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Development of type 2 diabetes reduced most by eating fish diet

A fish diet appears to provide the greatest reduction in risk against the development of type 2 diabetes in adults.

Eating a predominately fish diet seems to be the best way of avoiding the development of type 2 diabetes (T2D) compared to other dietary patterns. This is according to an analysis of data held in the UK Biobank.

Type 2 diabetes is a metabolic disorder that results in¬†hyperglycaemia and globally affects a huge number of people. For example, one estimate from 2017 suggested that approximately 462 million individuals were affected (6.28% of the world’s population), leading to one million deaths per year.

Fortunately, a number of cases of T2D can potentially be prevented by lifestyle changes, including maintaining a healthy body weight, consuming a healthy diet, staying physically active, not smoking, and drinking alcohol in moderation. 

In fact, a 2017 systemic review identified how the risk of diabetes is reduced by increased consumption of whole grains, fruits and dairy, but that the risk is increased by greater consumption of red meat, processed meat and sugar sweetened beverages.

Nevertheless, what is less clear is whether a particular eating pattern, e.g., a mainly fish diet, or one based on poultry or vegetarianism, has a greater impact on the risk of developing diabetes.

For the present analysis, the team used the UK Biobank database to explore the associations between different types of diets and the risk of incident T2D. Since many patients with T2D are overweight, the researchers also examined the extent to which adiposity might impact on these associations. Within the UK Biobank, participants complete food frequency questionnaires and based on responses, individuals were categorised as vegetarian, fish eaters, fish and poultry eaters and finally meat eaters.

A number of participants reported eating a varied diet and the effect on this type of diet was analysed separately.

The results were analysed using Cox-proportional hazard models which provided a measure of the association between the different diets and the risk of type 2 diabetes and models were adjusted for several factors including age, sex, alcohol intake, smoking status etc.

Fish diet and the risk of type 2 diabetes

A total of 203,790 individuals were included in the analysis with 1.6% who were vegetarian, 2.2% fish diet, 1.1% fish and poultry eaters, 87.3% meat eaters and 7.8% who reported eating a varied diet. The mean age of the groups ranged from 52.8 to 56.5 years and after excluding the first two years, individuals were followed-up for a median of 5.4 years. During the follow-up, 5,067 (2.5%) participants developed type 2 diabetes.

Using meat eaters as the reference, a fish diet had the lowest risk of developing type 2 diabetes (hazard ratio, HR = 0.41, 95% CI 0.31 – 0.55, p < 0.0001), followed by fish and poultry eaters (HR = 0.61, 95% CI 0.44 – 0.86). However, the association with vegetarian and a varied diet were non-significant. However, in the fully adjusted models, a significant association remained only for a fish diet (HR = 0.68) but not for fish and poultry eaters (HR = 0.84, 95% CI 0.60 – 1.17, p = 0.29) or any of the other diets.

Interestingly, the researchers found that general obesity was a partial mediator for fish diets, accounting for 49.8% of their lower risk of developing type 2 diabetes.

The authors concluded that fish diets produced the greatest reduction in the risk of developing diabetes and that this effect was largely due to the fact that fish eaters had a lower level of adiposity.

Boonpor J et al. Types of Diet, Obesity, and Incident Type 2 Diabetes: Findings from The UK Biobank Prospective Cohort Study Diabetes Obes Metab 2022.

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