Abstract
Although a high intake of plant foods such as fruits, vegetables, whole grains, nuts, and legumes has been recommended for chronic disease prevention, it has been unclear what is the optimal amount of intake of these foods and whether specific subtypes are particularly beneficial. The evidence from several recently published meta-analyses on plant foods and antioxidants and various health outcomes is reviewed as well as more recently published studies. In meta-analyses of prospective studies, inverse associations were observed between intake of fruits, vegetables, whole grains, and nuts and the risk of coronary artery disease, stroke, cardiovascular disease overall, total cancer, and all-cause mortality. The strongest reductions in risk were observed at an intake of 800 g/d for fruits and vegetables, 225 g/d for whole grains, and 15-20 g/d for nuts, respectively. Whole-grain and nut consumption was also inversely associated with mortality from respiratory disease, infections, and diabetes. Stronger and more linear inverse associations were observed between blood concentrations of antioxidants (vitamin C, carotenoids, vitamin E) and cardiovascular disease, cancer, and all-cause mortality than for dietary intake. Most studies that have since been published have been consistent with these results; however, further studies are needed on subtypes of plant foods and less common causes of death. These results strongly support dietary recommendations to increase intake of plant foods, and suggest optimal intakes for chronic disease prevention may be ∼800 g/d for intakes of fruits and vegetables, 225 g/d for whole grains, and 15-20 g/d for nuts. Diets high in plant foods could potentially prevent several million premature deaths each year if adopted globally.