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Are Krill Oil Supplements a Better Source of n-3 Fatty Acids than Fish Oil Supplements?
from the academy
QUESTION OF THE MONTH
Are Krill Oil Supplements a Better Source of n-3 Fatty Acids than Fish Oil Supplements?
n
-3 fatty acids include alpha-linolenic acid (ALA), derived primarily from plant sources; eicosapentaenoic acid (EPA); and docosahexaenoic acid (DHA), derived primarily from marine sources. n-3 fatty acids can also be obtained from supplements. Reports of numerous health benefits have contributed to the popularity of n-3 supplements (1). Fish oil supplements containing EPA and DHA typically provide approximately 180 to 300 mg EPA and 120 to 200 mg DHA per capsule (2). A new generation fish oil supplement on the market is krill oil. Krill oil is the oil from the shrimp-like crustacean that feeds off algae in deep ocean waters, which in turn is a major food source for animals higher on the food chain like fish, seals, and whales (2). Krill oil contains both EPA and DHA, but to a lesser degree than fish oil. There is also a difference in molecular structure between the two marine sources. n-3 fatty acids in fish oil are stored as triglycerides. In krill oil, 30% to 65% of the fatty acids are incorporated into phospholipids (3). Researchers recently investigated whether or not this difference in structure results in a difference in bioavailability (3). The researchers concluded that krill oil and fish oil “represent comparable sources of n-3 fatty acids, even if the EPA⫹DHA dose in krill oil was 62.8% of that in the fish oil.” Considering the wide range of claims for dietary supplements containing EPA and DHA, it is conceivable a registered dietitian (RD) may have clients with a wide range of questions that go beyond bioavailability and are more related to efficacy. However, the most common questions may center on cardiovascular disease (CVD). Below are two recommendations from the Disorders of Lipid Metabolism Nutrition Practice Guidelines found in the Academy of Nutrition and Dietetics’ Evidence Analysis Library (4,5).
n-3 SUPPLEMENTS AND RISK FOR CVD EVENTS If persons choose to consume EPA plus DHA supplements or EPA alone to reduce the risk of CVD mortality and events (sudden death and re-infarction), the RD should advise: ●
●
●
patients without coronary heart disease (CHD): intervention studies of n-3 supplementation have not been done in patients without CHD; patients with CHD, but no angina or implantable cardioverter defibrillators (ICD): supplementation with 850 mg/day EPA and/or DHA reduced sudden death by 45%; and patients with CHD with angina or ICDs: EPA and DHA supplements may be contraindicated.
The US Food and Drug Administration (5) advises that consumption of more than 3 g of n-3 fatty acids per day may cause gastrointestinal symptoms. Research findings in general find a correlation between eating two or more servings of fish per week with a lower incidence of heart disease. According to the 2010 Dietary Guidelines for Americans (6), mean intake of seafood in the United States is approximately 3.5 oz/wk. The guidelines recommend increased consumption of two servings of fish per week (4 oz⫽one serving) because of the range of nutrients fish provides beyond EPA and DHA. While a food-based approach to receiving adequate fatty acid levels is recommended, careful supplementation is a feasible alternative if dietary intake falls short. RDs play a pivotal role in translating dietary recommendations for fat and fatty acids into healthful dietary patterns. References
ELEVATED TRIGLYCERIDES AND EPA/DHA SUPPLEMENTS In patients with elevated triglycerides (TG), in addition to lifestyle modification with a cardioprotective diet, the RD can advise that high-dose supplemental eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (2 to 4 g/day) may be utilized under medical supervision. High doses of supplemental EPA and DHA have been shown to lower TG in patients with elevated TG (⬎200 mg/dL). This article was written by Eleese Cunningham, RD, with the Academy’s Knowledge Center in Chicago, IL. Academy members can contact the Knowledge Center by sending an e-mail to [email protected] doi: 10.1016/j.jand.2011.12.016
344
Journal of the ACADEMY OF NUTRITION AND DIETETICS
1. Riediger ND, Othman RA, Suh M, Moghadasian MH. Systemic review of the roles of omega-3 fatty acids in health and disease. J Am Diet Assoc. 2009;109(4):668-679. 2. Sarubin Fragakis AS, Thomson C. The Health Professional’s Guide to Popular Dietary Supplements. Chicago, IL: American Dietetic Association; 2007. 3. Ulven SM, Kirkhus B, Lamglait A, et al. Metabolic effects of krill oil are essentially similar to those of fish oil but at lower dose of EPA and DHA, in healthy volunteers. Lipids. 2011;46(1):37-46. 4. American Dietetic Association Evidence Analysis Library. Disorders of lipid metabolism (DLM), triglycerides, and omega-3 fatty acid supplements. http://www.adaevidencelibrary.com/template.cfm?template⫽ guide_summary&key⫽2994. Accessed November 22, 2011. 5. American Dietetic Association Evidence Analysis Library. Omega-3 supplements and risk for CVD events. http://www.adaevidencelibrary. com/topic.cfm?cat⫽4528. Accessed November 22, 2011. 6. US Department of Agriculture, US Department of Health and Human Services. Dietary Guidelines for Americans, 2010. http://health.gov/ dietaryguidelines/dga2010/dietaryguidelines2010.pdf. Accessed November 22, 2011.
© 2012 by the Academy of Nutrition and Dietetics
QUESTION OF THE MONTH
Are Krill Oil Supplements a Better Source of n-3 Fatty Acids than Fish Oil Supplements?
n
-3 fatty acids include alpha-linolenic acid (ALA), derived primarily from plant sources; eicosapentaenoic acid (EPA); and docosahexaenoic acid (DHA), derived primarily from marine sources. n-3 fatty acids can also be obtained from supplements. Reports of numerous health benefits have contributed to the popularity of n-3 supplements (1). Fish oil supplements containing EPA and DHA typically provide approximately 180 to 300 mg EPA and 120 to 200 mg DHA per capsule (2). A new generation fish oil supplement on the market is krill oil. Krill oil is the oil from the shrimp-like crustacean that feeds off algae in deep ocean waters, which in turn is a major food source for animals higher on the food chain like fish, seals, and whales (2). Krill oil contains both EPA and DHA, but to a lesser degree than fish oil. There is also a difference in molecular structure between the two marine sources. n-3 fatty acids in fish oil are stored as triglycerides. In krill oil, 30% to 65% of the fatty acids are incorporated into phospholipids (3). Researchers recently investigated whether or not this difference in structure results in a difference in bioavailability (3). The researchers concluded that krill oil and fish oil “represent comparable sources of n-3 fatty acids, even if the EPA⫹DHA dose in krill oil was 62.8% of that in the fish oil.” Considering the wide range of claims for dietary supplements containing EPA and DHA, it is conceivable a registered dietitian (RD) may have clients with a wide range of questions that go beyond bioavailability and are more related to efficacy. However, the most common questions may center on cardiovascular disease (CVD). Below are two recommendations from the Disorders of Lipid Metabolism Nutrition Practice Guidelines found in the Academy of Nutrition and Dietetics’ Evidence Analysis Library (4,5).
n-3 SUPPLEMENTS AND RISK FOR CVD EVENTS If persons choose to consume EPA plus DHA supplements or EPA alone to reduce the risk of CVD mortality and events (sudden death and re-infarction), the RD should advise: ●
●
●
patients without coronary heart disease (CHD): intervention studies of n-3 supplementation have not been done in patients without CHD; patients with CHD, but no angina or implantable cardioverter defibrillators (ICD): supplementation with 850 mg/day EPA and/or DHA reduced sudden death by 45%; and patients with CHD with angina or ICDs: EPA and DHA supplements may be contraindicated.
The US Food and Drug Administration (5) advises that consumption of more than 3 g of n-3 fatty acids per day may cause gastrointestinal symptoms. Research findings in general find a correlation between eating two or more servings of fish per week with a lower incidence of heart disease. According to the 2010 Dietary Guidelines for Americans (6), mean intake of seafood in the United States is approximately 3.5 oz/wk. The guidelines recommend increased consumption of two servings of fish per week (4 oz⫽one serving) because of the range of nutrients fish provides beyond EPA and DHA. While a food-based approach to receiving adequate fatty acid levels is recommended, careful supplementation is a feasible alternative if dietary intake falls short. RDs play a pivotal role in translating dietary recommendations for fat and fatty acids into healthful dietary patterns. References
ELEVATED TRIGLYCERIDES AND EPA/DHA SUPPLEMENTS In patients with elevated triglycerides (TG), in addition to lifestyle modification with a cardioprotective diet, the RD can advise that high-dose supplemental eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (2 to 4 g/day) may be utilized under medical supervision. High doses of supplemental EPA and DHA have been shown to lower TG in patients with elevated TG (⬎200 mg/dL). This article was written by Eleese Cunningham, RD, with the Academy’s Knowledge Center in Chicago, IL. Academy members can contact the Knowledge Center by sending an e-mail to [email protected] doi: 10.1016/j.jand.2011.12.016
344
Journal of the ACADEMY OF NUTRITION AND DIETETICS
1. Riediger ND, Othman RA, Suh M, Moghadasian MH. Systemic review of the roles of omega-3 fatty acids in health and disease. J Am Diet Assoc. 2009;109(4):668-679. 2. Sarubin Fragakis AS, Thomson C. The Health Professional’s Guide to Popular Dietary Supplements. Chicago, IL: American Dietetic Association; 2007. 3. Ulven SM, Kirkhus B, Lamglait A, et al. Metabolic effects of krill oil are essentially similar to those of fish oil but at lower dose of EPA and DHA, in healthy volunteers. Lipids. 2011;46(1):37-46. 4. American Dietetic Association Evidence Analysis Library. Disorders of lipid metabolism (DLM), triglycerides, and omega-3 fatty acid supplements. http://www.adaevidencelibrary.com/template.cfm?template⫽ guide_summary&key⫽2994. Accessed November 22, 2011. 5. American Dietetic Association Evidence Analysis Library. Omega-3 supplements and risk for CVD events. http://www.adaevidencelibrary. com/topic.cfm?cat⫽4528. Accessed November 22, 2011. 6. US Department of Agriculture, US Department of Health and Human Services. Dietary Guidelines for Americans, 2010. http://health.gov/ dietaryguidelines/dga2010/dietaryguidelines2010.pdf. Accessed November 22, 2011.
© 2012 by the Academy of Nutrition and Dietetics