Introduction: Impact of nutrition on reproduction: an overview.

This Views and Reviews explores existing data regarding the impact of nutrition, supplements, and lifestyle changes as they relate to weight on the fertility of both men and women. Challenges and shortcomings in developing and performing well-designed studies of nutrition and fertility are reviewed in these five papers, and the best evidence is presented. Recommendations are made based on the data, such as they are. It appears that folic acid supplementation above the level used by women to reduce the risk of neural tube defects may be of value in producing favorable pregnancy outcomes. Certain polyunsaturated fatty acids may have a beneficial effect on fertility, and a Mediterranean diet may prove advantageous in both men and women. Data do not consistently support a beneficial effect of vitamin D on reproduction, and caffeine use has not been shown to have a deleterious effect. Alcohol use may negatively impact reproductive success, and smoking appears to have a clearly negative impact in both men and women. Present data consistently show that obesity is associated with reduced reproductive efficiency in both women and men, but the data do not confirm that weight loss proximate to attempts at conception will reverse this effect. We would do well to appreciate that the ongoing state of being obese appears to be more relevant to reproduction than changing the obese state.