Vitamins & minerals
Vitamin D at 1,600 or 3,200 IU a day did not cut fractures in older adults, most of whom were not deficient
University of Eastern Finland researchers gave 2,495 older adults a placebo or one of two vitamin D3 doses for five years. The higher dose matched placebo on fractures; the lower one came with an unexplained excess.
Sep 14, 2026
Vitamin D missed its target in depressed young people
A trial gave 4,800 IU a day for eight weeks to young people who had both major depression and low vitamin D, the group where it should work best. Depression scores did not separate from placebo. Anxiety did.
Aug 16, 2026
Calcium supplements: uses, evidence, dosing and safety
Calcium is taken for bones, and a 2026 BMJ review found little to no benefit for fractures or falls. Its best evidence is somewhere almost nobody looks: preventing pre-eclampsia in pregnancy.
Aug 6, 2026
Vitamin C: uses, evidence, dosing and safety
Vitamin C has been tested against the common cold for sixty years and the answer is still a shrug: it may shorten one slightly, and taking it once a cold has started does almost nothing.
Aug 6, 2026
High-dose vitamin D did not slow advanced bowel cancer
A 455-patient phase 3 trial run through the US National Clinical Trials Network added high-dose vitamin D3 to standard chemotherapy for metastatic colorectal cancer. It did not delay progression.
Aug 6, 2026
Vitamin D: uses, evidence, dosing and safety
Vitamin D is the most-studied supplement there is, and the pattern across thirteen uses is almost always the same: correcting a deficiency helps, and adding more on top of enough does not.
Aug 6, 2026
Vitamin K status did not protect bone in a VITAL analysis
Vitamin K is sold as the partner vitamin D needs for bones. In 771 participants of the VITAL trial, higher vitamin K status did not slow two-year bone loss or improve what vitamin D did.
Aug 6, 2026
Vitamin A, not D, tracked with better lungs in asthma
A Thorax study of 1,165 children and 1,041 adults with asthma found blood vitamin A levels tracked with better lung function, while vitamin D did nothing measurable in children.
Jul 26, 2026
US supplement use hit 60% as multivitamins fell and ashwagandha rose, across 25 years of data
A JAMA Network Open analysis of 63,442 adults across 25 years of national survey data found supplement use rose from 51% to 60%, with multivitamins falling and ashwagandha, collagen and elderberry rising.
Jul 25, 2026
Calcium and vitamin D did little for fractures or falls
A review of 69 randomized trials and more than 150,000 people found that for healthy older adults, calcium, vitamin D, or both together did little to prevent fractures or falls.
Jul 17, 2026