And the magic number for the daily intake of fruits and vegetables is …

Eating more fruits and vegetables was associated with lower mortality in large observational studies, but there was a limit to how much these foods could improve health.

Nonlinear inverse associations of fruit and vegetable intake with mortality risk over 30 years appeared in two well-known prospective studies with more than 100,000 participants in total.

The widely touted “five a day” was, in fact, better than two servings a day in terms of:

• Total mortality: HR 0.87 (95% CI 0.85-0.90)
• Mortality from cardiovascular disease: HR 0.88 (95% CI 0.83-0.94)
• Cancer mortality: HR 0.90 (95% CI 0.86-0.95)
• Mortality from respiratory diseases: HR 0.65 (95% CI: 0.59-0.72)

Two daily servings of fruits and three of vegetables confer the greatest benefit; more servings than that did not produce an additional reduction in mortality risk, according to researchers led by Dong Wang, MD, ScD, of Brigham and Women’s Hospital and Harvard Medical School. His manuscript was published online at Circulation.

The exceptions were starchy vegetables (eg, peas, corn), fruit juices, and potatoes, which were not associated with a 3-decade mortality decline in the report.

Similar findings were seen in a meta-analysis that incorporated these two studies with 24 other prospective cohort studies with a total of 1,892,885 participants.

“These findings support current dietary recommendations to increase fruit and vegetable intake, and that the succinct message of 5 a day is consistent with the available evidence,” Wang’s group concluded.

Average consumption in the U.S. is just one serving of fruit and 1.5 servings of vegetables per day, Wang and colleagues noted, despite public health campaigns urging people to eat more of these. food for decades.

“Health professionals cannot change food policy, that is the role of governments, but they can help people understand how to implement simple dietary changes. The biggest benefits may come from encouraging those who rarely eat fruits or vegetables as diets rich in even modestly higher consumption of fruits and vegetables is beneficial, “according to Naveed Sattar MD, PhD, from the University of Glasgow, Scotland, and Nita Forouhi, MD, PhD, from the University of Cambridge, England .

Even small but sustainable dietary changes “may be sufficient for some health benefits and could set the stage for them to try additional adjustments,” the duo wrote in an accompanying editorial.

The biggest challenge is how to achieve dietary improvements across the population, which will require structural changes and interventions at the national policy level that increase access to healthy foods through subsidies for taxing unhealthy foods, Sattar and Forouhi argued.

For the study, Wang and his colleagues included women from the Nurses Health Study (n = 66,719) and men from the Health Professionals Follow-up Study (n = 42,016) who were free of cardiovascular disease, cancer, and diabetes at the start of the study. All had had their diet regularly assessed since the 1980s using a food frequency questionnaire.

The researchers adjusted for frequent fruit and vegetable eaters to be older, more likely to use multivitamins, and had a higher total energy intake, diet quality, level of physical activity, and prevalence of hypercholesterolemia. This group was also less likely to be current smokers and drank less alcohol.

The observational nature of the study left room for residual confusion despite these adjustments. Additionally, Wang’s team cautioned that there was a potential for reverse precaution (that is, people in poor health could change their diets to a healthier diet) and measurement errors by relying on self-reported food consumption.

“Additionally, it would have been informative if the authors had looked more specifically at deaths or cancers related to the digestive tract. Given the earlier concern raised about the consumption and mortality of frozen / canned fruits, it is important to expand the research to examine the differences between raw fruits, canned, frozen or cooked vegetables, “added Sattar and Forouhi.

“Still, the totality of the evidence … should convince healthcare professionals to promote the consumption of more fruits and vegetables as a key dietary strategy, and for citizens to adopt it,” the editorialists urged.