Fruit & vegetable intake and the risk of cardiovascular disease, total cancer and all-cause mortality
Although a high intake of fruit and vegetables has been recommended for the prevention of cardiovascular disease and some cancers, questions remain about the optimal intake of fruit and vegetables and whether specific types of fruit and vegetables are particularly beneficial. This is also reflected in differences in the level of fruit and vegetables that is recommended between different countries and organizations. For example the World Cancer Research Fund, the WHO and in England, an intake of 400 g/d is recommended, while 500 g/d is recommended in Sweden, 600 g/d in Denmark, 650-750 g/d in Norway and 640-800 g/d in the USA.
High intake of fruit & vegetables reduce the risk of cardiovascular disease
The current systematic review and meta-analysis therefore aimed to clarify the strength and the shape of the dose-response relationship between fruit and vegetable intake and specific types of fruit and vegetables and the risk of cardiovascular disease, cancer and all-cause mortality. PubMed and Embase databases were searched up to 29th of September 2016 and 95 prospective studies (142 publications) were included in the analyses.
For fruit and vegetables combined, the summary RR per 200 g/day was:
- 0.92 for coronary heart disease (0,90 for 200g/d of fruit and 0,84 for 200g/d of vegetables),
- 0.84 for stroke (0,82 for 200g/d of fruit and 0,87 for 200g/d of vegetables),
- 0.92 for cardiovascular disease (0,87 for 200g/d of fruit and 0,90 for 200g/d of vegetables),
- 0.97 for total cancer (0,96 for 200g/d of fruit or 200g/d of vegetables), and
- 0.90 for all-cause mortality (0,85 for 200g/d of fruit and 0,87 for 200g/d of vegetables).
Reductions in risk were observed up to 800 g/day of fruit and vegetables combined for all outcomes except cancer, where there was no further benefit with an intake above 600 g/day.
For coronary heart disease risk and stroke mortality, the inverse associations were approximately linear up to 800 g/d, while for all-cause mortality, the strongest reduction was observed up to 400 g/d, but with slight further reductions in risk up to 800 g/d.
Intake of specific types of fruit & vegetables and the risk of cardiovascular disease, total cancer and all-cause mortality
Of specific types of fruit and vegetables, we found inverse associations between the intake of apples and pears, citrus fruit, green leafy vegetables, cruciferous vegetables, and salads and cardiovascular disease and all-cause mortality, and between the intake of green-yellow vegetables and cruciferous vegetables and total cancer risk. Furthermore, beta-carotene-rich fruit and vegetables and vitamin C-rich fruit and vegetables showed inverse associations with coronary heart disease in the high vs low analysis, and in addition tomatoes were inversely associated with coronary heart disease in the dose-response analysis.
More than 5, 5 million premature deaths worldwide may be attributable to a low fruit and vegetable intake
It was estimated that approximately 5.6 and 7.8 million premature deaths worldwide in 2013 may be attributable to a fruit and vegetable intake below 500 and 800 g/day, respectively, if the observed associations are causal. Further studies are needed on less common causes of death and on the intake of other specific types of fruit and vegetables that have been less investigated to date. However, the current results support recommendations to increase fruit and vegetable intake in the general population and suggest that the optimal intake may be 800 g/d based on the current data.
Based on: Aune D. et al. Fruit and vegetable intake and the risk of cardiovascular disease, total cancer and all-cause mortality - a systematic review and doseresponse
meta-analysis of prospective studies. International Journal of Epidemiology, 2017 ; 1029–1056.