Food security and diet quality, not vitamin D status are significantly associated with depression: Results from NHANES 2015-2018

Abstract

Background: Observational research has suggested a link between vitamin D insufficiency and depression, while evidence from randomized trials examining the association have yielded inconsistent results. Food security and diet quality are also associated with both vitamin D insufficiency and depression. However, the potential interactions between these factors have not been well described.

Methods: In order to examine the associations between depression, vitamin D status, food security, and diet quality, data from 8988 US adults (≥20 years) in NHANES (National Health and Nutrition Examination Surveys) 2015-2018 were analyzed. Questionnaire-assessed depression, food security, and diet quality and laboratory-analyzed serum vitamin D were used.

Results: Lack of full food security and a 10-point decrease in Healthy Eating Index 2015 score were independently associated with higher risk of mild to severe depression (OR 3.72 and 1.20, respectively, p < 0.001). The association between insufficient serum vitamin D (<75 nmol/L) and depression was fully attenuated after adjusting for food security and diet quality (p = 0.41).

Limitations: A major limitation of this paper, like all analyses of NHANES, is the inability to establish the temporality of the relationships between food security and diet quality with depression.

Conclusions: Food security and diet quality, but not vitamin D status, were significantly associated with depression. This highlights how evaluating food security and diet quality are critical in research and public health interventions related to depression. Future interventions, especially into vitamin D insufficiency, as well as health policies should assess and address these factors.

Keywords: Depression; Diet quality; Food security; NHANES; Vitamin D.