Nutrition Connection: What is Metabolic Syndrome? • Fall 2007

High blood sugar. High blood pressure. High blood triglyceride levels. Low HDL (“good”) cholesterol levels. How are these findings connected?

Experts have developed a term for this group of conditions: metabolic syndrome. Affecting about one-quarter of US adults today (47 million people), metabolic syndrome tends to go hand-in-hand with excess weight and lack of activity. There is also a genetic component; some people are more susceptible to the syndrome than others.

Metabolic syndrome is characterized by presence of at least three of the following:

• Waist circumference greater than or equal to 35 inches (women) or 40 inches (men)
• Fasting blood glucose of greater than or equal to 100 mg/dL
• Triglycerides greater than or equal to 150 mg/dL
• Blood pressure greater than or equal to 135/85 mmHg
• HDL (“good”) cholesterol below 40mg/dL for men or below 50 mg/dL for women

The condition is called “metabolic” because some aspects of normal body metabolism are disrupted. (Metabolism describes the biochemical processes in the body that support all body functioning. It includes fueling cells with nutrients and energy, breaking down body materials, and building new ones.)

There is a cluster of changes in metabolism that place a person with metabolic syndrome at risk for illness. According to the National Institutes of Health (NIH), a person with metabolic syndrome is five times more likely to develop diabetes. One aspect of metabolic syndrome is insulin resistance. Remember that in Type 1 diabetes, a person’s body is not producing enough insulin, the hormone that helps cells use blood sugar for fuel. However, in Type 2 diabetes, the body is making insulin but in many cases, the cells are unable to use it effectively. There may be plenty of insulin in the body, but cells “resist” the effects of insulin, and blood sugar rises. In fact, many individuals with Type 2 diabetes also have related characteristics of metabolic syndrome.

Ongoing high blood sugar levels leave the body with a dilemma: what to do with the extra glucose. Some of this excess is bundled up into fat molecules called triglycerides. Triglycerides are the most basic and abundant form of fat storage in the body, and show up in many body tissues. However, it is not healthy to have high levels in the bloodstream. This is considered a risk factor for heart disease and stroke.

In fact, a person with metabolic syndrome is also twice as likely to experience heart disease, says the NIH. The American Diabetes Association recommends these target levels for blood lipids for anyone with diabetes:

• LDL cholesterol: below100 mg/dL
• HDL cholesterol: below 45 mg/dL for men or below 55 mg/dL for women
• Triglycerides: below150 mg/dL

Another aspect of high triglyceride levels is a possible effect on appetite. Scientists believe triglycerides may interfere with the action of a hormone called leptin. Leptin tells the brain to tell the body to stop eating; it is one piece of the appetite-control puzzle. This can spin an overweight person into a vicious cycle of leptin resistance—less appetite control, more eating. More eating—more excess body weight. More excess weight, more triglycerides, etc.

Another condition that sometimes accompanies metabolic syndrome is called fatty liver (fat deposits in the liver). Over time, this can damage the liver and lead to liver disease, such as cirrhosis. The body also lays down excess fat into muscles, which would normally be lean tissue. Some researchers believe extra fat “in the wrong places” may trigger a series of inflammatory responses in the body, contributing to development of chronic diseases, including atherosclerosis.

Yet another condition commonly associated with metabolic syndrome is sleep apnea. A person experiencing sleep apnea briefly stops breathing during sleep, sometimes as often as 20-30 times each hour. An episode of apnea (meaning literally “no breath”) can last 10 seconds or longer. In response, the body interrupts its sleep, moving into a lighter stage of sleep in an effort to breathe. This translates into poor quality sleep and may leave a person feeling tired during the day.

Experts say loud snoring can be a sign of sleep apnea. However, not everyone who snores loudly has sleep apnea. Is there a weight connection? Yes, in some cases. Excess fat in the throat area can contribute to pressure on the trachea (windpipe). Being overweight is a risk factor (though not the only cause), and losing weight can sometimes help control the condition.

In all, excess body weight seems to kick off a series of unhealthy events in the body. The American Dietetic Association states that “the growing number of overweight Americans is leading to an increase in the incidence of metabolic syndrome,” (press release, 6/5/05), and researchers at Johns Hopkins Bloomberg School of Public Health predict that by the year 2015, three-quarters of US adults will be overweight, and 41% will be obese—given current rates of increase among our population (press release, 7/10/07).

The Dietary Connection

Smart dietary choices are one way we can help to control metabolic syndrome. Controlled caloric intake is important to help discourage formation of excess body fat. Food choices low in fat also help to prevent blood lipid disorders. Where high triglycerides are a problem, avoidance of alcohol is also beneficial. Blood sugar control is very important. In addition, nutritionists are finding that these steps can be helpful:

• Consume plenty of omega-3 fatty acids as found in salmon, walnuts, flax seed, and canola oil.
• Eat plenty of high-fiber foods. A high-fiber diet tends to have a lower glycemic index, meaning carbohydrates turn into blood sugar at a slower rate. Foods high in fiber help control glucose metabolism and LDL blood cholesterol levels.
• Limit intake of foods sweetened with high-fructose sweeteners, such as regular soda pop. Studies indicate this form of sugar is particularly likely to raise blood sugar and blood triglycerides, while decreasing leptin levels.
• Choose foods high in magnesium, such as whole grains, nuts, and leafy green vegetables. Research suggests magnesium helps the body maintain healthy glucose metabolism.
• Consume adequate vitamin D and calcium. Studies indicate that low intake of dairy products is associated with Type 2 diabetes and metabolic syndrome. Maintaining adequate intake, especially though fat-free dairy products, may have a preventive effect.
• Manage overall calorie intake to help control body weight.
• Stay on a routine of exercise and physical activity. Exercising helps the muscles use glucose that is circulating in the bloodstream, and discourages storage of extra fat in the body. It also helps to encourage favorable energy balance to help maintain (or lose) weight. Weight loss can help many symptoms of metabolic syndrome improve.

While metabolic syndrome is a growing concern, the NIH states, “It is possible to prevent or delay metabolic syndrome, mainly with lifestyle changes. A healthy lifestyle is a lifelong commitment.” In fact, says Roberta Anding, American Dietetic Assn. spokesperson (press release, 9/1/07), “Any sort of lifestyle modification can help prevent more serious problems from developing. Studies have shown that even 30 minutes of moderate exercise can make a positive difference in treating metabolic syndrome.”

By Sue Grossbauer