eaters had a 52% and 34% lower risk of type 2 diabetes, respectively. However, participants with a varied diet had a 27% higher risk of type 2 diabetes. Interestingly, there was no association between vegetarian diets and type 2 diabetes. After considering participants’ BMI and waist circumference, only participants who ate fish had a lower risk of type 2 diabetes.
Further analysis revealed that reduced obesity rates contributed to the lower risk of type 2 diabetes in fish-only and fish and poultry diets, representing 49.8% and 30.6%, respectively, of the diminished risk. In participants consuming a varied diet, higher general obesity and abdominal fat rates accounted for 55.2% and 52.9% of the heightened risk of type 2 diabetes.
“In this large prospective cohort study, we showed that fish and fish and poultry diets were associated with lower risk of type 2 diabetes compared to meat-eaters, independent of sociodemographic and lifestyle factors. Obesity was attributed to half of the association of fish and poultry diets and a third of fish diets. Vegetarian diets were not associated with a lower risk of type 2 diabetes,” the researchers wrote.
Fish was associated with a lower risk of type 2 diabetes, partly because fish-containing diets were associated with lower BMI and waist circumference.
“Our study meaningfully extends the literature by showing adiposity, as indicated by BMI and WC [waist circumference], were indeed mediators for fish diets,” they wrote.
Further studies are needed to investigate the role of blood pressure and lipid profile in type 2 diabetes risk.
“In conclusion, this study showed that fish diets were associated with a lower risk of incident type 2 diabetes compared to diets including meat. The associations were partially mediated by adiposity,” the researchers wrote.
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