The 13 Essential Vitamins

The 13 Essential Vitamins

The 13 essential Vitamins


This article will breakdown the essential 13 vitamins that we as humans need. ASAP products make sure we’ve got you covered with all of your nutrients. We will outline what they do and what their deficiency or overuse means.

We will also give answers to these common questions:

What are common vegan deficiencies when it comes to vitamins? What vitamins do vegans need to supplement?


The 13 essential vitamins

Fat-soluble Vitamins

Vitamin A

Vitamin A, also called retinol, has many functions for the body. It is vital for:

- Vision

- Bone growth

- Reproduction and preventing fertility issues

- Tooth development

- Cell division and gene expression

- The immune system and preventing infections

Vitamin A deficiency can lead to blindness, measles and can increase the risk of disease and death [1]. These are both common among young children in areas with a high prevalence of vitamin A deficiency. These are generally poorer regions.

Too much vitamin A (usually achieved by supplementation) can negatively impact bone development and result in delayed growth in children and teenagers. Vitamin A toxicity can also cause severe birth defects. Long term overuse can cause high cholesterol levels, liver damage and nervous system changes.



Vitamin D 

According to studies, it is estimated that close to 40% of the Irish population has low levels of vitamin D. On top of getting vitamin D from our food, we can also synthesize vitamin D from sunlight. This means that vitamin D deficiency is highest during the winter months where we get limited sunlight.

Vitamin D may play a role in regulating mood and decreasing the risk of depression [2]. It also helps to regulate the amount of calcium and phosphate in the body. On top of this it plays a role in protecting humans from illnesses. This is important at a time where the world is coming out of the COVID-19 pandemic.

A lack of vitamin D can lead to osteoporosis, other autoimmune conditions, respiratory and cardiovascular disorders.

Vitamin D toxicity can lead to an increase in your blood calcium levels which can lead to the following health issues:

- nausea

- vomiting

- abdominal pain

- dehydration


Vitamin E

Vitamin E plays a role in maintaining healthy skin and eyes as well as supporting your immune system [3]. One should be able to get the required amount of vitamin E in their diet.

Vitamin E deficiency may cause nerve and muscle damage, loss of body movement control and muscle weakness.

High doses of vitamin E can cause excessive bleeding.


Vitamin K

Vitamin K is important for helping blood to clot which prevents excessive bleeding [4].

Low levels of vitamin K can raise the risk of uncontrolled bleeding but deficiencies are rare.


Water-soluble Vitamins

Vitamin C

Vitamin C, also known as ascorbic acid, has a wide range of benefits and functions in the body. It can lessen the severity of the common cold, act as an antioxidant and make collagen [5]. It cannot be made by the human body and so is an essential component of a diet.

A vitamin deficiency can lead to scurvy which is caused by the fact that collagen has not been formed. This disease causes easy bleeding, bruising and joint and muscular pain.

Vitamin C has low toxicity and so it is unlikely to reach the upper limit. If met however and for a period of time, kidney stones may appear. 


Thiamin (Vitamin B1)

Thiamin (vitamin B1) is essential for energy metabolism, especially breaking down carbohydrates to produce energy [6]. It also allows oxygen to be used by the body.

Thiamin deficiency can cause beriberi disease. This will result in fatigue, weakness, psychosis, and nerve damage. Beriberi also causes tingling and numbness in the feet and hands.

There is no established toxic level of thiamin because our body can flush excess amounts out.


Riboflavin (Vitamin B2)

Riboflavin (vitamin B2) is also used to release energy from food. On top of this, it keeps our eyes, skin and the nervous system healthy [7].

Riboflavin deficiency can cause endocrine abnormalities, such as thyroid hormone insufficiency, angular stomatitis, cheilosis, hair loss and reproductivce problems [8].

There is no observable toxicity seen from Riboflavin as of yet, most likely because of it’s solubility and capacity to be absorbed in the gastrointestinal tract are limited.


Niacin (Vitamin B3)

Like the previous two vitamins, Niacin (vitamin B3) is important for helping the body to release energy from food. It also creates cholesterol and fats as well as creating and repairing DNA [9].

Niacin comes in the form of either nicotinic acid or nicotinamide.

A severe niacin deficiency can lead to pellagra. It can also cause headaches, depression and fatigue.

Niacin toxicity can cause liver problems.


Pantothenic Acid (Vitamin B5)

Pantothenic acid (vitamin B5), like all the B vitamins is involved in releasing energy from food. It is essential for fatty acid synthesis [10].

A lack of pantothenic acid is uncommon. When someone does have a pantothenic acid deficiency is would usually be accompanied by other nutrient deficiencies. It can cause headaches, fatigue, disturbed sleep and gastrointestinal disturbances.

Again, cases of toxicity are very limited and so it’s effect is largely unknown.


Vitamin B6

Vitamin B6, also known as pyridoxine, is a group of six compounds. Vitamin B6 is vital in helping the body to use and store energy from protein and carbohydrates in food. It also helps the body form haemoglobin which carries oxygen around the body [11]. Vitamin is also linked with the regulation of mental function and being in a good mood [15].

Taking high levels of vitamin B6 for a long period of time can result in nerve damage and a loss of feeling in arms and legs [7].

Vitamin B6 deficiency can result in a weak immune system, anaemia and Scaly skin.


Biotin (Vitamin B7)

Biotin (Vitamin B7) is needed in small amounts only to help make fatty acids. It should be easily obtained in a balanced and varied diet. The bacteria that live in our bowel can also make biotin so there is rarely a need to supplement this [7].


Signs of biotin deficiency seem to be hair loss, brittle nails, skin rashes and redness around body openings[12].

There is no evidence in humans that biotin is toxic at high intakes.


Folic Acid (Vitamin B9)

Folic acid (vitamin B9) also known as folate, is essential in the formation of healthy red blood cells. It also helps in preventing birth defects in newborn babies and it can help to promote hair growth.  

Deficiency in folic acid, can cause brain and spinal cord defects in unborn babies [13]. Maintaining the recommended amount is therefore very important. It can also cause anaemia and fatigue.

Having high levels of folate in your blood can increase the risk of poor cognition in older adults [14].


Vitamin B12

Vitamin B12 (cobalamin) has similar roles to folic acid. It is involved in helping the body:

  • Release energy from good
  • Make red blood cells
  • Keep the nervous system healthy
  • Use folic acid [7] 

Vitamin B12 deficiency is extremely common in vegans. This is because it comes mainly from meat, fish and dairy products. Vitamin B12 is produced by the bacteria in the soil and because we wash our plants before eating them, we miss out on this vitamin. It is also produced by bacteria in the guts of animals (including humans). However, it is produced too far down the digestive system to be absorbed.

Vitamin B12 deficiency can cause fatigue and in rare cases, a condition called pernicious anaemia [7]..



ASAP meets 100% of your vitamin B12 and vitamin D recommended daily amounts (RDA). Vegans miss out on B12 in their diet, so it is important to supplement and why not do this through one of our delicious milks (link to our shop page).

In Ireland, skin cancer is the most common cancer. Therefore, we have decided that filling our drinks with 100% of your RDA of vitamin D will mean people don’t need to spend extended periods in the sun. We are a community here at ASAP and we endeavour to look after each other.

We have kept all vitamins within the upper limits to ensure they are safe. We have included smaller amounts of the other vitamins because we realise that in a balanced diet one will reach their other RDAs easily.

Want to read a similar article about minerals? Have a look at our Minerals breakdown (HP to minerals blog).

If you are worried that you are deficient or intaking levels that are too high in any of these vitamins we recommend that you consult your doctor.




  1. WHO (2021). Micronutrient deficiencies. Malnutrition and vitamin A deficiency. Available at: (Assessed: 09/06/2021).
  2. TILDA (2020). Vitamin D deficiency in Ireland – implications for COVID-19. Available at: (Assessed: April 2020)
  3. HSE (2022). Vitamin E. Vitamins and Minerals. Available at:
  4. HSE (2022). Vitamin K. Vitamins and Minerals. Available at:
  5. HSE (2022). Vitamin E. Vitamins and Minerals. Available at:
  6. National Institutes of Health (2021). U.S. Department of Health & Human Services. Thiamin. Available at: (Assessed at March 2021)
  7. HSE (2022). B vitamins and folic acid. Vitamins and Minerals. Available at:
  8. National Institutes of Health (2021). U.S. Department of Health & Human Services. Riboflavin. Available at:  (Assessed at March 2021)
  9. Harvard T.H Chan (2022). The Nutrition Source. Niacin – Vitamin B3. Available at:
  10. National Institutes of Health (2021). U.S. Department of Health & Human Services. Pantothenic Acid. Available at: (Assessed at March 2021)
  11. National Institutes of Health (2021). U.S. Department of Health & Human Services. Vitamin B6. Available at: (Assessed at March 2021)
  12. National Institutes of Health (2021). U.S. Department of Health & Human Services. Biotin. Available at: (Assessed at January 2022)
  13. NHS (2022). B vitamins and folic acid. Vitamins and Minerals. Available at:
  14. Trinity College Dublin (2021). The Irish Longitudinal Study on Ageing (TILDA). Available at: (Assessed at August 2021)
  15. Malouf, R. and Evans, J.G., 2003. Vitamin B6 for cognition. Cochrane Database of Systematic Reviews, (4).


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