Omega-3 Improves Insulin Sensitivity

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Insulin sensitivity is related to how the body metabolizes glucose and stores its energy source. It is most commonly brought up in relation to the topic of diabetes but insulin sensitivity can be a very complex issue and it may be caused by a variety of factors. Treatments for impaired insulin sensitivity are numerous and there are multiple medications Insulin resistance treatment, as well as diets for insulin resistance. However, recent studies have shown that help improving insulin sensitivity may also be found within a simple liquid filled capsule: omega-3 supplements.

Insulin is a hormone produced by beta cells within the pancreas and is responsible for utilizing glucose (blood sugar) so that it can be used or stored as the body’s energy source. Since it plays such an important role in keeping the body functioning properly, it can lead to serious health issues if not regulated. There are two main forms of insulin sensitivity issues:

High Insulin Sensitivity. This is seen mostly with Type 1 diabetes.  Someone with high insulin sensitivity requires less insulin to metabolize glucose and the body tends to produce more insulin than needed. This often leads to hypoglycemia, which is a condition of not having enough glucose in the bloodstream. The most common symptoms of hypoglycemia are shaking and delirium. In severe cases, coma and death may occur as well.

Low Insulin Sensitivity. This is the most common type of insulin related issue and is a hallmark of Type 2 diabetes.  It is also known as ‘insulin resistance’. With this condition, the body has difficulty metabolizing glucose and the pancreas responds by producing more insulin. This can lead to hyperinsulinemia, which is having too much insulin in the blood stream. Since there is difficulty with the utilization of glucose, hyperglycemia is also common in those with insulin resistance. High blood pressure, cardiac and vascular problems, bone density, and certain cancers are associated with long-term insulin resistance. The factors that cause insulin resistance are undetermined but the presence of visceral fat is thought to play a significant role.

Omega-3 fatty acids have long been suspected of having the potential to aid those suffering from abnormal insulin sensitivity but it wasn’t until recent years that the scientific community has conducted solid research into the topic that supports these claims on fish oil insulin interactions. The mechanism by which omega-3 fatty acids are believed to regulate insulin is by interacting with cell receptors. This interaction allows cells to bind with insulin more easily and may help reverse insulin resistance.

The effects of omega-3 on diabetes and both low and high insulin sensitivity have been studied in the last decade and the conclusions heavily support the effectiveness of omega-3 at improving insulin sensitivity. In a study published on 2007, the possible effect of omega-3 in the prevention of Type 1 diabetes in predisposed children was examined. It found that daily cod oil supplements, which contain both DHA and EPA, were given to study participants during infancy and early childhood. The results of the study showed a reduced risk for the development of low insulin sensitivity and Type 1 diabetes.

The preventative qualities of omega-3 fatty acids and fish oil are not limited to Type 1 diabetes but have also been seen to improve insulin resistance and prevent the onset of Type 2 diabetes as well. Within a study conducted in 2009, DHA, EPA, and ALA were observed to prevent or reverse insulin resistance.  The reversal of insulin resistance by omega-3 supplementation may also be possible for pregnant women with gestational diabetes.  A very recent study published in Clinical Nutrition observed that insulin resistance was significantly reduced when study participants were given 1000 mg doses of omega-3 supplements to help treat gestational diabetes.

Of the three most common omega-3 fatty acids, DHA and EPA have been shown to have the greatest impact on improving insulin resistance. These two fatty acids are found almost exclusive in fish and are the ones contained in omega-3 fish oil supplements. In the Journal of Nutritional Biochemistry, a study was published that looked at the effects of only DHA.  The study concluded that there was an improvement in those with obesity-related insulin sensitivity when DHA was administered.  The effects of EPA on insulin sensitivity in those with Type 2 diabetes was examined in a 2013 doubled blind and placebo-controlled study published in Singapore Medical Journal. Participants were given 2 grams of purified EPA daily and a decrease in insulin levels was noticed. This suggests that the pancreas was not triggered to produce excess insulin because insulin resistance was decreased. Similar conclusions about the effect of omega-3 on insulin resistance were found in studies taking place in 2009 and 2011 as well.

While omega-3 has been shown to help treat or prevent insulin sensitivity, a deficiency of omega-3 may actually be a significant factor in developing insulin sensitivity to begin with.  Omega-3 fatty acids are essential for maintaining health and a deficiency of them may cause a number of health-related issues. A study published in 2012 found that a diet high in fructose but low in omega-3 fatty acids had the potential to disrupt the signalling of insulin receptors in the part of the brain called the hippocampus. This suggests that a possible way to treat insulin resistance and avoid abnormal insulin sensitivity is to maintain a diet that includes omega-3 fatty acids or regularly take omega-3 fish oil supplements, before any health issues occur.

References

Fedor, D., & Kelley, D. (2009). Prevention of insulin resistance by n-3 polyunsaturated fatty acids. Current Opinion in Clinical Nutrition and Metabolic Care, 138-146. Retrieved June 28, 2015, from http://www.ncbi.nlm.nih.gov/pubmed/19202385

Gonzalez-Periz, A., Horrillo, R., Ferre, N., Gronert, K., Dong, B., Moran-Salvador, E., . . . Claria, J. (2009). Obesity-induced insulin resistance and hepatic steatosis are alleviated by  -3 fatty acids: A role for resolvins and protectins. The FASEB Journal, 23(6), 1946-1957. Retrieved June 28, 2015, from http://www.fasebj.org/content/23/6/1946.long

Norris, J., Yin, X., & Lamb, M. (2007). Omega-3 polyunsaturated fatty acid intake and islet autoimmunity in children at increased risk for type 1 diabetes. Journal of American Medical Association, 298(12), 1420-8. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/17895458

Oliver, E., Mcgillicuddy, F., Harford, K., Reynolds, C., Phillips, C., Ferguson, J., & Roche, H. (2012). Docosahexaenoic acid attenuates macrophage-induced inflammation and improves insulin sensitivity in adipocytes-specific differential effects between LC n-3 PUFA. The Journal of Nutritional Biochemistry, 23(9), 1192-1200.

Samimi, M., Jamilian, M., Asemi, Z., & Esmaillzadeh, A. (2015). Effects of omega-3 fatty acid supplementation on insulin metabolism and lipid profiles in gestational diabetes: Randomized, double-blind, placebo-controlled trial. Clinical Nutrition, 34(3), 388-93. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/24973862

Sarbolouki, S., & Javanbakht, M. (2013). Eicosapentaenoic acid improves insulin sensitivity and blood sugar in overweight type 2 diabetes mellitus patients: A double-blind randomised clinical trial. Singapore Medical Journal, 54(7), 387-90. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/23900468

Cassi O'Brien