Not just those elements you see on the periodic table in chemistry lessons - no! Zinc and Magnesium are essential trace minerals. We require small (i.e. trace) amounts for bodily function - and they are important.
Zinc helps regulate the expression and activation of biological molecules involved in bodily processes. This includes enzymes involved in transcription (like how our DNA is copied) and various channels and growth factors (Hara et al., 2017).
Zinc deficiency could cause eye and skin lesions (lumpy tissue damage), immunity problems, and growth issues to name a few. You can get dietary zinc by eating foods such as oysters, beef (see below - beef chuck is also known as 'braising steak' in the UK) and fortified cereals. The National Institute for Health, NIH, Health Professional Fact Sheets are excellent sources of information from the US Department of Health. Although having too much zinc is not typically toxic, excessive amounts expose you to its toxicity in the form of headaches, vomiting and nausea. The muscles and bones serve to store zinc but cannot store more than the body needs. We must, therefore, get enough zinc through diet. Considering small gender variations, the Food Standards Agency (FSA) recommends we aim for higher daily amounts of:
- 9 mg (aged 11-14)
- 5 mg (15 and above)
Magnesium is present in all body tissues - particularly bone. It has a relationship with calcium, potassium, and sodium (salt). The British Nutrition Foundation explain the 'need-to-know' of magnesium well. This plays a role in DNA replication, bone metabolism, and muscle and nerve function. Deficiencies are rare, but be aware, particularly if you have malabsorption disorders or become severely ill.
Around half of teenage girls in the UK are estimated to have intakes below the lower limits, and 20% of boys aged 11-14. Regularly having high-dose supplements might cause diarrhoea, but if you have no kidney problems there are no reported adverse effects of high intakes. Almonds and spinach are great sources of magnesium, as well as other green leafy vegetables, nuts, and even bread. High magnesium intakes have been associated with beneficial effects on factors relating to cardiovascular heart disease (Hruby et al., 2014). Magnesium supplementation shows a small, but clinically relevant, reduction in blood pressure (Kass, Weekes, & Carepenter, 2012). The estimated average requirements are:
- 300 mg a day for men (15-18 age group and adults 19-64 years)
- 270 mg a day for women (15-18 and adults 19-64 years)
There is a good chance you can get enough zinc and magnesium through a healthy diet, so happy eating!
Hara, T., Takeda, T. A., Takagishi, T., Fukue, K., Kambe, T., & Fukada, T. (2017). Physiological roles of zinc transporters: molecular and genetic importance in zinc homeostasis. The Journal of Physiological Sciences, 1-19.
Food Standards Agency. (2006). FSA nutrient and food based guidelines for UK institutions.
U.S. Department of Agriculture, Agricultural Research Service (2011). USDA National Nutrient Database for Standard Reference, Release 24. Nutrient Data Laboratory Home Page, http://www.ars.usda.gov/ba/bhnrc/ndl.
Hruby, Adela, Donnell, Christopher J., Jacques, Paul F., Meigs, James B., Hoffmann, Udo, & Mckeown, Nicola M. (2014). Magnesium Intake Is Inversely Associated With Coronary Artery Calcification:The Framingham Heart Study: The Framingham Heart Study. JACC: Cardiovascular Imaging, 7(1), 59-69.
L Kass, J Weekes, & L Carpenter. (2012). Effect of magnesium supplementation on blood pressure: A meta-analysis. European Journal of Clinical Nutrition, 66(4), 411-8.
Department of Health, Dietary Reference Values for Food Energy and Nutrients for the United Kingdom, HMSO, 1991.