One common misconception about fish oil (specifically the fatty acids EPA & DHA) is that it improves your blood sugar levels. I love fish oil and it can greatly improve many aspects of your health but the scientific evidence to support the use of fish oil for blood sugar control is just not there. In 2006, nutrition juggernaut, Dr. Alice Lichtenstein (and some others) wrote a review article that focused on the effects of omega-3 fatty acids and serum makers (e.g. things in our blood) of cardiovascular disease. One of the areas they looked at was blood sugar control.
Two ways that scientists can quantify the ‘controlling of blood sugar levels’ is through Hemoglobin A1c (HbA1c) and fasting blood sugar (FBS) levels. HbA1c is a long term marker of blood glucose control that is commonly used by physicians to monitor how well their diabetic patients are sticking to their carb controlled diets. Fasting blood sugar is exactly what it sounds like – what your blood sugar levels are when you haven’t eaten for a while (i.e. are fasted); this usually means an overnight fast. The researchers looked at 28 different randomized clinical trials (the best kind of studies for determining cause and effect) and found that fish oil supplementation yielded a wide range of results ranging from a 29mg/dL decrease to a 25mg/dL increase (yes you read that right – increase) in FBS.
The findings surrounding the effects of fish oil supplementation were just as exciting (or NOT exciting) in that here was a small but clinically insignificant impact on HbA1c. This means that from a statistical perspective there was an effect but the effect was so small that it wouldn’t have an impact on your health/life.
After doing some more of what I call “statistical voodoo” the researchers summed up all the research and concluded that fish oil caused a non-significant increase in FBS and HbA1c. So not only does fish oil have no effect on blood sugar control it actually has a minor (very minor) negative effect. As I mentioned at the beginning, I am a big believer in fish oil supplementation and recommend that all my clients supplement with fish oil on a daily basis but taking an EPA/DHA supplement each day in an effort to control blood sugar levels is an exercise in futility.