Docosapentaenoic Acid, DPA: The overlooked Omega-3 PUFA?

When it comes to healthy beneficial dietary fats the omega-3 polyunsaturated fatty acids (PUFA) are the stars on the red carpet. Most people have become familiar with the heart healthy benefits of having omega-3 fatty acids in their diet and they also know that the two major omega-3 fats are called EPA and DHA (eicosapentaenoic acid and docosahexaenoic acid, respectively). In addition, most people have become familiar with the fact that fish oil is enriched in EPA and DHA. Another highly beneficial source of EPA and DHA is the oil of the tiny shrimp-like crustacean called Krill. The added benefit of Krill oil is that it also contains a potent anti-oxidant compound called astaxanthin which fish oil lacks. Of course for vegetarians, and especially for vegans, these are not ideal sources of EPA and DHA. Often touted as beneficial vegan sources of for getting EPA and DHA is to consume plant-derived oils that are enriched in the precursor (alpha-linolenic acid, ALA) to EPA and DHA, for example flax seed oil. Although ALA can serve as the precursor for EPA and DHA synthesis in humans, this pathway is highly limited in its capacity and also varies between individuals. In healthy females only around 20% of dietary ALA is converted to EPA and less than 10% is converted to DHA. In healthy males only around 8% of ALA is converted to EPA and there is no conversion to DHA. The rates of EPA and DHA conversion from ALA is reduced by up to 40% when ALA is consumed along with pro-inflammatory omega-6 fatty acids, such as the essential fatty acid linoleic acid and arachidonic acid, as is typical in the Western-style diet. In addition, the consumption of alcohol has been shown to reduce the level of DHA in the liver and the blood. Therefore, direct dietary intake of omega-3 fats rich in EPA and DHA are of the most benefit clinically.

During the synthesis of DHA from either ALA or EPA is another important but often overlooked omega-3 PUFA called docosapentaenoic acid, DPA. Indeed, EPA is converted to DPA and then DPA is converted to DHA in human cells. However, as indicated in the previous paragraph, the reactions of EPA and DHA synthesis in humans are abysmal. Whereas fish and Krill oils are enriched in both EPA and DHA, less than 2% of the fatty acid in these oils is DPA. The significance of DPA for human physiology is apparent from the fact that human breast milk has nearly as much DPA as DHA, and DHA in breast milk has been convincingly shown to be critical for development of the neonatal brain. Like EPA and DHA, seafood represents the richest dietary sources of DPA with Atlantic mackerel and Florida pompano containing more DPA per 100 mg of edible meat than that of salmon which is one of the richest sources for EPA and DHA.

Numerous studies in humans have shown that a high level of DPA measured in the blood is correlated reduced total cholesterol, reduced serum triglyceride levels, and reduced intravascular inflammation, all of which are positively correlated to a reduction in the risk of atherosclerosis, coronary artery disease, and stroke. The process of blood coagulation involves platelets and inappropriate activation of platelets leads to potentially lethal thrombotic events (blood clots) in the vasculature. Additional benefits of DPA are that it is more effective at reducing platelet activation than EPA or DHA, thereby reducing the potential for blood clots. In comparison to other fatty acids, including EPA and DHA, the use of DPA in the oxidation process (simply stated, the conversion of food into energy) is low which allows the fatty acid to remain incorporated in important membrane lipids where it can be released rapidly in response to an appropriate stimulation event.

So the TAKE HOME from this overview of the benefits of DPA is don't forget nor neglect this critical cousin of EPA and DHA when considering a healthy life extending diet.

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