Health-conscious South Africans shell out millions of rands on vitamin and mineral supplements every year but new research shows that certain supplements — including Vitamin A, beta carotene and Vitamin E — may in fact be harmful.

Certain vitamin products can have negative side-effects. So, it's best to eat foods which contain these essential vitamins and minerals instead of stocking up on supplements.

Vitamins that can be problematic :

Vitamin A
Too much can lead to liver, bone and central nervous system problems.

Alternative: Food sources include fortified cereals, dark leafy greens, fruit and sweet potatoes.

Vitamin C
There is no conclusive evidence that this vitamin prevents colds, heart disease, cataracts or cancer.

Alternative: A glass of orange juice a day will provide almost all an adult requires.

Vitamin E
Large doses can thin the blood and may increase the risk of hemorrhagic stroke in those with uncontrolled blood pressure.

Alternative: Dry-roasted almonds are a good source of vitamin E.

Iron
Too much iron can worsen ulcers.

Alternative: Red meat, poultry, fortified cereals, dried beans, lentils and dark leafy greens are a good source.

Zinc
High doses can weaken the immune system and may reduce levels of HDL (good) cholesterol.

Alternative: Meat and poultry are high in zinc and vegetarians should eat plenty of grains, beans, nuts, lentils and diary products.