The Role of Diet in Cardio-Conditioning
Diet is an important component of health. Dietary problems have an impact on the quality of life, as well as the outcome of both acute and chronic diseases. While nutritional requirements may be modified by disease, wouldn’t it be better to, if possible, prevent the onset of this need? For example, diet therapy plays a major role in the prevention of atherosclerosis, a disease characterized by cholesterol-rich plaques of immune-system cells stemming from cigarette smoke, high blood pressure and high levels of cholesterol. Diet therapy also aids in the management of advanced coronary artery disease. Variety, balance and moderation are the basic components of dietary adequacy.
Cardiovascular Disease and Diet
The elevation of plasma cholesterol or LDL (low density lipoprotein) is a major risk factor in harming the cardiovascular system and can easily be modified by dietary intervention. The National Cholesterol Program (NCEP) has identified people at low risk for this development as maintaining a total serum cholesterol concentration level of no more than 200mg/dl. Those individuals at moderate risk are found to be between 200-239mg/dl, while those at high risk sustain a level of 240mg/dl or more. See your doctor for an accurate cholesterol analysis.
The basic diet therapy for people with elevations of LDL cholesterol involves reducing the intake of fat, mainly saturated, to less than 30% (total fat) and 10% (saturated fat) of total calories. Sources of saturated fat include animal fats (i.e. fatty meat, poultry skin and butterfat), as well as some vegetable fats (i.e. coconut oil, cocoa butter and palm oil). The total dietary intake of cholesterol should be less than 300mg per day.
Obesity is also a risk factor for cardiovascular disease (CVD). For every excess kilogram (or 2.2 pounds) of body weight, endogenous cholesterol synthesis (cholesterol created within the body) is increased by 20mg per day, so that with 10kg (22 pounds) of excess weight, 200mg of additional cholesterol enters the body. Insulin resistance is also increased with obesity, and even a modest decrease in weight, about 5-10kg (11-22 pounds), improves the hyperinsulinemia, which results from insulin resistance. The fall in levels of HDL (high density lipoprotein), or the protective cholesterol, is primarily due to the increased intake of carbohydrates and polyunsaturated fats. Monounsaturated oils (i.e. canola and peanut oils) maintain the HDL levels and, in fact, help in lowering LDL levels.
Trans-fatty acids are a suggested cause for CVD. Trans-fatty acids are formed when vegetable oils are hydrogenated to solid room temperature. In the US, diet margarine is the most commonly used type of fatty acid. The consumption of more than 7% of such calories may cause a significant increase in LDL cholesterol and a decrease in HDL cholesterol levels. Fish with polyunsaturated fats (the omeg-3 type) have a potent triglyceride lowering effect. High triglycerides are linked to causing coronary artery disease.
Hypertension and Diet
Elevated blood pressure increases the risk for CVD and strokes. Although not all patients are salt-sensitive, dietary sodium should be reduced to 2000mg per day. Even modest weight reduction in the obese may also reduce elevated blood pressure.
There is no doubt about the important role diet plays in cardio-conditioning. Diet therapy doesn’t have to be difficult. It simply involves the provision of adequate calories, proteins and other nutrients, restricting the dietary intake of cholesterol to less than 300mg per day and sodium to 1000-2000mg per day.
References: Harrison’s Text Book of Internal Medicine for Diet Therapy