Omega-3 is an essential polyunsaturated fatty acid (PUFA). PUFAs are made up of long chains of carbon atoms, with a carboxyl group (COOH) at one end and a methyl group (CH3) at the other end of the chain. Omega-3s have a carbon-carbon double bond located three carbons from the methyl end of the chain. The majority of the literature focuses on three different types of omega-3's, namely: alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). ALA, EPA and DHA are considered essential as they are required for optimal health but cannot be synthesised by the body. This is because we can only form carbon-carbon double bonds after the 9th carbon from the methyl end of a fatty acid. Small amounts, estimated to be less than 15% (1), of ALA can be converted into EPA and DHA but the process is limited. As such, EPA and DHA must be obtained through diet or supplementation (2).
The main types of Omega-3's
ALA - contains 18 carbon atoms
ALA is the most common omega-3 fatty acid in the diet. You can get it from plant based foods such as chia seeds, flax seeds, walnuts and hemp seeds. ALA is an important component of the diet and small amounts can be converted into EPA and DHA, but it does not provide the health benefits that are seen with EPA and DHA.
EPA - contains 20 carbon atoms
EPA is mainly found in oily fish, fish oils and algae (3). The fish synthesise their EPA from microalgae, as such you can supplement you diet with algae oil.
DHA - contains 22 carbon atoms
DHA is a key structural component of your brain, retina (eye), and sperm cells making it the most important omega-3 fatty acid. Like EPA, it is present in many oily fish and fish oils.
The health benefits of consuming Omega-3
Consuming adequate amounts of EPA and DHA have a wide range of health benefits, these include:
- PUFA intake can influence cell lipid and lipoprotein concentrations which, in turn, reduce inflammation (4).
- Fighting depression and anxiety
- Omega-3s can travel through the brain cell membrane and interact with the molecules responsible for your mood. Their anti-inflammatory nature may also help relieve symptoms of depression (5). Most studies conducted on patients with depression used a combination of omega-3 and antidepressants. More research is required on omega-3s alone for this to be conclusive.
- Improving retinal health
- DHA is found in high concentrations in the retina. It has been suggested that if you have a diet low in DHA, your retina can degrade over time (6).
- Promoting brain health and cognitive function
- Essential fatty acids constitute 1/3 of all brain fatty acids, mostly in the form of phospholipids of which DHA dominates.
- Consuming omega-3s may reduce your risk of developing Alzheimer's or dementia (7), however more research is needed to back this claim.
- Reduced risk of cardiovascular disease
- Having a diet rich in EPA and DHA lowers your triglyceride levels which can reduce your risk of heart disease, heart attack and stroke (1).
- Improving bone and joint health
- Studies on patients with arthritis revealed that omega-3 supplementation reduced the patients use of anti-inflammatory drugs (8).
- Fetal development
- Consumption of omega-3 during pregnancy is important for fetal growth and development. It has also been shown to improve the health and intelligence of the baby (9).
The western diet is very high in omega-6 fatty acids (seed and vegetable oils, grain-fed meats, soybeans and corn), with an omega-6/omega-3 ratio of 15:1, despite the recommended ratio ranging from 1:1 to 4:1 (10). This is significant because omega-3 and 6 compete for the same metabolic pathway. Whilst omega-6s do have their place in our diets, if you are consuming the higher ratio, you will not reap the health benefits of omega-3s (11).
Algae Oil as a Source of Omega-3
Many strains of marine algae have evolved to survive in a vast array of environments ranging from the arctic to the tropics, varying in UV exposure, temperature, and nutrient availability (12). Their high concentration of oil, 30-70% of their total dry weight (13), is what allows them to inhabit in these conditions. This oil concentration is a survival mechanism functioning as an energy stockpile. Omega-3 is accumulated due to this energy content, making microalgae the primary producers of EPA and DHA (14).
Whether on a plant based diet or wanting to reduce your fish intake, due to the high mercury levels or fish stock depletion, algae oil is a great supplement and a viable alternative to fish derived oil (14). Be sure to check the labels when buying algae oil supplements that they contain both EPA and DHA as concentrations of these fatty acids vary between algae species.