What’s the does-response relationship between fruit and vegetable intake and reduction chronic disease and all-cause mortality?
It is well known that a high intake of fruit and vegetables is the cornerstone of a healthy diet and recommended to the general public to reduce the risk of cardiovascular diseases and cancer which are the two most common causes of premature death worldwide and accounted for collectively 25.5 million deaths in 2013. However optimal levels of fruit and vegetable intake have been unclear and varies greatly between countries.
For example, current recommendations for fruit and vegetable intake range from at least 400 g/day by the World Cancer Research Fund, the WHO, and in England, to 500 g/day in Sweden, to 600 g/day in Denmark, 650–750 g/day in Norway, and 640–800 g/day in the USA.
A meta-analysis by Aune 2017 collected 95 studies that met their criteria and found an inverse association between intakes of fruits, vegetables and fruits and vegetables and the risk of coronary heart disease, stroke, cardiovascular disease, total cancer and all-cause mortality. In most of the analyses the reduction in risk were steeper at the higher range intake.
There was an 8–16% reduction in the relative risk (RR) of coronary heart disease, 13–18% reduction in the RR of stroke, 8–13% reduction in the RR of cardiovascular disease, 3–4% reduction in the RR of total cancer and 10–15% reduction in the RR of all-cause mortality for each 200 g/day (2 servings per day) increment in intake of fruit, vegetables, and fruit and vegetables combined.
Whereas an intake of 800 g/day (10 servings) was associated with 24%, 33%, 28%, 14% and 31% reductions in the RR, respectively (the lowest risk).
In conclusion anywhere between 6-10 servings per day seems to be ideal with the upper limit an ideal goal for the most protection from the listed chronic diseases and all-cause mortality.