There are four fat soluble vitamins. Vitamin A, D, E, and K. This is easy to remember by thinking that we store things in the “Attic” and fat-soluble vitamins can be stored in the body.
Vitamin D is often called the "sunshine vitamin."
When we consume food or a supplement that contains vitamins, the vitamin may be absorbed at 40-90% of the amount that was consumed. The intestinal cells absorb fat-soluble vitamins along with the dietary fats consumed. Therefore, it is very important when taking a fat-soluble vitamin to take it with a healthy dietary fat or a fat containing supplement in order to help with absorption. If the fat-soluble vitamins do not have a fat to travel with through the digestive process, the vitamins will not be optimally absorbed by the body.
It is also important to remember that fat soluble vitamins can be stored inside the body and can be toxic if too much is consumed. Typically, it is rare to consume enough dietary food to get a toxic level of a fat-soluble vitamin. However, toxicity can occur if mega-doses of fat-soluble dietary supplements are taken.
How are the fat-soluble vitamins absorbed by the body?
Fat-soluble vitamins begin digestion in the mouth when food is broken down into small particles which helps to release the vitamins. Then in the stomach, digestive enzymes work to release more of the vitamin from the food. In the colon, bile is used to emulsify the fat to aid in digestion and absorption. The absorption of the fats occurs in the small intestine. The fat-soluble vitamins are packed into chylomicrons with the dietary fats and moved to the lymphatic circulation before they are transported to the blood. The fat-soluble vitamins are transported by lipoproteins (which are lipid carries) through the water compartments in the body. If the fat-soluble vitamins are not readily used by the body they are stored inside the body’s tissues primarily the liver and adipose tissues.1
If you are taking a supplement that contains any of the fat soluble vitamins, that supplement MUST be taken with food for proper absorption.
About the Author: Sam Tucker is a graduate of New York Chiropractic College with a Master's in Applied Clinical Nutrition. She has recently completed the required supervised hours to earn her CNS credential and is anxiously awaiting to hear the score from her CNS Exam. In addition to building her clinical practice, Sam lives in Kentucky with her husband and her children.
1. Insel P, Ross D, McMahon K, Bernstein M. Nutrition, Sixth Edition. C 2017. Jones and Bartlett Learning. Burlington, MA. Pg 387-424.
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