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Providing perspectives on recent research into vitamins and nutritionals


Feeling Down? Could it be the Season or your Omega-3 Status?

By Michael McBurney

Today is the shortest day of the year in the Northern Hemisphere. A lack of sun exposure can lead to seasonal affective disorder. A new study from Japan finds low blood levels of omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are associated with depressive symptoms.

In a cross-sectional study conducted in 1,050 men and 1,073 women (≥40 years of age) living in Japan, adults with the highest concentrations of EPA+DHA in the blood were the least likely to experience depression symptoms. The adjusted odds ratio (OR) for individuals in the 5th quintile (relative to the lowest quintile) for serum EPA and serum DHA concentrations were 0.64 and 0.58, respectively. Statistically significant associations with depressive symptoms were not found for any of the other fatty acids.

Clinically, 12.5% of these Japanese subjects exhibited depressive symptoms, consistent with observations among similar-aged healthy Americans. However, the omega-3 status of Americans is vastly lower. Blood EPA and DHA concentrations in the Japanese averaged ~75 and ~170 µg/mL, respectively. Nationally representative US data on Americans 60y and older (CDC’s Second Nutrition Report) has plasma EPA and DHA concentrations averaging 14.9 µg/mL (49.4 µmol/L) and 46.5 µg/mL (142 µmol/L), respectively. American concentrations of EPA concentrations are about 50% lower and there is a 3-fold difference in blood DHA concentrations.

The relationship between omega-3 concentrations and depressive symptoms observed in this Japanese study was found at omega-3 concentrations rarely achieved by Americans. In addition to heart health, our low omega-3 concentrations may be affecting mental health. The evidence is sufficient for the US military to evaluate the omega-3 status of military personnel.

The Mayo Clinic has tips on preventing holiday stress and depression. So does WebMD. Neither websites mention omega-3 fatty acid status, and they should.

Main Citation

Horikawa C, Otsuka R, Kato Y, Nishita Y, Tange C, Kakutani S, Rogi T, Kawashima H, Shibata H, Ando F, Shimokata H. Cross-sectional association between serum concentrations of n-3 long-chain PUFA and depressive symptoms: results in Japanese community elders. 2015 Br J Nutr doi: 10.1017/S0007114515004754

Other Citations

Martiny K. Bright light treatment is effective in treating older patients with non-seasonal major depression. 2011 Evid Based Nurs doi: 10.1136/ebn.2011.100036

Thielke SM, Diehr P, Unutzer J. Prevalence, incidence, and persistence of major depressive symptoms in the cardiovascular health study. 2010 Aging Ment Health doi: 10.1080/136078609030456537

Murphy RA, Yu EA, Ciappio ED, Mehta S, McBurney MI. Suboptimal plasma long chain n-3 concentrations are common among adults in the United States, NHANES 2003-2004. 2015 PLoSONE doi: 10.3390/nu7125534