Water-Soluble vs. Fat-Soluble Vitamins

Medically Reviewed by Melinda Ratini, MS, DO on August 12, 2023
4 min read

You’ve heard about them growing up, you’ve seen them on food packaging, and you’ve read about them in nutrition articles: Vitamins. You've probably heard common phrases like: "Take your vitamins,” “Contains vitamins and minerals,” and “Feeling sluggish? Make sure you’re getting these vitamins.”

Although they play an important role in your health and body functions, not all vitamins are created equal. Knowing which vitamins do what and which ones are water or fat-soluble will save you a bit of headache. 

Vitamins aren’t just little gummies shaped like cartoon characters. They’re found in the food you eat and help your body function. Vitamins are important for your body. A well-rounded diet makes sure your body has all the vitamins it needs to work well. 

Vitamins have several important functions, including: 

There are two types of vitamins: water-soluble and fat-soluble. This means that they live in the fat of your body or the water of your body. They act differently, and they function differently when your body needs them. 

Fat-soluble vitamins are absorbed with the other fats from the food you eat. When they’re absorbed in this way, they go with the fats and are stored in your body’s fat tissue and liver. 

Fat-soluble vitamins can stay in your body for a while. When they’re stored in your body’s fat, they can be stored for up to 6 months until your body needs them. 

The primary fat-soluble vitamins in your diet are vitamins A, D, E, and K. Each one has its important function and can be found in a variety of food. 

Role of Vitamin A. Vitamin A has many important functions in your body: 

  • It strengthens your immune system.
  • It’s essential for your vision.
  • It supports reproductive functions
  • Vitamin A promotes cell growth and the maintenance of your organs.

Sources of Vitamin A. There are two types of vitamin A: One comes from animal products and the other from plant products. Vitamin A from plants requires a bit more work from your body, so you need to eat plenty of veggies to get enough vitamin A. 

Major sources of vitamin A include: 

  • Dairy
  • Liver
  • Some fish
  • Fortified grains
  • Carrots
  • Broccoli
  • Cantaloupe
  • Squash

Role of Vitamin D. Vitamin D works with calcium to strengthen your bones. It helps your muscles move, and supports your immune system. As you get older, your body needs more vitamin D to keep your bones and muscles healthy. 

Sources of Vitamin D.Vitamin D doesn’t occur naturally in most foods. Instead, your body produces vitamin D when sunlight directly hits your skin — not through a window. 

Role of Vitamin E. Vitamin E supports your immune system and prevents blood clots. Most importantly, vitamin E is an antioxidant that helps fight carcinogens and other cancer-causing agents. 

Sources of Vitamin E. You can find plenty of vitamin E in vegetable oils, nuts, and seeds. Green vegetables and fortified foods can give you extra vitamin E. 

Role of Vitamin K. Vitamin K plays an important role in blood clotting. Without it, you bruise more easily and you bleed more freely. Vitamin K also supports your bone health and prevents diseases like osteoporosis. 

Osteoporosis is when your bones become weak and brittle.

Sources of Vitamin K. You can find vitamin K in a lot of different foods, including: 

  • Leafy greens (spinach, kale, etc.)
  • Vegetable oils
  • Blueberries
  • Figs
  • Meat
  • Dairy
  • Soybeans

Water-soluble vitamins aren’t long-term like fat-soluble vitamins. They don’t get stored in your body. They enter your bloodstream, and anything your body doesn’t need is eliminated through your urine. 

Since water-soluble vitamins don’t last long in your body, they need to be replenished frequently.

The important water-soluble vitamins are vitamin C and the collection of B vitamins, including: 

  • B1 (thiamin)
  • B2 (riboflavin)
  • B3 (niacin)
  • B4 (pantothenic acid)
  • B6 (pyridoxine)
  • B7 (biotin)
  • B9 (folic acid or folate)
  • B12 (cobalamin)

Role of Vitamin C. There’s a reason vitamin C is the go-to vitamin when you get sick. It plays an important role in your body.

Some of the functions include: 

  • It’s an antioxidant that protects your cells from damage. 
  • It makes collagen, a powerful protein that helps wounds heal by providing the structure for your muscles, bones, and skin. 
  • It helps your body absorb iron from the fruits and veggies you eat. 
  • It supports your immune system to protect you from disease

Sources of Vitamin C. You’ll get the most vitamin C from raw fruits and veggies.

The best foods to eat are: 

  • Citrus fruits
  • Bell peppers
  • Broccoli
  • Strawberries
  • Cantaloupes
  • Tomatoes

Roles of B Vitamins. Each B vitamin plays a small role in the larger scheme of all the B vitamins. As a group, B vitamins help fuel your body. They create the energy your body needs to get through the day. 

One way the B vitamins do this is by promoting the formation of red blood cells. This helps deliver oxygen around your body and ensures every part is working. 

Sources of B Vitamins. You can find B vitamins almost everywhere. If you have a deficiency in a certain B vitamin, you may need to increase your intake of certain foods.

Foods high in B vitamins include: 

  • Whole grains
  • Seafood
  • Poultry
  • Eggs
  • Dairy
  • Leafy greens
  • Beans

If you’re eating a well-rounded diet, you may not need any supplements. Certain health conditions, dietary restrictions, or lifestyle circumstances may limit your ability to get certain vitamins, however. Talk with your doctor about vitamin supplements if you’re worried about your intake. 

Also, a large recent study has suggested that a daily multivitamin may help slow down the cognitive decline seen in some elderly people. More research is needed before a multivitamin is recommended for everyone.