What is insulin resistance?
Insulin is a hormone that facilitates the transport of blood sugar (glucose) from the bloodstream into cells throughout the body for use as fuel. In response to the normal increase in blood sugar after a meal, the pancreas secretes insulin into the bloodstream. With insulin resistance, the normal amount of insulin secreted is not sufficient to move glucose into the cells - thus the cells are said to be "resistant" to the action of insulin. To compensate, the pancreas secretes insulin in ever-increasing amounts to maintain fairly adequate blood-sugar movement into cells and a normal blood-sugar level.
What are the symptoms?
There are usually no obvious, outward signs of insulin resistance. However, with a severe form of insulin resistance, dark patches of skin called acanthosis nigricans can develop on the back of the neck. Sometimes a dark ring forms around the neck. These dark patches can also occur on the elbows, knees, knuckles and armpits.
More importantly, insulin has less visible effects on metabolic reactions throughout the body, including converting calories into fat. Insulin resistance influences the liver enzymes that produce cholesterol and acts on the kidneys (which can contribute to high blood pressure).
High insulin levels also have a role in the process that regulates inflammation. In time, insulin resistance can lead to type 2 diabetes, itself a risk factor for heart disease. Insulin resistance can be diagnosed with blood tests that show low levels of HDL cholesterol (the "good" cholesterol), a high triglyceride level, a high fasting insulin level or a high uric acid level.
What are the causes of insulin resistance?
There are genetic factors that can contribute to the development of insulin resistance, including a family history of diabetes, high blood pressure or heart disease, but lifestyle choice can play a major role, specifically carrying excess weight with the extra pounds accumulating in the abdomen (the classic "apple" shape). However, insulin resistance can also occur among thin people and present the same risks for heart disease, high blood pressure and diabetes as it does among the overweight.
What is the conventional treatment?
Weight loss and exercise are considered the best treatments for restoring the body's ability to respond to insulin normally. Since smoking contributes to insulin resistance, quitting is recommended to bring the condition under control (as well as to improve your overall health).
The FDA has not approved any drug specifically for the treatment of insulin resistance or pre-diabetes. However, in an effort to lower blood glucose levels and restore the body's normal response to insulin, physicians may prescribe drugs normally used to treat type 2 diabetes. These include two classes of pharmaceuticals, known as biguanides and thiazolidinediones, that sensitize muscle and other tissues to the effects of insulin. Metformin (a biguanide) can help reduce the risk of developing diabetes in those with insulin resistance but is not as effective as losing weight and increasing activity. Other medications used for diabetes that act by different mechanisms may also be prescribed. These include alpha-glucosidase inhibitors, which restrict or delay the absorption of carbohydrates after eating, resulting in a slower rise of blood glucose levels, as well as sulfonylureas and meglitinides, which act directly on the pancreas and are sometimes prescribed to increase insulin production.
What therapies does Dr. Weil recommend for insulin resistance?
Even small amounts of weight loss can reduce insulin resistance, so most of Dr. Weil's recommendations are aimed at reducing weight if you are overweight:
- Dietary changes:
- Watch your carbohydrate intake. The classic low-fat, high-carb diet that was the standard recommendation for preventing or treating heart disease for years can actually worsen insulin resistance. Instead, opt for a moderately low carbohydrate diet (40 to 45 percent of calories) and focus on low glycemic index sources of carbohydrate (those that raise blood sugar levels slowly). In general, choose low carbohydrate foods that are high in fiber.
- Emphasize moderate amounts of monounsaturated fat (30 to 35 percent of calories) from sources such as extra virgin olive oil, nuts and avocado rather than following a strict low-fat diet.
- Eat generous amounts of non-starchy vegetables: This means five or more servings daily. Choose a variety of vegetables that covers a full spectrum of colors. In addition, eat one to two servings of low-glycemic index fruit every day, such as cherries, grapefruit, apricots and apples.
- Eat fish frequently. Choose cold-water fish that are high in omega-3 fatty acids, such as wild Alaskan salmon and sardines. Omega-3s can help ameliorate the pro-inflammatory effects of insulin and also seem to improve cells' response to the hormone.
- Eat small, frequent meals. This can help keep blood sugar levels stable throughout the day, helping to avoid spikes in insulin.
- Vigorous aerobic exercise decreases the cells' resistance to insulin. Start any new exercise routine slowly, and aim for 30-45 minutes daily.
- Coenzyme Q10 (CoQ10). A powerful antioxidant, CoQ10 contributes to heart health by preventing the oxidation of LDL cholesterol, and by re-energizing the mitochondria in the heart cells, which is where energy metabolism occurs. Dosage: 90-120 mg per day; for best absorption, take with a meal containing fat.
- Alpha-lipoic acid. This antioxidant nutrient improves the cells' response to insulin and can help stabilize blood sugar levels. Dosage: 100 to 400 mg per day.
- Magnesium. Higher insulin and blood sugar levels are often observed in people with low plasma magnesium levels. Magnesium supplementation has been shown to improve insulin resistance in animal studies. Dosage: 100 mg - 400 mg per day, use half the amount of magnesium as you take of calcium. Look for magnesium citrate, chelate, or glycinate. Avoid magnesium oxide.
- Chromium. This mineral helps stabilize blood sugar, may improve serum lipid profiles, and may help the body utilize glucose and burn fat. The best form to use is GTF chromium. Dosage: 1,000 mcg per day.