Meta-Analysis of Zinc Status in Vegetarians
A few weeks ago, a meta-analysis of the zinc status of vegetarians was published (1). They only measured relative values of serum zinc and found that vegans had a slightly lower serum zinc level than non-vegetarians, a difference of 1.17 ± 0.45 µmol/l. For vegetarians in developed countries, the difference was even smaller at .76 ± .27 µmol/l.
Average serum zinc levels are around 20 µmol/l with a range of about 9 to 30 µmol/l (2), so it’s doubtful that the differences are meaningful. One caveat is that serum zinc levels are not necessarily indicative of the zinc levels in cells (3).
For full disclosure, I don’t rely only on my diet for zinc, I take a supplement and am under the strong impression that it helps prevent me from catching colds. I am, however, skeptical that the average vegan needs to supplement with zinc.
I have updated VeganHealth.org’s article Zinc with this information.
1. Foster M, Chu A, Petocz P, Samman S. Effect of vegetarian diets on zinc status: a systematic review and meta-analysis of studies in humans. J Sci Food Agric. 2013 Apr 17. | link
2. Ghasemi A, Zahediasl S, Hosseini-Esfahani F, Azizi F. Reference values for serum zinc concentration and prevalence of zinc deficiency in adult Iranian subjects. Biol Trace Elem Res. 2012 Dec;149(3):307-14. (Abstract only) | link
3. Dietary Supplement Fact Sheet: Zinc. Office of Dietary Supplements. National Institutes of Health. Last reviewed: June 05, 2013 | link