Vegetarian diets containing legumes, whole grains, nuts, and seeds, while do contain adequate quantities of zinc, the bioavailability is restricted due to phytic acid present in these foods. High levels of calcium can also reduce the bioavailability of zinc.
Zinc is a non-toxic element. Excessive supplementation can lead to copper deficiency (Sandstead, 1995). The best sources for zinc are red meats, liver, shellfish, nuts, whole grains, and legumes.
An adult human contains 2 to 3 grams of zinc. Of this, 0.1% is said to be replenished daily. The replenishment rate determines dietary recommendations for healthy individuals. Zinc deficiency amongst people across the world is estimated to be equal to or more than 25%.
There is strong evidence to support the fact that zinc, a key constituent of over 300 proteins, may be critical to defense against the initiation and progression of cancer (Ho, 2004).
Elimination of meat and increased intake of phytate-containing legumes and whole grains leads to lower levels of absorption of trace elements iron and zinc. However, the consequences of lower bioavailability are still not completely understood (Hunt, 2003).
Zinc is one of the essential components of the six enzyme classes present in the body. The mineral helps transmit messages from one cell to the other. Zinc deficiency is a major public health concern.
Its deficiency — according to literature — depresses growth, causes appetite loss, skin lesions, and diarrhea impairs testicular development, reduces immune and cognitive functions. It can lead to dwarfism, delayed puberty, impaired wound healing, and increases susceptibility to infectious disease.
To summarise, eat normal food and don’t rush into unnecessary supplementation until advised by your nutritionist or physician.
Here are some references for those who wish to explore this subject further.
Gibson, R. S. (1994). Content and bioavailability of trace elements in vegetarian diets. The American journal of clinical nutrition, 59(5), 1223S–1232S.
Ho, E. (2004). Zinc deficiency, DNA damage and cancer risk. The Journal of nutritional biochemistry, 15(10), 572–578.
Hunt, J. R. (2002). Moving toward a plant‐based diet: are iron and zinc at risk? Nutrition reviews, 60(5), 127–134.
Hunt, J. R. (2003). Bioavailability of iron, zinc, and other trace minerals from vegetarian diets. The American journal of clinical nutrition, 78(3), 633S–639S.
Age–Related Eye Disease Study Research Group. (2001). A randomized, placebo—controlled, clinical trial of high–dose supplementation with vitamins C and E, beta carotene, and zinc for age–related macular degeneration and vision loss: AREDS report no. 8. Archives of ophthalmology, 119 (10), 1417.
de Almeida Costa, G. E., da Silva Queiroz–Monici, K., Reis, S. M. P. M., & de Oliveira, A. C. (2006). Chemical composition, dietary fibre and resistant starch contents of raw and cooked pea, common bean, chickpea and lentil legumes. Food chemistry, 94(3), 327–330.