Fat Soluble Vitamins vs Water Soluble Vitamins

People with CF Need More Fat Soluble Vitamins

Vitamins on a table
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Vitamins are classified as either water soluble or fat soluble based on how they are absorbed and used by the body.

What’s the difference between fat soluble and water soluble vitamins, and what is its significance for people with cystic fibrosis?

Water soluble (Vitamin C and all of the B vitamins): Water soluble vitamins are vitamins that our bodies do not store. These vitamins dissolve in water when they are ingested, then go in to the blood stream.

The body keeps what it needs at that time, and excess amounts are excreted in the urine. Since they can’t be stored, everybody needs a continuous supply of water soluble vitamins in order to stay healthy.

Fat Soluble (Vitamins A, D, E and K): Fat soluble vitamins are those that are normally stored in the body. When these vitamins are ingested, they dissolve in fat. In a person with a healthy digestive system, the body uses what it needs at that time and stores the rest for future use. Since people with cystic fibrosis often have pancreatic insufficiency and do not digest or store fats properly, the excess is not stored but excreted in the stool. Due to this, people with cystic fibrosis need a continuous supply of fat soluble vitamins just as they do with water soluble vitamins.

What Does Vitamin A Do?

Vitamin A is integral in bone formation, tooth formation and vision. Vitamin A also contributes to immunity and cell function and keeps the intestines working properly.

What Does Vitamin D Do?

You probably know that vitamin D is found in milk and helps build strong bones. Vitamin D also helps with the development of teeth. People with CF are at higher risk for bone problems because they are unable to store vitamin D properly. Thus, vitamin D supplementation is very important in people with CF.

What Does Vitamin E Do?

Vitamin E is an antioxidant. Antioxidants prevent compounds in your body from combining with oxygen and forming dangerous free radicals. Vitamin E also fights infection and keeps red blood cells healthy. Red blood cells deliver oxygen throughout the body.

What Does Vitamin K Do?

Vitamin K not only helps with blood clotting but also keeps bones healthy.

A Special Note About Minerals

People with cystic fibrosis should maintain high-calorie diets and exercise regularly. In addition to continuous supplementation of vitamins, minerals are also an important aspect of nutrition.

Here are some minerals that are especially important to people with CF:

  • Sodium chloride, or "salt," helps us maintain electrolyte balances in our bodies. People with CF sweat a lot and lose lots of salt. It's important for a person with CF to ingest enough salt to compensate for such loses, especially on hot days.
  • Iron is an important component of red blood cells and helps oxygenate the body.
  • Zinc helps with growth and healing.
  • Calcium helps with bone development and nerve conduction. Calcium supplements are often taken by people with CF.

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