Insulin Resistance and Nutrition
Renata Trister DO
Glucose is the basic fuel that all cells in the body use to make energy. It is a simple monosaccharide found in plants; and is one of the three dietary monosaccharaides, along with fructose and galactose, that are absorbed directly into the bloodstream during digestion. Glucose is a common medical analyte measured in blood samples. A high fasting glucose blood sugar level may be a sign of pre-diabetes or diabetes mellitus. Glucose can only be put to work and transformed into energy once it is in the cells, not when it is circulating in the bloodstream. Ideally, blood glucose level is maintained in a fairly narrow range. Low blood sugar level is referred to as hypoglycemia; high blood sugar level is termed called hyperglycemia. Proper blood sugar level is important and inability to maintain a proper level leads to illness. Chronically elevated blood glucose levels result in the development of diabetes.
Insulin is a hormone, produced by the pancreas, and is central to regulating carbohydrate and fat metabolism in the body. Insulin causes cells in the liver, skeletal muscles, and fat tissue to absorb glucose from the blood. Insulin resistance is a physiological condition in which cells fail to respond to the normal actions of the hormone insulin. The body produces insulin, but the cells in the body become resistant to insulin and are unable to use it as effectively, leading to hyperglycemia. In response to this hyperglycemia, the pancreas produces even more insulin. This often remains undetected and is a risk factor for Type 2 Diabetes, hypertension and heart disease. Additionally, elevated insulin may be associated with weight gain and difficulty with weight loss.
It is well known that insulin resistance commonly coexists with obesity. However, causal links between insulin resistance, obesity, and dietary factors are complex and controversial. It is possible that one of them arises first, and tends to cause the other; or that insulin resistance and excess body weight might arise independently as a consequence of a third factor, but end up reinforcing each other. Some population groups might be genetically predisposed to one or the other. Genetics are one cause that predisposes people to develop insulin resistance, however, lifestyle and diet changes can have a profound effect on diminishing and eliminating these conditions. Diets of processed sugars, foods, and fats; along with obesity, lack of exercise, and smoking all contribute to insulin resistance and other serious health problems. Regular moderate exercise can helps regulate blood sugar and increase insulin sensitivity it also helps lower blood pressure, improve cholesterol levels, and result in weight loss.
Nutritional Support and Insulin Resistance
Diet along with vitamins, minerals, and phytonutrients can improve the sensitivity of the body to insulin.
The glycemic index (GI) provides a measure of how quickly blood sugar levels rise after eating a particular type of food. The effects that different foods have on blood sugar levels vary considerably. The glycemic index estimates how much each gram of available carbohydrate (total carbohydrate minus fiber) in a food raises a person’s blood glucose level following consumption of the food, relative to consumption of pure glucose. Glucose has a glycemic index of 100. A low-GI food will release glucose more slowly and steadily, which leads to more suitable postprandial (after meal) blood glucose readings. A high-GI food causes a more rapid rise in blood glucose levels and is suitable for energy recovery after exercise or for a person experiencing hypoglycemia. Thus the lower the GI the less the pancreas needs to work to keep blood sugar levels in the normal range. Consuming foods with a low glycemic index decreases the risk for development of type 2 diabetes. For those with type 2 diabetes, eating low GI foods and eliminating high GI foods is essential to controlling and reversing the disease.
Dietary fiber is the indigestible portion of food derived from plants. It plays an important role in promoting a healthy insulin response. There are two fiber types/components:
Soluble fiber dissolves in water. It is readily fermented in the colon into gases and physiologically active byproducts, and can be prebiotic. Soluble fibers tend to slow the movement of food through the system.
Insoluble fiber does not dissolve in water. It can be metabolically inert and provide bulking or prebiotic, metabolically fermenting in the large intestine. Bulking fibers absorb water as they move through the digestive system, easing defecation. Fiber appears to slow digestion, which helps to prevent a surge of blood sugar and resulting insulin response.
Fats The type of fats that are consumed can play a role in insulin resistance. Trans-isomer fatty acids, or trans fats, are a type of unsaturated fat, which is uncommon in nature but can be easily created artificially. Research indicates that trans fatty acids (TFAs) may increase weight gain and abdominal fat, despite a similar caloric intake. A 6-year experiment revealed that monkeys fed a trans fat diet gained 7.2% of their body weight, as compared to 1.8% for monkeys on a mono-unsaturated fat diet; concluding that “under controlled feeding conditions, long-term TFA consumption was an independent factor in weight gain. TFAs enhanced intra-abdominal deposition of fat, even in the absence of caloric excess, and were associated with insulin resistance, with evidence that there is impaired post-insulin receptor binding signal transduction.” When healthy fats, such as omega-3 essential fatty acids, are substituted into a high fat diet, insulin resistance in skeletal muscle may be prevented. These omega-3 fatty acids, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), demonstrate a beneficial effect on insulin and blood sugar by improving the function of insulin receptors and blood sugar transporters in the cell. They may also increase cell membrane fluidity, thus promoting insulin action. EPA and DHA also support cardiovascular health.
Magnesium is required for both proper glucose utilization and insulin signaling. Metabolic alterations in cellular magnesium, which may play the role of a second messenger for insulin action, contribute to insulin resistance. Thus, magnesium affects insulin secretion and action. Daily magnesium supplements appear to improve blood sugar transport into the cell. Type 2 diabetics frequently develop a low magnesium level.
Chromium promotes glucose uptake by the cell and may affect the action of insulin. Chromium deficiency is associated with elevated blood sugar levels, high cholesterol, and the development of plaque on artery walls. Beneficial effects of supplemental chromium on blood lipids such as cholesterol have been reported in controlled trials. Recent studies have also suggested that chromium can significantly reduce blood sugar levels in type 2 diabetics.
Biotin is a coenzyme for carboxylase enzymes, involved in the synthesis of fatty acids and in gluconeogenesis. It is a vitamin that is found in small amounts in numerous foods. There is some evidence that diabetes could result in biotin deficiency. Animal studies suggest that a biotin intake can improve the utilization of glucose without increased insulin secretion from the pancreas. Biotin has been shown to substantially lower fasting glucose in type 2 diabetic patients.
Conjugated Linoleic Acid (CLA) is a naturally occurring fatty acid that may support healthy blood sugar and insulin metabolism. It can also help reduce body fat deposits and improve immune function.
Alpha-Lipoic Acid (ALA) is an antioxidant. Antioxidants protect against damage to the body’s cells. There is some evidence that ALA may have at least two positive benefits for individuals with diabetes (type2diabetes). A few studies have suggested that alpha-lipoic acid supplements enhance the body’s ability to use its own insulin to lower blood sugar in people with type 2 diabetes. ALA may also help reduce the symptoms of peripheral neuropathy — nerve damage that can be caused by diabetes. In Europe, ALA has been used for years to provide relief from the pain, burning, tingling, and numbing caused by diabetic neuropathy.
Antioxidants An increase in the generation of damaging free radicals and resulting oxidative stress may be associated with insulin resistance. Antioxidants such as vitamins E and C, zinc, and selenium have been shown to protect against free radicals and reduce oxidative stress.