What are Fat-Soluble Vitamins?

6 min read

A key benefit of fat-soluble vitamins is that the body can store them in fatty tissues and the liver, and then rely on these vitamin stocks for future use.

Fat-soluble vitamins stay within the body for extended periods of time. There are many benefits to the long-lasting nature of fat-soluble vitamins. One key benefit is that the body can store these vitamins in fatty tissues and the liver, and then rely on these vitamin stocks for future use. But there are also some key risks to remember. For instance, it is easier to develop a toxicity from very high doses of consumption. Do keep in mind, however, that you won’t develop toxicity from a well-balanced diet rich in these vitamins, only from consuming these vitamin in great excess.

What is the function of fat soluble vitamins?

The function of vitamins that are fat-soluble differs by vitamin. Each vitamin within this category serves a different purpose for the body’s functions.

Vitamin A does many things for the body. It is known for its properties benefiting vision, but it also aids in the development of both teeth and bones and helps regulate the body’s immune system. It also assists cell division and reproduction. In addition, vitamin A helps moisten various membranes in the body, including the nose, lungs, eyes and mouth. It can even help prevent certain cancers.

It is best to eat varied foods in order to get the recommended amount of vitamin A, but supplements can also get you the recommended daily intake. The retinol found in vitamin A is available in some animal products such as fish, liver, and dairy products. The beta-carotene of vitamin A can be found in winter squash, carrots, leafy veggies, pumpkin, and apricots.

Vitamin D aids the body in its absorption of calcium, which is crucial for overall bone health. Appropriate levels of vitamin D can lead to healthier and stronger bones. It also serves to prevent the parathyroid’s hormone release, a hormone that can lead to weaker bones. In addition, Vitamin D boosts the body’s immune system and the maintains healthy functioning of the muscles. It is available through exposure to the sun as well as dietary supplements and diet. In terms of diet, vitamin D is most prevalently found in dairy and milk products that have been fortified with the vitamin. Food sources of vitamin D also include some fish such as sardines, salmon, and herring. In terms of the sun, vitamin D is most prevalently found outside, where it is warm and delightful. It can also be taken daily in a supplement, which can be very helpful when it is difficult to go out in the sun, like winter.

Vitamin E functions as an antioxidant for the body while also protecting red blood cells and vitamins C and A. Taking vitamin E supplements have also been linked in part to preventing cancer and heart disease, according to Colorado State University. The majority of vitamin E can be found in vegetable oils, where you can fulfill your daily intake by about 60%.

Vitamin K is created by the body in the intestines. It helps our blood clot and keeps bones healthy overall. It also helps to create proteins for bones, blood and the kidneys. The vitamin is found in almost all green vegetables as well as a number of vegetable oils such as olive oil and soybean oil, which makes it very easy to get the recommended daily dose. Most animal products have a very small amount of vitamin K in them as well. That said, the amount provided by animal products might not be enough to guarantee adequate intake.

How do fat-soluble vitamins enter the blood stream?

Fat-soluble vitamins enter the blood stream through lymph channels found in the wall of the intestines. Many fat-soluble vitamins are then carried throughout the body by proteins.

To be more specific, fat-soluble vitamins follow this sequence and pathway as they move throughout the body:

The vitamin is ingested through the food eaten. That food is partially digested in the stomach and then moves to the small intestine for further digestion. Bile is necessary for the fat-soluble vitamins to be absorbed. That bile moves into the small intestine where it breaks down fats. Vitamins are then absorbed through the intestine’s wall. Once absorbed, the fat-soluble vitamin goes into the lymph vessels and then the bloodstream. Usually, the fat-soluble vitamin has to be carried throughout the body via a protein. Excess vitamins are stored in the body’s fatty tissue and the liver. When the vitamin is needed, the body releases some from its reserves. During release, the vitamin moves from the liver into the bloodstream.

How long do fat-soluble vitamins stay in the body?

Vitamins that are fat-soluble can remain in the body for quite some time. They release over time and as such can last weeks or even months before stores are depleted. Your body will store them until you need the nutrient, at which time the vitamin will be released. The excess is always stored and released gradually depending on your body’s individual needs. You do not have to replenish the vitamin every day, as you do with water-soluble vitamins. Furthermore, the release is gradual so as to prevent the release of more than is needed.

Fat soluble vitamins: a list of examples

The fat-soluble vitamins include the following:

  • Vitamin A
  • Vitamin D
  • Vitamin E
  • Vitamin K

What are natural food sources of fat-soluble vitamins?

Vitamins that are fat-soluble are available in a wide range of foods, depending on the vitamin itself. In general, this category of vitamin can be found in many animal foods including butter, fish, liver, egg yolks, certain breakfast cereals, vegetable oils, nuts, whole grains, seeds, and dark leafy green vegetables. While you can get the recommended doses through diet alone, you would need to eat a very-well balanced diet. If you aren’t able to do so, you can always use dietary supplements to complement what you are consuming through diet.

How do I know if I have a fat-soluble vitamin deficiency?

It is more difficult to suffer from a fat-soluble vitamin deficiency, because of what has been mentioned about the body storing excess fat-soluble vitamins. Still, deficiencies can happen, and there are various signs that you might be suffering from one. Keep in mind that because there are multiple fat-soluble vitamins, the symptoms of each deficiency are unique.

Vitamin A deficiency is very rare but when it does happen, it can lead to severe conditions, such as blindness. The deficiency is far more common in countries that are underdeveloped and therefore have widespread malnutrition issues. It can also be very hard to spot a deficiency in vitamin A, given that the vitamin is stored in the body within the liver. Signs of a vitamin A deficiency can take nearly 2 years to manifest. Those delayed symptoms include dry, very rough skin in addition to slower bone growth, and diminished resistance to infections. Impaired vision at night can often be an early sign of a vitamin A deficiency.

A deficiency of vitamin D is a bit more common than previously thought. It can lead to bone loss, which manifests as bone mass loss and muscle weakness. Vitamin E deficiency is quite rare and is really only ever seen in those individuals who have trouble absorbing fats. It can also be seen in premature babies. Likewise, it is challenging to be deficient in Vitamin K. That is because it is found in nearly all green vegetables and is created by bacteria in the intestines. If you were to suffer from a vitamin K deficiency, it might manifest itself through hemorrhaging. Because our bodies create Vitamin K themselves, it is far more difficult to have a deficiency extreme enough to cause hemorrhaging.

Are any vitamins neither soluble in fat nor water?

No, vitamins are categorized by their solubility, of which there are only two categories. They are fat-soluble and water-soluble. Fat-soluble vitamins are dissolvable in fat and are stored within the body. Water-soluble vitamins are dissolvable in water. Because of their solubility, water-soluble vitamins do not last in the body long. Instead, they travel through the body very easily and even the slightest excess is excreted. Water-soluble vitamins have such a short storage period in the body that they need to be replenished every day. Fat-soluble vitamins, by contrast, do not need to be replenished very often. Reserves within the body can last weeks at a time, depending on how much your body has stored.

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