Keeping the young-elderly healthy: is it too late to improve our health through nutrition?

Healthy older individuals can take several measures to preserve and improve their health. Even if past nutritional and lifestyle practices were not optimal, much can be done to reduce the risk of chronic disease and disability in future years. The first challenge is to recognize and address the profound changes in body composition that occur with aging. Older persons tend to accumulate relatively more body fat and less lean body mass, ie, muscle and bone. With a gain in body weight, which usually occurs, these changes are exaggerated. Because muscle tissue has a much higher metabolic rate than does fat tissue, older individuals generally develop lower metabolic rates. To avoid excess weight gain, older individuals must make major restrictions in caloric intake and increases in energy expenditure. Women experience changes in body composition similar to those in men, with changes becoming more prominent at menopause. Exercise improves body composition among healthy elderly, both by reducing fat mass and by increasing bone and muscle mass, thereby helping to restore higher metabolic rates. In men and women aged >/=65 y and taking calcium and vitamin D supplements for 3 y, the rate of bone loss slowed and the incidence of nonvertebral fractures was reduced. Several population studies of older persons show that following nutritional and lifestyle guidelines for cancer prevention reduces risk by one-third. Improving serum lipid concentrations in adults over 65 y of age with coronary artery disease decreases the risk of future cardiac events by as much as 45%. Furthermore, the greatest benefit from control of hypertension is in older individuals.

Is garlic alternative medicine?

Garlic has been used medicinally since antiquity. In virtually every early civilization known, such as ancient India, Egypt, Rome, China, and Japan, garlic was part of the therapeutic regimen for a variety of maladies. Therefore, the ancient medicinal tradition of garlic use would qualify it as a folk medicine or as an alternative or complementary medicine. But is garlic an alternative to established methods of disease prevention or treatment? Scientists from around the world have identified a number of bioactive substances in garlic that are water soluble (e.g., S-allyl methylcysteine), and fat soluble (e.g., diallyldisulfide). Mechanisms of action are being elucidated by modern technology. The validity of ancient medicine is now being evaluated critically in cell-free systems, animal models, and human populations. Preventive and therapeutic trials of garlic are still in early stages. There are many promising lines of research suggesting the potential effects of garlic. The current state of knowledge does not recognize garlic as a true alternative, but it will likely find a place for garlic as a complement to established methods of disease prevention and treatment. Our goal should be to examine garlic together with other agents to evaluate its possible efficacy and toxicity under conditions of actual use in humans.

Cancer chemoprevention by garlic and garlic-containing sulfur and selenium compounds.

As early as 1550 B.C., Egyptians realized the benefits of garlic as a remedy for a variety of diseases. Many epidemiological studies support the protective role of garlic and related allium foods against the development of certain human cancers. Natural garlic and garlic cultivated with selenium fertilization have been shown in laboratory animals to have protective roles in cancer prevention. Certain organoselenium compounds and their sulfur analogs have been identified in plants. Organoselenium compounds synthesized in our laboratory were compared with their sulfur analogs for chemopreventive efficacy. Diallyl selenide was at least 300-fold more effective than diallyl sulfide in protecting against 7,12-dimethylbenz[a]anthracene (DMBA)-induced mammary adenocarcinomas in rats. In addition, benzyl selenocyanate inhibited the development of DMBA-induced mammary adenocarcinomas and azoxymethane-induced colon cancer in rats and benzo[a]pyrene-induced forestomach tumors in mice. The sulfur analog, benzyl thiocyanate, had no effect under the same experimental conditions. Furthermore, we showed that 1,4-phenylenebis(methylene)selenocyanate, but not its sulfur analog, significantly inhibited DMBA-DNA adduct formation and suppressed DMBA-induced mammary carcinogenesis. Collectively, these results indicate that structurally distinctive organoselenium compounds are superior to their corresponding sulfur analogs in cancer chemoprevention. Additionally, synthetic aromatic selenocyanates are more effective cancer chemopreventive agents than the naturally occurring selenoamino acids. Because plants are capable of utilizing selenium in a manner similar to that in sulfur assimilation pathways, future studies should aim at determining whether, under appropriate conditions, these potent cancer chemopreventive synthetic selenium compounds can be synthesized by garlic and related allium foods.