 "Can low vitamin D increase depression risk? Global evidence says yes")
Adults with very low vitamin D levels are more likely to experience depression, especially when levels fall below 30 nmol/L (nanomoles per litre), according to new research.
The finding comes from a large systematic review titled Vitamin D and depression in adults: A systematic review, published in the journal Biomolecules and Biomedicine. The review examined 66 studies from 31 countries covering 8,052 records from multiple scientific databases and found a strong link between low vitamin D and depression. However, the researchers emphasise that this does not yet prove that low vitamin D directly causes depression, and needs more research.
According to the World Health Organization (WHO), 5 per cent of all adults and 5.7 per cent of adults over the age of 60 suffer from depression worldwide. While medicines help, researchers are eager to explore additional, safer strategies to support mental well-being. The study authors say that vitamin D stands out because:
The brain has many vitamin D receptors, especially in mood-related regions such as the hypothalamus and pons.
Active vitamin D helps regulate brain signalling, reduces neuro-inflammation, controls oxidative stress and keeps intracellular calcium balanced, which are all factors already linked to depression.
What did the review find about vitamin D and depression?
According to the report, across 46 cross-sectional studies that were analysed by the researchers, lower vitamin D levels were consistently linked with higher depression scores or a clinical diagnosis of depression.
The threshold of 25-hydroxy vitamin D or 25(OH)D being less than 30 nmol/L appeared repeatedly where depression was more common. If your 25-hydroxy vitamin D is low, it can lead to symptoms like fatigue, muscle weakness and bone pain, and in severe cases, diseases such as osteoporosis in adults and rickets in children. Some studies, according to the report, also noted that this association was more pronounced in women, raising questions about hormonal or biological differences.
Case–control studies echoed the pattern. People with current or past major depressive disorder were more likely to have insufficient or deficient vitamin D than healthy individuals.
Should you take vitamin D supplements to prevent depression?
The authors urge caution. While the association is strong, evidence is still insufficient to prove that supplements prevent or treat depression.
However, they do recommend a practical approach of checking vitamin D levels in adults with depression and correcting clear deficiency because it matters for overall health, including bones and immune function.
How can adults maintain healthy vitamin D levels?
Even while research continues, it is wise to maintain healthy vitamin D levels. Adults can support this through:
- Safe sun exposure for 10 to 30 minutes daily during off-peak hours
- Foods such as fortified dairy or plant milk, mushrooms, egg yolks and fish
- Supplements if advised by a healthcare professional
The generally recognised threshold in the research suggests avoiding levels near 30 nmol/L or lower.
The researchers have underscored that low vitamin D and depression appear strongly linked, especially at very low levels. This does not mean vitamin D is the magic answer to mental health, but it might be one piece of a complex biological puzzle that affects mood. A thoughtful, personalised approach with medical guidance is the smartest way forward, stressed the scientists. For more health updates, follow #HealthWithBS
Since you're already here
…and clearly interested in your health, take a moment to explore our varied range of stories on wellness, medical research, and public health insights.
- Caught flu despite the jab? Why did I catch the flu even after taking the vaccine? Doctor explains
- Mental health help decoded Psychiatrist vs psychologist: Who does what and whom to approach for help
- First therapy session fears? Don’t fear therapy: Experts reveal what really happens in the first session
- Safe cough relief for kids Do kids even need cough syrups? Doctors say they may do more harm than good
- Secrets of a long life Want to live longer? Science says being active and organised is the key
- Heart under pressure Financial stress and heart attacks: Why money matters as much as cholesterol
- Myths vs immunity Vaccines, weather, kadha: What really helps immunity and what doesn’t
- Frown lines and fine lines From frowns to smiles: These 7 tiny expressions speed up visible ageing
- Caring without crashing Ageing parents, adult kids: How to grow together without burning out
This content is for informational purposes only and is not a substitute for professional medical advice.