According to Gram Research analysis of a five-year study of 1,039 young South African adults, higher milk intake was associated with a 6% lower risk of developing depression, while higher calcium and vegetable consumption were linked to significantly lower depression odds. The findings suggest that diet may influence mental health, though socioeconomic factors like income and education also play important roles.
A Gram Research analysis of young South African adults found that what you eat might influence your risk of depression. Researchers followed over 1,000 people aged 20 to 30 for five years, tracking their food choices and depression symptoms. The study discovered that drinking more milk and eating more vegetables and calcium-rich foods were linked to lower depression rates. However, drinking sugary beverages was connected to higher depression risk. The findings suggest that improving your diet could be one way to support your mental health, though other life factors matter too.
Key Statistics
A five-year cohort study of 1,039 young South African adults found that higher milk intake was associated with a 6% lower risk of incident depression compared to lower milk consumption.
In the same 2026 study, higher calcium intake was associated with 52% lower odds of depression at baseline, and higher vegetable intake was linked to 26% lower depression odds.
The African-PREDICT study found that 29.45% of young South African adults aged 20 to 30 years experienced depression symptoms at baseline, highlighting the high prevalence of mental health challenges in this population.
When researchers adjusted for sociodemographic factors like income and education, many dietary associations with depression weakened or disappeared, suggesting that social circumstances significantly influence both diet and mental health.
The Quick Take
- What they studied: Whether the foods and drinks young adults consume are connected to their risk of developing depression
- Who participated: 1,039 young South African adults aged 20 to 30 years old, about half female and half male, followed for five years
- Key finding: People who drank more milk had a 6% lower risk of developing depression, and those eating more vegetables and calcium had significantly lower depression rates
- What it means for you: Eating more vegetables, drinking milk, and getting enough calcium might help protect your mental health, but diet is just one piece of the puzzle. Your social situation and other life circumstances matter too.
The Research Details
This was a long-term study that followed the same group of young adults over five years. Researchers asked participants what they ate using three separate 24-hour food recalls, which means people described everything they consumed over three different days. This approach captures a more realistic picture of eating habits than asking someone to remember their diet from memory. At the start and end of the study, researchers measured depression using a standard questionnaire that doctors use to identify depression symptoms. The study was part of a larger international project called GLAD, which studies how lifestyle choices affect mental health in different countries.
Following the same people over time is stronger than just comparing different groups once. This approach helps researchers see whether diet actually comes before depression develops, not just whether depressed people happen to eat differently. The study also looked at whether other factors like age, income, and education level explained the connection, which helps separate diet’s true effect from other influences.
The study had good follow-up, with over half the original participants returning for the five-year check-in. Researchers used validated tools to measure both diet and depression, meaning these tools have been tested and proven reliable. However, the study only included young adults in one South African province, so results may not apply to older people or different regions. The researchers also adjusted their analysis for multiple factors, which strengthens confidence in the findings.
What the Results Show
The most striking finding was about milk. People who drank more milk had a 6% lower risk of developing new depression cases during the five-year period. This connection held up even after researchers accounted for total calories consumed. Calcium intake showed a similar protective pattern, with higher calcium consumption linked to 52% lower odds of depression at baseline. Vegetables also appeared protective, with higher vegetable intake associated with 26% lower odds of depression. These findings suggest that specific nutrients and foods may genuinely support mental health. The study also found that sugar-sweetened beverages showed the opposite pattern, with higher consumption linked to increased depression odds, though this connection weakened when researchers adjusted for other factors.
Fiber intake was associated with lower depression odds in the initial analysis, but this connection disappeared when researchers adjusted for sociodemographic factors like income and education. This suggests that fiber’s apparent benefit might actually reflect differences in people’s life circumstances rather than fiber itself. The researchers noted that many of the dietary associations they found became weaker or disappeared when they accounted for sociodemographic factors, indicating that poverty, education, and social circumstances are powerful influences on both diet and mental health.
This study adds important evidence from a low- and middle-income country context, as most previous research on diet and depression comes from wealthy nations. The findings align with other research showing that milk products and vegetables support mental health, but this is among the first studies to examine these connections in young South African adults. The study’s emphasis on sociodemographic factors reflects growing recognition that diet alone cannot explain mental health differences without considering poverty, education access, and social inequality.
The study only followed about half of the original participants to the five-year mark, which could introduce bias if people who dropped out had different diet and depression patterns. The research was conducted in one South African province, so findings may not apply to other regions or countries. The study measured diet using recalls of what people ate, which depends on memory and may not be perfectly accurate. Additionally, the study cannot prove that diet causes depression or vice versa, only that they are associated. Finally, many dietary associations disappeared when researchers accounted for sociodemographic factors, suggesting that poverty and inequality may be more important than diet alone.
The Bottom Line
Eating more vegetables, consuming milk or dairy products, and getting adequate calcium appear to support mental health based on this research. These dietary changes are generally safe and have other health benefits. However, diet is just one factor affecting depression. If you are experiencing depression symptoms, speak with a healthcare provider about comprehensive treatment options. Making dietary improvements works best alongside other mental health support, not as a replacement for professional care.
Young adults concerned about mental health should consider these findings, particularly those with access to affordable vegetables, milk, and calcium-rich foods. However, the study’s finding that sociodemographic factors matter significantly suggests that people living in poverty or with limited food access face bigger barriers than individual dietary choices. Healthcare providers working with young adults should consider both dietary and social factors when supporting mental health.
Mental health changes typically take weeks to months to become noticeable. If you make dietary improvements, give yourself at least 4 to 8 weeks to observe any mood changes. However, depression is complex, and diet alone is unlikely to resolve it. Combine dietary improvements with other evidence-based approaches like exercise, social connection, and professional support if needed.
Frequently Asked Questions
Does eating more vegetables help with depression?
Higher vegetable intake was associated with 26% lower depression odds in this study of young South African adults. While this suggests a protective effect, vegetables work best alongside other mental health strategies like professional support and exercise, not as a standalone treatment.
Is milk good for mental health?
This five-year study found that people drinking more milk had a 6% lower risk of developing depression. Milk provides calcium and other nutrients that may support brain health, though individual results vary and diet is just one factor affecting mental health.
Can sugary drinks cause depression?
The study found higher sugar-sweetened beverage consumption was associated with higher depression odds at baseline. However, this connection weakened when researchers adjusted for other factors, suggesting that socioeconomic circumstances may explain some of this relationship.
How long does it take for diet changes to improve mood?
Mental health improvements typically take 4 to 8 weeks to become noticeable. However, depression is complex and usually requires multiple approaches including diet, exercise, social connection, and professional support rather than dietary changes alone.
Does this study apply to people outside South Africa?
This study focused on young South African adults, so results may differ in other populations and countries. The findings align with other research on diet and mental health, but individual responses vary based on genetics, circumstances, and access to resources.
Want to Apply This Research?
- Log daily servings of vegetables, milk products, and calcium-rich foods alongside mood ratings on a 1 to 10 scale. Track for at least 4 weeks to identify patterns between dietary intake and mood changes.
- Set a specific goal like adding one extra vegetable serving daily or switching to milk-based snacks. Start with one change rather than overhauling your entire diet, which is more sustainable and easier to track.
- Use the app to create a weekly summary showing average vegetable servings, milk intake, and calcium consumption alongside average mood scores. Review monthly trends to see whether dietary improvements correlate with mood improvements over time.
This research suggests associations between diet and depression but does not prove that diet causes depression. Depression is a complex condition with multiple causes including genetics, life circumstances, trauma, and brain chemistry. Diet may support mental health but should not replace professional mental health treatment. If you are experiencing depression symptoms, consult a healthcare provider or mental health professional for proper evaluation and treatment. This article is for educational purposes and should not be considered medical advice.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.