EPA + DHA Associated with 25% Lower Risk of Depressive Symptoms in US Adults

Substantial evidence links low blood concentrations of long-chain PUFAs (LC-PUFAs), especially n-3 LC-PUFAs, to the risk of depressive illness, yet the data are inconsistent. For example, serum n-3 LC-PUFAs were not associated with severe depression in middle-aged Finnish men, but were significantly lower in patients with recurrent depressive illness. Others have reported significantly lower concentrations of DHA or total n-3 LC-PUFAs in patients with major depressive illness and bipolar disorder. Low LC-PUFA concentrations may be unrelated to dietary intake in randomized or case-control studies, although observational studies suggest that low seafood consumption is associated with higher rates of various mental disorders including depressive illness. Long-term fish intake was associated with less severe depressive symptoms in older adults in the Mediterranean Islands Elderly study. Fish is the main dietary source of n-3 LC-PUFAs. These observations suggest that increasing the intake of fish or n-3 LC-PUFAs might have a beneficial effect in patients with depressive illness and other mental disorders. One meta-analysis concluded that supplements containing at least 60% of the total n-3 LC-PUFAs as EPA were effective against primary depression. Another study reported that n-3 LC-PUFA supplementation was associated with improved depressive symptoms and quality of life in elderly women. But another systematic review and meta-analysis of 13 randomized trials of n-3 LC-PUFA treatment of major depressive disorder concluded that n-3 LC-PUFAs gave no significant benefit, except for a trend toward increased efficacy among lower quality trials. There was significant heterogeneity and publication bias in the trials. Some encouraging reports of benefit, the limited efficacy and adverse side-effects of current medications and a strong rationale for the use of n-3 LC-PUFAs in depressive illness and mood disorders support additional investigation of these fatty acids for depressive illness and other mental disorders. Further, the burden of mental health illness continues to grow. Predictions about world health suggest that unipolar depressive disorders will be the world’s leading cause of ill health and premature death by 2030. In the U.S., the 12-month prevalence of a major depressive episode was estimated at 8.3% for all adults 18 years of age or more, the highest rate among 10 developed countries participating in the WHO World Mental Health Survey Initiative. Associations between fish consumption and the prevalence of major depressive illness in several countries have been reported, based on intake estimates according to fish disappearance from the marketplace (food balance sheets). Claire Hoffmire and colleagues at the University of Rochester, USA, conducted a more detailed examination of this relationship using fish and EPA + DHA consumption estimates from the 2005-2008 National Health and Nutrition Examination Survey (NHANES) and the Patient Health Questionnaire to estimate the prevalence of depressive symptoms. The Patient Health Questionnaire is a self-assessment of the frequency of various signs and symptoms of depressive illness over the past 2 weeks. NHANES is a national, population-based survey that uses multistage, stratified and clustered sampling to obtain samples representative of the total US, non-institutionalized, civilian population of adults 20 years and older. Dietary information about fish intake was collected from a food frequency questionnaire and EPA + DHA consumption was estimated from two 24-hour dietary recalls. Total fish intake over a 30-day period was not associated with the occurrence of mild or moderate to severe depressive symptoms, regardless of the frequency consumed. Likewise, non-breaded fish was unrelated to the symptoms of depression. In contrast, the consumption of any breaded fish meals was associated with a significantly greater risk of depressive symptoms, although increasing frequency of consumption compared with low consumption did not increase the risk. The consumption of EPA + DHA was associated with a 25% lower risk of depressive symptoms in multivariate analysis, although the reduced risk was consistent across all levels of intake. Considering the limitations of dietary intake estimates, which the authors discuss in detail, these observations further support the benefits of consuming nonbreaded fish and EPA + DHA reported by others. The authors assume that the consumption of breaded fish implies fried fish, the consumption of which has previously been linked to greater risk of incident heart failure in women and older adults, and death from ischemic heart disease in adults 65 years of age or more. What distinguishes this report from previous epidemiological studies on n-3 LC-PUFAs and mental disorders is that it includes all adults 20 years of age and older regardless of risk status. As mental illness can occur at any age, the observed associations suggest that fish and n-3 LC-PUFA consumption are likely to be important throughout life. Hoffmire CA, Block RC, Thevenete-Morrison K, van Wijngaarden E. 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. Prostaglandins Leukot Essent Fatty Acids 2012;86:155-160. [PubMed]