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 (UK) 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.
A total of 203,790 participants without diabetes at baseline were included in the study. All study 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 eaters 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. And after considering participants’ BMI and waist circumference, only participants who ate fish only had a lower risk of type 2 diabetes.
Further analysis showed that reduced obesity rates played a role in the lower risk of type 2 diabetes in fish-only and fish and poultry diets, accounting for 49.8% and 30.6%, respectively, of the reduced risk. In participants eating a varied diet, higher general obesity and abdominal fat rates accounted for 55.2% and 52.9% of the increased 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 for 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 type 2 diabetes risk partly because fish-containing diets were associated with a 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.
