Omega-3s: Essential Fats for Your Heart, Brain, and Eyes

What are omega-3 fatty acids?

Omega-3s are unsaturated fats, specifically polyunsaturated fatty acids, that are required for maintaining health. Omega-3s are considered essential fatty acids because our bodies cannot make them and therefore, we need to get them through our food.

Omega-3s play a significant role in our bodies. They act as building blocks in cell membranes in many organs and tissues. In addition, omega-3s are involved in cell function including cell-to-cell interactions (1). Omega-3s are especially important for our heart, brain, and eyes (2).

What are the main types of omega-3s?

There are three main types of omega-3s: alpha-linoleic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). ALA is found in flaxseeds and flaxseed oil, canola/rapeseed oil, soybeans and soybean oil, pumpkin seeds/pepitas, and walnuts. EPA and DHA are both found in sardines, salmon, tuna, halibut, algae, lake trout, some plants, and nut oils. EPA and DHA are the omega-3s that have important health effects (1).

What are the benefits of omega-3s?

Eating foods rich in omega-3s may help (1):

• Lower the risk of heart disease, some cancers, and arthritis

• Reduce inflammation

• Regulate blood pressure

• Regulate blood clotting

• Regulate glucose tolerance  

While some studies demonstrate that a diet rich in omega-3s is associated with reduced atherosclerosis (the buildup of plaque in arteries) and improved cardiovascular health, this is not consistently supported by evidence (3, 4). However, eating foods with omega-3s is potentially a protective factor against heart disease due to effects on high blood pressure and high cholesterol (1, 4). For more information on eating for heart health, watch our February webinar.

For pregnant women, getting adequate essential fatty acids is critical for development of the fetal nervous system. Higher intake of omega-3s during pregnancy is associated with decreased maternal depression, reduced incidence of preterm birth, and reduced allergies and asthma in children. There is also an association between higher intake of omega-3s during pregnancy and improved neurocognitive outcomes in children (5).

Current and future research explores the role of omega-3s in depression and anxiety, cognitive decline and neurodegenerative diseases like Alzheimer’s disease, muscular performance during exercise, and stress disorders such as post-traumatic stress disorder (PTSD) (1, 6).  

What are the risks of not getting our omega-3s?

Newborns with omega-3 deficiency have reduced sensitivity to light, demonstrating the importance of omega-3s to eye health (3). In adults, low intake of omega-3s is associated with depression and anxiety (6).

 Should pregnant and breastfeeding women be concerned about mercury?

While fish is a great source of omega-3s that are critical for fetal development, some species of fish have high levels of mercury, a harmful toxin. The FDA has proposed fish consumption guidelines for pregnant and breastfeeding women. Choose salmon, sardines, and trout more often. Choose tuna less often, and buy canned light tuna. Avoid king mackerel, marlin, orange roughy, shark, swordfish, tilefish from the Gulf of Mexico, and bigeye tuna. The FDA’s full list of recommendations is available online (7).

 How can I incorporate more omega-3s into my diet?

Americans typically get adequate ALA but not enough EPA or DHA (8). The Dietary Guidelines for Americans 2015-2020 recommend that we eat fish twice per week, preferably oily fish like salmon and sardines (8). Enjoy these foods with omega-3s:

• Canned or fresh salmon

• Canned or fresh sardines

• Grilled trout

• Ground flaxseed

• Pepitas/pumpkin seeds

• Walnuts

• Edamame

We can also consider our method of preparation for foods. Instead of butter, cook in plant oils with omega-3s such as canola/rapeseed, flaxseed, and soybean oils.

 Can we get omega-3 fatty acids from fish oil?

Fish oil, including krill and algae oil, is a common dietary supplement that contains EPA and DHA (8). While there is moderate evidence that supplementing with fish oil lowers heart disease risk, it is not a widely accepted recommendation (8, 9). Rather, recommendations suggest eating fish at least twice a week due to both the nutrients in the fish itself and the benefits of swapping out other protein choices like red meat.

 References

1. Gammone MA et al. Omega-3 Polyunsaturated Fatty Acids: Benefits and Endpoints in Sport. Nutrients 2019;11(1):46.

2. Cholewski M et al. A Comprehensive Review of Chemistry, Sources and Bioavailability of Omega-3 Fatty Acids. Nutrients 2018;10(11):1662.

3. De Carvalho CCCR and Caramujo MJ. The Various Roles of Fatty Acids. Molecules 2018;23(10):2583.

4. Back M. Omega-3 fatty acids in atherosclerosis and coronary artery disease. Future Sci OA 2017;3(4):FSO236.

5. Nordgren T et al. Omega-3 Fatty Acid Intake of Pregnant Women and Women of Childbearing Age in the United States: Potential for Deficiency? Nutrients 2017;9(3):197.

6. Larrieu T and Laye S. Food for Mood: Relevance of Nutritional Omega-3 Fatty Acids for Depression and Anxiety. Front Physiol. 2018;9:1047.

7. FDA. Eating Fish: What Pregnant Women and Parents Should Know. 2018. Available from: https://www.fda.gov/Food/ResourcesForYou/Consumers/ucm393070.htm

8. Balk EM and Lichtenstein A. Omega-3 Fatty Acids and Cardiovascular Disease: Summary of the 2016 Agency and Healthcare Research and Quality Evidence Review. Nutrients 2017:9(8):865.

9. Lichtenstein AH. Do fish oil supplements actually help with heart health? Tufts Now. September 27, 2018. Available from: https://now.tufts.edu/articles/do-fish-oil-supplements-actually-help-heart-health