Experts believe that increased levels of omega-3s exert corrective effects. For example, one study demonstrated that, in the secondary prevention of cardiovascular disease, a ratio of 4:1 correlated with a 70% decrease in total mortality of study participants. Another study showed that a ratio of 2.5:1 reduced rectal cell proliferation in patients with colorectal cancer (progression slowed), yet a ratio of 4:1 did not produce any significant changes.
Eicosanoids and The Impact of Omega-3 Fatty Acids
Eicosanoids are signaling molecules used throughout our body, and they play an important role in physical activity, inflammation, immunity, and the central nervous systems. Even though they can be derived from both omega-3 and omega-6 fatty acids, the omega-6 tend to be pro-inflammatory. Thus, the fatty acids we make available to ours bodies can play a large role in determining the way in which many of our bodily functions occur.
Many of the most famous anti-inflammatory medications (non-steroidal anti-inflammatory drugs) act by down-regulation of the eicosanoid synthesis. The most famous of these drugs is aspirin.
Even though scientists are still not 100% sure if omega-3s can fully replace the role of anti-inflammatory drugs, they agree that omega-3s play a crucial role in regulating the eicosanoids. Thus, the potential to regulate the eicosanoid synthesis through improvement of the omega ratio holds much value.
Some Specific Highlights From Studies
The role of balancing the omega ratio has been shown to have the following clinically documented effects:
- A ratio of 4:1 correlated with a 70% decrease in total mortality of patients with cardiovascular disease
- A ratio of 2.5: 1 reduced rectal cell proliferation in patients with colorectal cancer (progression slowed), yet a ratio of 4:1 did not produce any significant changes
- A ratio of 3:1 suppressed inflammation in patients with rheumatoid arthritis
- A ratio of 5:1 had beneficial effect on patients with asthma, while a ratio of 10:1 had negative effects
Summary of Omega-3 Fatty Acid Benefits
Specific cardioprotective effects of omega-3 fatty acids:
- Reduces triglycerides
- Reduces blood pressure
- Inhibits platelets
- Reduces blood clotting
- Improves plaque structure
- Anti-arrhythmic (suppresses abnormal rhythms of the heart)
- Improves endothelial (interior surface of blood vessels and lymphatic vessels) function
- Cancer prevention
- Improves insulin sensitivity
- Enhances thermogenesis and lipid metabolism
- Benefits vision and brain function
- Decreases skin inflammation
Different Types of Omega-3s
Falling under the classification omega-3s are a large number of specific fatty acids, which we obtain from many different sources.
The most researched of theses are DHA and EPA. These omega-3 fatty acids can be obtained through diet (mainly from seafood) or synthesized within the body from ALA (alpha-linolenic acid – another omega-3). However, the conversion of ALA to DHA and EPA is not very efficient (conversion efficiency is below 5%). Additionally, the process used for conversion of ALA directly competes with the breakdown of omega-6 fatty acids. As a result, an abundance of omega-6 fatty acids further decreases the efficiency for humans to obtain needed EPA and DHA (from ALA) declines further. Luckily, DHA and EPA can be obtained directly through diet.
Fish and marine products are the best source of DHA and EPA. However, there is significant variant among different fish species. For example, while Pacific Herring can have 1.06g of EPA and 0.75g of DHA per 3 ounce serving, Pacific Cod only has 0.09g of EPA and 0.15 of DHA for the same 3 ounce portion. As a result, some marine products are much better than others for obtaining these fatty acids.
ALA is widely available from plant sources. The most popular of these appears to be Flax Seeds, which contain roughly 50% of its oil composition in the form of ALA. As a result, a single tablespoon of ground flax seed contains about 1600 mg of ALA. At the 5% efficiency level mentioned above, this can be converted to about 80 mg of DHA and EPA, which is actually quite unimpressive. However, the pure oil is a little better as a single tablespoon contains 8.5g of ALA (425 mg DHA and EPA). Some other sources of ALA include:
- Walnuts (1 ounce = 2.6 ALA)
- Canola Oil (1 tablespoon = 1.2 ALA)
- Mustard Oil (1 tablespoon = 0.8 ALA)
However, because these plant sources of omega-3 always contain some quantity of omega-6, the final amount of obtained DHA and EPA is unclear.