Associations between omega fatty acid consumption and depressive symptoms among individuals seeking behavioural weight loss treatment.

OBJECTIVE: The typical Western diet is deficient in omega-3 and high in omega-6 fatty acids (FAs). These FAs may play a role in depressive symptoms via inflammatory processes, especially in the context of obesity, a pro-inflammatory state. This study investigated associations between omega-3 and omega-6 FA intake and depressive symptoms in adults seeking behavioural weight loss treatment (BWLT).

METHODS: One hundred eighty-eight persons with overweight or obesity (83.50% women, 93.10% White, 55.01 ± 10.09 years old, body mass index 36.02 ± 15.79 kg/m) seeking BWLT completed the Block Food Frequency Questionnaire, which provides estimates of dietary FA intake, daily total energy intake (TEI) and macronutrient composition of the diet. Depressive symptoms were measured via the Center for Epidemiological Studies Depression Scale. Correlation and linear regression estimated associations between depressive symptoms and FAs.

RESULTS: On average, participants reported consuming 1866.2 ± 665.1 kcals/d, with 38% of TEI from fat and an omega-6:3 ratio of 9.2 (13.9 g omega-6 to 1.5 g omega-3). In univariate models, omega-6 intake was associated with depressive symptoms (r = .182, p = .012); however, this association was no longer statistically significant after controlling for TEI. Omega-3 intake was not associated with depressive symptoms.

CONCLUSION: The expected association between omega-3 and omega-6 FAs and depressive symptoms was largely unsupported. A robust association between FA intake and depressive symptoms may have been masked by a high level of chronic inflammation in this sample caused by excess weight and overall poor diet. Additional research is needed to determine whether BWLT improves FA intake, and whether associations between FA intake and depressive symptoms are strengthened after successful weight loss and improved diet.