Taking large doses of vitamins can be harmful, as your body only needs vitamins in very small amounts. Consuming excessive amounts of a vitamin can potentially result in toxicity.
Many of us take supplements not just to replace what we are missing but because we think that vitamins will give us an extra boost.
Individuals at risk of vitamin deficiency due to a pre-existing medical condition or inadequate diet should consider consulting a professional about supplementing. For example people on long term restrictive weight loss diets and people with malabsorption issues can benefit from supplements.
Folic acid supplements can also be beneficial if pregnant. Folic acid however is also fortified into breads and breakfast cereals in many countries. Folic acid can prevent neural tube defects in babies if taken by the mother during pregnancy.
Taking supplements is vastly different from eating whole foods. Eating plenty of fruits, vegetables, protein, whole grains and cereals provides the nutrients required in the correct amount and balance.
When you concentrate on one vitamin, mineral or nutrient in a supplement form, you are limiting the other nutrients available in food that help contribute to your overall health, such as phytonutrients.
The amount of vitamin stated in vitamin supplements is vastly different from the actual amount absorbed. Multiple vitamins compete for absorption when taken together. This results in some vitamins being poorly absorbed while others are completely absorbed.