Vitamins and minerals are often referred to as micronutrients and cannot be produced naturally by the body; therefore it is important to obtain them from your daily diet.
Nutritional deficiencies develop when the body is unable to absorb or take the appropriate amounts of nutrients from food which is consumed. Deficiencies can lead to a number of health problems including defective or stunted growth mental health issues such as dementia and digestive issues.
The amount and type of nutrients which you should be consuming are largely dependent on your age.
Iron is an essential mineral and is a main component of red blood cells, where it is responsible for binding with haemoglobin and transporting oxygen towards the cells. Dietary iron can be classified as heme iron and non-heme iron. Heme iron can only be found in animal foods, particularly in red meat and is easily absorbed - whereas non-heme iron is found in both animal and plant foods and is not as easily absorbed.
Iron deficiency is actually one of the most common nutritional deficiencies in the world and is estimated to affect almost a quarter of people worldwide (1). Unfortunately, this figure is even higher in preschool children, as high as 47%, unless they are eat iron-rich or iron-fortified foods (1). Vegetarians and vegans also have an increased risk of developing an iron deficiency, this is largely due to the fact they are only consuming plant based non-heme iron which is less readily absorbed than heme iron (2, 3).
Symptoms of iron deficiency include fatigue, weakness, a weakened immune system and impaired function of the brain (4, 5).
Vitamin D is a fat-soluble vitamin which travels through the bloodstream into the cells and instructs them whether to turn genes on or off. Therefore almost every cell in your body has a receptor for vitamin D. (17)
Vitamin D is largely produced in the skin on sun exposure. Those who live further from the equator have a higher chance of suffering from vitamin D deficiency as they often have less sun exposure (6, 7).
Symptoms of vitamin D deficiency are not easily visible as they are subtle and can take years or decades to develop (8, 9). Adult individuals who suffer from vitamin D deficiency can experience symptoms such as muscle weakness, bone loss or an increased risk of bone fractures (10).
Vitamin B12 is also referred to as cobalamin, it is a water soluble vitamin and is essential for the formation of blood along with the function of brain and nerve cells. Each of your cells requires B12 in order to function normally however the body is unable to produce B12 on its own.
Cobalamin can only be found in animal foods, therefore vegetarians and vegans are at an increased risk of becoming deficient. In fact, studies have shown that vegans and vegetarians can be eighty to ninety percent more likely to become deficient in B12 (11).
Symptoms of vitamin B12 deficiency include megaloblastic anaemia which is a blood disorder that can enlarge red blood cells, impaired brain function and elevated levels of homocysteine which appears to be a risk factor for numerous diseases (12, 13).
Vitamin A is also a fat soluble vitamin and plays a role in forming and maintaining healthy skin, teeth, bones and cell membranes. Vitamin A also produced eye pigments which is necessary for vision (14).
It is estimated that more than 75% of those individuals who consume a western diet are obtaining enough vitamin A and are unlikely to be deficient (15). However, vitamin A deficiency appears to be a common issue in developing countries with up to fifty percent of preschool aged children suffering from the condition (16).
A vitamin A deficiency can lead to temporary and in some cases permanent eye damage, globally vitamin A deficiency is the leading causes of blindness. The condition can even suppress the function of the immune system and increase mortality rates amongst children, pregnant and breastfeeding women (16).
For more information on vitamins and nutritional deficiencies, see our childhood nutrition and obesity prevention course
1. McLean, E., Cogswell, M., Egli, I., Wojdyla, D. and De Benoist, B., 2009. Worldwide prevalence of anaemia, WHO vitamin and mineral nutrition information system, 1993–2005. Public health nutrition, 12(4), pp.444-454.
2. Waldmann, A., Koschizke, J.W., Leitzmann, C. and Hahn, A., 2004. Dietary iron intake and iron status of German female vegans: results of the German vegan study. Annals of nutrition and metabolism, 48(2), pp.103-108.
3. Carpenter, C.E. and Mahoney, A.W., 1992. Contributions of heme and nonheme iron to human nutrition. Critical Reviews in Food Science & Nutrition, 31(4), pp.333-367.
4. Clark, S.F., 2008. Iron deficiency anemia. Nutrition in clinical practice, 23(2), pp.128-141.
5. Phillips, F., 2005. Vegetarian nutrition. Nutrition Bulletin, 30(2), pp.132-167.
6. Gozdzik, A., Barta, J.L., Weir, A., Cole, D.E., Vieth, R., Whiting, S.J. and Parra, E.J., 2010. Serum 25-Hydroxyvitamin D Concentrations Fluctuate Seasonally in Young Adults of Diverse Ancestry Living in Toronto, 2. The Journal of nutrition, 140(12), pp.2213-2220.
7. Holick, M.F., 2003. Vitamin D: a millenium perspective. Journal of cellular biochemistry, 88(2), pp.296-307.
8. Holick, M.F. and Chen, T.C., 2008. Vitamin D deficiency: a worldwide problem with health consequences–. The American journal of clinical nutrition, 87(4), pp.1080S-1086S.
9. Strange, R.C., Shipman, K.E. and Ramachandran, S., 2015. Metabolic syndrome: A review of the role of vitamin D in mediating susceptibility and outcome. World journal of diabetes, 6(7), p.896.
10. Pedersen, J.I., 2008. Vitamin D requirement and setting recommendation levels–current Nordic view. Nutrition reviews, 66(s2).
11. Pawlak, R., Parrott, S.J., Raj, S., Cullum-Dugan, D. and Lucus, D., 2013. How prevalent is vitamin B12 deficiency among vegetarians?. Nutrition reviews, 71(2), pp.110-117.
12. Langan, R.C. and Zawistoski, K.J., 2011. Update on Vitamin B 12 Deficiency. American family physician, 83(12).
13. Oh, R. and Brown, D.L., 2003. Vitamin B12 deficiency. American family physician, 67(5), pp.979-986.
15. Allen, L.H. and Haskell, M., 2002. Estimating the potential for vitamin A toxicity in women and young children. The Journal of nutrition, 132(9), pp.2907S-2919S.
16. West Jr, K.P., 2003. Vitamin A deficiency disorders in children and women. Food and nutrition bulletin, 24(4_suppl2), pp.S78-S90.