by Zhimeng Qui, Dietetic Intern
What are Omega-3s?
Omega-3 fatty acids are a crucial group of unsaturated fats that are in the poly-unsaturated fatty acid (PUFA) family. Within this group, there are three types of fatty acids: Eicosapentaenoic acid (EPA), Docosahexaenoic acid (DHA), and Alpha-linolenic acid (ALA). ALA, a short-chain omega-3 fatty acid obtained through the diet and is responsible for synthesizing long-chain omega-3 fatty acids, including EPA and DHA [1]. DPA is an intermediate between EPA and DHA [2].
Where do they come from?
EPA and DHA are predominantly obtained from marine organisms and deep-sea fish. These fatty acids are found in cold-water fish such as mackerel, herring, tuna, halibut, salmon and cod [2].
The omega-3 fatty acid that is most commonly found in Western diets is ALA. ALA is present in vegetable oils, nuts, flax seeds and flaxseed oil, leafy vegetables, and some animal fats, particularly those from grass-fed animals.
Did you know most Americans aren’t getting enough omega 3s?
Most Americans do not consume sufficient amounts of omega-3 fatty acids. Based on the World Health Organization’s (WHO) recommendation of a combined intake of EPA and DHA to be between 200 and 500 milligrams, the average American adult consumes only 24-60% of the recommended levels for optimal health.
Studies suggest that human beings evolved on a diet with an omega-6 to omega-3 essential fatty acid (EFA) ratio of approximately 1:1, while the ratio in a current Western diet is typically around 15:1. This high ratio is associated with the development of several chronic diseases, including cardiovascular disease, cancer, and inflammatory diseases, while increased levels of omega-3 PUFA (a low omega-6:omega-3 ratio) have protective effects. Thus, it is essential to increase our daily intake of omega-3s to achieve the appropriate ratio of fatty acids.
Why is it important to consume sufficient omega-3s?
The human body is unable to produce omega-3s on its own. While it can be partially converted from ALA, only a small percentage of ALA can be converted to EPA, DPA or DHA. Therefore, getting EPA and DHA from food is the best practical way to increase the levels of these omega-3 fatty acids in your body. There are also omega-3 supplements on the market if you want to take them, and studies show that any side effects of taking omega-3 supplements are usually mild. Some side effects include an unpleasant taste in your mouth, bad breath, heartburn, nausea, upset stomach, diarrhea and headaches [3]. However, studies have found that supplements may interact with the medications. For example, high doses of omega-3 supplements may cause blood thinning and increase risk for bleeding when taken with warfarin (Coumadin®) or other anticoagulant medications [3]. Supplements may also interfere with other medications or treatments like chemotherapy. Always check with your healthcare team to see if it is safe to add supplements to your diet and focus on food first.
Omega-3s have been shown to have potential health benefits. Below are several study results that demonstrate their effectiveness.
Brain function: The human brain is composed of approximately 60 percent fat, with approximately 20% of its dry weight being made up of PUFA [4]. These fatty acids play a crucial role in determining the performance of the brain throughout all stages of life [5,6].
Among other things, growing evidence suggests that omega-3 PUFAs are effective in preventing age-related loss of gray and white matter volume and therefore may be beneficial in mild cognitive impairment (MCI) or age-related cognitive decline [6].
Heart Disease: According to recent studies, the use of prescription ethyl-EPA, combined with statin therapy, may reduce the risk of cardiovascular disease (CVD) events in patients at risk. However, it remains unclear if oral EPA supplements alone are beneficial for CVD. Moreover, both oral prescription ethyl-EPA and EPA supplements have been shown to reduce the risk of myocardial infarction (MI) in patients with CVD risk.
Inflammation: Accumulating evidence suggests that omega-3 PUFAs, especially EPA and DHA, have anti-inflammatory properties and can potentially improve various inflammatory diseases, including inflammatory bowel disease, rheumatoid arthritis, asthma, cancer, and more.
Recommendation
The WHO recommends 200-500 mg of EPA and DHA combined per day. The American Heart Association suggests consuming 2 servings of fish, especially fatty fish, per week, with a serving size of 3 ounces cooked or roughly ¾ cup of flaked fish [7]. Individuals should not exceed a total intake of 3 grams of DHA or other omega-3 fatty acids per day, with no more than 2 grams of it coming from a dietary supplement, as this can potentially increase the risk of bleeding by slowing down blood clotting [5].
References
[1] Grosso G, Galvano F, Marventano S, Malaguarnera M, Bucolo C, Drago F, Caraci F. Omega-3 fatty acids and depression: scientific evidence and biological mechanisms. Oxidative medicine and cellular longevity. 2014;2014:313570. doi:10.1155/2014/313570 [2] Fu Y, Wang Y, Gao H, Li D, Jiang R, Ge L, Tong C, Xu K. Associations among Dietary Omega-3 Polyunsaturated Fatty Acids, the Gut Microbiota, and Intestinal Immunity. Mediators of inflammation. 2021;2021:8879227. doi:10.1155/2021/8879227 [3] National Institutes of Health. Omega-3 Fatty Acids – Consumer. Updated September 22, 2021. Accessed April 26, 2023. https://ods.od.nih.gov/factsheets/Omega3FattyAcids-Consumer/ [4] DiNicolantonio JJ, O’Keefe JH. The Importance of Marine Omega-3s for Brain Development and the Prevention and Treatment of Behavior, Mood, and Other Brain Disorders. Nutrients. 2020;12(8):2333. doi:10.3390/nu12082333 [5] Chang CY, Ke DS, Chen JY. Essential fatty acids and human brain. Acta neurologica Taiwanica. 2009;18(4):231-241. [6] Cutuli D. Functional and Structural Benefits Induced by Omega-3 Polyunsaturated Fatty Acids During Aging. Current neuropharmacology. 2017;15(4):534-542. doi:10.2174/1570159X14666160614091311 [7] American Heart Association. Fish and Omega-3 Fatty Acids. Updated April 5, 2021. Accessed April 26, 2023. https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/fats/fish-and-omega-3-fatty-acids