Mayo Clinic Health Library

Metabolic syndrome

Updated: 04-05-2013

Definition

Metabolic syndrome is a cluster of conditions — increased blood pressure, a high blood sugar level, excess body fat around the waist and abnormal cholesterol levels — that occur together, increasing your risk of heart disease, stroke and diabetes.

Having just one of these conditions doesn't mean you have metabolic syndrome. However, any of these conditions increase your risk of serious disease. If more than one of these conditions occur in combination, your risk is even greater.

If you have metabolic syndrome or any of the components of metabolic syndrome, aggressive lifestyle changes can delay or even prevent the development of serious health problems.

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Symptoms

Having metabolic syndrome means you have three or more disorders related to your metabolism at the same time, including:

  • Obesity, with your body fat concentrated around your waist (having an "apple shape"). For a metabolic syndrome diagnosis, obesity is defined by having a waist circumference of 40 inches (102 centimeters or cm) or more for men and 35 inches (89 cm) or more for women, although waist circumference cutoff points can vary by race.
  • Increased blood pressure, meaning a systolic (top number) blood pressure measurement of 130 millimeters of mercury (mm Hg) or more or a diastolic (bottom number) blood pressure measurement of 85 mm Hg or more.
  • High blood sugar level, with a fasting blood glucose test result of 100 milligrams per deciliter (mg/dL), or 5.6 millimoles per liter (mmol/L), or more.
  • High cholesterol, with a level of the blood fat called triglycerides of 150 mg/dL (1.7 mmol/L) or more and a level of high-density lipoprotein (HDL) cholesterol — the "good" cholesterol — of less than 40 mg/dL (1.04 mmol/L) for men or less than 50 mg/dL (1.3 mmol/L) for women.

Having one component of metabolic syndrome means you're more likely to have others. And the more components you have, the greater are the risks to your health.

When to see a doctor
If you know you have at least one component of metabolic syndrome — such as high blood pressure, high cholesterol or an apple-shaped body — you may have the others and not know it. It's worth checking with your doctor. Ask whether you need testing for other components of the syndrome and what you can do to avoid serious diseases.

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Causes

Metabolic syndrome includes several symptoms that have different causes.

Insulin resistance
Metabolic syndrome is linked to your body's metabolism, possibly to a condition called insulin resistance. Insulin is a hormone made by your pancreas that helps control the amount of sugar in your bloodstream.

Normally, your digestive system breaks down the foods you eat into sugar (glucose). Your blood carries the glucose to your body's tissues, where the cells use it as fuel. Glucose enters your cells with the help of insulin. In people with insulin resistance, cells don't respond normally to insulin, and glucose can't enter the cells as easily. As a result, glucose levels in your blood rise despite your body's attempt to control the glucose by churning out more and more insulin. The result is higher than normal levels of insulin in your blood. This can eventually lead to diabetes when your body is unable to make enough insulin to keep the blood glucose within the normal range.

Even if your levels aren't high enough to be considered diabetes, an elevated glucose level can still be harmful. In fact, some doctors refer to this condition as "prediabetes." Increased insulin resistance raises your triglyceride level and other blood fat levels. It also interferes with how your kidneys work, leading to higher blood pressure. These combined effects of insulin resistance put you at risk of heart disease, stroke, diabetes and other conditions.

Combination of factors
Insulin resistance probably involves a variety of genetic and environmental factors. Some people may be genetically prone to insulin resistance. But being overweight and inactive are major contributors.

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Risk factors

The following factors increase your chances of having metabolic syndrome:

  • Age. Your risk of metabolic syndrome increases with age, affecting less than 10 percent of people in their 20s and 40 percent of people in their 60s. However, warning signs of metabolic syndrome can appear during childhood.
  • Race. Hispanics and Asians seem to be at greater risk of metabolic syndrome than are people of other races.
  • Obesity. A body mass index (BMI) — a measure of your percentage of body fat based on height and weight — greater than 25 increases your risk of metabolic syndrome. So does abdominal obesity — having an apple shape rather than a pear shape.
  • History of diabetes. You're more likely to have metabolic syndrome if you have a family history of type 2 diabetes or a history of diabetes during pregnancy (gestational diabetes).
  • Other diseases. A diagnosis of high blood pressure, cardiovascular disease, nonalcoholic fatty liver disease or polycystic ovary syndrome — a similar type of metabolic problem that affects a woman's hormones and reproductive system — also increases your risk of metabolic syndrome.
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Complications

Having metabolic syndrome can increase your risk of developing these conditions:

  • Diabetes. If you don't make lifestyle changes to control your insulin resistance, your glucose levels will continue to increase. You may develop diabetes as a result of metabolic syndrome.
  • Cardiovascular disease. High cholesterol and high blood pressure can contribute to the buildup of plaques in your arteries. These plaques can cause your arteries to narrow and harden, which can lead to a heart attack or stroke.
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Preparing for your appointment

You're likely to start by seeing your family doctor or a general practitioner. However, in some cases when you call to set up an appointment, you may be referred immediately to an endocrinologist, who specializes in diabetes, among other disorders, or a cardiologist, who specializes in heart disease.

Because appointments can be brief, and because there's often a lot of ground to cover, it's a good idea to be well prepared for your appointment. Here's some information to help you get ready for your appointment and what to expect from your doctor.

What you can do

  • Be aware of any pre-appointment restrictions. At the time you make the appointment, ask if there's anything you need to do in advance. This might include restricting your diet, such as for a fasting blood sugar test or a cholesterol test.
  • Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.
  • Write down key personal information, including any major stresses or recent life changes. If you're monitoring your blood sugar or blood pressure at home, bring a record of the results, detailing the dates and times of testing.
  • Make a list of all medications, vitamins or supplements that you're taking.
  • Record your family medical history. In particular, note any relatives who have had diabetes, heart attacks or strokes.
  • Take a family member or friend along, if possible. Sometimes it can be difficult to recall all the information provided to you during an appointment. Someone who accompanies you may remember something that you missed or forgot.
  • Write down questions to ask your doctor. Be clear about aspects of your diabetes or blood pressure management that you need clarification on.

Your time with your doctor is limited, so preparing a list of questions will help you make the most of your time together. List your questions from most important to least important in case time runs out. For metabolic syndrome, some basic questions to ask your doctor include:

  • Are the symptoms I'm experiencing now related to metabolic syndrome or another condition?
  • What kinds of tests do I need to best manage my conditions?
  • What else can I do to protect my health?
  • What are other options to manage the conditions causing metabolic syndrome?
  • I have these other health conditions. How can I best manage them together?
  • Are there any restrictions that I need to follow?
  • Should I see another specialist?
  • Is there a generic alternative to the medicine you're prescribing?
  • Are there any brochures or other printed material that I can take home with me?
  • What websites do you recommend visiting?

In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask questions during your appointment at any time.

What to expect from your doctor
Your doctor is likely to ask you a number of questions. Being ready to answer them may reserve time to go over any points you want to spend more time on. Your doctor may ask:

  • When did you first begin experiencing symptoms that concerned you about the possibility that you have diabetes, high blood pressure or abnormal cholesterol levels?
  • Do you have a family history of diabetes, high blood pressure, heart disease or abnormal cholesterol levels?
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Tests and diagnosis

Although your doctor is not typically looking for metabolic syndrome, the label may apply if you have three or more of the traits associated with this condition.

Several organizations have criteria for diagnosing metabolic syndrome. These guidelines were created by the National Cholesterol Education Program with modifications by the American Heart Association. According to these guidelines, you have metabolic syndrome if you have three or more of these traits:

  • Large waist circumference, greater than 35 inches (89 cm) for women and 40 inches (102 cm) for men. Certain genetic risk factors, such as having a family history of diabetes or being of Asian descent — which increases your risk of insulin resistance — lower the waist circumference limit. If you have one of these genetic risk factors, waist circumference limits are 31 inches (79 cm) for women and 35 to 37 inches (89 to 94 cm) for men.
  • A triglyceride level of 150 mg/dL (1.7 mmol/L) or higher, or you're receiving treatment for high triglycerides.
  • Reduced HDL cholesterol ("good" cholesterol) — less than 40 mg/dL (1.04 mmol/L) in men or less than 50 mg/dL (1.3 mmol/L) in women, or you're receiving treatment for low HDL.
  • Increased blood pressure, meaning a systolic (top number) blood pressure measurement of 130 millimeters of mercury (mm Hg) or more or a diastolic (bottom number) blood pressure measurement of 85 mm Hg or more.
  • Elevated fasting blood sugar (blood glucose) of 100 mg/dL (5.6 mmol/L) or higher, or you're receiving treatment for high blood sugar.
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Treatments and drugs

Tackling one of the risk factors of metabolic syndrome is tough — taking on all of them might seem overwhelming. But aggressive lifestyle changes and, in some cases, medication can improve all of metabolic syndrome components. Getting more physical activity, losing weight and quitting smoking help reduce blood pressure and improve cholesterol and blood sugar levels. These changes are key to reducing your risk.

  • Exercise. Doctors recommend getting 30 or more minutes of moderate-intensity exercise, such as brisk walking, every day.
  • Lose weight. Losing as little as 5 to 10 percent of your body weight can reduce insulin levels and blood pressure and decrease your risk of diabetes.
  • Eat healthy. The Dietary Approaches to Stop Hypertension (DASH) diet and the Mediterranean diet, like many healthy-eating plans, limit unhealthy fats and emphasize fruits, vegetables, fish and whole grains. Both of these dietary approaches have been found to offer important health benefits — in addition to weight loss — for people who have components of metabolic syndrome. Ask your doctor for guidance before starting a new eating plan.
  • Stop smoking. Smoking cigarettes increases insulin resistance and worsens the health consequences of metabolic syndrome. Talk to your doctor if you need help kicking the cigarette habit.

Work with your doctor to monitor your weight and your blood glucose, cholesterol and blood pressure levels to ensure that lifestyle modifications are working. If you're not able to reach your goals with lifestyle changes, your doctor may also prescribe medications to lower blood pressure, control cholesterol or help you lose weight. Taking a daily aspirin — after discussing it with your doctor — may help reduce your risk of heart attack and stroke.

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Lifestyle and home remedies

You can do something about your risk of metabolic syndrome and its complications — diabetes, stroke and heart disease. Start by making these lifestyle changes:

  • Lose weight. Losing as little as 5 to 10 percent of your body weight can reduce insulin levels and blood pressure and decrease your risk of diabetes.
  • Exercise. Doctors recommend getting 30 or more minutes of moderate-intensity exercise, such as brisk walking, every day.
  • Stop smoking. Smoking cigarettes increases insulin resistance and worsens the health consequences of metabolic syndrome. Talk to your doctor if you need help kicking the cigarette habit.
  • Eat fiber-rich foods. Make sure you include whole grains, beans, fruits and vegetables in your grocery cart. These items are packed with dietary fiber, which can lower your insulin levels.
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Prevention

Whether you have one, two or none of the components of metabolic syndrome, the following lifestyle changes will reduce your risk of heart disease, diabetes and stroke:

  • Commit to a healthy diet. Eat plenty of fruits and vegetables. Choose lean cuts of white meat or fish over red meat. Avoid processed or deep-fried foods. Eliminate table salt and experiment with other herbs and spices.
  • Get moving. Get plenty of regular, moderately strenuous physical activity.
  • Schedule regular checkups. Check your blood pressure, cholesterol and blood sugar levels on a regular basis. Make additional lifestyle modifications if the numbers are going the wrong way.
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