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fat-soluble vitamins

Fat-soluble vitamins- types, functions, and food sources

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Our body requires a variety of vitamins to keep us healthy and working properly. Small amounts of vitamins are required to promote growth and reproduction. There are two types of vitamins that we need: water-soluble and fat-soluble vitamins. Most of the vitamins are obtained through our regular food intake but some people require additional vitamin supplements.

Though both types of vitamins are very important to our body, in this article you will learn about fat-soluble vitamins and how they function in your body. You will also learn about the characteristics, types, functions, and possible food sources of fat-soluble vitamins.

What are Vitamins?

Vitamins are essential micronutrients that our body needs in small amounts to function. They are divided into two categories: water-soluble (B-complex vitamins and C vitamins) and fat-soluble vitamins (A, D, E, and K). Water-soluble vitamins need regular replacement in the body. On the other hand, fat-soluble vitamins are stored in the liver and fatty tissues and eliminated much more slowly than water-soluble vitamins.

Fat-soluble vitamins

Fat-soluble vitamins mean these types of vitamins dissolve in the fat. They can be stored in the fat tissue for longer periods of time in our bodies. Because you don’t need them every day. These vitamins include vitamin A, D, E, and K. They can generally pose a greater risk of toxicity and adverse reactions when consumed in excess than water-soluble vitamins.

Fat-soluble vitamins are much better absorbed into your bloodstream when we eat them with higher-fat foods. We have to take these vitamins regularly with our meals to make our body functions efficiently and healthfully. We can get them from plant and animal foods or dietary supplements.

Vitamin A (Carotenoids and Retinoids)

What is Vitamin A?

Vitamin A helps our eyes adjust to light changes. It also plays an important role in our bone growth, tooth development, cell division, and regulation of the immune system. Our skin, eyes, and mucous membranes of the mouth, nose, throat, and lungs need vitamin A to remain moist. Fat-soluble Vitamin A is also an antioxidant that prevents certain cancers. Vitamin A deficiency may slow or prevent growth in children. It is also important for hair growth. Hair loss or alopecia can be a cause of vitamin A deficiency.

Fat-soluble vitamins- Vitamin A

Dietary sources

Vitamin A can be obtained through natural sources. Some sources include:

  • Dairy products
  • Fish liver oil
  • Liver of animals
  • Butter
  • Eggs
  • Cheese

Some fruits and vegetables especially those that are orange or dark green in color contain beta-carotene, which our body converts to vitamin A. It can be found in foods such as:

  • Carrots,
  • Pumpkin,
  • Winter squash,
  • Dark green leafy vegetables
  • Apricots
  • Spinach
  • Kale
  • Margarine
  • Certain breakfast cereals
  • Tomatoes

The recommended intake of Vitamin A:

The following are some recommended daily allowance values of taking vitamin A which may vary by age and gender.

  • Infants (age 0–12 months) need: 400–500 micrograms (mcg)
  • Children aged 1–3 years need: 300 mcg
  • Children aged 4–8 years need: 400 mcg
  • 9–13 years old children need: 600 mcg
  • Adult women need: 700 mcg
  • Adult men need: 900 mcg

Vitamin D (The sunshine vitamin):

Vitamin D is essential for maintaining strong and healthy bones. It regulates the circulation of calcium and phosphorus and promotes the absorption of these minerals from the diet.

When vitamin D is absorbed into the bloodstream, our liver and kidneys change the Calciferol in calcitriol, the biologically active form of vitamin D.

Exposure to ultraviolet light is necessary for the human body to produce the active form of vitamin D. If you spend ten to fifteen minutes on sunlight on the hands, arms and face is enough to receive enough vitamin D. You have to do this twice in a week and without applying any sunscreen. Vitamin D can be stored in our body for later use in the form of calcidiol.

Fat-soluble vitamins- Vitamin D

Dietary sources:

Another name of Vitamin D is Calciferol. It comes in two main dietary forms:

  1. Vitamin D2 (ergocalciferol): This type of vitamin D is available in mushrooms and some plant-based foods like almond, soy, oatmeal, and cashew fortified plant-based milk, orange juice, tofu, cereals. A single cup of plant-based milk can supply around 30 percent of adults recommended daily intake of vitamin D.

2. Vitamin D3 (cholecalciferol): Found in animal-sourced foods, such as eggs and fish oil, salmon, herring, and sardine fish, cod liver oil, Canned Tuna, oysters shrimp, cow’s milk, and produced by our skin when exposed to sunlight.

We can only make vitamin D in our skin during periods of direct summer sunshine and store for later. This means that we have the ability to keep a reserve stash of vitamin D for the cold, dark days.

Vitamin D Deficiency:

Risk factors of vitamin D deficiency are dark skin color, old age, obesity, low sun exposure and also diseases that impair fat absorption.

Vitamin D deficiency linked with soft bones, weak muscles and an increased risk of bone fractures which is known as Osteomalacia in adults and rickets in children.

Other signs of vitamin D deficiency linked to fatigue, depression, hair loss, and impaired wound healing. Vitamin D status relates to the risk factors for cardiovascular disease and stroke. Low levels of vitamin D are also indirectly linked with the development of breast cancer in women.

The recommended intake of vitamin D:

The recommended daily intake values of vitamin D may vary by our age. Some general guidelines suggest the following daily values:

  • Infants (0–12 months of age): 10 mcg
  • People 1–70 years of age: 15 mcg
  • Above the age 70: 20 mcg

Vitamin E: Tocopherol

Vitamin E is a powerful antioxidant, that protects our cells against premature aging and damage by free radicals.  Alpha-tocopherol is the most common form of vitamin E.

Vitamin E protects vitamins A and C, red blood cells, and essential fatty acids from destruction. Taking antioxidant supplements such as vitamin E  might help prevent heart disease and cancer.

Fat-soluble vitamins- Vitamin EFood Sources for Vitamin E:

About 60 percent of vitamin E in the diet comes from vegetable oil (soybean, corn, cottonseed, and safflower). This also includes products made with vegetable oil (margarine and salad dressing). Vitamin E sources also include fruits and vegetables, grains, nuts (almonds and hazelnuts), seeds (sunflower) and fortified cereals.

Vitamin K

What is vitamin k?

Vitamin K is naturally produced by the bacteria in our intestines and helps the body form blood clots. This prevents a person from bleeding out from small scratches or cuts. Without Vitamin K, you would run the risk of bleeding to death.

Vitamin K can also help with reducing the risk of heart disease, take care of our bone health and also reduce the buildup of calcium in the blood.




Fat-soluble vitamins- Vitamin KFood Sources of Vitamin K:

The two most common groups Vitamin K are:

  • Vitamin K-1,  which is found in plant sources
  • Vitamin K-2,  which is often found in animal sources

Good food sources of vitamin K are:

  • Kale
  • Liver
  • Spinach
  • Parsley
  • Butter
  • Egg yolks
  • Turnip greens
  • Cauliflower
  • Cabbage
  • Broccoli
  • Soybean oil
  • Cottonseed oil
  • Canola oil
  • Olive oil

Vitamin K deficiency:

Vitamin K is not stored in our body as vitamin A or D.  So this can cause a person to experience a vitamin K deficiency very quickly and lead to have a greater risk of excess bleeding. Low levels of vitamin K reduced bone density that can lead to fractures in women.

The Bottom Line

Fat-soluble vitamins in the human diet that are Vitamin A, D, E and K are essential for health and play many important roles in the body. Our body needs only a small amounts of these vitamins.

These vitamins abundant in fatty foods and you can enhance their absorption by adding fat or oil to your meals.

They can store in the body for long periods lead to a greater risk of toxicity than water-soluble vitamins.  For optimal health, try to get all of the fat-soluble vitamins in adequate amounts with your daily meals.


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