Vitamins are either water soluble or fat soluble.

What Is the Difference Between Fat Soluble & Water Soluble?

by Sara Ipatenco

Your body relies on 13 essential vitamins to function properly, according to the University of Maryland Medical Center. These 13 vitamins are divided into two categories: water soluble and fat soluble. You need plenty of vitamins from each category, but they don't all function the same way in your body. A clear understanding of the difference will help you get the right amount of each.

Water-Soluble Vitamins Explained

Water-soluble vitamins are simply defined as vitamins that dissolve in water, according to the University of Colorado Extension. Vitamins that dissolve in water must be replenished on a daily basis because any excess that you consume is excreted in your urine. Because your body gets rid of the excess of these vitamins, you don't need large doses to maintain your health. The exception is vitamin B-12, which can be stored in your liver, according to the University of Maryland Medical Center.

Water-Soluble Vitamins and Sources

All eight of the B vitamins – thiamine, riboflavin, niacin, vitamin B-6, vitamin B-12, folate, biotin and pantothenic acid – as well as vitamin C, are water-soluble vitamins. The B vitamins help you metabolize the foods you eat and play a role in the health of your nervous system, too. Enriched grain products, meat, fish, eggs and dark leafy greens are among the top sources of these eight B vitamins. Vitamin C promotes a strong immune system, keeps your skin healthy and helps your body absorb iron. Citrus fruits, bell peppers, berries, tomatoes and potatoes are among your best food sources of vitamin C.

Fat-Soluble Vitamins Defined

Fat-soluble vitamins dissolve in fat and are stored in your liver and fatty tissues. Your body can store fat-soluble vitamins for long periods of time, but that makes toxicity more likely. If you consume too much of certain vitamins, such as vitamin A, you can experience negative side effects such as headache, nausea and vomiting, according to the University of Colorado Extension. Because your body is able to hold onto fat-soluble vitamins, you don't need huge doses anyway.

Fat-Soluble Vitamins and Sources

The four fat-soluble vitamins are vitamins A, D, E and K. Vitamin A plays a role in the health of your eyes and keeps your mucus membranes moist and working properly. The top sources of vitamin A include dark-colored fruits, dark leafy greens, egg yolks and beef. Vitamin D helps your body absorb calcium and phosphorus. Fortified milk, fatty fish and cod liver oil are the best dietary sources of vitamin D. Vitamin E helps protect your red blood cells from damage and aids your body in using vitamins A and C. Vitamin E can be found in avocado, papaya, dark green vegetables, nuts and seeds. You need plenty of vitamin K to keep your blood clotting normally. Dark-colored vegetables, fish, liver, eggs and fortified cereals are the best food sources of vitamin K.

About the Author

Sara Ipatenco has taught writing, health and nutrition. She started writing in 2007 and has been published in Teaching Tolerance magazine. Ipatenco holds a bachelor's degree and a master's degree in education, both from the University of Denver.

Photo Credits

  • Brand X Pictures/Brand X Pictures/Getty Images