Chapter 3– Medical Complications of Obesity and Eating Disorders individuals (National Heart, Lung and Blood Institute, 1993). Fifty-five percent of obese men have high blood pressure compared to 27 percent of lean men. Fifty-two percent of obese women have high blood pressure compared to 19 percent of lean women. Similar to high blood cholesterol levels, the mean level of both systolic and diastolic blood pressure increases in linear fashion with increasing body weight (National Institutes of Health, 1993). High blood pressure accelerates atherosclerosis. A person with a systolic blood pressure greater than 160 mm Hg or a diastolic blood pressure greater than 95 mm Hg has a five-fold increase in risk of coronary heart disease compared to persons with normal blood pressure. Hypertension poses the greatest risk in persons older than 45 years of age and is a strong predictor of stroke. The association between obesity and hypertension has long been recognized. When weight is lost, blood pressure usually drops. For example, hypertension nearly vanished among people who had great caloric deprivation during World War II. Bray (1985) noted that 50 to 80 percent of persons who lose weight also have a reduction in blood pressure. Studies have shown that this drop occurs even when the sodium content of the diet was kept constant. Schotte and Stunkard (1990) reported that weight losses of 10.4 kg in obese individuals who were hypertensive and not receiving their antihypertensive medications still reduced systolic blood pressure by 15.8 mm Hg and diastolic blood pressure by 13.6 mm Hg. In the Framingham study, weight losses of 15 percent were associated with a 10 percent reduction in systolic blood pressure (Kannel and colleagues, 1967). Many other studies have also documented that weight loss reduces blood pressure, including one study that reported a 1 mm Hg reduction in both systolic and diastolic blood pressure for every kilo-
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gram of weight loss in young, obese women with hypertension (McMahon and colleagues, 1985). The National Institutes of Health (1993) recommends weight loss as a key goal for obese individuals with hypertension. Other dietary factors that may influence blood pressure include potassium, calcium, magnesium and dietary fat intake (National Institutes of Health, 1993). High potassium intake may protect against developing high blood pressure. Calcium deficiency may make a person more at risk of developing high blood pressure. Preliminary studies suggest that low dietary magnesium intake may also increase risk for high blood pressure, though these studies need to be confirmed. A certain type of fat, the omega-3 fatty acids found in rich concentrations in fatty fish such as salmon, mackerel and haddock, may also help lower blood pressure.
Diabetes Diabetes, one of the most serious yet relatively common problems in modern times, results from a deficiency of insulin—a hormone produced by the pancreas. There are two main forms of diabetes. Type I diabetes, also called insulin-dependent diabetes mellitus (IDDM) usually occurs in childhood and is characterized by a complete inability to manufacture insulin in the body. Type II diabetes, also called non-insulin-dependent diabetes (NIDDM) usually develops later in life and is characterized by varying ability to make insulin and resistance to the action of insulin in the body. Type I diabetes is due to an absolute lack of insulin. The mechanisms within the pancreas that produce insulin are damaged and can no longer produce insulin. This severe type of diabetes must be treated quickly with insulin, which the patient must take for life. Dietary changes cannot prevent this type of diabetes, but dietary intake must be controlled and carefully matched with insulin taken. Type II diabetes also results from a deficiency