Key Findings:
The Mediterranean diet (MD) has many health benefits with regard to lower incidence of cardiovascular disease and cancer. The diet includes both omega 3 and omega 6 fatty acids. This paper provides recommendations on the levels of various fatty acids that should be in the diet to mimic the results of the MD. Research indicates that maintaining high intake of omega 6 in lieu of saturates will not reduce CVD complications. Evidence is presented that omega 6 PUFAs have a strong mammary tumor-enhancing effect. Epidemiologic studies have found a positive association between dietary omega 6 PUFAs and breast cancer risk. Research is described whereby omega 3 PUFAs were shown to have chemopreventive properties against various cancers and their complications, including colon and breast cancer. The authors recommend an optimal dietary fat pattern to reduce the risk of both CVD and most cancers should include a low intake of saturates and omega 6 PUFAs. Small amounts (1% to 2% of energy intake) of LA are sufficient to prevent omega 6 deficiency. The amounts of omega 6 in most Western foods are so high that it could be difficult to obtain an intake of omega 6 lower than 4% of energy, which would probably be the optimal level. The intake of omega 3 PUFAs should be a minimum of 3 g/day on average for an adult with at least 2 g/d from ALA.
ABSTRACT:
Cardiovascular diseases and cancers are leading causes of morbidity and mortality. Reducing dietary saturated fat and replacing it with polyunsaturated fat is still the main dietary strategy to prevent cardiovascular diseases, although major flaws have been reported in the analyses supporting this approach. Recent studies introducing the concept of myocardial preconditioning have opened new avenues to understand the complex interplay between the various lipids and the risk of cardiovascular diseases. The optimal dietary fat profile includes a low intake of both saturated and omega 6 fatty acids and a moderate intake of omega 3 fatty acids. This profile is quite similar to the Mediterranean diet. On the other hand, recent studies have found a positive association between omega 6 and breast cancer risk. In contrast, omega 3 fatty acids do have anticancer properties. It has been shown that certain (Mediterranean) polyphenols significantly increase the endogenous synthesis of omega 3 whereas high intake of omega 6 decreases it. Finally, epidemiological studies suggest that a high omega 3 to omega 6 ratio may be the optimal strategy to decrease breast cancer risk. Thus, the present high intake of omega 6 in many countries is definitely not the optimal strategy to prevent cardiovascular disease and cancers. A moderate intake of plant and marine omega 3 in the context of the traditional Mediterranean diet (low in saturated and omega 6 fatty acids but high in plant monounsaturated fat) appears to be the best approach to reduce the risk of both cardiovascular diseases and cancers, in particular breast cancer. (Authors abstract)