Once fats are consumed, they are broken down into smaller molecules. Omega 3 fats begin as ALA (alpha-linolenic acid ) and then break down into two of the most popular fatty acid molecules considered critical for human health:
- Eicosapentaenoic acid — EPA
- Docosahexaenoic acid — DHA
Fish sources of omega-3 fatty acids contain EPA and DHA because fish consume ALA-rich algae and break it down into EPA and DHA, while plant sources only contain ALA. When we consume plant sources of fatty acids, we must rely on our body to convert ALA to EPA and DHA. Our ability to convert the ALA to the more beneficial EPA and DHA can vary based on many factors including our nutrition status and genetics. For this reason, it can often be advantageous to have a fish-based source of omega-3's as it is a more efficient source of EPA and DHA. But for those who prefer vegetarian sources, flax and other omega-3-seed oils are good options. To account for the conversion that must occur in the body, a higher amount of flaxseed (or other seed oil) must be taken to receive comparable (and therapeutic) levels of EPA and DHA to those found in fish oil.
EPA is most popularly known for its effect in reducing inflammation. Because of this property, it is commonly recommended for any health condition associated with inflammation. EPA helps keep the blood from clotting easily, which is generally considered a beneficial effect, but should be cautioned for those already taking a blood-thinning medication or for those preparing for surgery.
DHA is a major fatty acid found in sperm, brain cell structures, and in the retina. DHA is often referred to as "brain food" because of the high-concentrations of DHA found in the brain tissue. DHA is richly supplied during breastfeeding as it is a major component of breast milk. In humans, DHA is either obtained from the diet or synthesized from EPA.
- A note on dosing: as you can see, the beneficial aspect of fish oil supplementation comes from its EPA and DHA content. For this reason, when choosing a fish oil supplement, it is important to read the ingredients list for the amount of EPA and DHA supplied. Just because a supplement claims to contain say, "3,000 mg of omega-3's," it may only contain a small amount in the form of EPA and DHA. Most of the therapeutic effects of these fatty acids are only achieved when the EPA+DHA levels are at least 2,000 mg daily.