Posted on March 21, 2025 - 2:55 am by Ali Chappell

Insulin and Heart Disease: The Link We Have Been Ignoring

We talk a lot about heart disease being the #1 killer, but not enough people are talking about why it happens. Sure, you’ve heard about cholesterol, high blood pressure, and even genetics—but there’s a missing piece. And that missing piece is insulin.

Most people think insulin is just about blood sugar and diabetes. But in reality, high insulin levels, even before blood sugar becomes a problem, affect every major system in your body—including your heart.

The 1966 Warning We Ignored

Back in 1966, a study published in The Lancet, one of the most prestigious medical journals, identified elevated insulin levels as the strongest independent predictor of heart disease.

Yes, you read that right.

We’ve known for almost 60 years that high insulin levels are directly linked to heart disease, but most cardiologists today still don’t test fasting insulin. In fact, many of them don’t even know it can be measured.

Instead, we still treat symptoms like cholesterol, blood pressure, and inflammation—without ever asking what’s causing those issues in the first place.

High Insulin and Blood Pressure

Insulin affects your kidneys and how they retain sodium. When insulin is elevated, your kidneys hold on to more sodium, which causes water retention and increases blood pressure. This is why people with insulin resistance often have salt sensitivity or feel bloated after salty foods.

But it’s not just about water retention. Insulin also tightens your blood vessels—literally making them narrower. This raises your blood pressure even further.

High Insulin and Cholesterol

You may have been told that your cholesterol is high, especially your triglycerides. But high triglycerides are one of the strongest signs of insulin resistance. At the same time, insulin resistance tends to lower HDL—the “good” cholesterol—and increase the number of small, dense LDL particles, which are more dangerous than regular LDL.

So if your triglycerides are high and your HDL is low, it’s not just a cholesterol problem—it’s an insulin problem.

High Insulin and Inflammation

Insulin is a growth hormone. When it’s chronically elevated, it causes low-grade inflammation throughout the body. This inflammation damages the lining of your blood vessels and sets the stage for plaque buildup and cardiovascular disease.

We often hear about “inflammation” as this vague thing you need to reduce. But insulin is one of the root causes—yet very few people are looking at it.

The Silent Role of Insulin in Heart Attacks and Strokes

When you combine water retention, narrowed arteries, cholesterol changes, and inflammation, you get the perfect storm: increased risk of heart attack and stroke.

Insulin is the common thread that runs through all of it.

Why Aren’t We Testing for It?

That’s the million-dollar question.

There is no standardized range for insulin, and some labs still call levels in the 20s or even 30s “normal.” Many providers were never trained to look at insulin or understand its role outside of diabetes.

But insulin can be tested—and should be. Fasting insulin should be under 8 mIU/mL. Yet most people walking around with levels in the teens or twenties are told they’re “fine.”

What You Can Do

Ask your provider to test your fasting insulin and triglyceride-to-HDL ratio
Focus on lowering insulin naturally with a Low Insulin Lifestyle
Don’t just accept prescriptions for blood pressure or cholesterol without addressing the root cause

The Bottom Line

If we truly want to prevent heart disease—not just manage it—then we have to start looking upstream at what’s causing all the damage in the first place.

And more often than not, that root cause is insulin.