Higher fresh fruit consumption may lower the risk of diabetes and also reduce the risk of death or vascular complications among those who already have diabetes, according to a new study.
“To our knowledge, this is the first large prospective study demonstrating similar inverse associations of fruit consumption with both incident diabetes and diabetic complications. These findings suggest that a higher intake of fresh fruit is potentially beneficial for primary and secondary prevention of diabetes,” said the researchers, led by Huaidong Du, MD, PhD, of Oxford University in England.
“For individuals who have already developed diabetes, restricted consumption of fresh fruit, which is common in many parts of the world (eg, China and other Asian countries) should not be encouraged.”
Most dietary guidelines, including those for patients with diabetes, recommend a higher level of fruit consumption. However, fruit may not be viewed as being as healthy as fresh vegetables for patients with diabetes because of its relatively high sugar content, the researchers said.
More than 500,000 Chinese adults (mean age, 51 years) were recruited from 10 diverse areas across China during 2004 to 2008. Participants completed a detailed questionnaire interview and underwent physical measurements and blood tests, with their health tracked over 7 years.
Among 30,300 participants (5.9% of total) who had diabetes at baseline, 3389 deaths occurred (overall mortality rate, 16.5 per 1000). In addition, there were 9746 cases of macrovascular disease and 1345 cases of microvascular disease.
Overall, 18.8% of participants reported eating fresh fruit daily, and 6.4% never or rarely consumed fruit. The proportion of non-consumers was about three times higher among persons with previously diagnosed diabetes (18.9%) than among those with newly detected diabetes (6.7%) or no diabetes (6.0%).
In persons who were free of diabetes at the start of the study, daily consumption of fresh fruit was associated with a 12% lower relative risk of developing diabetes compared with those who never or rarely consumed fresh fruit, which was a clear dose-response relationship.
This association was not significantly modified by sex, age, region, survey season, or a range of other factors, including smoking, alcohol consumption, physical activity, body-mass index, and family history of diabetes, the researchers stated.
In persons who already had diabetes before the start of the study, consumption of fresh fruit more than 3 days a week was associated with a 17% lower relative risk of dying from any cause and a 13% to 28% lower risk of developing diabetes-related complications that affect large blood vessels (ischemic heart disease and stroke) and small blood vessels (kidney diseases, eye diseases, and neuropathy) compared with those who ate fruit less often than 1 day per week.
In addition to being a good source of dietary fiber, minerals, and antioxidants, fruit “may work synergistically to confer several benefits on metabolism—including anti-oxidative, anti-inflammatory, anti-proliferative, anti-platelet, anti-hypertensive, anti-dyslipidemic, anti-hyperglycemic, and antiatherogenic effects—and modulation of the composition and metabolic activity of gut microbiota, which could reduce the risk of diabetes as well as of vascular complications among those who have already developed diabetes,” stated the researchers.
Reference: Du H, Li L, Bennett D, et al. Fresh fruit consumption in relation to incident diabetes and diabetic vascular complications: a 7-y prospective study of 0.5 million Chinese adults. PLoS Med. 2017;14:e1002279.