Omega-3 fatty acids come up a lot in the news. Perhaps you’ve heard that omega-3 supplements can help protect humans against certain chronic illnesses, or that omega-3s may be helpful to decrease symptoms of certain diseases. But what are omega-3s? And should you be taking omega-3 supplements? That’s what we are going to explore in today’s blog post.
Disclaimer: As always, this is general information intended for healthy adults. Your needs may vary based on medical status, lifestyle, or life-stage. Please never replace generalized health information you’ve read online with individualized clinical care.
What are omega-3 and omega-6 fatty acids?
Omega-3 and omega-6 fatty acids are the two major classes of polyunsaturated fatty acids (PUFAs). To read more about dietary fats in general, please see this post.
Omega-3 fatty acids have a carbon-carbon double bond 3 carbs from the methyl end of the chain, hence the name “omega-3s.”
There are many types of omega-3 fatty acids, but there are three main types of omega-3 fatty acids are focused upon when it comes to human health: alpha-linolenic (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).
Omega-3s play many important roles in the body. They are one of the major components of cell membranes. They also play a role in providing energy for the body, and are involved in cell signaling, which is important to cardiovascular, immune, and endocrine function. DHA is especially high in the retina, brain, and in sperm.
ALA is an essential fatty acid, meaning your body cannot make it, and thus you must obtain the nutrient from food sources. The human body is able to convert some ALA to EPA (primarily in the liver), and some EPA to DHA, but only in small amounts, with conversion rates typically less than 15%.
Because conversion is so inefficient, it is important to obtain EPA and DHA from the diet to ensure adequate amounts in the body. Which begs the question…
How much omega-3 fatty acids do I need?
Experts have not defined estimated dietary intakes of omega-3 fatty acids. However, adequate intake (AI) values have been proposed by the Institute of Medicine (IOM) for ALA only, because ALA is the only omega-3 that is essential.
The AI values for healthy adult females over 19 years of age is 1.1 grams per day of ALA omega-3s, and 1.6 grams of ALA per day for healthy adult males. It is recommended that pregnant women get at least 1.4 grams ALA per day, and breastfeeding women get at least 1.3 grams per day.
Some researchers have proposed that the ratio of omega-6 to omega-3 fatty acids consumed in the diet is important, and may have implications for the pathogenesis of various chronic diseases, including cancer and cardiovascular disease. However, there has not yet been a consensus of how important the omega-6:omega-3 fatty acid ratio is, and what the optimal ratio would be.
The USDA currently recommends people consume no more than 3 grams of EPA and DHA per day combined.
Research suggests that most people in the US consume the recommended amount of ALA.
What foods contain omega-3 fatty acids?
Some plant oils contain ALAs. Flaxseed (linseed) oil is a rich source of ALAs; soybean and canola oils are other rich sources. Walnuts, hemp hearts, flaxseeds, and chia seeds also contain ALA.
Omega-3s are also found in fatty fish. Salmon, mackerel, tuna, herring, and sardines contain high amounts of long chain omega-3s. Fish that are lower in fat (such as tilapia and cod) contain less omega-3 fatty acids.
Some eggs, yogurts, plant-based yogurts, milks, plant milks (including flax milk), tofus, and juices are fortified with DHA and omega-3 fatty acids. Typically, these are advertised as containing DHA or omega-3s; check your package for further details.
Many people take supplements to get omega-3s. Fish oil and krill oil are popular seafood-based supplements, and algal oil is an increasingly popular vegan alternative.
Here is a quick comparison chart of different foods that are common sources of omega-3s in the human diet: