Fat-Soluble Vitamins: Definition, Functions, Dietary Sources, and More


The body needs 13 essential vitamins, and these can be divided into two categories: fat-soluble and water-soluble. 

In this article, we’ll talk about one category in particular – fat-soluble vitamins. 

Discover what fat-soluble vitamins are, its functions, dietary sources, and more. 

Fat-Soluble Vitamins Definition

Fat-soluble vitamins dissolve in fat. These vitamins are absorbed by fat globules within your body and then carried throughout the bloodstream. There are 4 fat-soluble vitamins, including Vitamin A, Vitamin D, Vitamin E, and Vitamin K. 

Fat-soluble vitamins are found in high-fat food sources, including liver, fatty fish, beef, egg yolks, and dairy products. Unlike water-soluble vitamins, any excess of fat-soluble vitamins doesn’t leave the body immediately; instead, they are stored in the fatty tissue or liver for later use. 

Fat-Soluble Vitamins List

Vitamin A (and its precursor*, beta-carotene)
*A precursor is converted by the body to the vitamin.
Needed for vision, healthy skin and mucous membranes, bone and tooth growth, immune system healthVitamin A from animal sources (retinol): fortified milk, cheese, cream, butter, fortified margarine, eggs, liver
Beta-carotene (from plant sources): Leafy, dark green vegetables; dark orange fruits (apricots, cantaloupe) and vegetables (carrots, winter squash, sweet potatoes, pumpkin)
Vitamin DNeeded for proper absorption of calcium; stored in bonesEgg yolks, liver, fatty fish, fortified milk, fortified margarine. When exposed to sunlight, the skin can make vitamin D.
Vitamin EAntioxidant; protects cell wallsPolyunsaturated plant oils (soybean, corn, cottonseed, safflower); leafy green vegetables; wheat germ; whole-grain products; liver; egg yolks; nuts and seeds
Vitamin KNeeded for proper blood clottingLeafy green vegetables such as kale, collard greens, and spinach; green vegetables such as broccoli, Brussels sprouts, and asparagus; also produced in the intestinal tract by bacteria

(source: https://www.healthlinkbc.ca/health-topics/ta3868

Vitamin A. Vitamin A is important for the immune system, reproduction, and normal vision. It also helps the heart, lungs, kidneys, and other organs function properly. There are two types of Vitamin A. The first type – preformed Vitamin A – is found in poultry, fish, meat, and dairy products. The second type – provitamin A – is found in vegetables, fruits, and other plant-based products. The most common type of provitamin A found in dietary supplements is beta-carotene. 

  • Dietary Sources: Vitamin A is naturally found in many foods and is added to some foods. You can get recommended amounts of Vitamin A by eating a wide variety of foods, including beef liver and other organ meats, fish, green leafy vegetables, fruits, dairy products, milk, and fortified breakfast cereals. 
  • Daily Recommended Intake: 
Life StageRecommended Amount
Birth to 6 months400 mcg RAE
Infants 7–12 months500 mcg RAE
Children 1–3 years300 mcg RAE
Children 4–8 years400 mcg RAE
Children 9–13 years600 mcg RAE
Teen boys 14–18 years900 mcg RAE
Teen girls 14–18 years700 mcg RAE
Adult men900 mcg RAE
Adult women700 mcg RAE
Pregnant teens750 mcg RAE
Pregnant women770 mcg RAE
Breastfeeding teens1,200 mcg RAE
Breastfeeding women1,300 mcg RAE

(source: https://ods.od.nih.gov/factsheets/VitaminA-Consumer/

  • Deficiency: Vitamin A deficiency is rare. However, some groups of people such as vegans may be at risk since preformed Vitamin A is only found in animal-sourced foods. Also, while Vitamin A is found in many fruits and vegetables, it is not always efficiently converted into retinol – the active form of Vitamin A. Symptoms of Vitamin A deficiency may include dry skin, dry eyes, night blindness, acne and breakouts, throat and chest infections, and poor wound healing. 

Vitamin D. Known as the ‘sunshine vitamin’, Vitamin D is produced by the body in response to skin being exposed to sunlight. It also occurs naturally in some foods, including some fish, egg yolks, and fish liver oils, as well as in fortified grain and dairy products. Vitamin D promotes calcium absorption in the gut and maintains adequate phosphate and serum calcium concentrations to enable normal bone mineralization. It is also needed for bone growth. 

  • Dietary Sources: Some dietary sources of Vitamin D include salmon, sardines, cod liver oil, egg yolks, soy milk, orange juice, and fortified cereals and oatmeal. Exposure to sunlight is one of the best sources of this vitamin.
  • Daily Recommended Intake:
0-12 months*10 mcg
(400 IU)
10 mcg
(400 IU)
1–13 years15 mcg
(600 IU)
15 mcg
(600 IU)
14–18 years15 mcg
(600 IU)
15 mcg
(600 IU)
15 mcg
(600 IU)
15 mcg
(600 IU)
19–50 years15 mcg
(600 IU)
15 mcg
(600 IU)
15 mcg
(600 IU)
15 mcg
(600 IU)
51–70 years15 mcg
(600 IU)
15 mcg
(600 IU)
>70 years20 mcg
(800 IU)
20 mcg
(800 IU)

(source: https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/)

  • Deficiency: Vitamin D deficiency can occur for a number of reasons. Either your exposure to sunlight is limited, you don’t consume the recommended levels of Vitamin D, or your digestive tract cannot adequately absorb this vitamin. Vitamin D deficiency can lead to a loss of bone density, which can result in fractures (broken bones) and osteoporosis. Severe Vitamin D deficiency can also result in other diseases. In children, it can result in rickets – a rare disease that causes bones to become soft and bend. In adults, severe Vitamin D deficiency can lead to osteomalacia – this causes muscle weakness, bone pain, and weak bones. 

Vitamin E. Vitamin E is a potent antioxidant that helps repair damaged cells. Naturally occurring vitamin E exists in 8 chemical forms (alpha-, beta-, gamma-, and delta-tocopherol and alpha-, beta-, gamma-, and delta-tocotrienol) that have varying levels of biological activity. Alpha- (or α-) tocopherol is the only form of Vitamin E that is recognized to meet human requirements. In addition to its activities as an antioxidant, Vitamin E is involved in immune function, regulation of gene expression, and other metabolic processes. 

  • Dietary Sources: Vitamin is naturally found in some foods, added to others, and is also available as a dietary supplement. Some foods high in Vitamin E include almonds, sunflower seeds, hazelnuts, asparagus, avocado, broccoli, mango, turnip greens, kiwifruit, lobster, cranberries, canola oil, and palm oil. 
  • Daily Recommended Intake:
0–6 months*4 mg4 mg
7–12 months*5 mg5 mg
1–3 years6 mg6 mg
4–8 years7 mg7 mg
9–13 years11 mg11 mg
14+ years15 mg15 mg15 mg19 mg

(source: https://ods.od.nih.gov/factsheets/VitaminE-HealthProfessional/

  • Deficiency: Vitamin E deficiency is a very rare condition, occurring as a result of abnormalities in metabolism or dietary fat absorption, rather than from a diet low in Vitamin E. Vitamin E deficiency can cause nerve problems due to poor conduction of electrical impulses along the nerve due to changes in nerve function and structure. Signs of Vitamin E deficiency may also include neuromuscular problems, neurological problems, retinopathy, immune response impairment, and hemolytic anemia. 

Vitamin K. Vitamin K refers to a group of fat-soluble vitamins that play a crucial role in blood clotting, regulating blood calcium levels, and bone metabolism. The body needs Vitamin K to produce prothrombin – a clotting factor and protein critical in bone metabolism and blood clotting. Vitamin K comes in two forms: phylloquinone (Vitamin K1) or menaquinone (Vitamin K2). Phylloquinone (Vitamin K1) can be found in plants, such as kale and spinach. On the other hand, menaquinone (Vitamin K2) is found in the body and is created naturally in the intestinal tract. 

  • Dietary Sources: Vitamin K is naturally found in a wide variety of foods, including green leafy vegetables (i.e. broccoli, lettuce, kale), some fruits (i.e. figs and blueberries), vegetable oils, soybeans, cheese, eggs, and meat.  
  • Daily Recommended Intake:
Life StageRecommended Amount
Birth to 6 months2.0 mcg
7–12 months2.5 mcg
1–3 years30 mcg
4–8 years55 mcg
9–13 years60 mcg
14–18 years75 mcg
Adult men 19 years and older120 mcg
Adult women 19 years and older90 mcg
Pregnant or breastfeeding teens75 mcg
Pregnant or breastfeeding women90 mcg

(source: https://ods.od.nih.gov/factsheets/VitaminK-Consumer/

  • Deficiency: Vitamin K deficiency is very rare. Most people get enough Vitamin K from the foods that they eat. However, certain groups of people including people with medical conditions (celiac disease, ulcerative colitis), newborns who don’t receive an injection of vitamin K at birth, and people who had bariatric surgery may have trouble getting Vitamin K. The signs and symptoms associated with Vitamin K deficiency may include easy bruising, blood in the urine and/or stool, excessive bleeding from wounds, heavy menstrual periods, and small blood clots appearing under the nails.

Treatment for Fat-Soluble Vitamins Deficiency

If your diet lacks the necessary fat-soluble vitamins, eating foods rich in those vitamins is the best treatment. Doctors sometimes recommend taking vitamin supplements to get the necessary vitamins – you might receive these supplements either as an injection or as oral medications.  

The Bottom Line

There are 4 fat-soluble vitamins, including Vitamin A, Vitamin D, Vitamin E, and Vitamin K – each of these vitamins play a crucial role in your body. 

Fat-soluble vitamins are found in high-fat food sources, including liver, fatty fish, beef, egg yolks, and dairy products. Unlike water-soluble vitamins, any excess of fat-soluble vitamins doesn’t leave the body immediately; instead, they are stored in the fatty tissue or liver for later use. 

Deficiency of fat-soluble vitamins can occur if you don’t eat foods containing these vitamins, or if your body has trouble absorbing or processing these vitamins. Deficiencies can be treated by eating foods rich in those vitamins or through supplements. 

Disclaimer: The information on this site is not intended to be a substitute for professional medical advice, diagnosis, or treatment. All information contained on this web site is for general information purposes only.

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