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TalkingNutrition

Providing perspectives on recent research into vitamins and nutritionals

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Do Your New Year’s Resolutions Include Achieving Recommended Omega-3 Intakes?

By Julia Bird

In some parts of the world, consuming foods rich in long chain omega-3 fatty acids is part of the normal diet. Countries like Japan, Sweden and Portugal are famous for the use of fatty fish in their cuisine, and ecological surveys of fish consumption have found that people in these countries have relatively high intakes of fish.

Where I grew up in Australia, however, fish intakes are relatively low. When I decided that I wanted to make a healthy change a few years ago to meet recommendations about fatty fish consumption, and thus increase my consumption of heart-healthy omega-3 fatty acids, I had an upward struggle. I had not grown up consuming much fish apart from the occasional fish finger, tuna sandwich and even more rare, yet undeniably traumatic, consumption of my mother’s fried leatherjacket*. Not only was fish not a normal part of my diet, I did not know how to cook fish and I did not like either the taste or smell of it. In the interest of my health, I made the courageous step to at least get used to cooking and eating fish. You could say that it was a resolution that I implemented slowly over the past ten years, with the use of strongly flavored sauces and condiments particularly at the start. Nowadays a serving of fish, mostly fatty, makes it to my plate at least twice a week. I now even enjoy eating fish.

Fish consumption in itself, however, is not the main goal. Associations between the long chain omega-3 fatty acids found in fish and a reduction in cardiovascular disease, and possible cognitive benefits, and the poor conversion of pre-cursor ALA to the longer chain variants DHA and EPA are behind these recommendations.  A recent cross-over study, by  Djuricic  and co-workers, looked at whether meeting recommendations for omega-3 fatty acid intakes via either fish or EPA/DHA supplements allowed low fish consumers to attain blood levels adequate for reduction in cardiovascular disease. In Serbia, where the study was conducted, fish consumption is low and around half the population consumes fish less than once a week. The researchers randomized 35 middle-aged men and women who normally consumed fish less than once per week to a cross-over study to consume either cold smoked salmon twice a week (providing 274+671 mg EPA and DHA per day) or two fish oil capsules per day with meals (providing 396+250 mg EPA and DHA per day). The supplementation period was for 8 weeks, and was followed by a 6-month washout period.

Both treatments resulted in a statistically significant increase in red blood cell and platelet long chain omega-3 fatty acid levels. Despite different doses provided by the fish and supplements, there was no significant difference in the levels obtained between the dietary and supplemental sources. While the mean percentage of EPA and DHA in red blood cells was somewhat low at 5.4% at the start of the study (levels of less than 4% are considered to be a strong concern, according to Harris), and mean levels increased to 6.7%, the intervention did not help subject achieve target levels of 8% EPA and DHA in red blood cells. It is likely that this relatively modest dose of EPA and DHA over a short period of time was not enough to bring subjects into the healthy range.

These are the results of an intervention study, and show that incorporating fish or supplements were both effective in raising levels of omega-3 in the body. How well do your omega-3 fatty acid intakes meet recommendations? There are some sophisticated dietary analysis programs available free to help people calculate omega-3 intakes such as Supertracker, a DHA calculator based on the normal US diet, and food frequency questionnaires such as this one from the Canadian University of Waterloo. It is also possible to reflect on your normal diet and consider whether you consume fish, especially fatty fish like salmon, mackerel, herring or tuna, once or twice a week, or a supplement with 200-500 mg EPA+DHA per day. If you don’t meet the mark, will your New Year’s resolution this year be to increase your intake of DHA and EPA?


Main citation:

Ivana D. Djuricic, Sanja D. Mazic, Jelena M. Kotur-Stevuljevic, Vladimir R. Djordjevic, Sladjana S. Sobajic. Long-chain n-3 PUFA dietary recommendations are moderately efficient in optimizing their status in healthy middle-aged subjects with low fish consumption: A cross-over study. Nutrition Research, Available online 3 January 2014. http://dx.doi.org/10.1016/j.nutres.2013.12.008


Supporting citations:

Harris WS. The omega-3 index: clinical utility for therapeutic intervention. Curr Cardiol Rep. 2010 Nov;12(6):503-8. doi: 10.1007/s11886-010-0141-6. http://www.ncbi.nlm.nih.gov/pubmed/20809235

Jianjun Zhang, M.D., Satoshi Sasaki, M.D., Ph.D., Keiko Amano, M.D., Ph.D., Hugo Kesteloot, M.D., Ph.D. Fish Consumption and Mortality from All Causes, Ischemic Heart Disease, and Stroke: An Ecological Study. Preventive Medicine, Volume 28, Issue 5, May 1999, Pages 520–529. http://dx.doi.org/10.1006/pmed.1998.0472

*The smell of the fish cooking, and the presence of bones in these small fish, were particularly off-putting to me as a child.



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