Get to Know Your Vitamin A, D, E, K’s Today
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We learn the ABCs as children, but now it’s time to focus on the ADEK’s—the essential fat-soluble vitamins and minerals that keep our bodies functioning at their best. Vitamins and minerals are essential nutrients that your body needs to thrive.
Fat soluble vitamins are vitamins that can dissolve in fats and oils. They are absorbed with fats in the diet and are stored in the body’s fatty tissue and in the liver (3). There are 13 essential vitamins total, but this article will start with the fat-soluble vitamins – A, D, E, K (2).
Table of Contents
Vitamin A
Vitamin A is part of the fat-soluble retinoids, primarily retinol and retinyl esters (1). It is important for:
- Immune function
- Reproduction
- Growth and development
- Formation and maintenance of organs (4)
The human diet has two sources for vitamin A:
- Performed vitamin A (retinol and retinyl esters) – which are found in foods from animal sources like dairy, fish, eggs, and organ meats (4).
- Provitamin A carotenoids are plant pigments that include beta-carotene (1). These are found in vegetables, fruits and other plant-based products and are converted to vitamin A in the body (4).
Foods that can give you your source of vitamin A:
- Certain types of fish (salmon)
- Green, leafy vegetables (spinach)
- Fruits (mango)
- Dairy products (cheese, milk)
- Fortified breakfast cereals
- Beef liver
- Eggs (4) (1)
In addition to Vitamin A, other essential vitamins like folic acid and pantothenic acid play crucial roles in maintaining overall health.
A deficiency in Vitamin A can cause reduction in night vision, susceptibility to infection, dry skin, itching, skin ulcers, growth and developmental issues in children and infants leading to stunted physical growth and delayed mental development (8).
Vitamin D
Vitamin D is a nutrient that helps your body absorb calcium which is vital for building strong bones. Along with calcium, vitamin D protects you from developing osteoporosis (5). It can also help with your muscles, nerves and immune system to fight off bacteria and viruses (5).
Along with Vitamin D, ascorbic acid (Vitamin C) is another essential nutrient that supports immune function and overall health.
Foods rich in Vitamin D (5):
- Milk
- Breakfast cereals
- Fatty fish
- Beef liver
- Egg yolk
- Mushrooms
Vitamin D is made in the skin when you are exposed to sun, however people don’t tend to spend too much time in the sun because it can cause skin cancer and other skin damage; therefore, it is important to supplement vitamin D to maintain adequate levels in your body (5).
A deficiency in vitamin D causes osteomalacia (which causes bone pain) and fractures. It can also cause fatigue and decreased muscular strength (8).
Vitamin E
Vitamin E acts as an antioxidant in the body which protects cells from the damage caused by free radicals that are made when we eat food (6). It also helps:
- Boost the immune system
- Widen blood vessels to keep blood from clotting
- Cell to cell interaction (6)
Foods rich in Vitamin E include:
- Green vegetables (spinach, broccoli)
- Nuts (peanuts, hazelnuts, almonds) and seeds (sunflower)
- Vegetable oils (sunflower, safflower, corn, soybean) (7)
A vitamin deficiency in Vitamin E can lead to serious health issues, highlighting the importance of maintaining adequate levels through diet or supplementation.
A deficiency in vitamin E can cause:
- Diminished reflexes
- Impaired proprioceptive and vibratory sensitivity
- Night blindness
- Ataxia
- Fertility problems in both men and women (8)
Vitamin K
Vitamin K is a nutrient that is important for blood clotting and healthy bones (9). You can get your source of vitamin K from certain foods such as:
- Green, leafy vegetables (spinach, lettuce, kale)
- Vegetable oils
- Certain fruits, like blueberries
- Meat, cheese, eggs, soybeans (9)
According to dietary reference intakes, the recommended amount of Vitamin K varies by age and gender, emphasizing the need for tailored nutritional guidelines.
A deficiency in vitamin K can cause:
- Hemorrhages after small trauma
- Osteopenia and increased fracture risk
- Muscle weakness (8)
Closing Thoughts
The fat-soluble vitamins – A, D, E, and K—are vital for maintaining overall health. Because we do not produce vitamins on our own, it is important to get vitamins from our nutrition and supplementation. If you are unable to get enough vitamins from your diet, a vitamin supplement can help ensure you meet your nutritional needs. Achieving optimal levels, as confirmed through blood work, is essential. If supplementation is required, be sure to consult your doctor and check that the vitamins will not interfere with any medications you may be taking.
References
[1] National Institutes of Health, Office of Dietary Supplements. “Vitamin A - Health Professional.” U.S. Department of Health and Human Services, n.d., https://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/.
[2] National Institute on Aging. “Vitamins and Minerals for Older Adults.” National Institute on Aging, n.d., https://www.nia.nih.gov/health/vitamins-and-supplements/vitamins-and-minerals-older-adults.
[3] National Cancer Institute. “Fat-Soluble Vitamin.” NCI Dictionary of Cancer Terms, National Cancer Institute, n.d., https://www.cancer.gov/publications/dictionaries/cancer-terms/def/fat-soluble-vitamin.
[4] National Institutes of Health, Office of Dietary Supplements. “Vitamin A - Consumer.” U.S. Department of Health and Human Services, n.d., https://ods.od.nih.gov/factsheets/VitaminA-Consumer/.
[5] National Institutes of Health, Office of Dietary Supplements. “Vitamin D - Consumer.” U.S. Department of Health and Human Services, n.d., https://ods.od.nih.gov/factsheets/VitaminD-Consumer/.
[6] National Institutes of Health, Office of Dietary Supplements. “Vitamin E - Consumer.” U.S. Department of Health and Human Services, n.d., https://ods.od.nih.gov/factsheets/VitaminE-Consumer/.
[7] National Institutes of Health, Office of Dietary Supplements. “Vitamin E - Health Professional.” U.S. Department of Health and Human Services, n.d., https://ods.od.nih.gov/factsheets/VitaminE-HealthProfessional/.
[8] Andrès, Emmanuel, et al. “Fat-Soluble Vitamins A, D, E, and K: Review of the Literature and Points of Interest for the Clinician.” Journal of Clinical Medicine, vol. 13, no. 13, 2024, article 3641, https://doi.org/10.3390/jcm13133641
[9] National Institutes of Health, Office of Dietary Supplements. “Vitamin K: Fact Sheet for Consumers.” Office of Dietary Supplements, https://ods.od.nih.gov/factsheets/VitaminK-Consumer/.
