We hear about omega-3’s all the time. But what are they? Why do we need them? How do we get them in our diets? And what do vegans and vegetarians need to be aware of? It’s all about omega-3’s today!
What they are:
Omega-3 fatty acids are polyunsaturated fatty acids (PUFA) that are essential for human health. They’re referred to as essential because our bodies can’t produce them; we need to get them from food or supplements.
We need omega-3’s for many important functions such as building healthy cells, blood clotting, building cell membranes in the brain, and maintaining brain and nerve function. They’re also associated with protection from heart disease and possibly stroke, with new studies identifying benefits for a wide range of conditions such as some cancers, rheumatoid arthritis, type-2 diabetes, Alzheimer’s disease, and age-related brain decline.
There are three types of omega-3 fatty acids involved in human physiology:
- ALA (alpha linolenic acid)
- DHA (docosahexaenoic acid)
- EPA (eicosapentaenoic acid)
ALA is the simplest of the three, but arguably the most important since our bodies can’t make it from scratch. There are two important metabolic roles that dietary ALA plays. First and foremost, ALA is broken down as an energy source for our cells – as much as 85% of dietary ALA is used in this way. The other major role of ALA is to be converted by elongation into EPA and DHA.
Sources of ALA, include flax seeds, walnuts, chia seeds, hemp seeds, tofu, tempeh, spinach, cauliflower, winter squash, and olive oil.
DHA is of particular importance for brain function. The human brain is approximately 60% fat (by weight) and about 15-20% of all the fat in our brain is comprised of DHA. Important! Reduced DHA levels are associated with cognitive impairment, reduced neurological development, and nervous system deficiencies. DHA is especially important during pregnancy and lactation.
EPA contributes to our inflammatory system. The proper function of this system depends on the presence of messaging molecules called prostaglandins, many of which are made directly from EPA. And most of the prostaglandins made from EPA are anti-inflammatory in their effect. So you can see how the risk of inflammation-related disease is related to the amount of EPA in our diets.
Sources of DHA and EPA include fatty fish (such as salmon, tuna, and mackerel), egg yolks, and some dairy products. It’s important to note that the DHA and EPA content of these animal foods is strongly linked to the diet of the animal came from. As a general rule, the dairy products and eggs obtained from cows and hens that have had access to natural pasture plants and grass have much superior omega-3 content compared to those from animals that did not have the opportunity to eat pasture plants containing omega-3’s.
Okay, so what does this all mean?
What this all adds up to is that our immune, cardiovascular, nervous, and inflammatory systems can’t function properly without sufficient amounts of EPA and DHA. And since ALA is used to synthesize EPA and DHA, ALA plays a critical role in the health of many body systems as the key building block for EPA or DHA. This is especially important for us veg heads who don’t eat many sources of EPA or DHA, and even more important for vegans who can only take in ALA.
Theoretically, we should be able to eat foods that contain ALA and then trust that our bodies will convert it to EPA and DHA. How reliably this happens is an area of uncertainty in the scientific community.
But what about omega-6’s?
You’ve probably also heard about omega-6 fatty acids, right? Omega-6’s are PUFAs, and are present in our diets mostly in the form of linoleic acid from plant oils such as corn oil, sunflower oil, and some nut and seed oils. Omega-6’s are waaaaaay more plentiful in the typical western diet than omega-3’s are.
The problem isn’t that they’re unhealthy – in fact the American Heart Association recommends that at least 5 -10% of food calories come from omega-6 fatty acids – it’s just that our body has only so much capacity for utilizing these fatty acids, and if that capacity is saturated with omega-6’s we end up absorbing fewer omega-3s.
The idea ratio of omega-6:omega-3 fatty acids in our diet is still an area of considerable debate. It has been estimated that in the US the ratio is somewhere between 20:1 and 8:1 (meaning we consume at least 8 times more omega-6 than omega-3). Most studies suggest that a healthier ratio lies somewhere between 4:1 and 2:1, however, this has not been agreed upon.
So what do I do?
Well, I think it’s fair to say we could all benefit from more omega’3 fatty acids in our diets. Simple changes, like increasing your intake of nuts (walnuts are especially rich) or seeds (flax and chia are both great) can go a long way. Aim for eggs and dairy from grass-fed or pasture raised animals, which will be richer in omega’3s. For those of you who eat fish, consider fatty fish (like salmon) on a regular basis. And if you eat meat, consider purchasing the meat off grass-fed and pasture raised animals.
For those who are strict vegetarian or vegan, it’s considerably more difficult to get EPA and DHA directly from food. The recommendation is, therefore to increase your intake of ALA-containing foods.
The American Dietetic Association recommends and average of 500mg of total EPA and DHA per day – this works out to approximately two servings of fatty fish per week.
The Child Health Foundation recommends that pregnant and lactating women should get an average of 200mg of DHA per day.
For vegans and strict vegetarians, one recommendation is to increase consumption of ALA-containing foods so that you’re consuming approximately 4 grams of ALA per day since you’re relying on your body to convert ALA to DHA and EPA.
There are also vegan omega’3 supplements derived from algae (which is where the fatty fish get their omega-3’s to begin with). Whether or not vegans with adequate ALA intake actually need to take a supplement is currently unclear. It’s a decision you should make for yourself, and speak to your doctor about if you’re concerned about your omega-3 intake.
Some food sources of ALA:
- 2 Tbsp chia seeds = 4.9 grams
- 2 Tbsp flax seeds = 3.19 grams
- ¼ cup walnuts = 2.72 grams
- 1 cup soybeans = 1.01 grams
- 125g tofu = 0.66 grams
- 1 cup Brussels sprouts = 0.27 grams
- 1 cup cauliflower = 0.21 grams
- 1 cup winter squash = 0.19 grams
- 1 cup broccoli = 0.19 grams
- 1 cup spinach = 0.17 grams