Understanding the impact of aging on the cardiovascular system first requires an understanding of those effects pertaining to disease processes and lifestyle changes typical in aging. In most healthy older individuals, the cardiovascular system is adequate to meet the body's need for the pressure and flow of blood. However, age-related changes in the cardiovascular system do occur, including:
- stiffening of the arteries, which increases systolic blood pressure (amount of pressure against the arterial walls), imposing a greater load on the heart;
- decline in various peripheral circulatory factors, including a decrease in muscle mass with age during exercise, a decreased ability to direct blood flow to muscles, and a decreased ability of muscle to utilize oxygen;
- decline in aerobic exercise capacity, whether measured as total work performance or maximal oxygen consumption (in older people who maintain a high level of physical activity, however, the decline appears to be approximately half of the 10 percent per decade decrease seen in sedentary individuals); and
- decline in maximal exercise heart rate (a universal age-related occurrence).
Because these age-related changes in the cardiovascular system are highly nonuniform, some changes can result in a definite impairment, while others may not cause any symptoms at all. Thus, aging is by no means associated with a generalized decline in cardiovascular functions; it should instead be viewed as a complex, highly selective and individualized process.
What, then, is a prudent anti-aging approach to heart health? While the benefits of cardiovascular activity are well-established and often receive the bulk of attention when discussing heart health, the scientific literature suggests a number of nutritional approaches also are worthy of consideration for achieving optimal cardiac fitness.
Less Red Meat, More Healthy Protein
Previous studies have linked consumption of red meat to increased risks of cardiovascular disease and cancer. Adam Bernstein, from Harvard School of Public Health, and colleagues studied data collected on 84,136 women, ages 30 to 55, enrolled in the Nurses' Health Study.1 The research team examined the women's medical histories and lifestyles, including dietary habits, and tracked the incidence of non-fatal heart attacks and fatal coronary heart disease for 26 years.
Women who consumed two servings per day of red meat, as compared to those who consumed only half a serving per day, had a 30 percent higher risk of developing coronary heart disease. By comparison, the data also showed that eating more servings of protein sources such as poultry, fish and nuts was significantly associated with a decreased risk of coronary heart disease. Compared to eating one serving each day of red meat, women who substituted other protein-rich foods experienced significantly lower risk of coronary heart disease:
- 30 percent lower risk associated with eating one serving per day of nuts;
- 24 percent lower risk associated with eating one serving per day of fish;
- 19 percent lower risk associated with eating one serving per day of poultry;
- 13 percent lower risk associated with eating one serving per day of low-fat dairy products.
Watermelon and Blood Pressure
Watermelon is a rich natural source of L-citrulline, a compound closely related to L-arginine, which is crucial to the formation of nitric oxide, which helps to widen blood vessels and thereby mediate blood pressure. Arturo Figueroa, from Florida State University, and colleagues evaluated four men and five women, average age 54 years, with pre-hypertension (134/77 ± 5/3 mmHg).2 Subjects were randomly assigned to six weeks of watermelon supplementation or placebo (a harmless substance participants believed was a watermelon supplement), followed by a four-week washout period and then crossover. The team found that supplementation with 6 grams of L-citrulline from watermelon improved arterial function and lowered aortic blood pressure in all pre-hypertensive subjects. The researchers posit that L-citrulline supplementation (from watermelon) could lead to reduced doses of antihypertensive drugs being needed to control blood pressure, or could even prevent progression from pre-hypertension to hypertension.
More Barley = Less Cholesterol
Previous studies have suggested that fiber can help reduce the risk of cardiovascular disease by lowering cholesterol and improving glucose tolerance. Barley is a food rich in beta glucans, a type of soluble fiber. Nancy Ames, from the Cereal Research Centre at Agriculture and Agri-Food Canada, and colleagues completed a meta-analysis of 11 studies, finding that barley and beta-glucan isolated from barley significantly lowered both total and low-density lipoprotein (LDL) cholesterol concentrations.3 Observing that beta-glucan has unique characteristics relating to solubility and molecular weight, which may help it to confer its cholesterol-lowering properties, the team concluded: "Increased consumption of barely products should be considered as a dietary approach to reduce LDL cholesterol concentrations."
References
- Bernstein AM, et al. Major dietary protein sources and risk of coronary heart disease in women. Circulation, August 2010.
- Figueroa A, et al. Effects of watermelon supplementation on aortic blood pressure and wave reflection in individuals with prehypertension: a pilot study. American Journal of Hypertension, July 8, 2010.
- AbuMweis SS, et al. Beta-glucan from barley and its lipid-lowering capacity: a meta-analysis of randomized, controlled trials. European Journal of Clinical Nutrition, Oct. 6, 2010.
