Low Omega-3 intake is associated with high rates of depression and preterm birth on the country level

Timothy H Ciesielski,Scott M Williams

doi:10.1038/s41598-020-76552-x

Timothy H Ciesielski, Scott M Williams

Open Access

https://doi.org/10.1038/s41598-020-76552-x

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Abstract

Low circulating levels of long chain omega-3 polyunsaturated fatty acids (LC omega-3 PUFA) have been linked to major depressive disorder (MDD) and preterm birth (PTB), and prenatal depression associates with PTB. We therefore hypothesized that low Omega-3 intake would associate with higher MDD and PTB rates on the country-level. To test this hypothesis, we obtained country-level estimates for omega-3 intake, MDD prevalence, PTB rate, and per capita income for 184 countries in 2010. We then estimated the LC omega-3 PUFA levels that these intakes produce by accounting for direct consumption and the endogenous conversion of ingested plant-based precursors. Penalized splines indicated that MDD and PTB rates decreased linearly with increasing LC omega-3 PUFA, up to ~ 1000 mg/day for MDD and up to ~ 550 mg/day for PTB. Adjusted linear regression models below these thresholds revealed that a one standard deviation increase in LC omega-3 PUFA (380 mg/day) was associated with an MDD decrease of 5 cases/1000 people and a PTB decrease of 15 cases/1000 livebirths. In light of the extensive prior evidence on the individual-level, these findings indicate that low intake of LC omega-3 PUFA and its precursors may be elevating MDD and PTB rates in 85% of the countries studied.

Highlights

Low circulating levels of long chain omega-3 polyunsaturated fatty acids (LC omega-3 PUFA) have been linked to major depressive disorder (MDD) and preterm birth (PTB), and prenatal depression associates with PTB
The unadjusted model for countries below 1000 mg/day (n = 177) indicates that MDD prevalence decreases by 0.46 cases per 100 people for each 1 SD increase in LC Omega-3 PUFA intake (380 mg/day)
There was no significant association between LC Omega-3 PUFA and PTB rate above the 550 mg/day threshold (Table 3)

Summary

Introduction

Low circulating levels of long chain omega-3 polyunsaturated fatty acids (LC omega-3 PUFA) have been linked to major depressive disorder (MDD) and preterm birth (PTB), and prenatal depression associates with PTB. The evidence from clinical trials includes mixed findings for both outcomes, but the results indicate that omega-3 supplementation can, on average, reduce depressive symptomology and the risk of preterm birth[23,25] At this point, we cannot characterize the clinical efficacy in specific settings, because none of the 30+ MDD trials[23] or 70+ PTB trials[25] concurrently accounted for all 3 critical factors: baseline intakes, sufficiency thresholds, and the endogenous conversion of ingested precursors. Given these possible weaknesses in the clinical trial evidence, it is critical to consider the scientific literature beyond the RCTs of Omega-3 PUFA supplements. If this is the case, it is possible that diets with low Omega-3 PUFA content may simultaneously increase the risk of depression and preterm birth

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