More than 40 percent of North American adults are seriously overweight, which puts them at high risk for heart attacks, diabetes, certain cancers and premature death (Population Studies, Feb 9, 2023;77(1)). Researchers at Boston University have explained how being obese is a major cause of heart attacks and death from heart attacks by preventing the bad LDL (Low Density Lipoprotein) cholesterol from performing its beneficial functions such as helping to form cell membranes (J Lipid Res, Sep 28, 2023;100451).
Obesity prevents cholesterol from being deposited where you need it and sends it into arteries where it can form plaques that eventually may break off to cause heart attacks. Obesity can also overstimulate your immune system to cause a host of diseases.
How Obesity Raises LDL Cholesterol
Cholesterol is a fat that is insoluble in the bloodstream, so the only way that the fatty cholesterol can be carried in the bloodstream is inside balls called lipoproteins. The lipoprotein ball called LDL cholesterol has major beneficial functions to supply cholesterol to:
• all the cells in your body, because cholesterol is necessary to make cell membranes
• your liver to make bile
• your glands to make many different hormones including your sex hormones, parathyroid hormones and other hormones
• kidneys to control urine production
• skin to make vitamin D
• immune system to make cells and cytokines to kill invading germs
Your liver can make all the cholesterol you need, but most people get about 20 percent or more of their cholesterol from their food. Eating foods with saturated fat and added sugars can raise blood cholesterol levels so high that you are at increased risk for suffering heart attacks, strokes and some types of cancers. Most adults should restrict saturated fats (meat, milk, egg yolks, cheese, butter), foods and drinks with added sugars, and many other packaged processed foods and fast foods that will raise LDL cholesterol.
HDL cholesterol is a lipoprotein ball that helps shuttle extra cholesterol from your bloodstream into your liver, which breaks down cholesterol and flushes it from your body.
How Obesity Causes Inflammation
The study from Boston University demonstrated that obesity causes an overactive immune system (inflammation) that shifts the beneficial deposition of cholesterol from tissues that need and use it into arterial walls that form plaques and immune cells that cause inflammation. In this study, obese people had bariatric surgery to decrease food absorption and were tested 6 and 12 months later. They were found to have lost a lot of weight, inflammation decreased and blood level of LDL cholesterol dropped significantly (J Lipid Res, Sep 28, 2023;100451).
Losing Fat Can Markedly Lower LDL Cholesterol
LDL cholesterol balls are supposed to deposit their cholesterol into normal LDL receptors in cells to offer lots of health benefits. However, in obese people, the high fat content in their cells prevents LDL cholesterol from delivering cholesterol to normal LDL receptors that cells need to form healthy cells. Instead, the LDL deposited cholesterol into two scavenger receptors that can cause excess and harmful cholesterol to accumulate in arteries to form plaques that can break off to cause heart attacks. As patients continued to lose weight, the LDL lipoprotein ball improved its ability to deposit cholesterol into normal LDL receptors in cells so they could function more normally.
If you are overweight, you have many ways available to reach a more healthful weight. Check with your doctor to see if you have medical problems that need treatment, and then make the lifestyle changes that will help you lose weight:
• Join an exercise group or set up a home exercise program
• Get advice on a healthful diet
• Participate in groups of people with similar weight loss goals
• Talk to your doctor about weight loss drugs, including the latest ones that are proving successful for some people. Also discuss drugs to lower cholesterol, high blood pressure and clotting. If you are extremely obese, you may want to discuss weight loss surgery.
Gabe Mirkin, M.D., is a sports medicine doctor and fitness guru. A practicing physician for more than 50 years and a radio talk show host for 25 years, Dr. Mirkin has run more than 40 marathons and is now a serious tandem bike rider with his wife, Diana. His website is http://drmirkin.com/. Click to read Gabe’s full bio.