Omega-3s and Heart Disease: Flax Oil versus Fish Oil

Health Professional

A recent study published this past September compared the benefits of flax oil versus fish oil in raising blood levels of heart healthy omega 3's. Adequate omega 3 intake is linked to lower blood pressure, lower triglycerides, increased HDL cholesterol, and reduced arterial inflammation.

Flax oil contains the omega 3 fatty acid ALA (alpha-linolenic acid), while fish oil contains EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). The benefits of ALA continue to be studied, but EPA and DHA have been positively linked to heart benefits.

The body can convert ALA to EPA and DHA, but it's been well known that this conversion process is not efficient. According to a recent study published in Nutrition Reviews, 8-20% of ALA is converted into EPA. From this, only 0.5-9% is converted to DHA.

To test the benefits of ALA supplements (flax oil) in amounts commonly consumed, the study followed 62 firefighters. The participants were divided into 6 groups and monitored for 12 weeks. Here are the six groups:

1.2 grams of flax oil per day
2.4 grams of flax oil per day
3.4 grams of flax oil per day
0.6 grams of fish oil per day
1.2 grams of fish oil per day
Sunflower placebo

Results showed an increase of EPA and DHA in the blood for those taking both levels of fish oil supplements. The EPA levels in red blood cells almost doubled by the studies end.

Now, the flax oil supplements did not have the same result. Those receiving 1.2 grams of flax oil daily did not show a significant rise in EPA and DHA, only ALA. The 2.4 g and 3.6 g flax oil supplements increased ALA, EPA, and DHA levels. EPA was increased 30% with a 2.4 g supplement and 40% with 3.6 g of flax oil daily. However, there was no corresponding increase in DHA. This confirmed the original belief that conversion of ALA into DHA is minimal.

The results of this study support my recommendations related to omega 3 supplements. First, consume a diet rich in omega 3 fatty acids (i.e. fish, nuts, flaxseed). Second, select a fish oil supplement high in EPA and DHA. Choose a supplement with 850 mg of DHA and EPA per gram of fish oil. Third, if you do not tolerate fish oil, select a flax oil supplement providing at least 1 gram of omega 3 fatty acids daily.

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