Although many people use vitamin and mineral supplements to improve their health and physical performance, excessive consumption can pose significant risks.
Among water-soluble vitamins, such as thiamine B1, riboflavin B2 and vitamin B6, adverse effects are generally rare. Thiamine has little toxicity, while high doses of riboflavin only cause changes in urine color. However, megadoses of vitamin B6 can lead to irreversible sensory neuropathy, especially in prolonged supplementation above 200 mg/day (100x above the recommendations). Folic acid, in high doses, can interfere with zinc metabolism, and niacin B3 can cause vasodilation and facial flushing, although these effects are generally harmless. Vitamin C, in doses above 1 g/day, can increase the risk of kidney stones, diarrhea and reduce the benefits of exercise.
In fat-soluble vitamins, such as vitamin A, chronic high doses can cause bone, liver and neurological damage. The safe dose is up to 10 times the daily recommendation. Vitamin D, in megadoses, can cause hypercalcemia and calcification of soft tissues, while vitamin E, although less toxic, can interfere with the endogenous antioxidant system in very high doses.
Minerals, which are essential for the body's balance, can also be harmful in excess. High doses of zinc interfere with the absorption of other minerals, such as selenium, while high levels of copper and iron can cause liver and kidney damage. Furthermore, excessive intake of minerals at the same time can generate harmful interactions.
Therefore, the use of supplements should respect the recommended daily doses (RDAs). Excessive consumption, especially over a prolonged period, can have serious negative effects, highlighting the importance of professional guidance before supplementation.
Rui Lopes
BMS Nutritionists
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