The Essential Vitamins (and Where To Get Them)

There are numerous essential vitamins that we need to obtain from our diet.

These vitamins include vitamins A, B1, B2, B3, B5, B6, B12, C, D, E, K, folate, and biotin.

Four of these vitamins are fat-soluble: vitamins A, D, E, and K. The remaining vitamins are water-soluble.

In this article, we will briefly explain the importance of each essential vitamin. Further, we will look at the recommended daily allowance (RDA) and the best food sources for each one.

All RDA figures are sourced directly from the US National Institutes of Health.

Vitamin A

The Structure and Name of Vitamin A (Retinol).

There are two primary ways to get vitamin A from our diet.

Pre-formed vitamin A, otherwise known as retinol, is available from animal-based foods such as liver and eggs (1).

In contrast, we can also convert carotenoids found in plant-based foods to vitamin A.

However, this conversion rate can vary depending on the person and the specific food (2).

Some of these carotenoids, including astaxanthin, lutein, and lycopene, may have further benefits due to their antioxidant properties (3).

Vitamin A is fat-soluble, and it is particularly important for the optimal functioning of the immune system. The vitamin also plays a crucial role in vision (4, 5).

See this guide to the functions of vitamin A for more information.

Name Recommended Daily Allowance Food Sources
Vitamin A Adult men: 900 mcg RAE (6)

Adult women: 700 mcg RAE

Liver, eggs, sweet potatoes, carrots

For a full list of the best food sources of vitamin A, see this guide here.

Vitamin B1 (Thiamin)

Also called thiamin, vitamin B1 plays a crucial role in the conversion of food into energy.

For this and other reasons, the vitamin is also essential for a healthy nervous system (7).

Thiamin is water-soluble, and it plays a vital role in maintaining healthy skin, hair, and nails.

Name Recommended Daily Allowance Best Food Sources
Vitamin B1 (thiamin) Adult men: 1.2 mg

Adult women: 1.1 mg (8)

Meat, organ meats, seafood, soybeans, wheat germ (9)

Here is a full list of foods high in thiamin.

Vitamin B2 (Riboflavin)

Similar to other B vitamins, vitamin B2 is important for producing energy from the food we eat, and it is necessary for the optimal absorption of carbohydrates, fat, and protein (10).

Vitamin B2 is better known as riboflavin, and it is a water-soluble vitamin.

The vitamin is present in a range of animal and plant-based foods.

Name Recommended Daily Allowance Best Food Sources
Vitamin B2 (riboflavin) Adult men: 1.3 mg

Adult women: 1.1 mg (11)

Eggs, mushrooms, meat, organ meat, soybeans (12)

Vitamin B3 (Niacin)

The Structure and Name of Vitamin B3 (Niacin).

Niacin is an important vitamin for the digestive and nervous systems, and like other B vitamins, it also plays a role in converting food into energy (13).

We can find this vitamin in a wide range of animal-based and plant-based foods.

Name Recommended Daily Allowance Best Food Sources
Vitamin B3 (niacin) Adult men: 16 mg

Adult women: 14 mg (14)

Fish, legumes, meat, nutritional yeast, poultry (15)

For more on the best food sources, see this list of niacin-rich foods.

Vitamin B5 (Pantothenic acid)

Vitamin B5 is another water-soluble B vitamin that plays a part in producing energy from food (16).

Further to this, B5 also has a key role in maintaining a healthy nervous system, synthesizing coenzyme A, and producing hormones (17, 18).

Name Recommended Daily Allowance Best Food Sources
Vitamin B5 (pantothenic acid) Adult men: 5 mg

Adult women: 5 mg (19)

Eggs, legumes, meat, organ meat, mushrooms, seeds, shellfish, whey (20)

Here is a full list of foods high in vitamin B5.

Vitamin B6 (Pyridoxine)

Vitamin B6, also known as pyridoxine, is available from both animal-based and plant-based foods.

However, it is important to note that the vitamin’s relative bioavailability is lower in plant foods.

Animal sources of B6 have a near-100% bioavailability, but the presence of fiber and pyridoxine glucoside in plant foods decreases the bioavailability (21).

Vitamin B6 has vital functions for brain and cellular development, energy metabolism, and supporting the nervous and immune systems (22).

Name Recommended Daily Allowance Best Food Sources
Vitamin B6 (pyridoxine) Adult men: 1.3 mg

Adult women: 1.3 mg (23)

Banana, fish, nuts, organ meats, peppers, potatoes, seeds sunflower seeds (24)

Here is a complete list of the best dietary sources of vitamin B6.

Vitamin B12 (Cobalamin)

Vitamin B12 is probably the most famous of all the B vitamins.

This essential vitamin is of great importance to our health, and inadequate intake can potentially lead to anemia, nerve damage, and other serious consequences (25).

Vitamin B12 is only available from animal foods, so vegans need to supplement with either B12 tablets, nutritional yeast, or other fortified food (26, 27).

For more on vitamin B12, see this article about its functions in the body.

Name Recommended Daily Allowance Best Food Sources
Vitamin B12 (cobalamin) Adult men: 2.4 mcg

Adult women: 2.4 mcg (28)

Eggs, dairy, meat, poultry, seafood, nutritional yeast, other fortified foods (29)

See here for a full list of foods rich in B12.


Folate is generally known as ‘folate,’ but it may sometimes be referred to as vitamin B9 (30).

This essential vitamin is particularly important for cell development and producing and repairing DNA.

Research also demonstrates that folate supplementation can reduce the risk of neural tube defects during pregnancy (31).

Name Recommended Daily Allowance Best Food Sources
Folate (vitamin B9) Adult men: 400 mcg

Adult women: 400 mcg (32)

Avocado, dairy, eggs, legumes, meat, seafood, spinach, whole grains (33)

For more information on folate-rich foods, see this list of foods high in folate.


Biotin is a little-known B vitamin that is also called vitamin B7 and may sometimes be referred to as ‘vitamin H’ (34).

This vitamin has a role in cell signaling, gene expression, energy metabolism, and the nervous system (35).

There is currently no set RDA for biotin due to a lack of available data to determine a recommended level.

However, the Food and Nutrition Board at the National Academies of Sciences, Engineering, and Medicine set an adequate intake (AI) level at 30 mcg for adults (36).

To learn more about biotin and see a list of the best dietary sources, see this guide:

20 Foods High In Biotin (Vitamin B7)

Name Adequate Intake Best Food Sources
Biotin (vitamin B7) Adult men: 30 mcg

Adult women: 30 mcg (36)

Almonds, dairy, eggs, fish, liver, organ meats, soybeans (37)

Vitamin C (Ascorbic acid)

The Structure and Name of Vitamin C (Ascorbic Acid).

Vitamin C is a water-soluble vitamin that functions as an antioxidant, and it can help to boost immune health (38).

The vitamin also plays a role in the formation of collagen (39).

Generally speaking, plant foods are the best sources of vitamin C.

However, certain animal foods—such as beef liver and spleen—also contain good amounts of this vitamin.

Name Recommended Daily Allowance Best Food Sources
Vitamin C Adult men: 90 mg

Adult women: 75 mg (40)

Bell peppers, berries, citrus fruit, leafy green vegetables, tomatoes, certain organ meats (41)

Vitamin D

Sometimes referred to as ‘the sunshine vitamin,’ vitamin D is one of the four fat-soluble vitamins. It is also unique in that we can obtain it from either our diet or sunlight exposure (42).

The most common dietary forms of vitamin D are vitamin D2 (ergocalciferol) and D3 (cholecalciferol). We can find D2 in plant foods like mushrooms, and UV-enriched mushrooms can be a very significant source of vitamin D. In contrast, we can find vitamin D3 in animal foods, and oily fish contains particularly high levels (43, 44).

For more information on D2 and D3, see how they compare for effectiveness here.

Vitamin D has many important functions within the human body, and maintaining adequate levels may help to lower the risk of certain chronic diseases (45, 46).

Name Recommended Daily Allowance Best Food Sources
Vitamin D Adults aged 19-70: 15 mcg

Adult aged >70: 20 mg (47)

Eggs, mushrooms, oily fish, fortified foods (48)

For more rich food sources of vitamin D, see this list of foods here.

Vitamin E

Vitamin E is another fat-soluble vitamin, and it plays a vital role in the human immune system.

On this note, research suggests that enhanced plasma levels of vitamin E may “enhance the function of the immune system” (49).

Another critical benefit of vitamin E is that the vitamin’s antioxidant properties protect fatty acids from oxidizing in the body (50).

There are several different vitamin E compounds. Among these, alpha-tocopherol is thought to have the most importance (51).

Name Recommended Daily Allowance Best Food Sources
Vitamin E Adult men: 15 mg

Adult women: 15 mg (52)

Cooking oil, nuts, seeds (53)

For more information on foods rich in vitamin E, see this article:

A list of the best food sources of vitamin E

Vitamin K

Vitamin K is a fat-soluble vitamin that is available in two dietary forms (54):

  • Vitamin K1 (phylloquinone)
  • Vitamin K2 (menaquinones)

Vitamin K1 is the plant form, and the best dietary source is green vegetables. In contrast, vitamin K2 is available from animal foods such as aged cheese and meat (menaquinone-4) and fermented foods, such as natto (menaquinone-7) (54).

Initial research suggests that vitamin K2—particularly menaquinone-7—may have the best bioavailability (55, 56).

Maintaining adequate levels of vitamin K is thought to have a beneficial role in cardiovascular health and preserving healthy bones (57).

Name Recommended Daily Allowance Best Food Sources
Vitamin K Adult men: 120 mcg

Adult women: 90 mcg (58)

Gouda cheese, Jarlsberg cheese, leafy green vegetables, natto, soybeans (59)

For further information:

Here is a list of foods high in vitamin K1.

And here are the best food sources of vitamin K2.

Choline: a Vitamin-like Nutrient

Lastly, choline is not currently classed as a vitamin, although it has vitamin-like properties. Despite not officially being a vitamin, choline is an essential nutrient, and we need to obtain it from our diet (60, 61).

Additionally, choline appears to haves some potential benefits for human health. Among these, the nutrient appears to have a protective effect on the liver, and low-choline diets may even increase the risk of fatty liver disease (62, 63).

Further research suggests that choline may also be necessary for optimal brain development and cognitive health (64, 65).

There is no recommended daily allowance for choline, but an adequate intake level has been set.

Name Adequate Intake Best Food Sources
Choline Adult men: 550 mg

Adult women: 425 mg (66)

Beef, eggs, liver, wheat germ (67)

For more information, see this guide to the benefits of choline.

To find out which are the best food sources, see this list of foods high in choline.

Final Thoughts

While we often hear about the importance of a particular vitamin, the truth is that they are all important.

There are many different vitamins, and they are essential for a reason: we need them in sufficient quantities to maintain optimal health.

An omnivorous diet focusing on whole foods is the best way to ensure we get a wide range of essential vitamins.

Regarding more restrictive diets, such as the vegan diet, supplementation is an important consideration to ensure a sufficient intake of essential vitamins.

Lastly, vitamins are not the only essential nutrients to consider; here is a full guide to essential minerals.

For more nutrition guides, see these articles here.

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Michael Joseph, MSc

Michael works as a nutrition educator in a community setting and holds a Master's Degree in Clinical Nutrition. He believes in providing reliable and objective nutritional information to allow informed decisions.