Metabolic Syndrome Explained

Metabolic syndrome, also known as Metabolic Syndrome X, Syndrome X, or Insulin Resistance, is characterized by three or more of five metabolic changes, leading to significant cardiometabolic risk, increased risk of multiple cancers, and fatty liver disease. Recognizing these abnormalities and understanding their root causes is crucial.

There are 5 criteria for Metabolic Syndrome. This condition is present when 3 or more of the criteria are present. The criteria inclusion criteria are:

Increased waist circumference / abdominal obesity
Hypertension
High triglycerides
Low HDL
Insulin Resistance (IR)

Currently, only 6.8% of adults in the U.S. have none of the five findings associated with metabolic syndrome. Insulin resistance is absent in just 12% of adults, meaning it’s present in 88%. Alarmingly, about one-third of U.S. teens have prediabetes or insulin resistance.

Examples: A person with high blood pressure, a larger waist, and prediabetes has metabolic syndrome. Another individual with high triglycerides, low HDL, and high blood pressure also meets the criteria for metabolic syndrome. However, a person with only low HDL and hypertension does not have metabolic syndrome.

Let's look at each of the possible criteria separately.

Measure waist circumference — Men often rely on pant waist size, which may underestimate their waist circumference, especially if they have a belly that hangs over their pants. The measurement should be taken at the center of the belly button or the widest area of the abdomen.

Increased Waist Circumference (WC)

Increased waist circumference (WC) is defined as greater than 35 inches for women and 40 inches for men in the U.S. However, for individuals of Asian and Hispanic descent, the cutoff is lower—greater than 31 inches for women and 35 inches for men.

Proper waist measurement is important—no breath-holding or sucking in! Measure at the belly button or the widest area, below the ribcage and above the hips.

Hypertension

A normal blood pressure (BP) is below 120/80. While 120/80 is often called "normal," it’s actually slightly elevated—the highest normal BP is 119/79. For metabolic syndrome, BP must be ≥130/85 or require hypertension medication. If either the systolic (top number) or diastolic (bottom) number is elevated, it qualifies as hypertension.

A person has hypertension if their systolic BP is elevated, even if the diastolic is always under 85 (e.g., 132/80, 136/72, 140/75). The same applies if the diastolic is high while the systolic is normal (e.g., 120/90, 124/86, 120/85). Someone taking medication with readings like 110/70 still has hypertension—it’s controlled, not cured.

High Triglycerides (TG)

Triglycerides are part of a standard cholesterol panel and should be measured after at least 8 hours of fasting, as nonfasting levels are typically high. Elevated triglycerides are an early sign of insulin resistance, with levels ≥150 considered high.

Low High Density Lipoprotein (HDL) Cholesterol

High density lipoprotein cholesterol (HDL-C or HDL) is part of a standard cholesterol panel. Fasting doesn’t affect HDL levels, but since triglycerides require fasting, the test is usually done after 8+ hours without food. Low HDL, like high triglycerides, is an early sign of insulin resistance. HDL levels are sex-based: below 50 is low for women, and below 40 is too low for men.

Insulin Resistance (IR)

Insulin resistance is defined if any of the following are present:

prediabetes
T2DM (type 2 diabetes mellitus)
Fasting blood glucose (FBG) ≥ 100
A1c ≥ 5.7%
elevated fasting insulin level (at least ≥12)
presence of medication for the above conditions (in some classification systems)

As with hypertension, lowering blood glucose with medication may normalize FBG and A1c. This controls these numbers, but it does not control insulin levels or IR, and it certainly does not cure these conditions.

As with hypertension, when a person takes a medication to lower blood glucose levels, the treatment results in numbers such as FBG and A1c normalizing. This does not mean the person is cured of IR; it is only controlled.

What is the cause of Metabolic Syndrome?

The root cause of all five criteria of metabolic syndrome is insulin resistance. Anything that raises insulin levels worsens resistance, creating a cycle. IR stems from chronic stress, inflammation, high insulin levels, high cortisol levels, and a high-carb diet. Under insulin's influence, dysfunctional adipose tissue disrupts hormones, raising aldosterone, which results in increased blood pressure as well as releasing other inflammatory messages.. Dysfunctional adipose tissue also has a lower metabolic rate and retains fat. Consider IR to be the driver of metabolic syndrome and chronic diseases.