More than 60 million Americans have some form of cardiovascular disease (CVD), and more than 2,600 people die from CVD each day. Hypertension is found in about 50% of individuals above 55 years. Metabolic syndrome—characterized by elevated blood glucose and insulin responses—is one of the most common conditions seen today and is estimated to be present in about 22% of men and 24% of women. A central factor in all of these conditions is altered body composition. Adults with altered body composition are at high risk for developing:
Body Composition and Optimal Health (Information)
- Cardiovascular disease (CVD)
- High blood pressure
- Dyslipidemias such as high blood cholesterol
- Metabolic syndrome
- Type 2 diabetes
What is Altered Body Composition?
Body composition is a measure of the amount of body mass (weight) that is present as fat, bone, and lean muscle. Altered body composition may occur from increased fat and/or loss of lean muscle, which result in an increase of fat-to-lean body mass. Although the most common form of altered body composition is from excess fat, decreased skeletal mass by loss of bone, such as seen with osteoporosis, is also a form of altered body composition. Body composition can be determined by:
How Can I Support Healthy Body Composition?
- Body Mass Index (BMI): BMI is calculated from weight and height or can be obtained from an easy-to-use chart. Individuals with a BMI of 25 to 29.9 are considered overweight, while individuals with a BMI of 30 or greater are considered obese.
- Waist Circumference or Waist-to-Hip Ratio (WHR): People who accumulate fat in the abdominal area (apple-shaped body) are at a significantly increased risk for developing diseases as compared to those with fat accumulation primarily in the hips and thighs (pear-shaped body).5,6,13,14 A waist circumference greater than 35 inches for women or 40 inches for men, or a WHR of 0.8 or greater in women, or 1.0 or greater in men indicates abdominal adiposity.
- Bioelectric Impedence Analysis (BIA): BIA uses electric signals at different frequencies, which are impeded (slowed down) differently depending on whether they are moving through fat or lean muscle mass.
An important part of a clinical management program to improve body composition is adequate nutrition to support lean body mass, while appropriately limiting caloric intake. The low-calorie diets commonly used in weight-loss programs may not be beneficial, and such diets may produce side effects of fatigue, dizziness, and weakness, and result in loss of lean muscle mass.12 Research has shown that clinical programs that include a supplemental meal replacement are more successful for weight loss.16 Interventions for healthy body composition should always include resistance exercise as well, since increasing muscle mass increases energy needs, helps combat fatigue, and decreases the likelihood that fat mass will return after the program is completed.
Soy Protein, Isoflavones, and Healthy Body Composition
Soy protein is a high-quality protein source that may improve blood pressure and blood lipids.18-20 Based on a thorough review of the research literature, the FDA has issued a health claim stating that a daily consumption of 25 grams of soy protein as part of a diet low in saturated fat and cholesterol may reduce the risk of CVD.
Specific preparations of soy protein have also been shown to promote healthy body composition. For example, a soy-based medical food has been shown to promote lean body mass over a non-soy based meal replacement in a weight management program. And, perimenopausal women fed 40 grams of an isoflavone-containing soy protein daily for weeks showed increases in lean mass, whereas a control group consuming whey protein did not.
Glycemic Index (GI), Fructose, and Metabolic Syndrome
The GI assesses blood glucose response to a food, and research documents that people at risk of diabetes should maintain a diet with low GI foods.14,25-27 Recently, a soy-based medical food was shown to have a low GI, suggesting it could be a suitable source of protein and nutrients while maintaining healthy blood glucose and insulin levels.
The source of sweetener in any food should be considered as well, and fructose is a low GI, naturally occurring sweetener. Fructose is suggested as a preferred sugar source for diabetics since large doses of fructose (50 grams) only modestly raise blood sugar or insulin levels, and small doses show virtually no effect on blood sugar or insulin.
Fiber and BMI
Fiber is known to promote healthy digestion, blood insulin, and blood glucose levels, as well as maintenance of healthy cholesterol levels; and, fiber is associated with lower risk of CVD. In the 10-year-long CARDIA Study of more than 2,000 adults, those individuals with the highest intake of fiber had the lowest body weight and WHR, and those with the highest body weight showed higher blood lipids and blood pressure. Fiber intake of 20 to 30 grams per day should be considered in the optimal diet for promoting healthy body composition.
Homocysteine, Folate, Vitamin B12, and Optimal Health
Elevated blood homocysteine is associated with aging and obesity, and is an independent risk factor for CVD. Research also shows that it is associated with altered body composition in both adults and children.38,39 Folate and vitamin B12 are key vitamins that promote reduction of homocysteine levels.
Calcium, Magnesium, and Potassium Balance
Early studies suggested restricting sodium may be helpful in older persons, but more recent data—including those from the large, multicenter Dietary Approaches to Stop Hypertension (DASH) trial—suggest calcium, potassium, and magnesium are more important in maintaining healthy blood pressure.3,40-43 Low intake of calcium is also associated with higher levels of body fat, and calcium supplementation has been shown to promote healthy body composition and decrease fat retention in clinical trials and animal studies.
Bone Health and Body Composition
Throughout life, skeletal and lean muscle masses are related. Bone density decreases dramatically after the age of 40, so that by 80 years of age, men have lost on average 12% and women 25% of bone.7 Major factors in bone health are adequate intake of bone-support nutrients, and weight-bearing exercise to promote new bone growth.
Calcium supplementation has been shown to slow or even prevent bone loss in older individuals. About half the weight of bone mineral is from phosphorus, and it is important that intake of phosphorus and calcium be in balance.49 Low magnesium, vitamin D, and vitamin K levels are associated with decreased bone mass and increased prevalence of fractures. Supplementation with these nutrients is important in promoting bone density. In addition, research suggests that soy with isoflavones reduces the bone resorption often seen during and after menopause.