Vitamins are organic compounds that are needed in small quantities to help your body grow and develop normally. The 13 essential vitamins can be divided into two categories: fat-soluble, which are stored in the body’s fatty tissues, and water-soluble, which are removed from the body in your urine.

The 13 Essential Vitamins

Buying Vitamins and Supplements Safely

Many people believe that the U.S. Food & Drug Administration regulates vitamins and other dietary supplements like drugs, but this is not the case. In fact, vitamins and dietary supplements – including prenatal vitamins – do not need to undergo any sort of regulatory approval process, and supplement manufacturers are often able to market their products with exaggerations or even complete fabrications about the health benefits on the bottles.

Before buying a vitamin supplement, keep the following things in mind:

  • Talk to your doctor to see if a vitamin supplement is necessary and to make sure it is not harmful, especially if you regularly take any prescription medications.
  • Read all labels and inserts to make sure you understand what the supplement does.
  • Research the effects of vitamins and supplements using reputable sources – do not rely solely on the manufacturer’s information alone.
  • Avoid any dietary supplements that promise a quick cure or change to your body (such as a rapid loss of weight).
  • If you suspect a dietary supplement is dangerous, report it to the Federal Trade Commission, which oversees consumer fraud and mislabeling.

Prenatal Vitamins

Many women are prescribed prenatal vitamins and minerals during pregnancy to ensure they receive enough nutrients for both themselves and their growing babies. The specific prescriptions may differ from woman to woman, but the most common prenatal vitamins and minerals include:

  • Vitamin B9 (folic acid) – Folic acid is highly recommended both before and during pregnancy to prevent potential birth defects like spina bifida and congenital heart disease. It may also help counteract the effects of postpartum depression after pregnancy, although there are conflicting studies on the matter.
  • Iron – Although technically a mineral instead of a vitamin, iron is often included as an ingredient in prenatal vitamins since many women experience a mild form of anemia (iron deficiency) during pregnancy. Iron is required to deliver oxygen to both baby and mother, so a supplement is often recommended.
  • Vitamin D – Because it is found in some foods that should be avoided during pregnancy (like tuna and certain cheeses), some women may need to supplement their intake of vitamin D to ensure proper bone development as the fetus grows.

No matter which prenatal vitamin you take during your pregnancy, it is important to consult with your obstetrician to make sure you are getting all the nutrients you need for a healthy and safe pregnancy and birth.

Do You Need a Vitamin Supplement?

While most people can meet recommended daily requirements by eating a balanced diet, others choose to add a dietary supplement in order to maximize the benefits of these essential vitamins.

Most multivitamins have all 13 vitamins in moderate amounts. Single vitamin supplements are typically recommended to meet specific nutrient deficiencies like low vitamin D levels or a B12 deficiency in older adults or vegetarians. They are also used to supplement an increased need for certain nutrients such as folic acid during pregnancy.

Before adding a vitamin supplement to your diet, you need to determine the recommended daily intake of each nutrient. This will help you calculate your individual needs and make sure you are not exceeding the maximum dose when combining a supplement with food.

If you choose to take a vitamin supplement, make sure to talk with your healthcare provider about any interactions a supplement may have with medications or medical conditions.

Fat-Soluble Vitamins

Fat-soluble vitamins are stored in adipose tissue, meaning that any excess vitamins not used by the body on a daily basis would be saved in fat stores for later use. These vitamins are released again when fat gets burned

Because of this, taking excessive amounts of the fat-soluble vitamins – A, D, E and K – could lead to a buildup in the body that eventually leads to toxicity. In most cases, this type of toxicity occurs only in people who take multivitamins or otherwise exceed the recommended daily requirement of fat-soluble vitamins on a long-term basis.

Fat-Soluble Vitamin Details

Vitamin A
Vitamin A plays a key role in maintaining normal vision, providing support to the immune system, and reproduction. It also helps the heart, lungs, kidneys, and other organs work properly. There are two types of vitamin A: preformed vitamin A and provitamin A.

  • Preformed vitamin A, which can be used directly by the body, is found in meat, poultry, fish, and dairy products.
  • Provitamin A, a substance found in some foods that the body can use to make a vitamin, is found in fruits, vegetables, and other plant-based products. Beta-carotene is an example of provitamin A.

Sources: Carrots, sweet potato, kale, spinach, broccoli, eggs, and beef liver

Vitamin D
Vitamin D helps the body absorb calcium from food and supplements to help maintain strong bones and prevent rickets in children and osteomalacia in adults.

Sources: Fatty fish, beef liver, cheese and egg yolks, fortified milk and other food products with vitamin D added to them, and exposure to the sun.

Vitamin E
The body needs vitamin E to help protect the cells from the damage caused by free radicals. It’s also critical for building and maintaining a strong immune system as well as widening the blood vessels to keep blood from clotting.

Sources: Vegetable oils, nuts, green vegetables, and fortified foods such as cereal, fruit juices, and margarine

Vitamin K
Vitamin K helps regulate normal blood clotting. Because of this, it is sometimes used to counteract the effects of certain blood thinners.

Sources: Green leafy vegetables, vegetable oils, some fruits (such as blueberries and figs), meat, cheese, eggs, and soybeans

Water-Soluble Vitamins

Water-soluble vitamins are not stored in fat, but instead dissolve in the body’s water supply. Any of these nutrients that are not used on a daily basis get expelled from the body through the urine, making toxicity much more difficult.

However, it is still possible to overdose on water-soluble vitamins – which include the B vitamins and vitamin C – which can cause significant problems in the body. Generally this occurs by taking supplements and multivitamins on a prolonged basis.

Water-Soluble Vitamin Details

 Vitamin C
Vitamin C is a powerful antioxidant that helps repair and regenerate tissues, supports immunity, helps the body absorb iron, and of course, lessens the duration and symptoms of a common cold.

Sources: Citrus fruits and juices, red and green peppers, strawberries, cantaloupe, baked potatoes, broccoli, and tomatoes

Vitamin B1 – Thiamin
Like all of the B vitamins, which are part of an enzyme needed for energy metabolism, thiamin helps turn the food you eat into the energy you need. Thiamin is an important part of carbohydrate metabolism and it also plays a role in the growth, development, and function of the cells in your body.

Sources: Meat, fish, legumes, whole grains, fortified pasta, rice, and cereal, nuts, and seeds.

Vitamin B2 – Riboflavin
Riboflavin works as an antioxidant and is needed to help the body change vitamin B6 and folate into forms it can use. It’s also responsible for maintaining healthy blood cells and protecting skin and eye health.

Sources: Brewer’s yeast, green vegetables, lean meats, low-fat milk, eggs, cheese, organ meat, almonds, and fortified cereals, bread, and grain products

Vitamin B3 – Niacin
Niacin helps make various hormones in the adrenal glands, improves circulation, and some studies have shown that niacin (at a very high dose) can boost levels of good HDL cholesterol and lower triglycerides.

Sources: Yeast, milk, fish, eggs, cereal grains, beets and other vegetables

Vitamin B5 – Pantothenic acid
Pantothenic acid helps in the production of red blood cells, assists in the production of various hormones in the adrenal glands, is required to synthesize cholesterol, and is important for digestive health.

Sources: Meat, vegetables, brewer’s yeast, egg yolks, milk, nuts, seeds, fish, and whole unprocessed grains

Vitamin B7 – Biotin
Pyridoxine helps maintain normal nerve function, produces antibodies and hemoglobin, and it is also involved in brain development during pregnancy.

Sources: Cereal, legumes, vegetables, milk, cheese, eggs, fish, liver, meat, and flour

Vitamin B9 – Folate/Folic Acid
Folic acid is the synthetic form of B9 found in supplements and fortified foods, while folate occurs naturally in foods. It plays a role in proper brain function, is needed to make DNA, and is critical during pregnancy, infancy, and adolescence when cells and tissues are growing.

Sources: Leafy vegetables, fruit and juices, nuts, beans, and grains

Vitamin B12
Helps make DNA, nerve and blood cells, contributes to a healthy brain and immune system, helps prevent megaloblastic anemia. B12 is only found in animal products unless plant foods have been fortified with it.

Sources: Clams, beef liver, fish, dairy products, meat, and poultry

Vitamin Deficiency

Nutrient deficiency can be a big problem, both in the U.S. and internationally. There are three primary causes of vitamin deficiency:

million children around the world who have vitamin A deficiencyWHO
  • Lack of access to a variety of foods that offer
  • Ignorance about the recommended daily requirements for micronutrients
  • Dietary restrictions, both self-imposed and those required by certain medical conditions (allergies, intolerances, autoimmune diseases, etc.)

It is important for anyone who eats a modified diet to be aware of the vitamins and other nutrients that they may be missing out on. Talk to a doctor or a dietitian to make sure you are getting all of the vitamins you need on a daily basis.

Vitamin A Deficiency

In particular, vitamin A deficiency results in more preventable blindness in children than any other cause according to the World Health Organization. The largest incidence of vitamin A deficiency occurs in developing countries, but it can also occur in the U.S. and other developed nations, especially among low-income populations. Women who are pregnant or breastfeeding also have a high risk of vitamin A deficiency.

One of the ways that vitamin A deficiency is being combatted is through the fortification of staple foods, such as cereal flours, cooking oils and even sugar. In the U.S., some foods like skim milk are fortified with provitamin A.

Vitamin Overdose

vitamin toxicity incidents occurred in 2015 48,898 incidents occurred in children age 5 or youngerAmerican Association of Poison Control Centers

Although rare, when taken in extremely large quantities, it is possible to experience vitamin toxicity under certain circumstances. According to the American Association of Poison Control Centers, nearly 67,000 incidents of vitamin toxicity occur each year, with a large majority of them occurring in children.

Most overdoses occur in the fat-soluble vitamins D, C, and E (in that order), although the water-soluble vitamin B3 (Niacin) also has a relatively high number of toxic incidents compared to other B-complex vitamins. The reason why fat-soluble drugs may be more likely to cause toxicity is that the vitamins are released as fat gets burned. If vitamin intake is also high, then the release of fat-stored vitamins can increase the amount of those vitamins in the blood, potentially leading to dangerous levels. It is much harder to overdose on water-soluble vitamins, as they are expelled in urine and do not remain in the body for very long.

The good news is that it is generally difficult to overdose on vitamins. Most cases of vitamin overdose are due to people unnecessarily taking multivitamins or getting vitamin injections. This is why it is so important to discuss taking vitamins and supplements with your doctor first.