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Avoiding Dangerous Vitamin Interactions
March 31st, 2026

What Vitamins Should You Not Take Together?

Certain vitamin combinations can interfere with absorption or create dangerous interactions. Iron and calcium are particularly problematic together, as calcium can reduce iron absorption by up to 60%. Fat-soluble vitamins (A, D, E, K) should be spaced apart since they compete for absorption pathways. Vitamin C can enhance iron absorption but may interfere with vitamin B12. High-dose zinc blocks copper absorption, while vitamin E can interfere with vitamin K's blood-clotting functions. Taking magnesium with calcium requires careful timing since they compete for the same absorption sites. Always space conflicting vitamins by at least 2 hours for optimal absorption.

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