Dietary intake of fish, omega-3, omega-6 polyunsaturated fatty acids and vitamin D and the prevalence of psychotic-like symptoms in a cohort of 33,000 women from the general population

BMC Psychiatry. 2010 May 26;10:38. doi: 10.1186/1471-244X-10-38.

Abstract

Background: Low intake of fish, polyunsaturated fatty acids (PUFA) and vitamin D deficiency has been suggested to play a role in the development of schizophrenia. Our aim was to evaluate the association between the intake of different fish species, PUFA and vitamin D and the prevalence of psychotic-like symptoms in a population-based study among Swedish women.

Methods: Dietary intake was estimated using a food frequency questionnaire among 33,623 women aged 30-49 years at enrollment (1991/92). Information on psychotic-like symptoms was derived from a follow-up questionnaire in the years 2002/03. Participants were classified into three predefined levels: low, middle and high frequency of symptoms. The association between diet and psychotic-like symptoms was summarized in terms of relative risks (RR) and corresponding 95% confidence intervals and was evaluated by energy-adjusted multinomial logistic regression.

Results: 18,411 women were classified as having a low level of psychotic-like symptoms, 14 395 as middle and 817 as having a high level. The risk of high level symptoms was 53% (95% CI, 30-69%) lower among women who ate fish 3-4 times per week compared to women who never ate fish. The risk was also lower for women with a high intake of omega-3 and omega-6 PUFA compared to women with a lower intake of these fatty acids. The effect was most pronounced for omega-6 PUFAs. The RR comparing the highest to the lowest quartile of omega-6 PUFAs intake was 0.78 (95% CI, 0.64-0.97). The associations were J-shaped with the strongest reduced risk for an intermediate intake of fish or PUFA. For fatty fish (herring/mackerel, salmon-type fish), the strongest inverse association was found for an intermediate intake (RR: 0.81, 95% CI, 0.66-0.98), whereas a high intake of fatty fish was associated with an increased risk of psychotic-like symptoms (RR: 1.90, 95% CI, 1.34-2.70). Women in the highest compared with the lowest quartile of vitamin D consumption experienced a 37% (95% CI, 22-50%) lower risk of psychotic-like symptoms.

Conclusion: Our findings raise a possibility that adult women with a high intake of fish, omega-3 or omega-6 PUFA and vitamin D have a lower rate of psychotic-like symptoms.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Animals
  • Cohort Studies
  • Diet / statistics & numerical data*
  • Diet Surveys
  • Dietary Fats / metabolism
  • Fatty Acids, Omega-3 / metabolism*
  • Fatty Acids, Omega-6 / metabolism
  • Feeding Behavior / classification*
  • Female
  • Fishes / metabolism*
  • Humans
  • Middle Aged
  • Prevalence
  • Psychotic Disorders / epidemiology*
  • Psychotic Disorders / prevention & control
  • Risk Factors
  • Schizophrenia / epidemiology*
  • Schizophrenia / etiology
  • Schizophrenia / prevention & control
  • Seafood*
  • Surveys and Questionnaires
  • Sweden / epidemiology
  • Vitamin D / metabolism*

Substances

  • Dietary Fats
  • Fatty Acids, Omega-3
  • Fatty Acids, Omega-6
  • Vitamin D