Multivitamin

Won't lower blood pressure in people who already eat well. Not superior to nutrition education alone for correcting vitamin deficiencies. Doesn't replace a balanced diet. No proven benefit for preventing hypertension in the general population. The epigenetic aging effects found are small and their real-world clinical meaning is still unknown.

• Children's multivitamins may contain manganese levels exceeding safe upper limits, especially when combined with dietary intake — 34% of tested products exceeded IOM upper limits in one study
• Multivitamin labels may be inaccurate — one study found 88.5% of products with manganese listed contained more than labeled, with a mean 42.5% excess
• Rare but serious allergic reactions (including Kounis syndrome / allergic angina) have been reported with injectable multivitamin formulations
• People with poor diets may get a false sense of security from taking a multivitamin instead of improving food quality
• Post-bariatric surgery patients relying on multivitamins alone may still develop bone loss if calcium and vitamin D intake remains inadequate