New information About Omega-3 Fatty Acids: Focus on Diabetes

Kathy J. Shattler, M.S, RD

Kathy J. Shattler, M.S, RD Is our Newest Advisory Board member.

Kathy has over 20 years experience as a Registered Dietitian. She has worked as metabolic support specialist, certified diabetic educator, public health program manager, state surveyor for HCFA/CMS compliance, home health dietitian and with private physicians. Currently, she works as the Dietitians and Nutritionists Continuing Education Division director at the internet based business, CEU4U.COM.  CEU4U.COM offers CDR and CE Broker approved educational opportunities that are conveniently located on-line.

 

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Why should you care about Omega 3? Simply stated, recent research is linking Omega 3 fatty acids to improved health in far more ways than anyone previously thought possible.

Omega-3 Fatty Acids (FA) is a class of polyunsaturated fatty acids (pufa). Important nutritionally essential omega-3 FA include ALA or α-linolenic acid, EPA or eicosapentaenoic acid and DHA or docosahexaenoic acid. For our purposes, we will refer to these fatty acids as ALA, EPA and DHA.  The human body cannot make EPA or DHA, but can competitively make EPA and DHA from ALA in the normal human body. The most widely available sources of EPA or DHA include wild salmon, herring, mackerel, anchovies and sardines. Farmed salmon, being grain fed, have a higher proportion of omega-6 fatty acids than wild salmon. Other oily fish include tuna. Consumers of fish should be aware of the potential presence of PCBs, dioxins. lead, cadmium, mercury nickel and arsenic - pollutants and heavy metals that are often removed in high quality supplements. Omega 3s are now being linked to better diabetic control.

Why is the intake of EPA and DHA so important in diabetes?  People with diabetes do not generally die of high blood sugars; they die of microvascular and macrovascular complications of which one of the most serious is heart disease.  A recent study in Lancet (2007) (The leading medical journal in the UK) involved over 18,000 patients with unhealthy cholesterol profiles. The patients in the study group received either 1,800 mg of EPA with a statin drug or a statin drug alone. Statin drugs include the following: Lipitor, Mevacor, Zocor, Crestor, Lescol, Prevachol and Baycol. Statin drugs are commonly prescribed to lower cholesterol. The trial went on for five years. It was found at the end of the study that those in the EPA group had superior heart function. Non-fatal coronary events were also significantly reduced.

People with diabetes are 6 times more likely to suffer a first heart attack and 3-8 times more likely to die from heart disease than those without diabetes. The American Heart Association (AHA) recommends eating fish (particularly fatty fish) at least two times per week to prevent heart related complications and to treat already existing heart problems.  They also recommend that patients with documented heart disease consume about 1 g of EPA + DHA per day in capsule form. Patients who need to lower triglycerides in particular are recommended 2-4 g of EPA + DHA UNDER A PHYSICIANS CARE. Supplementation at this level may lower triglycerides by 20-40%.

Why should the physician know if you are taking fish oil capsules? Several reasons exist of which one is bleeding complications. An increase in the risk of hemorrhagic stroke or drug interactions (i.e. Coumadin, aspirin) is more likely to occur with a supplementation of more than 3 g per day. Some physicians also become concerned over the potential increase in LDLs and reduced glycemic control among diabetics with the high dosage of omega-3 fatty acids. It may be noted that to treat triglycerides over 500 mg/dl a new drug containing EPA and DHA called Lovaza is available that provides 465 mg EPA and 375 mg DHA in a one gram capsule. By contrast, over the counter Omega 3 fish oil capsules range from 30% (165mg EPA/110mg DHA) to 50% (300mg EPA/200 mg DHA). Supplements need to be pharmaceutical grade meaning that they need to be free of pesticides and contaminants associated with fish oils. Lovaza is free from contaminants.

AHA also recommends foods high in ALA. What is wrong with this recommendation? Conversion of ALA to EPA and DHA is limited in people with diabetes, the aging process and those with common nutrient deficiencies of B3, B_6, C, Zinc and Magnesium. A diet high in linoleic acid (from corn, safflower oil, primrose, pumpkin, wheat germ etc) can inhibit conversion by as much as 40%. Saturated fats and trans fats inhibits ALA conversion.  The American diet is high in saturated fats and trans fats found mainly in baked goods, fried foods, margarines, lard and fast foods to name a few. Ethanol (the alcohol in drinks) also inhibits conversion. A ratio high in omega-6 pufas to omega-3’s inhibits conversion. Even without these variables, conversion of ALA to EPA and DHA range from 0% to 15% with some studies showing less than .5%.  The only published significance of ALA in diabetes is the reduction of platelet build-up which can help avoid or reverse neuropathy. So, the question is asked, is it better to increase your ALA in your diet to avoid diabetic complications or focus on increasing EPA and DHA? It is clear that while much more research is needed, some of these questions can already be answered.

Many people ask what the mechanism of action is of EPA and DHA in reducing the incidence of cardiovascular, or heart, related complications in diabetes. So far, we have identified that they lower triglycerides, decrease platelet clumping, inhibit plaque formation, reduce inflammation and stimulate the relaxation of cells in the walls of blood vessels. Despite these positive affects, it should be noted that omega-3 fatty acids have no effect on lowering total cholesterol. While they may increase HDLs (good cholesterol) by 1-3%, they may also increase LDLs (bad cholesterol) by 5-10%. Therefore, for individuals with high blood levels of total cholesterol or LDLs, significant improvements will likely not be seen and a different treatment or additional treatment may need to be selected.

This article wouldn’t be complete without elaborating on the omega-6 to omega-3 ratio (especially Linoleic Acid vs. Alpha Linolenic Acid) of fatty acids. A good ratio is important for maintaining cardiovascular health.  Both types of fats compete for the same enzymes and the same metabolic pathway. The American diet typically contains ratios of 10:1-15:1 omega-6 to omega-3 ratios. The recommendations are closer to a 4:1 or even a 1:1 ratio. The most effective way to alter the ratio to a favorable one is to increase EPA and DHA intakes.

There are no RDAs (Recommended daily Allowance) for omega-3 fatty acids. The acceptable intake (AI) is 1.6 g for men and 1.1 for women.

Conclusions:

There is little consensus on exactly how much omega-3 to take and what form it should be in. More research is needed on the mechanisms by which the different fats could affect diabetes complications and even glycemic control. It is clear from the American Heart Association that some agreement has been reached on the usefulness of omega-3 fats in the positive effects on heart disease associated with diabetes and recommendations for supplementation have been made. Studies need to incorporate population, drug and genetic variables to further understand how omega-3 fats affect diabetes complications.

References

American Heart Association Recommendations. (2007). Fish and Omega-3 Fatty Acids, AHA recommendations. http://atvb.ahajournals.org/cgi/content/full/23/2/151. Accessed May 3, 2008.

American Diabetes Association. Diabetes and Cardiovascular (Heart) Disease. http://www.diabetes.org/diabetes-statistics/heart-disease.jsp . Accessed November 20, 2007.

Barre, DE. (2007). The role of consumption of Alpha-Linolenic, Eicosapentaenoic and Docosahexaenoic Acids in human metabolic syndrome and type 2 diabetes - a mini review. J of Oleo Science. 56;(7):319-325.

Comparing omega-3s from fish and flax seed oil. http://www.omega3sealoil.com/Chapteer4_3c.html Accessed November 20, 2007

Feldman, Donna. (2007). Omega-3 Fats and Health-an Update. A CEU4U.COM continuing education module. http://www.ceu4u.com. Reviewed November, 2007.

Harris, WS. (2006). The Omega-6/Omega-3 Ratio and Cardiovascular Risk: Uses and abuses. Curr Atherosclerosis Reports. 8:453-459.

Mayo Clinic Omega-3 Fatty Acids. http://www.mayoclinic.com/health/fish-oil//NS_patient-fishoil. Accessed 10/27/07.

Yokoyama M,et al. (2007). Effects of eicosapentaenoic acid on major coronary events in hypercholesterolaemic patients (JELIS): a randomized open-label, blinded endpoint analysis. Lancet;369:1090-98.

USDA Office of Dietary Supplements. http://ods.od.nih.gov/Health_Information/omega_3_fatty_acids.aspxAccessed 10/28/07.

Omeg 3 and people allergic to fish
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