Key Points at a Glance
- A large observational study of over 31,000 U.S. women (2003–2017) found that those consuming nine or more servings per day of ultra‑processed foods – many of which contain artificial sweeteners – had approximately a 50% higher risk of developing depressive states compared to those consuming four or fewer servings.
- In a subgroup analysis, high consumption of artificial sweeteners and artificially sweetened beverages showed a roughly 26% increased risk over low consumers.
- Because this was an observational design, the study shows correlation—not causation—and cannot rule out reverse causality or confounding factors.
- Broader reviews, including a 2022 WHO systematic review, found minimal long‑term benefit of non‑sugar sweeteners for weight control and noted possible undesirable effects at typical intake levels.
- FDA-approved sweeteners are considered safe at regulated levels (e.g. aspartame), although moderation is advised—particularly for those concerned with mood or inflammation.
A Daily Choice With Hidden Consequences
Choosing a diet soda or a low‑calorie snack might feel healthier at the moment. But a recent large-scale study suggests that regular consumption of ultra‑processed foods—especially those containing artificial sweeteners—may be associated with a greater risk of developing depressive states. As these products are viewed as low‑calorie alternatives, their potential mood impact warrants close attention.
Why This Connection Matters
Ultra‑processed foods now contribute an estimated 53% of total calories in U.S. adults, and up to 61% among children. If such foods contribute to depressive symptoms, the implications for public mental health are significant. Understanding how diet influences mood is increasingly vital in a society facing rising concerns over mental well‑being.
What Researchers Discovered
Researchers tracked 31,712 women aged 42–62 who did not have depressive states at baseline. Over 14 years, participants reported their diet and mental health roughly every four years. The top 20% of ultra-processed food consumers—those eating nine or more servings daily—had up to a 49–50% higher risk of developing depressive states compared to the lowest intake group (four or fewer servings). High intake of artificial sweeteners and diet beverages stood out with an estimated 26% higher risk compared to low consumers. The analysis adjusted for age, BMI, physical activity, sleep habits, income, marital status, pain, hormone therapy use, and other factors. Still, researchers caution that reverse causality—early mood symptoms influencing food choices—cannot be fully ruled out.
Possible Pathways Linking Sweeteners and Mood
Gut‑Brain Axis
Diets higher in ultra‑processed foods can alter the gut microbiome, disrupting gut‑brain communication and triggering inflammation or changes in neurotransmitter production—factors linked to mood regulation.
Neurotransmitter Signals
Laboratory and animal research suggest that artificial sweeteners may influence pathways involved in brain signalling – chemical messengers tied to mood regulation – and that disruption in these signals could affect brain chemistry.
Blood Sugar & Metabolic Response
Although artificial sweeteners reduce calorie intake, their long-term effects on insulin sensitivity, appetite, and cravings remain unclear. Some evidence links habitual use to modest weight gain or metabolic disturbances over time.
What the Broader Research Says
The World Health Organization’s 2022 review, covering 283 studies, concluded that non‑sugar sweeteners offer minimal long-term metabolic benefits and may be linked to increased risk of chronic illness. While randomised scientific studies often show short-term calorie reduction, observational studies paint a more mixed or concerning picture. Mood-related outcomes remain uncommon in existing data, making this recent depressive state link especially novel.
Important Caveats
Because the study is observational, it cannot prove that sweeteners or ultra‑processed foods cause depressive states—only that they’re associated. The participants were predominantly white, middle‑aged women, so results may not apply across genders or age groups. Self-reported dietary and mood data introduce possible measurement error. And despite statistical adjustment, residual confounding from lifestyle or environmental factors cannot be ruled out.
Practical Steps for Smarter Choices
If you consume artificial sweeteners regularly and are concerned about mood, consider:
- Moderation: Stay within established acceptable daily intake levels (e.g., ~40 mg/kg/day for aspartame in the EU; ~50 mg/kg/day in the U.S.).
- Choose whole foods: Emphasise fruits, vegetables, legumes, whole grains, and lean protein.
- Observe patterns: Note whether mood changes follow consumption of diet sodas or sweetened snacks—switching to naturally flavoured water or unsweetened options may help.
- Consult a health professional: Especially if mood symptoms persist or change after dietary adjustments.
Data Insight
Women in the study who cut their ultra‑processed food intake by at least three daily servings over time had a measurable reduction in their risk of developing depressive states compared with peers whose intake remained high, suggesting even modest dietary shifts may correlate with improved mood outcomes.
The Bottom Line
This emerging evidence links high consumption of ultra‑processed foods—especially those containing artificial sweeteners—to increased risk of depressive states. While plausible biological mechanisms exist, rigorous human experimental studies are needed. For now, moderation and a focus on whole, nutrient‑dense foods represent practical steps for supporting mood health.
Your Next Steps
Want more evidence-based insights like this?
This blog post aims to be informational and should not replace professional health advice. Always consult with a health professional for personalised advice.
References
- Samuthpongtorn C, Nguyen LH, Okereke OI, Wang DD, Song M, Chan AT, et al. Consumption of Ultraprocessed Food and Risk of Depression. JAMA network open [Internet]. 2023 Sep 20;6(9):e2334770–0. Available from: https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2809727
- WHO. Health effects of the use of non-sugar sweeteners: a systematic review and meta-analysis [Internet]. www.who.int. 2022. Available from: https://www.who.int/publications/i/item/9789240046429
- CDC. Ultra-processed Food Consumption in Youth and Adults: United States, August 2021–August 2023 [Internet]. National Center for Health Statistics Search. Available from: https://www.cdc.gov/nchs/products/databriefs/db536.htm
- European Food Safety Authority. Aspartame [Internet]. European Food Safety Authority. 2023. Available from: https://www.efsa.europa.eu/en/topics/topic/aspartame
- Rondinella D, Raoul PC, Valeriani E, Venturini I, Cintoni M, Severino A, et al. The Detrimental Impact of Ultra-Processed Foods on the Human Gut Microbiome and Gut Barrier. Nutrients [Internet]. 2025 Feb 28;17(5):859–9. Available from: https://www.mdpi.com/2072-6643/17/5/859
- Mengist B, Lotfaliany M, Pasco JA, Agustini B, Berk M, Forbes M, et al. The risk associated with ultra-processed food intake on depressive symptoms and mental health in older adults: a target trial emulation. BMC Medicine. 2025 Mar 24;23(1).
Moderation and awareness really seem to matter here.