Fat Soluble Vitamins (A, D, E, K): Definition, Foods, Functions, Deficiency

What Are Fat Soluble Vitamins?

Fat Soluble Vitamins Definition

These are types of vitamins, which dissolve in fats and oils. Fat soluble vitamins get absorbed together with fats that are present in the diet and later end up being stored in the body’s fatty tissue. They are derived from plants, animal foods, or dietary supplements. Forms of fat soluble vitamins are vitamin A, D, E, and K.

Fat soluble vitamins, combined with dietary fats, are absorbed through the small intestine and get excreted in a slow process.

The functions of fat soluble vitamins are to hold and strengthen the bone to aid the muscle in movement.

What Are Fat Soluble Vitamins Characteristics?

There are distinctive characteristics of fat soluble vitamins, which make them stand out from other vitamins.

Storage: Fat soluble vitamins can be found in your liver and fatty tissue, as they are stored there.

Absorption and Excretion: Fat soluble vitamins are absorbed by the small intestine with dietary fat, which slowly get excreted.

Toxicity: Since fat soluble vitamins are not easily excreted, and stay for a longer period in the body, they can, in turn, affect the body by causing toxicity. High intake of supplements can make you fall ill by causing an imbalance of vitamins but this can be avoided by maintaining a healthy diet. Therefore, try not to get carried away with the sweetness of the jellies.

What Are Fat Soluble Vitamins Foods or Sources?

Sources of Vitamin A

Vitamin A has two types: the preformed vitamin A and the pro-vitamin A. Preformed vitamin A, which is also referred to as retinol, can be found in animal products. The main sources are:

  • Meat
  • Cheese
  • Eggs
  • Halibut fish oil
  • Liver
  • Kidneys
  • Cream

The pro-vitamin A is found in plant-based foods like fruits and vegetables. Beta-carotene is a common type of pro-vitamin A that produces the dark pigments found in plants. Some foods with beta-carotene are:

  • Cantaloupe
  • Pink grapefruit
  • Apricots
  • Carrots
  • Pumpkin
  • Sweet potatoes
  • Winter squash
  • Dark green, leafy vegetables
  • Broccoli

Sources of Vitamin D

The most familiar source of vitamin D is sunlight and other sources are fish oil and fatty fish. Below are foods that are a good source and rich in vitamin D:

  • Cod liver oil
  • Fresh herring
  • Swordfish
  • Raw maitake mushrooms
  • Salmon
  • Sockeye
  • Sardines
  • Fortified skim milk
  • Tuna
  • Egg
  • Chicken

Sources of Vitamin E

Vitamin E is a fat soluble compound. Foods rich in vitamin E are:

  • Nuts (peanuts, almonds, hazelnuts)
  • Green-leafy vegetables (spinach, broccoli, safflower)
  • Oil-containing foods (sunflower seeds, soybean oil)

Sources of Vitamin K

Vitamin K is of two types: vitamin K1 and K2. Few main sources of vitamin K1 are:

  • Leafy green vegetables (kale, Swiss chard)
  • Vegetable oils
  • Some fruits (prunes, kiwi, avocado, blackberries, blueberries, pomegranate…)

Sources of vitamin K2 (menaquinones) are:

  • Grass-fed butter
  • Grass-fed meat
  • Eggs
  • Dairy products
  • Natto (fermentated from soybeans)
  • Sauerkraut
  • Yogurt

For more info, check this post Vitamin K Foods: Vegetables, Fruits, Animal Products, Grains, Oils and Fats

Fat Soluble Vitamins Functions

Functions of Vitamin A

There are many functions, which vitamin A performs. Retinol creates pigments inside the retina of the eye and not only that, it is very important for the eye to have a good vision, mostly when is dark or night-vision, and the vital for the general health of the eye. The National Eye Institute conducted an age-related eye disease study, which revealed that high levels of antioxidant intakes, such as vitamin A, combined together with zinc, might lessen the risk of developing advanced age-related macular degeneration (AMD) to about 25%. In the study, it revealed that the most common causes for vision loss in older people are AMD.

Another important function of vitamin A is that it aids in the growth of skin and helps to repair the skin as well. Vitamin A is the active ingredient in most of Retin-A products today. Retin-A is a brand name for Tretonin, which is a prescription drug used for the treatments of acne and other skin ailments.

Other important functions of vitamin A are the development or formation and maintenance of teeth, soft tissue, bones, the immune system, white blood cells, and mucous membranes.

Functions of Vitamin D

Vitamin D is very essential for bone health. Vitamin D performs the key function of the regulation of calcium and maintenance of the levels of phosphorus in the blood. Calcium and phosphorus are particularly important for sustaining healthy bones.

Vitamin D reduces risk of diabetes. Many studies have revealed the reversed relationship between blood concentrations of vitamin D inside the body and the risk of type 2 diabetes. The study suggested that people with type 2 diabetes and have insufficient vitamin D levels might have problems with insulin secretion and glucose tolerance.

Low levels of vitamin D have been linked with a higher risk and severity of chronic childhood ailments, infections and allergic diseases, including asthma, atopic dermatitis, and eczema. High levels of vitamin D in the body may increase the anti-inflammatory effects of glucocorticoids, and highly beneficial as a supportive therapy for infants with steroid-resistant asthma.

Functions of Vitamin E

Vitamin E is a vital antioxidant. It acts as a protective shield against cell damage. Vitamin E might provide great help in resisting or lowering several possible health problems, ranging from cancer to heart diseases, and even dementia.

Fat soluble vitamin E has many other functions. It is essential to healthy immune system. This vitamin can protect long-term eyesight as well.

People who suffer from cystic fibrosis, Crohn’s disease, or not able to secrete bile from the liver due to ailment into the digestive tract, taking water-soluble forms of vitamin E may remedy these problems.

Functions of Vitamin K

Vitamin K has several benefits to our body. According to several studies on the benefits of vitamin K, experts have suggested that vitamin K aids in the maintenance of strong and healthy bone density, which reduces the possible risk of bone fractures.

A higher percentage of older adults have been suggested to have an improved episodic memory due to higher levels of vitamin K in their body.

By preventing accumulation of minerals leading to the build-up in the arteries, vitamin K could help the body keep lower blood pressure. When the arteries are free, it allows the heart to freely pump blood through the body. There are other suggestions that high intake of vitamin K has proven to minimize the risk of stroke and lower its occurrence.

Fat Soluble Vitamins Deficiency

Vitamin A Deficiency

Vitamin A deficiency is common in most developing countries; however, it is rare in the United States. Records show that lack of vitamin A or the deficiency of this important vitamin has been the number one cause of childhood blindness in Southeast Asia region.

Other statistics place the number of children that become blind due to the deficiency of vitamin A around the world is 250,000 to 500,000 annually. Sadly, according to the World Health Organization, half of those children die within 12 months of going blind.

The symptoms of severe vitamin A deficiency are:

  • Night blindness
  • Dry eyes
  • Diarrhea
  • Skin problems

Vitamin D deficiency

The body is majorly responsible for creating vitamin D; however, deficiency can occur due to several factors.

Severe vitamin D deficiency is mainly linked to many ailments and diseases.

Vitamin D deficiency in pregnant women would increase the risk of preeclampsia and needing a caesarean section. Check it for more info Vitamin D Deficiency Signs and Symptoms during Pregnancy

Other negative effects of poor vitamin D are the gestational diabetes mellitus and bacterial vaginosis in pregnant women.

Here is a detailed post on vitamin D deficiency you may check – Vitamin D Deficiency: Risk Factors, Causes, Signs, Treatments

Vitamin E deficiency

Vitamin E deficiency is not common and rarely occurs. However, some people are susceptible to the deficiency. Skeletal myopathy, ataxia, anemia, peripheral neuropathy, impairment of the immune response, nerve damage and retinopathy are signs and symptoms of severe deficiency of vitamin A.

Vitamin K Deficiency

Vitamin K is very essential to the body because the body cannot produce prothrombin without vitamin K. Prothrombin, a protein produced by the liver, is a major factor in the blood that helps it to clot and bone metabolism.

The occurrence is likely to affect newborns especially those who have malabsorption issues, due to short-bowel syndrome, celiac disease.

Newborns generally receive vitamin K injection (read this post for more Vitamin K at Birth: Drops or Injection?) as preventive measures, to avoid bleeding from the skull, which is really fatal.

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