What is metabolic syndrome?

Metabolic syndrome refers to the presence of a cluster of risk factors specific for cardiovascular disease. Metabolic syndrome greatly raises the risk of developing diabetes, heart disease, stroke, or all three. 

According to the National Heart, Lung and Blood Institute (NHLBI), the cluster of metabolic factors involved includes:

• Abdominal obesity. This means having a waist circumference of more than 35 inches for women and more than 40 inches for men. An increased waist circumference is the form of obesity most strongly tied to metabolic syndrome.
• High blood pressure of 130/80 mm Hg (millimeters of mercury) or higher. Normal blood pressure is defined as less than 120 mm Hg for systolic pressure (the top number), and less than 80 mm Hg for diastolic pressure (the bottom number). High blood pressure is strongly tied to obesity. It is often found in people with insulin resistance.
• Impaired fasting blood glucose. This means a level equal to or greater than 100 mg/dL
• High triglyceride levels of more than 150 mg/dL. Triglycerides are a type of fat in the blood.
• Low HDL (good) cholesterol. Less than 40 mg/dL for men and less than 50 mg/dL for women is considered low.

The NHLBI and AHA recommend a diagnosis of metabolic syndrome when a person has 3 or more of these factors.

Most people who have metabolic syndrome have insulin resistance. The body makes insulin to move glucose (sugar) into cells for use as energy. Obesity, commonly found in people with metabolic syndrome, makes it more difficult for cells in the body to respond to insulin. If the body can’t make enough insulin to override the resistance, the blood sugar level increases, causing type 2 diabetes. Metabolic syndrome may be a start of the development of type 2 diabetes.

What causes metabolic syndrome?

Experts don't fully understand what causes metabolic syndrome. Several factors are interconnected. Obesity plus a sedentary lifestyle contributes to risk factors for metabolic syndrome. These include high cholesterol, insulin resistance, and high blood pressure. These risk factors may lead to cardiovascular disease and type 2 diabetes.

Because metabolic syndrome and insulin resistance are closely tied, many healthcare providers believe that insulin resistance may be a cause of metabolic syndrome. But they have not found a direct link between the two conditions. Others believe that hormone changes caused by chronic stress lead to abdominal obesity, insulin resistance, and higher blood lipids (triglycerides and cholesterol).

Other factors that may contribute to metabolic syndrome include genetic changes in a person's ability to break down fats (lipids) in the blood, older age, and problems in how body fat is distributed.

Who is at risk for metabolic syndrome?

Knowing your risk factors for any disease can help guide you to take the appropriate actions. This includes changing behaviors and being monitored by your healthcare provider for the disease.

Risk factors most closely tied to metabolic syndrome include:

• Age. You are more likely to have metabolic syndrome the older you are.
• Ethnicity. African Americans and Mexican Americans are more likely to get metabolic syndrome. African-American women are about 60% more likely than African-American men to have the syndrome.
• Body mass index (BMI) greater than 25. The BMI is a measure of body fat compared with height and weight.
• Personal or family history of diabetes. Women who have had diabetes during pregnancy (gestational diabetes) or people who have a family member with type 2 diabetes are at greater risk for metabolic syndrome.
• Smoking
• History of heavy drinking
• Stress
• Being past menopause 
• High-fat diet
• Sedentary lifestyle

What are the symptoms of metabolic syndrome?

Having high blood pressure, high triglycerides, and being overweight or obese may be signs of metabolic syndrome. People with insulin resistance may have acanthosis nigricans. This is darkened skin areas on the back of the neck, in the armpits, and under the breasts. In general, people do not have symptoms.

The symptoms of metabolic syndrome may look like other health conditions. See your healthcare provider for a diagnosis. 

How is metabolic syndrome diagnosed?

Expert organizations have developed criteria to diagnose metabolic syndrome. Criteria include:

• Abdominal obesity
• BMI above 25
• High triglycerides
• Low HDL cholesterol
• High blood pressure or using medicine to lower blood pressure
• High fasting blood glucose
• Increased blood clotting. This means you have more plasma plasminogen activator and fibrinogen, which cause blood to clot.
• Insulin resistance. This means you have type 2 diabetes, impaired fasting glucose, or impaired glucose tolerance. The impaired glucose tolerance test measures the body's response to sugar.

Each organization has its own guidelines for using the above criteria to diagnose metabolic syndrome. 

How is metabolic syndrome treated?

Your healthcare provider will figure out the best treatment for you based on:

• How old you are
• Your overall health and past health
• How sick you are
• How well you can handle specific medicines, procedures, and therapies
• How long the condition is expected to last
• Your opinion or preference

Because metabolic syndrome increases the risk of developing more serious long-term (chronic) conditions, getting treatment is important. Without treatment, you may develop cardiovascular disease and type 2 diabetes. Other conditions that may develop as a result of metabolic syndrome include:

• Polycystic ovarian syndrome (PCOS)
• Fatty liver
• Cholesterol gallstones
• Asthma
• Sleep problems
• Some forms of cancer

Here are the types of treatment that may be recommended for metabolic syndrome.

Lifestyle management

Treatment usually involves lifestyle changes. This means losing weight, working with a dietitian to change your diet, and getting more exercise. Losing weight increases HDL ("good") cholesterol and lowers LDL ("bad") cholesterol and triglycerides. Losing weight can also reduce the risk for type 2 diabetes.

Losing even a modest amount of weight can lower blood pressure and increase sensitivity to insulin. It can also reduce the amount of fat around your middle. Diet, behavioral counseling, and exercise lower risk factors more than diet by itself.

Other lifestyle changes include quitting smoking and cutting back on the amount of alcohol you drink.

Diet

Changes in diet are important in treating metabolic syndrome. According to the AHA, treating insulin resistance is the key to changing other risk factors. In general, the best way to treat insulin resistance is by losing weight and getting more physical activity. You can do this by doing the following:

• Include a variety of foods in your diet.
• Use healthy fats. Polyunsaturated and monounsaturated fats may help keep your heart healthy. These healthy fats are found in nuts, seeds, and some types of oils, such as olive, safflower, and canola.
• Choose whole grains such as brown rice and whole-wheat bread instead of white rice and white bread. Whole-grain foods are rich in nutrients compared with more processed foods. Whole grains are higher in fiber, so the body absorbs them more slowly. They do not cause a rapid spike in insulin, which can trigger hunger and cravings. The 2015-2020 Dietary Guidelines from the USDA recommend that at least half of your grains be whole-grains.
• Eat more fruits and vegetables. According to the 2015-2020 Dietary Guidelines, a person on a 2,000-calorie-per-day diet should eat 2.5 cups of vegetables and 2 cups of fruit a day. This amount will vary depending on how many calories you need. Be sure to choose a variety of fruits and vegetables. Different fruits and vegetables have different amounts and types of nutrients.
• When eating out, take part of your restaurant meal home. When dining out or ordering take-out food, ask for a take-home box or avoid super-size selections when you order. Many restaurant portions are too large for one person, so consider sharing an entrée. Or order an appetizer instead of a main dish from the entrée menu.
• Read food labels carefully. Pay close attention to the number of servings in the product and the serving size. If the label says a serving is 150 calories but the number of servings per container is 3 and you eat the entire container, you are getting 450 calories. Choose foods that are low in added sugar.

Exercise

Exercise helps people who are overweight or obese by helping to keep and add lean body mass, or muscle tissue, while losing fat. It also helps you lose weight faster than just following a healthy diet because muscle tissue burns calories faster.

• Walking is a great exercise for just about anyone. Start slowly by walking 30 minutes daily for a few days a week. Gradually add more time so that you are walking for longer periods most days of the week.
• Exercise lowers blood pressure and can help prevent type 2 diabetes. Exercise also helps you feel better emotionally, reduces appetite, improves sleep, improves flexibility, and lowers LDL cholesterol.
• Talk with your healthcare provider before starting any exercise program.

Medicine

People who have metabolic syndrome or are at risk for it may need to take medicine as treatment. This is especially true if diet and other lifestyle changes have not made a difference. Your doctor may prescribe medicine to help lower blood pressure, improve insulin metabolism, lower LDL cholesterol and raise HDL cholesterol, increase weight loss, or some combination of these.

Weight-loss surgery

Weight-loss surgery (bariatric surgery) is an effective treatment for morbid obesity in people who have not been able to lose weight through diet, exercise, or medicine. It may also help people who are less obese but who have significant complications from their obesity.

• Studies have shown that gastric bypass surgery helped lower blood pressure, cholesterol, and body weight at one year after the procedure.
• Weight-loss surgery can be done in several ways, but all are either malabsorptive, restrictive, or a combination of the two. Malabsorptive procedures change the way the digestive system works. Restrictive procedures are those that greatly reduce the size of the stomach. The stomach then holds less food, but the digestive functions remain intact.

What are the complications of metabolic syndrome?

Metabolic syndrome greatly raises the risk of developing diabetes, heart disease, stroke, or all three.

Can I prevent metabolic syndrome?

The best way to prevent metabolic syndrome is to maintain a healthy weight, eat a healthy diet, and be physically active. Your diet should have little salt, sugars, solid fats, and refined grains.

Living with metabolic syndrome

Metabolic syndrome is a lifelong condition that will require changes in your lifestyle. If you already have heart disease or diabetes, follow your healthcare provider’s recommendations for managing these conditions. 

Lifestyle changes involved in managing metabolic syndrome include:

• A healthy diet
• Physical activity and exercise
• Stopping smoking if you’re a smoker or use other tobacco products
• Losing weight if you are overweight or obese

Key points about metabolic syndrome

• Metabolic syndrome is a condition that includes a cluster of risk factors specific for cardiovascular disease.
• The cluster of metabolic factors include abdominal obesity, high blood pressure, impaired fasting glucose, high triglyceride levels, and low HDL cholesterol levels.
• Metabolic syndrome greatly raises the risk of developing diabetes, heart disease, stroke, or all three.
• Management and prevention of metabolic syndrome include maintaining a healthy weight, eating a healthy diet, eliminating the use of cigarettes or other tobacco products, and being physical active.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

• Know the reason for your visit and what you want to happen.
• Before your visit, write down questions you want answered.
• Bring someone with you to help you ask questions and remember what your provider tells you.
• At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.
• Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.
• Ask if your condition can be treated in other ways.
• Know why a test or procedure is recommended and what the results could mean.
• Know what to expect if you do not take the medicine or have the test or procedure.
• If you have a follow-up appointment, write down the date, time, and purpose for that visit.
• Know how you can contact your provider if you have questions.