An article written by two highly-respected physicians and an investigative reporter concludes that, "Emerging evidence shows that insulin resistance is the most important predictor of cardiovascular disease and type 2 diabetes" (Clinical Pharmacist, Jul 14, 2017;9(8)). Another recent article suggests that high blood sugar levels caused by eating sugar-added foods and other refined carbohydrates are the main cause of heart attacks, many cancers and other life-shortening diseases (Br J Sports Med, Aug 5, 2017;51(15):1111-1112), and lists studies that show how diet, exercise, and avoidance of being overweight can both prevent and treat these diseases.
Definition of Insulin Resistance
• Normal: After you eat, your blood sugar is expected to rise. Your pancreas immediately responds by releasing insulin into your bloodstream. The function of insulin is to drive sugar from your bloodstream into cells. Insulin lowers blood sugar quickly by driving sugar from your bloodstream into your liver (Diabetes Care, Nov 2017 ). Insulin should prevent your blood sugar level from rising above a harmful level of 140 mg/ml one hour after you eat.
• Insulin Resistance: Insulin "resistance" means that your pancreas is making plenty of insulin but your cells are not responding to it so your blood sugar levels are staying too high. The most likely reason is that your liver is full of fat so it cannot accept the sugar and blood sugar levels continue to rise (Journal of Clinical Investigation, Sept 26, 2016). Your doctor can tell if your liver is full of fat with an inexpensive test called a liver sonogram (Nutrition, Metabolism & Cardiovascular Diseases, Dec 30, 2015). Your doctor can also measure insulin resistance with a blood test in which you eat a regular meal and then have your blood sugar level checked one hour later. If your blood sugar level is above 140 mg/cc, your liver is not clearing enough sugar from your bloodstream to prevent the sugar from sticking to cell membranes and damaging them (Atherosclerosis, Jan 2017;256:15-20).
When your blood sugar level rises above 140 mg/ml, sugar starts to attach to the outer surface membranes of all types of cells in your body. Once attached, the sugar can never get off the cells. It is converted by a series of chemical reactions eventually to sorbitol that destroys the cells to cause plaques in arteries that increase heart attack risk, damage DNA to increase cancer risk, damage nerves to cause blindness, deafness, impotence and dementia. They can even stick to bone matrices to damage them and cause osteoporosis (J Biol Chem, Sep 10, 1978;253(17):5985-9).
Preventing Insulin Resistance
To prevent insulin resistance, or to reverse it when it is already occurring, limit or avoid the foods that cause the highest rises in blood sugar, including:
• All sugared drinks. The highest rises in blood sugar and thus the most cell damage comes from taking sugared drinks including fruit juices (Am J Clin Nutr, Jun 28, 2017; Curr Opin Cardiol, Sept 2017;32(5):572-579). Solid food remains in your stomach, since only liquid soup can pass into your intestines, but sugared liquids pass into your intestines rapidly with each stomach contraction that follows eating (JAMA, August 25, 2004).
• All foods with added sugars. Foods with added sugars lead to insulin resistance and diabetes by causing a high rise in blood sugar (Clin Sci (Lond), Oct 17, 2017;131(21):2561-2573). When blood sugar levels rise too high, the extra sugar is converted to a fat called triglycerides. Then the good nascent HDL carries the triglycerides to the liver to increase risk for a fatty liver that causes diabetes.
• Foods made from flour (ground whole grains). When grains are eaten whole (intact seeds) they are broken down and digested slowly, but grinding them to make flour allows them to be rapidly absorbed in the intestines to increase blood sugar levels. Foods made from corn flour, rice flour and other wheat substitutes cause the same high rise in blood sugar as products made from wheat flour. The highest rises in blood sugar levels after eating flour occur in people who are overweight, pre-diabetic or diabetic.
• Most commercial dry breakfast cereals: The majority of packaged breakfast cereals are made from refined (ground-up) grains and added sugars.
Healthful foods that do not cause a high rise in blood sugar include:
• Minimally processed breakfast cereals without added sugars. Minimally processed cereal grains such as oats, wheat, barley, quinoa or brown rice may be whole, rolled, steel cut, shredded, puffed or flaked (not ground into a powder). These cereals usually do not cause a high rise in blood sugar and are good sources of soluble fiber, a gel that binds to sugars to delay their absorption.
• Whole fruits. Fruits contain the same sugars that are added to cookies, but they cause less than half of the rise in blood sugar as an equal amount of sugar in a cookie. Fruits also contain soluble fiber. Eating fruits is associated with preventing diabetes (European Journal of Nutrition, Dec 4, 2017:1-10).
• Most vegetables, beans, cooked whole grains, nuts and other seeds. Many people avoid nuts because they believe they are fattening, but the fat in nuts is inside the cells and you lack the enzymes necessary to break down the fat cells. Most of the fats in nuts pass to your colon where bacteria have the enzymes to break them down and convert them to short chain fatty acids that are anti-inflammatory and help to lower cholesterol. See More Good News About Nuts
Other Ways to Avoid Insulin Resistance
• Avoid being overweight, particularly in your belly. Most people who have big bellies and small buttocks already have insulin resistance characterized by high blood sugar levels after meals and significant cell damage.
• Exercise every day. Even minimal exercise, such as regular brisk walking, can help to reverse insulin resistance. Your body has only two places where it can store extra sugar: your muscles and your liver. Resting muscles remove almost no sugar from your bloodstream and the little that they can take up requires insulin to do so. Contracting muscles remove large amounts of sugar and don't even need insulin to do so. However, this effect of muscles removing sugar from the bloodstream without needing insulin lasts only up to about 17 hours (Am J Clin Nutr, 2008(July);88(1):51-57). Even passive exercise on a motor-driven stationary bicycle lowers blood sugar levels and helps to prevent and treat diabetes (Med Sci Sports Exerc, April 6, 2016).
• Avoid vitamin D deficiency. Low levels of vitamin D decrease your cells' ability to respond to insulin and take in sugar from the bloodstream. Get a blood test called hydroxy vitamin D. If it is below 20 ng/ml, you probably need more sunlight or vitamin D pills.