12 January - 20 June 2016

Omega-3, diet and depression

25 Sept 13

Two recent studies have investigated diet and risk of depression.  The first study published in the Journal of Nutrition, by researchers from the National Institute of Health, the University of Delaware and Eastern Virginia Medical School has investigated blood levels of omega-3 fatty acids and elevated depressive symptoms.  Beydoun et al used the 20 item Center for Epidemiologic Studies Depression Scale in 1746 adults aged between 30 and 65 and found that elevated depressive symptoms were prevalent in 25.6% of women and 18.1% of men.  By using the mean of two 24-hour dietary recalls, n–3 highly unsaturated fatty acids, n–3 polyunsaturated fatty acids, and plausible ratios with n–6 (ω6) fatty acids were estimated. Linoleic acid and alpha linolenic acid was found to be at adequate levels for 43 to 59% of men and women, although only 5.3% of men and 17.2% of women had adequate intakes of EPA and DHA.   Highest intakes of omega-3 PUFAs was found to be associated with a 49% reduction in risk of elevated depressive symptoms, however there were no significant effects observed in men.  Beydoun et al also report similar results for the ratio of omega-3 HUFA to omega-6 HUFA in women.  The scientists discuss a number of mechanisms for these results including that serotonergic neurotransmitter system regulates omega-3 and omega-3s promote anti-inflammatory compounds while omega-6s promote proinflammatory eicosanoids, which can cause psychiatric disturbances and emulate symptoms of depression. 

The second study, a prospective follow up study of more than 2000 men by Ruusunen from the University of Eastern Finland investigates whether dietary intake of folate and vitamin B12, serum concentrations of n-3 PUFAs, consumption of coffee and tea, or caffeine intake are associated with the risk of getting a diagnosis of severe depression.   The study included middle-aged or older Eastern Finnish men, who were follow up during an average of 13-20 years.   At baseline dietary intake of foods and beverages was quantitatively assessed by a four-day food recording.  Every four years diet was assessed by a food frequency questionnaire, where responders were asked about their frequency of consumption of 38 food and beverage items during the previous 12 months.  Depressive symptoms were assessed by the 18-item HPL depression scale at the baseline and at the four year follow up examinations.  During follow up Ruusunen states that a healthy diet consisting of vegetables fruits, berries, whole grains, poultry, fish and low fat cheese was associated with a lower prevalence of depressive symptom and a lower risk of depression.    Increased intake of folate was also associated with a decreased risk of depression in addition increased coffee consumption was non-linearly associated with a decreased risk of depression.  However sugar contained deserts, snack and drinks, manufactured and processed meat, French rolls and baked or processed potatoes was associated with a increased prevalence of elevated depressive symptoms.   N-3 PUFSA, serum ratio of n-6 to n-3 PUFAs, tea drinking, B12, total caffeine intake, B12 intake were not related to risk of depression. 

RSSL's Lipids Laboratory, part of the Investigative Analysis Team has expertise in all aspects of fat analysis and fatty acid profiling, including the determination of omega-3 and omega-6 fatty acids. For more information please contact Customer Services on Freephone 0800 243482 or email enquiries@rssl.com

RSSL’s Functional Ingredients Laboratory can quantify caffeine in foods and beverages.  For more information please contact Customer Services on Freephone 0800 243482 or email enquiries@rssl.com

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