Importance of Vitamins and Supplements: Who Should Be Taking Them? - An Evidence-Based Review

Importance of Vitamins and Supplements: Who Should Be Taking Them? - An Evidence-Based Review

Discover the importance of vitamins and supplements in our daily diet with a comprehensive evidence-based review. Learn who should be incorporating these essential nutrients into their daily routine to support overall health and well-being. From boosting immunity to improving metabolism, vitamins and supplements play a vital role in our overall health. Find out how these nutrients can optimize your health and who can benefit the most from their use. Stay informed and empowered to make the best choices for your health with reliable information on vitamins and supplements. Start maximizing your health potential with the right vitamins and supplements.

Vitamins and minerals are essential nutrients the body needs in small amounts for various physiological functions. While a balanced diet can typically provide these nutrients, individuals with specific conditions or dietary limitations may benefit from supplementation. This review explores the importance of vitamins and supplements, highlighting groups who may require additional support.

Essential Role of Vitamins and Minerals:

Micronutrients, including vitamins and minerals, play crucial roles in various bodily processes, including:

Energy production

B vitamins (e.g., B1, B2, B3) are vital for converting food into usable energy [1]. Here's how B vitamins contribute to energy production:

  • Carbohydrate Metabolism: 
    • Vitamin B1 (thiamine) acts as a coenzyme in the breakdown of carbohydrates into glucose, which serves as the primary energy source for cells.
    • Vitamin B2 (riboflavin) and vitamin B3 (niacin) are involved in the Krebs cycle, a central metabolic pathway that generates energy-rich molecules called ATP.
  • Amino Acid Metabolism:
    • Vitamin B6 (pyridoxine) participates in the metabolism of amino acids, which can be converted into energy through processes like gluconeogenesis.
  • Fatty Acid Metabolism:
    • Vitamin B12 (cobalamin) plays a role in the metabolism of fatty acids, enabling the breakdown of fats into acetyl-CoA, which is then used for energy production.
  • Cellular Respiration:
    • Vitamin B5 (pantothenic acid) serves as a coenzyme in the citric acid cycle, a key stage of cellular respiration where energy is released in the form of ATP.
  • Red Blood Cell Production:
    • Vitamin B12 and folate (vitamin B9) are essential for the production of red blood cells, which carry oxygen to tissues, facilitating energy metabolism.
  • Central Nervous System Function:
    • B vitamins are involved in the synthesis of neurotransmitters, which are chemical messengers that facilitate communication between nerve cells. Adequate levels of B vitamins contribute to cognitive function and alertness.

Overall, B vitamins act as coenzymes and cofactors in numerous enzymatic reactions, enabling the efficient release and utilization of energy from macronutrients. They work together to ensure the body has the energy it needs to carry out its various

Immune function

Vitamin C, vitamin D, and zinc contribute to a healthy immune system [2, 3, 4]. Studies have shown that Vitamin C and oral zinc formulations may shorten the duration of symptoms of the common cold. The meta analysis published in the British Medical Journal showed that Vitamin D supplementation protected against acute respiratory tract infection overall.

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Bone health

Vitamin D and calcium are essential for maintaining strong bones and preventing osteoporosis [5, 6]. Food is the best source of calcium. Dairy products, such as milk, yogurt and cheese are high in calcium. Certain green vegetables and other foods contain calcium in smaller amounts. Some juices, breakfast foods, soy milk, almond milk, cereals, snacks, breads and bottled water have added calcium. Women over age 50 and men over age 70 need 1,000 mg of calcium daily. Men and women over age 50 also need 800-1,000 IU of Vitamin D each day. Your body makes Vitamin D from sunlight, but it may be difficult for some people to get enough from sunlight and food alone. 

Cell health and development

Vitamin A and folate are crucial for proper cell division and development [7, 8]. Vitamin A, also known as retinol, is a fat-soluble vitamin essential for various physiological processes in the human body. It plays a critical role in maintaining optimal vision, promoting cell growth, supporting immune function, facilitating reproduction, and ensuring strong and healthy bones.

  • Vision: Vitamin A is vital for maintaining healthy eyesight. It is a precursor to rhodopsin, a pigment found in the retina of the eye, which allows us to see in low-light conditions. Without sufficient vitamin A, rhodopsin cannot be produced, leading to a condition called night blindness, characterized by difficulty seeing in dim light.
  • Cell Growth: Vitamin A is necessary for the growth and differentiation of cells throughout the body. It regulates gene expression, cell signaling, and cell division. Sufficient vitamin A intake is associated with healthy cell growth, tissue repair, and wound healing.
  • Immune Function: Vitamin A plays a crucial role in supporting the immune system. It enhances the production and activity of immune cells, such as lymphocytes and antibodies, which help protect the body against infections and diseases.
  • Reproduction: Vitamin A is essential for both male and female reproductive health. In men, it is involved in sperm production and motility. In women, it contributes to the development of the reproductive system and the regulation of the menstrual cycle.
  • Bone Health: Vitamin A is involved in bone metabolism and helps maintain strong and healthy bones. It promotes the formation of new bone tissue and inhibits the breakdown of existing bone, preventing bone loss and osteoporosis.


Iron is necessary for the transport of oxygen throughout the body and for the production of red blood cells.

  • Oxygen Transport: Iron is an essential component of hemoglobin, a protein found in red blood cells that binds to oxygen molecules and carries them throughout the body. Without sufficient iron, the body cannot produce enough hemoglobin, leading to a condition called iron-deficiency anemia. In iron-deficiency anemia, the red blood cells are smaller and contain less hemoglobin, resulting in reduced oxygen-carrying capacity.
  • Metabolic Functions: Iron is also involved in various metabolic processes in the body, including energy production, DNA synthesis, and immune function. It plays a role in the electron transport chain, which generates energy in cells. Iron is also required for the synthesis of certain hormones and neurotransmitters.
  • Sources of Iron: Dietary sources of iron include red meat, poultry, fish, beans, lentils, spinach, and fortified cereals. The absorption of iron from plant-based sources (non-heme iron) is lower compared to animal-based sources (heme iron). Vitamin C enhances the absorption of non-heme iron, so it is recommended to consume iron-rich plant foods with vitamin C-rich foods like citrus fruits, tomatoes, or bell peppers.

Overall, iron is a vital mineral that plays a crucial role in the body's ability to transport oxygen, produce red blood cells, and support various metabolic functions. Maintaining healthy iron levels through a balanced diet and appropriate medical care is essential for overall health and well-being.

Individuals Who May Benefit from Supplementation

While a balanced diet is generally preferred, specific groups may benefit from additional nutrient intake through supplements:

  • Pregnant and lactating women: Folic acid supplementation before and during pregnancy helps prevent birth defects, and vitamin D is recommended for both mothers and infants [9, 10].
  • Individuals with restrictive diets: Vegans and vegetarians, especially those who don't consume fortified foods, may require vitamin B12 supplements due to its limited availability in plant-based sources [11].
  • People with specific medical conditions: Individuals with malabsorption syndromes, celiac disease, inflammatory bowel disease, or undergoing dialysis may require tailored supplementation based on their specific needs [12, 13, 14].
  • Adults over 50: Absorption of vitamin B12 decreases with age, and vitamin D deficiency becomes more prevalent in this population, making supplementation a potential consideration [15, 16].


Vitamins and minerals are essential for optimal health. While a balanced diet is the primary source, specific individuals with dietary limitations, medical conditions, or increased nutrient demands may benefit from evidence-based supplementation under the guidance of a healthcare professional. Individualized assessments and personalized recommendations are crucial to ensure safe and effective use of supplements. Always consult your healthcare provider when taking vitamins and supplements. 


  1. Yetley, E. A., & McNaughton, J. L. (2005). The role of B vitamins in human health. Nutrition in Clinical Practice, 20(3), 321-334.
  2. Hemilä, H., & Chalker, E. (2013). Vitamin C for preventing and treating the common cold. Cochrane Database of Systematic Reviews, (1).
  3. Martineau, A. R., Jolliffe, D., & Hooper, M. (2017). Vitamin D supplementation to prevent acute respiratory tract infections in healthy adults living in northern latitudes and temperate regions: A systematic review and meta-analysis of individual participant data. BMJ, 356, j4416.
  4. Science M, Johnstone J, Roth DE, Guyatt G, Loeb M. Zinc for the treatment of the common cold: a systematic review and meta-analysis of randomized controlled trials. CMAJ. 2012;184(10):E551-E561. doi:10.1503/cmaj.111990.
  5. Holick, M. F. (2016). Vitamin D deficiency. The New England Journal of Medicine, 374(26), 2667-2681.
  6. National Osteoporosis Foundation. (2023, January). Calcium and vitamin D: Essential nutrients for bone health.
  7. Bailey, R. L., Stover, P. J., & McNulty, H. M. (2015). A review of vitamin A deficiency and its consequences for public health. The American Journal of Clinical Nutrition, 101(6), 1003S-1008S.
  8. De Franco, E., & Isoherranen, N. (2014). Folate status and human health: A continuum from deficiency to high intake. Advances in Nutrition, 5(1), 74-84.
  9. Centers for Disease Control and Prevention. (2023, September 8). Taking folic acid.
  10. National Institutes of Health. (2023, September 27). Vitamin D.
  11. Institute of Medicine (US) Committee on Vitamin B12. (1998). Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. National Academies Press.
  12. Green, P. H., & Beutler, E. (2022). Celiac disease. The New England Journal of Medicine, 386(21), 2037-2046. 
  13. Han, E., & Mao, Y. (2014). Update on Crohn's disease pathogenesis and treatment. Therapeutic Advances in Gastroenterology, 7(3), 233-244.
  14. Kalantar-Zadeh, K., & Kopple, J. D. (2009). Current controversies in vitamin D deficiency in chronic kidney disease. Journal of the American Society of Nephrology, 20(5), 926-932.
  15. Institute of Medicine (US) Standing Committee on the Scientific Evaluation of Dietary Reference Intakes and its Panel on Folate, Other B Vitamins, and Choline. (1998). Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. National Academies Press.
  16. Holick, M. F. (2017). Vitamin D deficiency. The New England Journal of Medicine, 377(16), 1677-1686.

National Institutes of Health. (2023, October 26). Dietary supplements.

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