Five servings of fruits and vegetables a day — in particular, three vegetables and two fruits — provide the greatest mortality benefit, according to an observational study and meta-analysis in Circulation.
Researchers analyzed results from the Nurses’ Health Study and Health Professionals Follow-Up Study. Over 100,000 people regularly completed food-frequency questionnaires and were followed for up to 30 years. During that time, nearly a third of participants died.
After multivariable adjustment, the greatest mortality benefit was seen for five servings of produce a day, compared with two servings (hazard ratio, 0.88). Eating more than five servings a day was not associated with greater risk reductions.5 Fruits & Veggies a Day May Be Optimal in Terms of Survival — https://www.jwatch.org/fw117568/2021/03/01/5-fruits-veggies-day-may-be-optimal-terms-survival
There is a link to download the original study on the NEJM Journal Watch page. The discussion section of the study is worth reading if you’re interested in the details.