What is metabolic syndrome?

Everything you need to know about metabolic syndrome, including how to tell if you’re at risk and the best ways to prevent it.

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When metabolic health is compromised, several serious symptoms can emerge.

Metabolic syndrome is a cluster of metabolic health risk factors that can significantly increase the risk of diseases, including cancer, heart disease, neuro-cognitive disorders like dementia, and Type 2 diabetes. People with metabolic syndrome also are more likely to experience chronic, low-grade, systemic inflammation, which may increase the risk of severe outcomes, including flu and COVID-19

Alarmingly, between 2011-2016, nearly 50 percent of people in the US over the age of 60 had metabolic syndrome. And due to the rising rates of overweight and obesity, the prevalence is increasing among adolescents as well. Before diagnosis, a person typically receives a series of other diagnoses—for high blood pressure or high blood sugar, for instance—that indicate underlying metabolic dysfunction. 

In the simplest terms, a diagnosis of metabolic syndrome is an urgent sign that one’s metabolic health—the way the body processes and uses energy and nutrients from the food we eat—is dysfunctional, and without changes, health risks increase. For clinicians, a diagnosis of metabolic syndrome serves as a guide, prompting a search for additional risk factors and triggering specific treatment protocols; for patients, a diagnosis may be a powerful motivator to make necessary lifestyle shifts to lower their risk of disease.

What is Metabolic Syndrome?

Metabolic syndrome is a group of five risk factors that can significantly elevate a person’s risk of chronic diseases like Type 2 diabetes, heart disease, and cancer. Having at least three of the following in the US will lead to a diagnosis (other countries have different criteria):

  • A waist circumference over 40 inches for men and 35 inches for women
  • High triglycerides (over 150 mg/dL) or taking medication for high triglycerides
  • Low high-density lipoprotein (HDL) cholesterol (under 40 mg/dL for men and 50 mg/dL for women) or taking medication for low HDL cholesterol
  • High blood pressure (130 mm Hg systolic or greater or 85 mm Hg diastolic or greater) or taking medication for high blood pressure
  • High fasting blood glucose (100 mg/dL or greater) or taking medication for high blood glucose

Having just one of these factors could cause concern, but the chance of disease increases significantly with each additional risk factor. For instance, in one study, people with normal fasting glucose and two risk factors for metabolic syndrome were more than four times more likely to develop Type 2 diabetes over a five-year median follow up period, and those with four risk factors were about 10 times more likely to develop it, compared to people with no risk factors.



What causes metabolic syndrome?

“One underlying cause of metabolic syndrome is insulin resistance or a condition called hyperinsulinemia,” says Bret Scher, MD, a cardiologist based in San Diego and medical director of DietDoctor.com. In people with insulin resistance, the process of glucose metabolism is dysfunctional. Normally, the digestive system breaks down food into amino acids from protein, fatty acids from fats, and glucose and other sugars from carbohydrates. The pancreas produces insulin to help move glucose into the cells so it can be used as fuel to propel other processes. Insulin resistance occurs when cells don’t recognize or respond to insulin as efficiently, leaving more glucose to circulate in the bloodstream or taking longer to normalize blood sugar. That triggers more insulin production, leading to hyperinsulinemia, a condition in which insulin levels in the blood are elevated.

Overweight and obesity are closely linked to metabolic syndrome, but “what matters more is where you’re carrying that excess weight,” says Dr. Scher. “Abdominal obesity is more predictive of poor metabolic health than simply being overweight.” The reason for this is threefold: Visceral fat (the type that wraps around your internal organs) impairs liver function, increasing glucose intolerance; it produces inflammatory compounds, which increase insulin resistance and high blood pressure; and it’s a general marker for excess body fat. 

Recent research in 12,047 adults highlights that even normal-weight people with metabolic syndrome still face a significantly higher mortality risk than people without metabolic syndrome, regardless of their weight. In the follow-up study period, cardiovascular issues were the leading cause of death among people with metabolic syndrome, and being normal weight didn’t reduce that mortality risk. According to the study authors, “Although obesity is a well-known risk factor for poor metabolic health, metabolic health issues such as insulin resistance and diabetes risk also affect normal-weight people.” And weight doesn’t always reflect metabolic health; other research shows that normal-weight people with more body fat are more likely to have metabolic syndrome. Abdominal obesity is more commonly attributed as a top-three risk factor in women compared to men. 

Am I at risk for metabolic syndrome?

As of 2016, 88% of the US population had at least one metabolic risk factor, but some people are more likely to develop metabolic syndrome. At the greatest risk are those with abdominal obesity, a sedentary lifestyle, and insulin resistance. People with a family history of diabetes and women who have had diabetes during pregnancy are also at a higher risk. Age factors in as well. “Metabolic syndrome tends to be more common in men at younger ages and women in older ages,” says Dr. Scher. Women’s risk increases after menopause, when estrogen declines, along with the cardiovascular protection that may come with it.

Race and ethnicity also appear to play a role; the syndrome is most common among people of Hispanic ethnicity. People of Asian descent are predisposed to insulin resistance and metabolic syndrome], and both South and East Asians tend to have more body fat and less muscle. “Muscle cells are more metabolically active than fat,” explains Dr. Scher, absorbing more glucose from the bloodstream. “They can also use glucose in ways that don’t depend on insulin.” 

The simplest way to know if you’re at risk is to calculate your waist-height ratio to determine if you’re carrying too much weight, specifically around your midsection, says Dr. Scher. To do that, measure your waistline one inch above your belly button and divide that number in inches by your height in inches. If the number is greater than 0.5, you’re at risk (though it’s worth noting that this threshold doesn’t hold up as well in non-European populations). 

Also, see your primary care physician for a complete checkup to help determine your metabolic health. Get your blood pressure, fasting glucose, and HDL cholesterol levels checked. Specific blood tests can also measure several other markers that point to poor metabolic function, such as hemoglobin A1c, which estimates glucose control over the previous three months, and C-reactive protein, which measures inflammation. Ask your physician for all these results.

Bear in mind, however, that your medical provider may only raise concerns if your blood test results are outside the “normal” range for your age and gender. What is optimal for preventing disease is still a matter of debate. For a comprehensive review of what Levels advisors recommend in interpreting your cholesterol panel and metabolic blood tests, read more here.  

I’m high risk but haven’t been diagnosed. How can I prevent metabolic syndrome?

The first defense against metabolic syndrome is to reduce excess weight and improve glucose metabolism. That starts with improving your diet, says Dr. Scher. Exercise and sleep are also crucial. Here are four steps you can take to strengthen metabolic health:

  • Lose weight, if you need to. Weight loss is one of the most effective ways to improve insulin sensitivity and reduce other biomarkers for metabolic disease. But just cutting calories isn’t the answer because you’ll end up losing muscle as well as fat. When University of California, Los Angeles researchers analyzed 31 long-term weight loss studies, they found that calorie-restricted diets that fail to prioritize nutrition and food quality simply don’t work. What does: moderately reducing calories, choosing whole foods low in carbs and sugar to avoid fluctuations in blood sugar and insulin, and exercising more. Dr. Scher’s advice: “Burn body fat through increased exercise, and consume foods that provide adequate nutrition and protein while controlling your hunger and minimizing high-glycemic carbohydrates so you don’t overeat.”
  • Eat better. To treat and prevent metabolic syndrome, the American Heart Association recommends a diet rich in fruits, vegetables, whole grains, skinless poultry, fish, nuts, lean meats, and vegetable protein. This is consistent with research supporting the health benefits of a Mediterranean diet. Studies also show that high glycemic variability (or frequent blood sugar spikes) are associated with poor health outcomes, so it may be advisable to avoid sugar and refined grains. But because glucose responses to foods are highly individual, it’s hard to pin down a one-size-fits-all approach; personal nutrition may be vital in reversing metabolic dysfunction.
  • Get moving. Exercise improves insulin sensitivity and reduces inflammatory compounds that promote disease. Experts recommend 150 minutes of moderate exercise or 75 minutes of intense exercise a week. But if you’re not hitting that goal, don’t stress. “Doing a little [exercise] is better than doing none,” says Dr. Scher. Walking is a good place to start. If you’re short on time, quick, high-intensity workouts (HIIT) can help you reap significant health benefits in less time. In a 2018 study, researchers evaluated the effects of three weekly HIIT workouts on the metabolic health of 22 men and women between the ages of 62 and 64. Each workout consisted of five 1-minute cycling intervals interspersed with 1 1/2 minutes of rest (plus a 2-minute warm-up) for a total exercise time of less than 15 minutes. The results were remarkable: reduced body fat, less visceral fat, lower LDL cholesterol, and increased insulin sensitivity after just six weeks. If HIIT sounds too strenuous, Dr. Scher recommends any type of resistance training, such as pushups, squats, resistance band workouts, Ashtanga yoga, or Pilates. 
  • Manage stress. Chronic stress exacerbates several markers for metabolic syndrome, including high blood pressure, weight gain (especially in women, though experts don’t know why), and Type 2 diabetes (particularly among men). Start by taking a hard look at your job. People who experience stress at work are more than twice as likely to develop metabolic syndrome as those who don’t have a stressful work life. Recent research has also linked a variety of other stressors to poor metabolic health, including psychological distress (such as anxiety or depression) and marital dissatisfaction. One study found that women in unhappy marriages were 10 times more likely to develop metabolic syndrome. Cognitive-behavioral therapy and mindfulness (such as meditation, breathing exercises, and yoga) can help you learn to self-regulate your emotional reaction to chronic stressors. 
  • Get the right amount of quality sleep. A 2021 review of research involving 300,202 patients found people with short sleep and long sleep had significantly increased risk of metabolic syndrome. Even one night of sleep deprivation reduces insulin sensitivity. Between seven and eight hours of sleep is considered optimal for metabolic health, according to a 2015 meta-analysis involving more than 480,000 participants.

How might metabolic syndrome affect my life? What health problems or complications might develop?

Metabolic syndrome is a serious condition that significantly raises your risk of several health issues, including heart disease, Type 2 diabetes, and stroke. These three conditions are in the top 10 leading causes of death for Americans, and they can also lead to disability and reduced mobility, which can significantly impact your quality of life as you get older.

How is metabolic syndrome treated?

The immediate goal of traditional clinical treatment for metabolic syndrome is to reduce the risk of heart disease and diabetes. Treatments include:

  • Medication: Controlling each underlying condition with prescription medication is the first line of defense. “By the time someone is diagnosed with metabolic syndrome, they are usually taking many different medications” to lower blood pressure, blood sugar, and cholesterol, says Dr. Scher. 
  • Lifestyle changes: Medications control the symptoms, but they don’t address the underlying cause of disease. That’s where making changes to your lifestyle comes in. The lifestyle behaviors that treat metabolic syndrome are the same as the prevention tactics listed above. Diet, exercise, stress management, and sleep are all key.
  • Health monitoring: Your primary care provider may recommend that you also see an endocrinologist, a cardiologist, or a doctor who specializes in treating diabetes. That physician will set up a schedule of medical visits to track your condition. Between visits, you can self-monitor by keeping tabs on your weight and waist circumference, using a blood glucose monitor, and checking your blood pressure. Ask your doctor about the specific monitoring actions you should take.