People With Antioxidant-Favoring Lifestyles Are 30-35% Less Likely to Be Depressed or Anxious

Depression and anxiety together affect hundreds of millions of people worldwide, yet the biological pathways connecting everyday lifestyle choices to mental health remain poorly mapped. A new cross-sectional analysis published in Scientific Reports by Glareh Koochakpoor and colleagues adds a compelling piece to that puzzle: adults whose diets and habits skew toward a net antioxidant status were significantly less likely to screen positive for either condition, with the signal driven almost entirely by women.

Oxidative Balance Score as a Predictor of Depression and Anxiety

The study is built around a metric called the Oxidative Balance Score, or OBS: a composite index that weights 16 dietary factors and 4 lifestyle factors to estimate whether a person's daily exposures tilt toward oxidative stress or toward antioxidant protection. Antioxidant-favoring inputs include dietary fiber, vitamins C and E, magnesium, zinc, and regular physical activity; pro-oxidant inputs include high iron intake, obesity, smoking, and heavy alcohol use. Oxidative Balance Scores have been developed as tools to evaluate the overall oxidation-reduction status of individuals, though no single standardized calculation method yet exists, which creates variation across studies.

In this cohort, participants who fell into the highest OBS tertile, meaning those with the most antioxidant-favoring profiles, had 35% lower odds of depression (OR: 0.65; 95% CI: 0.49 to 0.86) and 30% lower odds of anxiety (OR: 0.70; 95% CI: 0.53 to 0.92) compared to those in the lowest tertile. Those are not trivial differences in a population where 33.9% met the threshold for depression and 35.9% for anxiety, as measured by the Iranian-validated Hospital Anxiety and Depression Scale.

Why the Brain Is Especially Vulnerable to Oxidative Damage

The biological rationale behind this association is not new territory. Oxidative stress has long been implicated in depression, anxiety, schizophrenia, and bipolar disorder, though whether it causes these conditions or results from them remains an open question. The brain is particularly exposed: its high metabolic rate and lipid-rich tissue make it a prime target for reactive oxygen species, and oxidative damage there can impair synaptic plasticity, reduce neurogenesis, and disrupt neurotransmitter signaling.

A high-OBS lifestyle may counter those processes through several routes. B vitamins, magnesium, and zinc, all scored positively in the OBS, serve as cofactors in the synthesis of serotonin and dopamine. Antioxidant-rich diets appear to suppress the chronic low-grade inflammation linked to neurotoxicity and depressive symptoms. And dietary antioxidant capacity has been associated across observational studies with lower rates of depression and anxiety in the broader population, lending prior credibility to the direction of the finding here.

The researchers also point to the hypothalamic-pituitary-adrenal axis: a healthier oxidative balance may help regulate the body's stress-response system, and may enhance GABAergic signaling, the inhibitory neurotransmitter pathway that promotes calm.

Sex-Stratified Results: The Signal Lives in Women

One of the study's most striking results is the sex difference. Among women, higher OBS was significantly associated with lower odds of both depression (OR: 0.65; 95% CI: 0.45 to 0.93) and anxiety (OR: 0.64; 95% CI: 0.45 to 0.91). Among men, the associations were in the same direction but did not reach statistical significance for either outcome.

The authors suggest estrogen may explain part of this gap. Estrogen has recognized antioxidant and neuroprotective properties, and women generally show greater resistance to mitochondrial dysfunction under oxidative stress. If that is correct, the OBS may be amplifying a protective baseline that is already stronger in women, making the marginal benefit of a high-antioxidant lifestyle more detectable in this group. Whether the null finding in men reflects a true biological difference, a statistical power issue, or some unmeasured confound is not answerable from this data alone.

How the Study Was Built and Where It Falls Short

The data came from the Isfahan Functional Disorders cohort, a large Iranian adult sample. Dietary intake was measured using a 106-item semi-quantitative food frequency questionnaire. OBS was calculated by categorizing dietary components into tertiles after energy adjustment, then combining them with lifestyle scores for physical activity, smoking, alcohol, and obesity based on BMI and waist circumference thresholds. Logistic regression models were adjusted for age, sex, socioeconomic status, education, marital status, sleep quality, and notably, antidepressant use.

That last adjustment is worth noting: the authors acknowledge the inverse associations here were somewhat weaker than in some prior studies, and speculate that adjusting for antidepressant use may have attenuated the signal, since antidepressant users have depression by definition and may also have altered dietary habits.

The cross-sectional design is the central limitation. It captures a snapshot, not a trajectory, so reverse causality is entirely possible: depression and anxiety can reduce physical activity, worsen diet quality, and promote smoking and alcohol use, all of which would lower OBS scores independent of any effect on mental health. Self-reported dietary data introduces further measurement noise. Variations in how OBS is calculated across studies also make direct comparisons difficult. And whether oxidative stress mediates psychiatric disorder risk or results from it remains a genuinely open mechanistic question that cross-sectional data cannot resolve.

What Prospective Research Could Confirm

The authors call for prospective cohort studies and, ideally, randomized trials that track OBS changes over time alongside mental health outcomes. That kind of longitudinal design would allow researchers to establish whether improving oxidative balance, through dietary upgrades, physical activity, smoking cessation, or weight management, actually reduces incident depression and anxiety, or whether the correlation dissolves when the directionality is tested properly.

For now, this study adds to a growing body of evidence suggesting that the aggregate oxidative environment shaped by daily habits may matter for brain health in ways that single-nutrient or single-behavior research tends to miss. The OBS framework, imperfect as its standardization remains, offers a richer lens than asking simply whether someone eats enough vitamin C. Whether that lens will eventually focus into a clinical tool depends on whether the association survives the test of time.

Evidence rating

EMERGING — 67/100

Caveats:

• Cross-sectional design prevents establishing cause and effect — people with depression or anxiety may eat differently as a result of their condition, not the other way around.
• Dietary data relied entirely on self-reported food frequency questionnaires, which are prone to recall error and misclassification.
• Findings were statistically significant only in women; no significant association was found in men, limiting generalizability.
• The study population is Iranian adults only; results may not apply to other ethnic or dietary contexts.
• Residual confounding remains possible despite adjustment for several variables.
• Prospective studies are needed to confirm whether improving oxidative balance actually reduces risk of depression or anxiety.

Cross-sectional analysis of a single Iranian adult cohort. Shows statistical association between higher Oxidative Balance Score and lower odds of depression and anxiety, but cannot establish causation; reverse causality is plausible. Not yet replicated in an independent prospective population.

References

1. Glareh Koochakpoor, Asma Salari-Moghaddam, Mohammadreza Bagheri, et al. (2026). Association between oxidative balance score and psychological disorders in adults. Scientific Reports. https://doi.org/10.1038/s41598-026-46301-7
2. Ángela Hernández-Ruiz, Belén García-Villanova, Eduardo Guerra-Hernández, Pilar Amiano, Miguel Ruiz-Canela, Esther Molina-Montes (2019). A Review of A Priori Defined Oxidative Balance Scores Relative to Their Components and Impact on Health Outcomes. Nutrients. https://doi.org/10.3390/nu11040774
3. Samina Salim (2014). Oxidative Stress and Psychological Disorders. Current Neuropharmacology. https://doi.org/10.2174/1570159×11666131120230309
4. (2021). Association of dietary total antioxidant capacity with depression, anxiety, and sleep disorders: A systematic review of observational studies. Journal of Clinical and Translational Research. https://doi.org/10.18053/jctres.07.202105.005
5. Fangting Lin, Ruolin Zhou, Qingjian Ou, Kexin Tu, Yujing Fang, Caixia Zhang (2025). Oxidative Balance Score Calculated Using Different Methods and Its Associations with Colorectal Cancer Risk. Nutrients. https://doi.org/10.3390/nu17040679
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