Food sources of Omega-3
Many seeds such as flaxseed are sources of an omega-3 fatty acid called ALA, which is most abundant in plants. Great sources of ALA are nuts and seeds, with flaxseeds and chia seeds containing the highest levels. One tablespoon of groud flaxseed will provide approximately 1.5g of ALA, which is for most people will meet their daily needs. If you don’t like the texture/ flavour of flaxseed are and looking to get more ALA in your diet, you can always get some flaxseed oil, and add it to a smoothie. It has quite a mild nutty taste.
Fish oil contains the omega-3 fatty acids EPA and DHA. There are 2 types of fish: oily fish (such as mackerel) and none oily fish (such as cod). With oily fish, the omega-3 fatty acids are are found in the flesh of the fish, whereas the omega-3 fatty acids in non-oily fish are found in the liver – hence the popularity of cod liver oil (in its various forms). 100g of mackerel will provide approximately 2.5g of omega-3 fatty acids, the majority of which are EPA and DHA. These fats are also found in smaller quantities on most animal fats such as beef. If you don’t eat fish for one reason or another you can get these fatty acids from a good quality fish oil, or stick with vegetable sources of ALA.
For information on the difference between flaxseed oil and cod liver oil as a source of omega-3 you can read this article.
How much Omega-3 do I need to consume?
Despite the clear health benefits of omega-3 fatty acids, and their necessity in maintaining a healthy body, there is no set guideline for how much omega-3 fatty acids we need to consume. Fortunately, the body is able to store these fatty acids, and so there is no need for a daily supply, but because they are so important in maintaining good health, I would recommend a minimum of consuming at least 2g omega-3s 3 times a week (although there is no harm in consuming more). If you struggle with this, I would recommend supplementing your diet with a good quality omega-3 supplement. A great way to increase omega-3 in your diet is to snack on nuts and seeds (particularly walnuts, pecans and flax seeds).
What is Omega-3
Omega-3 actually refers to a sub-category of polyunsaturated fats. More specifically it is any polyunsaturated fatty acid whose carbon chain has its first double valence bond three carbons from the beginning, or in other words – molecules which all share a common structural trait. Almost the same way all our fingers have 3 bones and 3 knuckles, but are different lengths and are needed for slightly different things. There are a number of fatty acids which are classed as omega-3s, but only 3 are of great importance to human nutrition- eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and alpha-linolenic acid (ALA). Below you can see the structural differences between EPA and ALA so you can see the similarities and differences.
Benefits of omega-3
The primary health benefits attributed to omega-3 fatty acids are; promoting cardiovascular health, promoting joint health, improving neurone (or brain) function, and promoting overall health. Large studies on omega-3 fatty acids, such as the GISSI and JELIS study have shown that these fatty acids certainly do promote cardiovascular health. Briefly, I will cover the specific benefits of the 3 important omega-3 fatty acids:
Alpha-linolenic acid (ALA)
ALA is the only omega-3 which is considered to be essential, because both EPA and DHA can be made from ALA by our body. The conversion flow is ALA > EPA> DHA, but this conversion is inhibited by omega-6 fatty acids which are abundant in modern diets, meaning a dietary source of EPA and DHA are advisable. Aside from being able to be converted into EPA and DHA, ALA is involved in numerous biological functions from neurone protection to cardiovascular protection. ALA is a vital omega-3 for many functions, but it is not known for exerting a specific benefit on the body, and studies into ALA alone are limited or inconsistent in their findings.
Eicosapentaenoic acid (EPA)
EPA has been subject to much clinical research, one of the most prominent of which is the JELIS study in Japan which specifically looked at EPA. The JELIS study showed that that EPA was particularly beneficial in promoting cardiovascular health, and preventing cardiovascular disease. There is also evidence that EPA supplementation can improve mental disorders such as schizophrenia, anxiety and depression – suggesting it has some neurological benefit, although due to limited research this isn’t fully understood. EPA has also been shown to reduce inflammation, which can increase joint mobility and reduce pain in joints. As EPA can be converted to DHA, some of the benefits observed by EPA could be a result of its conversion to DHA.
Docosahexaenoic acid (DHA)
DHA is most recognised for its role in brain function, and is the most abundant fatty acid in brain tissue. Low dietary DHA levels are associated with neurone death, and its link to mental health is quite clear and important. DHA has also been shown to reduce inflammation which will have similar benefits to EPA on joints.
Omega-3 and prostate cancer
There has been recent concern that omega-3 can increase the risk of prostate cancer after a study found a correlation. These findings have since been heavily criticized, and in reality the findings are inconsistent at best. If a risk is present, it will only be very small, and the benefits to the cardiovascular system alone are likely to outweigh the risks. I certainly won’t be avoiding omega-3 fatty acids, and will still consume them whenever I can.
There are 3 important omega-3 fatty acids – ALA, EPA and DHA, and these fatty acids area associated with improving cardiovascular health, joint health, mental health and general health. They are thoroughly researched, and their benefits (particularly to the cardiovascular system) are beyond doubt. Foods high in these fatty acids include nuts, seeds and oily fish, and although no RDA has been established, you should be consuming these foods regularly. There are no proven negative effects of consuming omega-3 fatty acids, although there is speculation they may increase the risk of prostate cancer.