Minerals and vitamins play a major role in keeping you healthy. But it does not mean that their overdose will make you live longer or keep you away from diseases. Ideally, we are supposed to get the required nutrient value from our balanced diet. Also, high doses of certain minerals and vitamins may be useful for certain people.
Do not take any supplement without consulting your doctor, especially if you are a pregnant woman or a lactating mother. Also, you need to talk to your doctor before taking any vitamin or supplement if you are a vegetarian, are an athlete, have very limited exposure to sun, or are malnourished.
Here we have mentioned 8 vitamins and supplements that can be dangerous if taken in high doses
Beta-carotene is an antioxidant which is converted by our body into Vitamin A. For healthy adults, the highest recommended dose of beta- carotene is 2,130 IU (women) and 3,000 IU (men). Foods like spinach, kale, carrots, and cantaloupe are rich in beta-carotene. Although some people take beta-carotene as an anti-cancer antioxidant, this might rather increase the risk of lung cancer.
2) Folic Acid
Folic acid can be found in asparagus, cereals, fortified bread, and legumes. You must consume 400 micrograms of folic acid daily. Doctors prescribe this supplement only to pregnant women, as it is believed to reduce the risk of developing neural tube defects in newborns. Doctors warn that folic acid taken along with food can increase the risk for colon cancer.
Selenium is found in foods like tuna, brazil nuts, and beef. Daily recommended dose of this supplement is 55 micrograms. People usually take selenium to reduce their risk of developing prostate cancer, but a recent study  have proved that selenium can increase the risk of prostate cancer in men who are already having good amounts of this mineral. Research  conducted in 2007 showed that selenium supplements is linked to 50% increased risk of developing type 2 diabetes.
4) Vitamin B6
People of age between 19-50 should get the recommended dose of 1.4 milligrams of vitamin B6 daily. It can be found in bananas, baked potatoes and chickpeas. For people aged 50 or above, the recommended dose is 1.7 milligrams for males and 1.5 milligrams for females. This vitamin is believed to prevent cognitive impairment and decrease the levels of homocysteine (a type of amino acid linked to heart disorders), but studies show mixed results. The two studies failed to see any improvement in cognitive functioning, but it did show the reduced levels of homocysteine. Also, it is not clear if this vitamin prevents heart attack.
5) Vitamin B12
The daily recommended dose of vitamin B12 is 2.4 micrograms. Foods rich in vitamin B12 include lean beef, fish and fish oil products, shellfishes, and fortified cereal. Vegetarians and vegans are generally deficient in this vitamin. Deficiency of vitamin B12 can cause age-related dementia and anemia, so these supplements can be helpful. But that does not mean that consuming high doses will reduce cognitive loss. Also, they do not boost your energy.
6) Vitamin C
Melons, tomatoes, and citrus fruits are loaded with Vitamin C. Females are advised to take 75 milligrams and males 90 milligrams of Vitamin C daily. These supplements are thought to relieve common cold, but assessment of 30 clinical trials failed to show any related signs of this vitamin preventing common cold. However, it might help in some exceptional cases like people living in cold areas, or an athlete. Smokers might require Vitamin C in high doses.
7) Vitamin E
Green leafy vegetables, nuts and vegetable oils are rich in Vitamin E. You must consume 15 milligrams of vitamin E. It is found to show the reduced risk of Alzheimer’s disease, heart disorders and cancer. Also, high dose of this vitamin increases the risk of strokes. However, a study showed that Vitamin E from food can prevent Alzheimer’s disease.
The daily recommended dose for men is 11 milligrams and for women is 8 milligrams. Zinc can be obtained from lean beef, breakfast cereal and oysters. People take zinc supplements to treat common cold, but studies failed to show any noticeable difference. Also, zinc supplements might weaken your immune system.