It is generally accepted that eating more fruit reduces the risk of developing diabetes, but little is known about how fruits confer this advantage.
Type 2 diabetes affects a huge number of individuals with a 2017 review estimating that globally, up to 451 million adults had the condition and that this figure was set to rise to 693 million by 2045. There is evidence that consumption of whole fruits but not juice, reduces the risk of developing diabetes.
However, what is less clear is the relationship between fruit intake and measures of insulin resistance and beta-cell dysfunction. Researchers from the School of Medical and Health Sciences, Perth, Australia, set out to examine the relationship between intake of different fruits and measures of glucose tolerance, insulin sensitivity and the incidence of diabetes after several years follow-up.
The research cohort included 7,674 individuals with a mean age of 54 years (45% male). The median level of fruit intake was 162g/day with the most common fruits being apples (23% of total), bananas (20%) and oranges/other citrus fruits (18%). All other fruits contributed to less than 8% of the total. When comparing those with the highest versus lowest total intake of whole fruits and after adjustment for demographic factors, there was 36% lower odds of having diabetes after five years among 4,674 individuals for whom data was available at this point in time. However, there were no significant associations for any particular fruits or with consumption of fruit juice.
It is reported that the authors suggested that the potential benefits of greater consumption of fruit were related to the presence of soluble fibres that were metabolised by the gut microbiome and the release of short-chain fatty acids which are known to modulate glucose metabolism. It was also possible that the reduced risk could be attributed to the presence of flavonoids within fruits which have anti-diabetic properties. The authors concluded that eating whole fruits appeared to preserve insulin sensitivity and mitigate type 2 diabetes.
