Two weeks of supplementation with 200 mg of DHA was enough to induce an antioxidant effect in men, according to results published today in The FASEB Journal.
"This study shows that regularly consuming small amounts of DHA is likely to improve the health status of people, especially in regards to cardiovascular function," said study co-author Michel Lagarde from the University of Lyon.
Some action but not enough
Labelling reference intake values for long-chain omega-3 fatty acids – most notably EPA (eicosapentaenoic acid) and DHA – are a hot topic in industrial, regulatory, and academic circles.
In July, the European Food Safety Authority’s (EFSA) Panel on Dietetic Products, Nutrition and Allergies (NDA) determined that 250mg should be the reference intake value for EPA plus DHA.
Such a stance was challenged by “compelling evidence” published in the Journal of the American College of Cardiology, which reported that daily EPA plus DHA intakes should be at least 500 mg per day for healthy individuals, while people with known heart disease or heart failure should aim for up to 1,000 mg daily.
These conclusions are in agreement with recommendations from the American Heart Association, which states that people with coronary heart disease should consume about one gram of EPA plus DHA a day.
A group of prominent lipid scientists also urged the EU to rethink of draft daily reference intake levels for the fatty acids. “Better no regulation than a bad regulation”, they said.
Led by Dr Evelyn Véricel, the French researchers recruited 12 healthy men aged between 53 and 65 and assigned them to consume increasing doses of DHA of 200, 400, 800, and 1600 milligrams per day for two weeks.
The researchers report that after two weeks of 200 mg per day vitamin E levels in the blood platelets increased, while the same dose was also associated with reductions in levels of isoprostane in the urine. Isoprostanes are accurate markers of oxidative stress in humans. However, the 1600 mg per day dose was associated with increased isoprostane levels, said the researchers.
“Therefore, supplementation with only 200 mg/d DHA for 2 wk induced an antioxidant effect,” said the researchers.
“It is concluded that low consumption of DHA could be an effective and non-pharmacological way to protect healthy men from platelet-related cardiovascular events,” they concluded.
Commenting independently on the study, Gerald Weissmann, MD, Editor-in-Chief of The FASEB Journal said: “Now that we have a very good idea about how much DHA is just right, the next step is to try it out in an expanded clinical trial that involves many more people.”
Source: FASEB Journal
September 2009, Volume 23, Pages 2909-2916, doi: 10.1096/fj.09-133421
"Increasing intakes of the long-chain -3 docosahexaenoic acid: effects on platelet functions and redox status in healthy men"
Authors: N. Guillot, E. Caillet, M. Laville, C. Calzada, M. Lagarde, E. Véricel