What are the negative effects of taking too much of a vitamin?

Getting too much of any nutrient can be dangerous. While it’s true that everybody needs to take in certain vitamins and minerals on a daily basis to help maintain good health, the rationale that, “if one is good, more is better” won’t hold up here.

Vitamins and minerals are powerful substances; taking more than you need (unless directed by your doctor) may be bad for your health. Getting too much of certain vitamins can even be toxic.

Vitamins Can Be Toxic?

Any nutrient, when taken to excess, may have negative health effects. Still, there are certain factors that make some vitamins more potentially dangerous than others. Taking too much of a vitamin, also called mega-dosing, can have differing effects on the body, depending on whether it is a fat-soluble vitamin or a water-soluble vitamin.

The type of “solubility” has to do with how the vitamins are absorbed and transported, whether or not they can be stored in the body, and how easily they are lost from the body.

Fat-Soluble VitaminS

The fat-soluble vitamins are A, D, E, and K. Fat-soluble vitamins can be stored in the body for use as needed. This means that these vitamins can also build up to toxic levels when consumed in excessive amounts.

Too much vitamin A can lead to birth defects. Excess levels of vitamin E may increase the risk of hemorrhaging; and too much vitamin K can lessen or reverse the effect of blood thinner medicines and prevent normal blood clotting.

Water-Soluble Vitamins

All B vitamins and vitamin C are water-soluble. Water-soluble vitamins are easily dissolved in the body and excreted in the urine. Still, this doesn’t mean that you can take vitamins B and C in unlimited quantities.

There is a misconception that if you consume too much of a water-soluble vitamin your body will just get rid of it. The truth is, there can be problems with excessive amounts of water-soluble vitamins too, so upper limits have also been set for the water-soluble vitamins as well.

“Certain water-soluble vitamins in excess can cause problems. Too much vitamin B6 can cause nerve problems, too much niacin can cause flushing, and excess vitamin C can cause kidney stones,” says Ruth Frenchman, MS, RD, a spokesperson for the American Dietetic Association. Excess folic acid may also mask a vitamin B12 deficiency, which is more common in people over the age of 50.

Not Too Much, Not Too Little. aim for balance.

Now you understand why it’s so important to stick to established guidelines for how much of any vitamin to consume. By choosing a well-balanced multivitamin like Geritol®, you can help ensure you’re getting just the right vitamins in just the right amounts.


What are the characteristics of fat- and water-soluble vitamins? 2005-2013 WebMD. Retrieved from: http://answers.webmd.com/answers/648730/what-are-the-characteristics-of-fat January 22, 2013.

Kathleen M. Zelman, MPH, RD, LD, Know the Difference Between Fat- and Water-Soluble Nutrients. 2005-2013. Retrieved from: http://www.webmd.com/vitamins-and-supplements/nutrition-vitamins-11/fat-water-nutrient January 22, 2013.