Blood Sugar: A Cardiac Risk Factor?

by William Davis, M.D. Health Professional

Study after study has established this fact: The higher your blood sugar, the higher your risk for heart disease. The extreme instance of high blood sugars contributing to heart disease can be found, of course, in people with diabetes. But you don't have to be diabetic for blood sugar to act as a coronary risk factor.

In fact, blood sugar can be well below the diabetic range yet contribute to increased risk. Take the 33-year long, 18,000-participant Whitehall Study of male British civil servants. All participants were given 50 grams of glucose and blood sugar measured 2 hours later. What blood sugar after the glucose challenge was associated with increased heart attack? An incredible 83 mg/dl. Interestingly, much of the increased risk from higher blood sugars did not become evident until 5-10 years after the study began, seen because of the unusually long timeline of the observation. It also suggests that studies conducted over shorter periods might not fully reveal the cardiovascular risk of high blood sugars.

How about fasting blood sugar? The Baltimore Longitudinal Aging Study and the Hoorn Study both showed that risk begins to increase at a fasting blood sugar of 93 mg/dl, increasing sharply at 110 mg/dl and above. Blood sugars as low as 110 mg/dl are associated with other coronary risk factors, including inflammatory measures like C-reactive protein.

Even the conservative American Diabetes Association (ADA) labels blood sugars above 100 mg/dL "impaired fasting glucose."

If you are concerned about your blood sugar, it is an easy matter nowadays to check your own blood sugar. (See my prior post, You don't have to be diabetic to check your blood sugar.) You can check blood sugars first thing in the morning ("fasting") or 1-2 hours after a meal ("postprandial").

Higher blood sugars, both fasting and postprandial, are not just coronary risk factors, but are most powerfully associated with potential for developing diabetes in the future.

What steps can you take to reduce your blood sugars, both fasting and postprandial? Here's a starting list:

  • Reduce carbohydrates - Carbohydrates increase blood sugar, regardless of type. While conventional wisdom says that low-glycemic index foods, like pasta and whole grains, are desirable, in truth, they increase blood sugar considerably. Reducing carbohydrates is among the most powerful strategies available for reducing blood sugar. You will readily witness this if you monitor your own blood sugars.

  • Lose weight - Reducing carbohydrates leads to weight loss which, in turn, leads to reduced blood sugar. The effect can be powerful enough to turn many diabetics (adult type) into non-diabetics.

  • Exercise - Anyone with diabetes will tell you that blood sugars plummet after physical activity or exercise. Frequent moderate exercise is all it requires.

  • Adequate sleep-Sleep deprivation increases stress hormones that counteract insulin, thereby increasing blood sugar. Getting adequate sleep as often as possible helps control blood sugar, as well as adding years to your life.

  • Cinnamon - Though study results have varied, most have shown a blood sugar-reducing effect. There's also some debate over whether the Ceylon variety or the more common Cassia are preferable, but positive results have been observed with both. It takes only
    ¼ teaspoon or less to obtain these results. Cinnamon is believed to exert insulin-like effects and to slow stomach emptying, slowing the release of sugars into the blood stream.

  • Vinegar - Adding vinegar (standard, apple cider, rice, balsamic) to a meal causes substantial slowing of stomach emptying, thereby extending the time for sugar absorption.

The lesson to learn here is that blood sugars that are only marginally increased, even in the 90s and low 100s, can increase long-term risk for heart disease. Checking your blood sugars and keeping them low, e.g., below 100 mg/dl, can help reduce or eliminate this source of heart disease risk.

William Davis, M.D.
Meet Our Writer
William Davis, M.D.

William R. Davis is a Milwaukee-based American cardiologist and author. He wrote for HealthCentral as a health professional for Heart Health and High Cholesterol.