Omega-3 Fatty Acids
The 2015-2020 US dietary guidelines and the American Heart Association recommend at least 250-500mg of omega-3 fatty acids daily or 2 to 3 servings of 4-6oz of oily fish 🐟 per week.
However, When selecting fish, you should be conscious of fish with higher mercury levels. The bigger the fish (like swordfish, albacore, yellowtail and big eye tuna) the likely higher the mercury levels are.
How much is a serving of fish/protein? As a guide, use the palm of your hand as the size of one serving.
For an adult, 1 serving = 4-6 ounces
Eat 2 to 3 servings a week from the "Best Choices" list below (OR 1 serving from the "Good Choices" list).For children, a serving is 1 ounce at age 2 and increases with age to 4 ounces by age 11 (1)
Fatty/oily fish is an excellent source of omega-3 fatty acids, especially DHA and EPA. Fatty/oily fish include salmon, trout, pacific oysters, anchovies, sardines, and mackerel. Fish provide all of the essential fatty acids, including being great sources of both EPA and DHA.
Walnuts, chia and hemp seeds, flax, and algae oil are good plant sources of the omega-3 fatty acid, alpha-linolenic acid (ALA). ALA converts to EPA and then DHA in the body. However, the body is very inefficient at converting ALA to EPA and DHA. One study showed that only ∼2 to 10% of ALA is converted to EPA or DHA, while other studies reported even less (Chiu et al. 2008). Moreover, while flax is a source of EPA, it is not a good source of DHA. Algae oil is produced through a fermentation process that produces DHA but not EPA. Therefore, algae oil and flax oil need to be combined to get both DHA and EPA and yet, still this process is inefficient. As a result, fish and fish oil supplements are better sources of DHA and EPA.
What are the benefits of EPA and DHA?
The essential fatty acids DHA and EPA are important for brain 🧠, eye 👁, and heart ❤️ health and have both been found to reduce inflammation in the body. Specifically, EPA plays an important role in reducing cellular inflammation and DHA is essential for brain and eye development. Your brain is 60% fat. DHA accounts for 25% of that fat and 97% of the omega-3 fatty acids found in the brain (2). Studies have shown that EPA and DHA are important for proper fetal development, including neuronal, retinal, and immune function development. EPA and DHA also play a role in cardiovascular function, weight management, and improved cognitive function in those with very mild Alzheimer's disease (3).
Fetal Development Role:
The US Dietary Guidelines recommend that pregnant women consume 2 to 3 servings of fish per week or 8-12 oz of fish per week from the Best Choices list above. This equates to roughly 300–900 mg of EPA+DHA per day.
EPA and DHA are vital for the proper development of the brain and retina. Studies have shown that maternal supplementation increased hand and eye coordination scores and enhanced infant problem-solving skills at 9 months (Judge et al. 2007, Dunstan et al. 2008).
Maternal EPA and DHA supplementation during pregnancy may also protect children against allergies. For instance, Olsen et al (2008) showed that supplementation during pregnancy was associated with a decreased incidence of asthma in the children at 16 years old (4). Furuhjelm et al (2009) showed that 1 year old infants whose mothers supplemented with daily DHA and EPA had a decreased risk of food allergy and IgE-associated eczema (5).
Cardiovascular Role:
EPA and DHA have been shown to have anti-inflammatory effects, reduce oxidative stress, and improve cellular function in the heart through changes in gene expression. Studies have found that EPA and DHA could reduce the risk of a cardiovascular event by improving plaque stability and vascular permeability, and decreasing endothelial activation. High doses of prescription EPA has also been shown to protect high-risk individuals from cardiovascular events (6) (7).
I found this study to be particularly valuable. It is also linked throughout and below in resources. As always, for those on other medications, it is important to consult your doctor or dietitian whenever adding a supplement to your routine.
Resources:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3262608/
https://www.verywellmind.com/the-health-benefits-of-dha-89183#citation-1
https://www.health.harvard.edu/staying-healthy/should-you-be-taking-an-omega-3-supplement
https://pubmed.ncbi.nlm.nih.gov/18614738/