Vitamins enhance benefits of exercise for heart
the benefits of exercise for heart health, according to new
research on mice.
The combination of the nutrients and exercise significantly reduces the risk of atherosclerosis by boosting the body's production of nitric oxide, which protects against a variety of cardiovascular disorders, report researchers led by medicine nobel laureate Louis Ignarro from UCLA.
Ignarro's team found that moderate exercise reduced the development of atherosclerosis, or hardening of the arteries, in mice that are genetically prone to heart disease. Exercise alone has been shown to increase nitric oxide in the body.
But adding the amino acid L-arginine and the antioxidants vitamins C and E to the mix significantly magnified the effect, said Ignarro, who shared the 1998 Nobel Prize for his discoveries in the role that nitric oxide plays in the cardiovascular system.
"This is the first study that shows that if you exercise in addition to taking dietary supplements you have a markedly enhanced production of nitric oxide - in science, we like to call it a synergistic effect," said Ignarro.
The researcher, along with others from the University of Naples in Italy and the Mayo Clinic Foundation, studied six groups of eight-week-old LDL receptor-deficient male mice with high cholesterol over 18 weeks. The mice were randomly divided into three dietary groups: one fed a high-cholesterol diet alone, another fed a high-cholesterol diet along with the antioxidant vitamins C and E, and a third fed a high-cholesterol diet and given both the antioxidants and L-arginine. Some of the mice also were put on a swimming regimen, while others did not exercise.
The mice from all three dietary groups lost weight and had lower cholesterol when they exercised. The atherosclerotic lesions were significantly reduced in the mice whose diets included the antioxidants and amino acid, the researchers will report in this week's online edition of the Proceedings of the National Academy of Sciences.
They explain that exercise increases the amount of endothelial NO synthase, an enzyme that converts L-arginine to nitric oxide, which in turn lowers abnormally elevated blood pressure, prevents unwanted blood clotting and early inflammation associated with coronary artery disease, and protects against stroke and myocardial infarction.
The antioxidant vitamins C and E work together to remove destructive oxidants from the blood stream, thereby stabilizing the nitric oxide, which can thus rise to higher levels in the blood stream and produce a more beneficial effect.
Ignarro also noted that the supplements work well even in the absence of exercise.
Sedentary mice fed with the supplements showed a 40 per cent reduction in atherosclerosis lesions compared with the mice that were on a regular, high-cholesterol diet but neither given the supplements nor put on an exercise regimen. The mice that exercised, but were not fed the supplements, showed a 35 per cent reduction in the lesions.
The researcher concluded that simple lifestyle changes - doing moderate exercise, eating a low-fat diet and taking dietary supplements - can make a difference to vascular health. "It works in mice, it'll work in humans."
