Fat Soluble Vs. Water Soluble Vitamins: What's the Difference?

Quick Health Scoop

• The 13 essential vitamins our body needs are classified into two main groups: water and fat-soluble vitamins
• The fat-soluble vitamins list includes Vitamins A, D, E, and K
• Examples of water-soluble vitamins include the B Vitamin family and Vitamin C
• When comparing fat-soluble vs water-soluble, each vitamin serves unique functions, making it important to eat a balanced diet to get all the fat and water-soluble vitamins you need every day

If you’ve been trying to eat better, you know that the key to a healthy lifestyle lies in a nutritious, balanced diet filled with fruits, vegetables, whole grains, dairy, healthy fats (such as nuts and seeds), and lean protein, including Omega-3 fatty acids. The variety of foods you eat is important because different foods provide different vitamins, minerals, and other nutrients. 

Vitamins are classified into two main groups: water-soluble and fat-soluble vitamins. As a quick refresher, there are 13 essential vitamins that our bodies need for normal cell function, growth, development and overall optimal health. The known vitamins include the fat-soluble vitamins: A, D, E, and K, and the water-soluble vitamins: C and the B vitamins: thiamin (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyridoxine (B6), biotin (B7), folate/folic acid (B9), and cobalamin (B12).¹ 

But what is the difference between fat-soluble and water-soluble vitamins? Is one type better than the other? Which specific nutrients are fat-soluble and water-soluble vitamins—and what food sources contain them?

Let’s dig deeper to learn more about fat-soluble vitamins vs water-soluble vitamins.

What Are Fat-Soluble Vitamins?

The body stores fat-soluble vitamins in fatty tissue, and they’re absorbed more easily in the presence of dietary fat. The four fat-soluble vitamins are Vitamins A, D, E, and K.² Each of these fat-soluble vitamins functions in a different way, playing an important role in the body. This explains why you need to eat a balanced diet to make sure you’re getting adequate amounts of all the fat-soluble vitamins. 

Below we’ll list each vitamin’s function, food sources, and the Daily Value (DV) for each nutrient. This amount is based on recommended amounts for the nutrient to be consumed each day for children over age four and adults.

Vitamin A

• Functions: Vitamin A is a fat-soluble nutrient that plays a key role in eye function and healthy vision, the immune system, and it supports healthy skin.^{2, †}
  
• Food Sources: Beef liver, some fish (like salmon), green leafy vegetables, and other green, orange, and yellow vegetables, such as broccoli, sweet potatoes, carrots, and squash. Fruits, including cantaloupe, apricots, and mangos. Dairy products, fortified breakfast cereals.³
  
• DV: 900 mcg RAE*/day³

Vitamin D (aka “The Sunshine Vitamin”)

• Functions: Vitamin D is a fat-soluble vitamin that supports healthy muscles and nerves and helps support your immune system.⁴ Vitamin D also helps the body absorb Calcium, which you need to build strong, healthy teeth and bones.^{2, †}
  
• Food Sources: Fatty fish (like trout, salmon, and tuna), fish liver oils, beef liver, cheese, egg yolks, and mushrooms. Because very few foods naturally contain Vitamin D, many foods are fortified with this essential nutrient, including milk, cereal, and orange juice.⁴ Our skin can also make vitamin D when it is exposed to direct sunlight (without sunscreen) for 15-30 minutes per day.
  
• DV: 20 mcg (800 IU)/day⁴

Vitamin E

• Functions: Vitamin E is a fat-soluble nutrient that boasts antioxidant properties (by neutralizing free radicals in the body) and supports a healthy immune system, and is essential for many cells, including heart muscle cells.^{5, †}
  
• Food Sources: Vegetable oils (including wheat germ, sunflower, and safflower oils), nuts (such as almonds, hazelnuts, and peanuts), and seeds (like sunflower seeds).⁵
  
• DV: 15 mg/day⁵

Vitamin K

• Functions: Vitamin K is a fat-soluble nutrient that is essential for blood clotting and supports healthy bones.^{6, †}
  
• Food Sources: Green leafy vegetables (like broccoli, lettuce, and spinach), vegetable oils, some fruits (think blueberries and figs), meat, cheese, eggs, and soybeans.⁶
  
• DV: 120 mcg/day⁶

According to recent national surveys, 46% of the U.S. population has inadequate daily intake of Vitamin A and 95% have inadequate intake of Vitamin D.⁷ Further, 29% of U.S. adults are diagnosed as Vitamin D deficient.⁸ In addition, approximately 60% of the U.S. population has intake levels of Vitamin E below recommended levels.⁹ A deficiency in Vitamin K is rare, however, much of the population consumes amounts below daily recommendations.⁶

The risks of fat-soluble vitamin deficiency can range from rickets, nerve damage, and vision problems, to a weakened immune system, bleeding problems, and osteoporosis.^3-6

There are also defined upper intake levels for fat-soluble vitamins, as excesses are stored and not excreted in the urine. 

• Vitamin A: 3,000 mcg/day
• Vitamin D: 100 mcg/day (4,000 IU – however CRN upper limit is 10,000 IU/d)
• Vitamin E: 1,000 mg/day
• Vitamin K: not defined

What Are Water-Soluble Vitamins?

The nine water-soluble vitamins include the Vitamin B “family” and Vitamin C, and each of these water-soluble vitamins functions in a different way. Because the body does not store water-soluble vitamins, any “leftovers” leave the body through the urine.²

Vitamin B1 (Thiamin)

• Functions: As a Vitamin B water-soluble nutrient, Thiamin helps convert food into energy and supports nervous system function and cellular energy production.^{10 †}
  
• Food Sources: Whole grains and fortified grain products (like bread, cereal, and rice), meat (especially pork), fish, legumes (such as black beans and soybeans), nuts, and seeds.¹⁰
  
• DV: 1.2 mg/day¹⁰

Vitamin B2 (Riboflavin)

• Functions: Riboflavin helps convert food into energy.^†
  
• Food Sources: Eggs, organ meats (like kidneys and liver), lean meats, low-fat milk, green vegetables (like asparagus, broccoli, and spinach), and fortified foods (like bread and cereal).¹¹
  
• DV: 1.3 mg/day¹¹

Vitamin B3 (Niacin)

• Functions: Niacin helps convert food into energy, and also helps nervous system function.^12†
  
• Food Sources: Animal foods (like poultry, beef, and pork); some types of fish, nuts, legumes, and grains; and fortified foods (like bread and cereal).¹²
  
• DV: 16 mg/day¹²

Vitamin B5 (Pantothenic Acid)

• Functions: Pantothenic Acid helps convert food into energy and supports many body functions, Pantothenic Acid also supports the body’s natural stress response.^†
  
• Food Sources: Beef, poultry, seafood, organ meat, eggs, milk, avocados, vegetables (like  broccoli, mushroom potatoes, and shiitake mushrooms), whole grains (such as brown rice, oats, and whole wheat), peanuts, sunflower seeds, and chickpeas.¹³
  
• DV: 5 mg/day¹³

Vitamin B6 (Pyridoxine)

• Functions: Vitamin B6 supports a healthy metabolism.¹⁴ Vitamin B6 is also important for normal red blood cell formation and necessary for normal functioning of the nervous system.² The upper limit for Vitamin B6 is 100 mg/day from all sources (food, beverages, and supplements). ^† 14
  
• Food Sources: Poultry, fish, organ meats, avocados, potatoes and other starchy vegetables, and non-citrus fruits.¹⁴
  
• DV: 1.7 mg/day¹⁴

Vitamin B7 (Biotin)  

• Functions: Biotin helps convert carbohydrates, protein, and fat into energy.¹⁵ Biotin also supports healthy skin and hair and supports nervous system function.^†
  
• Food Sources: Meat, fish, eggs, organ meats (such as liver), nuts, seeds, and certain vegetables (like broccoli, spinach, and sweet potatoes).¹⁵
  
• DV: 30 mcg/day¹⁵

Vitamin B9 (Folate)

• Functions: Folate is naturally found in the food that we eat. A form of folate, folic acid, is the form used in supplements and fortified foods. Folate plays a critical role in the proper development of the baby’s nervous system, which is especially important for women of childbearing age, including pregnant women.¹⁶ Folate also helps support nervous system function and helps convert food into cellular energy.^† 
  
• Food Sources: Beef liver, vegetables (like asparagus, Brussels sprouts, and dark green leafy vegetables like spinach and mustard greens), fruits (especially oranges) and their juices, beans, peas, and nuts.¹⁶
  
• DV: 400 mcg DFE**/day¹⁶

Vitamin B12 (Cobalamin)

• Functions: Vitamin B12 helps support nervous system function and red blood cell formation.^{17 †} Supplementing with Vitamin B12 is especially important for those who follow a vegetarian or vegan diet, as food sources for B12 are mainly found in animal sources.
  
• Food Sources: Beef liver, clams, fish, meat, poultry, eggs, milk, nutritional yeast, and fortified foods (like cereals).¹⁷
  
• DV: 2.4 mcg/day¹⁷

Vitamin C (aka Ascorbic Acid)

• Functions: Vitamin C is a water-soluble vitamin that has antioxidant properties. It is important for healthy skin, as it supports collagen synthesis, and it also helps the body absorb Iron.² In addition, Vitamin C helps support the immune system.^{18 †} Consult with your healthcare provider if you are interested in adding a Vitamin C supplement to your diet.†
  
• Food Sources: Cantaloupe, citrus fruits (like oranges and grapefruit) and their juices, kiwifruit, strawberries, broccoli, baked potatoes, red and green peppers, and tomatoes.¹⁸
  
• DV: 90 mg/day¹⁸

Because the body doesn’t store water-soluble vitamins, you need to make sure you regularly consume enough of them through your diet. Approximately 46% of the U.S. population has an inadequate daily intake of Vitamin C. For the B Vitamins, inadequate intake was found in 11% of the population for B6 (Pyridoxine) and 12% for B9 (folate).⁷

The risks of a water-soluble vitamin deficiency range from memory loss, muscle weakness, and heart problems to skin disorders, hair loss, and birth defects.^10-18

Vitamin B6 does have a tolerable upper limit of 100 mg/day and Folate (Vitamin B9) has a tolerable upper limit of 1,000 mcg/day, as too much Folate can mask a Vitamin B12 deficiency.¹⁶ Vitamin B12 excesses are excreted in the urine and there is no defined tolerable upper intake level.

The Bottom Line

To eat a balanced diet, you need to include a variety of foods so that you’re consuming all of the water and fat-soluble vitamins. The body stores fat-soluble vitamins in fatty tissue and they’re absorbed more easily in the presence of dietary fat. The fat-soluble vitamins list includes Vitamins A, D, E, and K. In contrast, the body does not store water-soluble vitamins (the B Vitamin family and Vitamin C) and any “leftovers” leave the body through the urine. When comparing fat-soluble vs water-soluble vitamins, each nutrient serves different functions. Therefore, aim to eat a nutritious, balanced diet filled with fruits, vegetables, whole grains, dairy, lean protein, healthy fats, nuts, and seeds.  

Continue to check back on the Nature Made blog for the latest science-backed articles to help you take ownership of your health.

Learn More About Vitamins & Supplements:

• Fish Oil Benefits: Why Omega-3s Are So Good For You
• Experts Answers to Your Frequently Asked Questions About Melatonin
• Ashwagandha Benefits: How The Herb Helps Reduce Stress

This information is only for educational purposes and is not medical advice or intended as a recommendation of any specific products. Consult your health care provider for more information.

*Retinol Activity Equivalents (RAE): 1 mcg RAE = 1 mcg retinol, 2 mcg beta-carotene from supplements, 12 mcg beta-carotene from foods, 24 mcg alpha-carotene, or 24 mcg beta-cryptoxanthin.³

**Dietary Folate Equivalents (DFE) = mcg naturally occurring folate + (1.7 x mcg folic acid).¹⁶ 

† These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease.

References 

1. National Center for Complementary and Integrative Health. “Vitamins and Minerals.” February 2018. Accessed on: March 31, 2021. https://www.nccih.nih.gov/health/vitamins-and-minerals
2. Medline. “Vitamins.” February 26, 2021. Accessed on: March 31, 2021. https://medlineplus.gov/ency/article/002399.htm
3. National Institutes of Health Office of Dietary Supplements. “Vitamin A.” January 14, 2021.  Accessed on: March 31, 2021. https://ods.od.nih.gov/factsheets/VitaminA-Consumer/
4. National Institutes of Health Office of Dietary Supplements. “Vitamin D.” March 22, 2021.  Accessed on: March 31, 2021. https://ods.od.nih.gov/factsheets/VitaminD-Consumer/
5. National Institutes of Health Office of Dietary Supplements. “Vitamin E.” March 22, 2021.  Accessed on: March 31, 2021. https://ods.od.nih.gov/factsheets/VitaminE-Consumer/
6. National Institutes of Health Office of Dietary Supplements. “Vitamin K.” March 22, 2021.  Accessed on: March 31, 2021. https://ods.od.nih.gov/factsheets/vitamink-consumer/
7. Reider, Carroll A et al. “Inadequacy of Immune Health Nutrients: Intakes in US Adults, the 2005-2016 NHANES.” Nutrients 12,6 1735. 10 Jun. 2020, doi:10.3390/nu12061735.
8. Liu, X et al. Vitamin D deficiency and insufficiency among US adults: prevalence, predictors and clinical implications. Br J Nutr. 2018 Apr;119(8):928-936.
9. Fulgoni VL 3rd, Keast DR, Bailey RL, Dwyer J. Foods, fortificants, and supplements: Where do Americans get their nutrients? J Nutr. 2011 Oct;141(10):1847-54. doi: 10.3945/jn.111.142257. Epub 2011 Aug 24. PMID: 21865568; PMCID: PMC3174857.
10. National Institutes of Health Office of Dietary Supplements. “Thiamin.” March 22, 2021.  Accessed on: March 31, 2021. https://ods.od.nih.gov/factsheets/Thiamin-Consumer/
11. National Institutes of Health Office of Dietary Supplements. “Riboflavin.” March 22, 2021.  Accessed on: March 31, 2021. https://ods.od.nih.gov/factsheets/Riboflavin-Consumer/
12. National Institutes of Health Office of Dietary Supplements. “Niacin.” March 22, 2021.  Accessed on: March 31, 2021. https://ods.od.nih.gov/factsheets/Niacin-Consumer/
13. National Institutes of Health Office of Dietary Supplements. “Pantothenic Acid.” March 22, 2021.  Accessed on: March 31, 2021. https://ods.od.nih.gov/factsheets/PantothenicAcid-Consumer/
14. National Institutes of Health Office of Dietary Supplements. “Vitamin B6.” January 15, 2021.  Accessed on: March 31, 2021. https://ods.od.nih.gov/factsheets/VitaminB6-Consumer/ 
15. National Institutes of Health Office of Dietary Supplements. “Biotin.” January 15, 2021.  Accessed on: March 31, 2021. https://ods.od.nih.gov/factsheets/Biotin-Consumer/
16. National Institutes of Health Office of Dietary Supplements. “Folate.” March 22, 2021.  Accessed on: March 31, 2021. https://ods.od.nih.gov/factsheets/Folate-Consumer/
17. National Institutes of Health Office of Dietary Supplements. “Vitamin B12.” January 15, 2021.  Accessed on: March 31, 2021. https://ods.od.nih.gov/factsheets/VitaminB12-Consumer/ 
18. National Institutes of Health Office of Dietary Supplements. “Vitamin C.” March 22, 2021.  Accessed on: March 31, 2021. https://ods.od.nih.gov/factsheets/VitaminC-Consumer/