By now you most likely have heard that you need more Omega-3 fatty acids in your diet. It seems to be all the rage these days – providing a panacea of health benefits ranging from improved skin and mood, to easier pregnancies and healthier babies. But just where do we go about finding these oh-so-important fats?
There seems to be some.. shall we say.. misguided, information floating around out there about what are good sources of omega-3 fatty acids. (*If you are unsure what makes omega-3’s so important, check out my article series on Fats).
Let’s first do a quick recap on what omega-3 fatty acids are. They are composed of three important substances: EPA, DHA and ALA. ALA (alpha-linolenic acid) is the kind found in plant foods such as chia seeds and flax seeds. EPA (eicosapentanoic acid) and DHA (docosahexanoic acid) are both found only from animal sources such as oily fish and fish oils.
EPA and DHA are absolutely critical to healthy brain function, and brain development in babies. DHA is particularly important for retinal development and nervous system function, while EPA is vital for proper immune system development and preventing depression. Women who are deficient in these important omega-3 fats during pregnancy may be more likely to suffer from preeclampsia and preterm labour, according to this study.
I see a lot of advice – specifically aimed at vegetarians – to eat lots of flax seeds and chia seeds to get Omega-3’s. The argument is that the ALA present in these seeds is converted into EPA and DHA in our bodies, so this makes them a good source of these nutrients. Unfortunately this conversion rate is shockingly inefficient and can be hindered by many factors, including age; rancidity and oxidation of the seeds; and lack of an important enzyme needed for this conversion (the same enzyme involved in a conversion of Omega-6 fatty acids, which usually leaves little leftover for ALA conversion when the diet is too high in Omega-6, which is the case for most of us). Also, ALA is much more bioavailable in flax seed oil, or milled flax, as opposed to the whole seeds. The problem with this is that the delicate fats oxidize and go rancid rapidly in these products (which then hinders the ALA conversion to EPA and DHA – it’s a double edged sword).
So the problem with obtaining all of your omega-3 intake from plant foods, is that you are mostly getting the ALA version of Omega-3.
Having said that, there are some well-documented cardiovascular benefits from ALA, and these should not be overlooked. However, we need to understand that the benefits of EPA and DHA on development of the brain, nervous system and immune system cannot be obtained solely from sources of ALA. I would even go so far as to argue that EPA and DHA are much more important (especially during preconception and pregnancy), and that other dietary and lifestyle factors to prevent and treat cardiovascular disease should be considered first, instead of loading up your diet with flaxseed.
There are some other reasons why I wouldn’t recommend flax seeds in high doses. One is that they are one of the most potent phytoestrogens in our food supply (up there with soy). A phytoestrogen is a substance that comes from food and acts like estrogen in our bodies. This can alter hormone levels, and have serious effects for those who are already estrogen-dominated. In fact, I usually recommend that women AND men stay away from phytoestrogens as much as possible (especially women who haven’t reached menopause yet). Too much estrogen can have negative effects on fertility for both sexes, and can cause bloating, mood swings, depression, insomnia, fatigue and low libido. Once women have reached menopause however, small amounts of phytoestrogens from sources such as flax, can help to boost very low estrogen levels (common after menopause).
Another downside to flax is its goitrogenic effect. Goitrogens are substances that hinder the thyroid gland by interfering with iodine uptake by the gland. A lack of iodine results in an enlarged thyroid (goiter). If you read my article on Sea Salt vs. Table Salt, you will recall that iodine is absolutely critical for brain function and mental health in infants and mothers during pregnancy. Low thyroid function can lead to a myriad of other health problems (thyroid hormones are one of only two known substances to act on every SINGLE cell in the human body – the other is vitamin D – it literally effects everything).
Though chia seeds are not goitrogenic, or a phytoestrogen, they still have the problem of only containing the ALA version of Omega-3, and so have none of the benefits of EPA and DHA.
So what are better sources of EPA and DHA? Seafood and fish oils definitely take the cake. The Omega-3 from these sources are present in much higher concentrations and are more bioavailable, without any of the downsides or dangers of too much flax. Wild seafood is absolutely essential – there are many many reasons why I wouldn’t recommend farmed seafood (for more info on this, check out my article onGetting to Know Your Meat), one of which is that wild seafood has WAY higher levels of Omega-3 fats. Sockeye salmon and sardines are the cream of the crop in this regard. These fish are also very low in mercury and other contaminants so are safer during pregnancy (and, really, for everybody).
If you don’t have access to fresh wild seafood, the next best thing would be fish oil supplements such as krill oil or fermented cod liver oil. Be sure to buy the highest quality you can find as these supplements have a tendency to go rancid during production and storage in lesser-quality supplements.