Marine omega-3s may reduce depressive symptoms: Study

Intakes of EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) were linked to a 25% reduction in the number of depressive symptoms, according to data collected over a 24 hour period for 10,480 adults.

However, fish consumption measured over a 30-day period and fish oil supplementats were not found to have any effect on depressive symptoms, Claire Hoffmire and her co-workers report in the journal Prostaglandins, Leukotrienes and Essential Fatty Acids​​.

“The low correlations between fish meals and EPA+DHA we observed indicates that reported fish meals in the past 30 day may not be a strong predictor of fish-derived dietary omega-3 PUFA [polyunsaturated fatty acids],”​ they wrote.

“Therefore, we believe EPA+DHA from a 24-hour recall is a more accurate predictor of dietary omega-3 PUFAs in this study as findings from this analysis do support the a priori hypothesis that dietary omega-3 poly-unsaturated fatty acids reduce depressive symptoms.”​

Positive​

While the findings are not robust, the outcomes were described as “positive”​, by Harry Rice, PhD, VP of regulatory and scientific affairs for the Global Organization for EPA and DHA Omega-3 (GOED).

Dr Rice told NutraIngredients-USA that he would consider the outcome positive “given that the 24- hour recall data support a benefit of long-chain omega-3 intake and number of depressive symptoms.​

“The reality is that the heterogeneity of depression makes it a particularly difficult condition to study.​

“If I had to predict where the science will net out in years to come, I'd guess that EPA & DHA will be shown to benefit certain types of depression more than others.”​

Study details​

Hoffmire and her co-workers at the University of Rochester School of Medicine and Dentistry analyzed data on fish consumption and depressive symptoms collected using 30-day food frequency questionnaires and 24 hour dietary recalls. Data was available for 10,480 adults participating in the 2005–2008 National Health and Nutrition Examination Survey.

Results showed that consumption of meals containing fish were not associated with depressive symptoms. In addition, consumption of breaded fish was actually linked to anincreasein the risk of greater depressive symptom severity, they said.

On the other hand, EPA and DHA intakes assessed using the 24 hour recall method showed a significant 25% reduction in depressive symptoms.

Inconclusive​

While the data is inconclusive, the researchers noted that it is scientifically plausible that EPA and/or DHA can influence depressive symptoms.

“In the human body, DHA and EPA, and many of their metabolites produced via a variety of biochemical pathways, have substantial anti-inflammatory and tissue protective effects in several tissues,”​ they explained.

“As DHA is very highly concentrated in the central nervous system and a vital nutrient in its optimum development, its deficiency disrupts serotonin, norepinephrine, and dopamine transmission across cellular membranes, neurotransmitters that contribute to the mood and cognitive dysfunction aspects of depression.​

“EPA, meanwhile, may play a more important role related to the somatic symptoms which affect up to 80% of individuals with major depression.”​

Hoffmire and her co-workers called for more longitudinal studies to investigate the potential link between fish intake and omega-3 levels with depressive symptoms.

Source: Prostaglandins, Leukotrienes and Essential Fatty Acids​​
Published online ahead of print, doi: 10.1016/j.plefa.2012.03.003
“Associations between omega-3 poly-unsaturated fatty acids from fish consumption and severity of depressive symptoms: An analysis of the 2005–2008 National Health and Nutrition Examination Survey”​
Authors: C.A. Hoffmire, R.C. Block, K. Thevenet-Morrison, E. van Wijngaarden