In my last post I provided a basic introduction to vitamins. Today I am going to discuss the fat soluble vitamins A, D, E and K in greater detail.
Fat soluble vitamins dissolve within the body’s fat cells and are usually found in fats and fatty foods. Unlike water soluble vitamins, (which are quite easily removed from food during cooking and preparation) fat soluble vitamins normally stay in the food when it is cooked. If they are not needed immediately, the body will store fat soluble vitamins for later use in the liver and fatty tissues. Therefore, fat soluble vitamins do not need to be consumed as frequently as water soluble vitamins to ensure proper functioning of the body’s cells.
Consuming too many fat soluble vitamins can be harmful to your body in the long term. Since your body stores any extra fat soluble vitamins, excessive consumption for a prolonged period means that these stores can eventually build up to toxic levels. Not only can this cause damage to your body but it can also lead to a number of undesirable symptoms. However, if you consume safe levels of fat soluble vitamins by sticking with food as your primary source (and perhaps using the occasional supplement) you can realise the benefits that these vitamins provide.
So what exactly are the fat soluble vitamins and what do they do?
1) VITAMIN A:- The main role of vitamin A is to promote healthy vision and night vision but it also helps with normal growth and reproduction. Liver is the richest source of vitamin A available but dairy products (such as milk, eggs and butter) and vegetables (such as carrots, peas and spinach) also contain good levels of the vitamin.
The recommended daily allowance (RDA) for vitamin A is 0.7mg for men and 0.6mg for women. Failure to get enough can cause problems with your vision and in the worst cases make it impossible to see in the dark. However, getting too much vitamin A also has adverse effects including weak bones, hair loss and diarrhea.
2) VITAMIN D:- Vitamin D is often known as the sunshine vitamin because exposure to sunlight prompts your body’s cells to start producing it. It’s major role is to assist with the absorption of calcium and phosphorous which in turn promotes healthy bones and teeth. Vitamin D is also responsible for controlling when minerals are used in the body. Apart from sunlight, dairy products (such as eggs, milk and butter), fatty fish and fish oils are all good sources of vitamin D.
The RDA for vitamin D is 0.01mg for both men and women. Not getting enough can lead to rickets (softening of the bones in young children and animals) and osteomalacia (the loss of calcium and protein from the bones) in adults. However, overdosing can lead to calcium deposits on various organs which has the potential to cause serious, long term damage.
3) VITAMIN E:- Vitamin E is a powerful antioxidant which protects and repairs the body’s cells from the damage caused by oxygen. It also offers protection from a number of diseases. Vitamin E can be found in abundance in oils and margarine from corn, wheat germ and nuts whilst fruit and vegetables also contain lower levels of this vitamin.
The RDA for vitamin E is 4mg for men and 3mg for women. Failure to get enough can lead to age spots (a brown pigmentation of the skin) and hemolytic anemia (a condition where the blood cells become so delicate that they rupture). The effects of overdosing on vitamin E have not been documented at the time of writing but I highly recommend you stick to the RDA until further research into this area is completed.
4) VITAMIN K:- Vitamin K’s main function is to help the blood clot but it also assists with calcium retention in the body. Green leafy vegetables (such as spinach, broccoli and cabbage) are rich in vitamin K but eggs and milk also contain lower levels of the vitamin.
The RDA for vitamin K is 0.08g for men and 0.06g for women. Not getting enough can be very serious and cause heavy, uncontrolled bleeding in multiple areas of the body. However, consuming too much vitamin K can damage both your blood cells and your liver.
As you can see, the fat soluble vitamins all have unique but vital functions in your body. It is therefore essential that your diet allows you to consume the RDA of vitamin A, D, E and K. If you are not currently getting the necessary levels of these fat soluble vitamins in your diet then I strongly urge you to make the changes today. Incorporate some of the foods mentioned in this article into your meals and if necessary use supplements, Just be sure not to go overboard. Overdosing on fat soluble vitamins can be just as bad as not getting enough. However, if you stick to the recommended levels you should be able to realise all the benefits of vitamins A, D, E and K without any adverse affects.
Sources:
Toxicity of Vitamins Information (Medical News Today)
Fat Soluble Vitamins Information (Colorado State University Extension)