Genetic engineering of foods to reduce the risk of heart disease and cancer

Using RNAi to improve plant nutritional value: from mechanism to application

RNA interference (RNAi) is an ancient mechanism of gene suppression, whose machinery and biological functions are only partially understood. Intensive studies have focused on developing RNAi technologies for treating human diseases and for improving plant traits. Yet application of RNAi to improving the nutritional value of plants for human and animal nutrition, and development of the related RNAi technologies are still in their infancy. Here we discuss current knowledge of plant RNAi function, as well as concepts and strategies for the improvement of plant nutritional value through the development of plant RNAi technologies.

Cancer in the elderly: is it preventable?

It is the goal of the American Cancer Society to decrease the mortality from cancer by 50% and the incidence of cancer by 25% by the year 2015 in the United States. Achieving this goal requires intervention at the primary (incidence) and secondary (mortality) prevention stages, and will involve a concerted effort of the individual practitioner, governmental agencies, local, state, and national interest groups, and the population at large. Primary care practitioners must increase their level of enthusiasm for cancer prevention, and actively counsel patients about cancer risks and preventive measures. Practitioners should encourage inclined patients by providing support and specialty resources, such as dieticians, exercise therapists, and smoking and alcohol cessation programs. The greatest effort lies in the general population, who must adopt a healthier lifestyle, including appropriate diet, smoking cessation, control of obesity, and daily exercise. None of these lifestyle changes are easy to embrace, but once educated about lifestyle and risk of cancer, people have a powerful incentive to change. Continued public awareness campaigns and encouragement from health care providers are essential for the success of such programs. The success in smoking cessation shows that achieving societal lifestyle changes on a large scale is possible. The elderly are especially prone to benefit from primary and secondary prevention techniques, and it must not be assumed that only the young will realize the benefits of prevention and screening. The association of age and cancer risk will always be present, but need not be as consequential as it is now. Although cancer prevention may have a limited role in antiaging per se, the feasibility of cancer risk reduction has a definite role in aging successfully.

Mechanisms mediating lipoprotein responses to diets with medium-chain triglyceride and lauric acid

Medium-chain triglycerides (MCT) are often used in specialized formula diets or designer fats because of their special properties. Yet their influence on lipid metabolism is not completely understood. In this two-period cross-over study, the effects of MCT (8:0 + 10:0) in contrast to a similar saturated fatty acid (12:0) were compared. Eighteen healthy women ate a baseline diet [polyunsaturated (PUFA)/saturated fat = 0.9] for 1 wk. Then, they consumed test diets (PUFA/saturated fat = 0.2) for 4 wk. Monounsaturated fat and cholesterol were constant in baseline and treatment diets. MCT and 12:0, substituted for part of the PUFA, provided 14 energy (en)% of the test diets. In comparison to the PUFA baseline diet, a 16% increase in mean serum low density lipoprotein (LDL)-cholesterol (C) on the 12:0 diet was accompanied by a 21% decrease in mean receptor-mediated degradation of LDL by freshly isolated mononuclear cells (MNC) in vitro. The MNC assay theoretically gives an indication of receptor-mediated degradation of LDL. In contrast, the MCT diet raised mean receptor-mediated degradation of LDL by 42%, a finding out of line with the mean 11% increase in serum LDL-C. Perhaps MCT, by increasing the rate of LDL-C production, overcame the rate of LDL-C clearance. The 12:0 diet enhanced some factors involved in reverse cholesterol transport (e.g., high density lipoprotein fractions) while MCT had a different or less pronounced effect. The overall effects of MCT on cholesterol metabolism may or may not be desirable, whereas those of 12:0 appear largely undesirable as previously reported.