Who Found the Role of Zinc, and How a 1961 Study in Iran Changed the Story

The history of zinc is short on human evidence before 1961. The first human report that later work tied to zinc had iron-deficiency anemia in its title, and zinc's essential role in people was established in 1963. ## Rat diets came first, in 1934 In 1934, W. R. Todd, C. A. Elvehjem and E. B. Hart published "Zinc in the nutrition of the rat" in the American Journal of Physiology, volume 107, pages 146 to 156. According to PubMed, that paper is indexed through a 1980 reprint in Nutrition Reviews (PMID [7010227](https://pubmed.ncbi.nlm.nih.gov/7010227/); DOI [10.1111/j.1753-4887.1980.tb05879.x](https://doi.org/10.1111/j.1753-4887.1980.tb05879.x)). PubMed carries no abstract for that reprint, so this page cites the title and date only. ## A syndrome in Shiraz, 1961 In 1961, Ananda S. Prasad, James A. Halsted and Manucher Nadimi published "Syndrome of iron deficiency anemia, hepatosplenomegaly, hypogonadism, dwarfism and geophagia" in The American Journal of Medicine (volume 31, pages 532 to 546; PMID [14488490](https://pubmed.ncbi.nlm.nih.gov/14488490/); DOI [10.1016/0002-9343(61)90137-1](https://doi.org/10.1016/0002-9343(61)90137-1)). A 1983 reprint in Nutrition Reviews lists the authors at Shiraz, Iran, and, according to PubMed, indexes it under adult males (PMID [6353293](https://pubmed.ncbi.nlm.nih.gov/6353293/)). The surprise is in the title. The 1961 report was about iron, and zinc does not appear in it. The syndrome combined iron-deficiency anemia with an enlarged liver and spleen, reduced sex-gland function (hypogonadism), short stature (dwarfism) and geophagia, the habit of eating earth. The iron side of this story has its own [history of iron supplements](/blog/history/history-of-iron-supplements-and-the-ferritin-test). ## Zinc becomes essential in people, 1963 Prasad's 2013 review, "Discovery of human zinc deficiency: its impact on human health and disease," states in its abstract that "the essentiality of zinc in humans was established in 1963" (Advances in Nutrition 4(2):176-190; PMID [23493534](https://pubmed.ncbi.nlm.nih.gov/23493534/); DOI [10.3945/an.112.003210](https://doi.org/10.3945/an.112.003210)). The same abstract says that in 1963 only three enzymes were known to need zinc, and that more than 300 now are. Growth retardation is among the major clinical problems the review lists for zinc deficiency in people. Our [zinc monograph](/ingredients/zinc) covers the enzyme and food side of the story. ## Zinc and vitamin A transport A 2000 study in rats in The Journal of Nutrition describes zinc as "an important factor for the synthesis of" retinol-binding protein, the carrier that moves vitamin A out of liver stores (PMID [10917908](https://pubmed.ncbi.nlm.nih.gov/10917908/); DOI [10.1093/jn/130.8.1958](https://doi.org/10.1093/jn/130.8.1958)). The rats were a model of type I diabetes, so the finding describes transport in those animals and is not a human treatment result. ## How the cold trials entered the record The cold question entered the zinc record through lozenge trials. According to PubMed, a 2024 Cochrane review pooled 34 randomized trials of zinc and the common cold, 17 of them testing lozenges (PMID [38719213](https://pubmed.ncbi.nlm.nih.gov/38719213/); DOI [10.1002/14651858.CD014914.pub2](https://doi.org/10.1002/14651858.CD014914.pub2)). For prevention, the review found little or no reduction in the risk of colds (low-certainty evidence). For ongoing colds, it found that zinc may reduce the mean duration by about 2.4 days across eight treatment trials (low-certainty evidence), and that non-serious side effects probably increase (moderate-certainty evidence). The review does not settle the question. For the wider immune side of zinc, see the [immune health guide](/health/immune-health). ## Why the upper limit sits where it does The NIH sets the adult upper limit for zinc at 40 mg a day from food and supplements combined, at the level where zinc starts to affect copper status. The recommended intake is 11 mg a day for men and 8 mg a day for women (NIH Office of Dietary Supplements, zinc fact sheet, updated January 6, 2026). That is why zinc needs a separate look from copper, and why the two minerals cannot be judged in isolation. ## What the label says on one zinc tablet Our Zinc 50 mg Citrate Chelate tablet lists 50 mg of zinc from 162 mg of zinc citrate, with one tablet as the label serving. The label directs one tablet daily. A bottle holds 60 tablets, priced at $15.99 on the [store page](https://mtangelvitamins.com/products/advanced-zinc-citrate-50mg?utm_source=learn_hub&utm_medium=content&utm_campaign=blog_post&utm_content=history-of-zinc-from-ancient-ointments-to-essential-nutrient). One tablet is already above the 40 mg adult limit, so add up zinc across every label before adding another bottle. ## Key dates | Year | What happened | Source | | --- | --- | --- | | 1934 | "Zinc in the nutrition of the rat" published | Todd, Elvehjem and Hart (PMID [7010227](https://pubmed.ncbi.nlm.nih.gov/7010227/)) | | 1961 | Iron-deficiency syndrome with dwarfism reported from Shiraz, Iran | Prasad, Halsted and Nadimi (PMID [14488490](https://pubmed.ncbi.nlm.nih.gov/14488490/)) | | 1963 | Essential role of zinc in humans established; three zinc enzymes known | Prasad 2013 review (PMID [23493534](https://pubmed.ncbi.nlm.nih.gov/23493534/)) | | 2024 | 34 zinc and cold trials pooled, 17 testing lozenges | Cochrane review (PMID [38719213](https://pubmed.ncbi.nlm.nih.gov/38719213/)) | | 2026 | Adult upper limit 40 mg a day; RDA 11 mg men, 8 mg women | NIH ODS, updated January 6, 2026 | ## Frequently asked questions ### Was zinc known to be essential before 1961? Zinc was studied in rat diets in 1934, which is the earliest zinc nutrition paper this page cites. The human essential role came later. According to Prasad's 2013 review in Advances in Nutrition, the essentiality of zinc in humans was established in 1963, about 29 years after the 1934 rat paper. The 1961 report described a syndrome of iron-deficiency anemia and dwarfism in Shiraz, Iran, and did not name zinc in its title. ### Where did zinc first show up in medicine? This page starts in 1934 because that is the earliest zinc nutrition paper it can cite from a PubMed record. It does not describe any earlier medical use of zinc, because no earlier primary sources were checked for this page. ### Is 50 mg of zinc a day more than adults need? Yes. The NIH recommends 11 mg a day for men and 8 mg for women. The adult upper limit is 40 mg a day from food and supplements combined, so 50 mg from a single source is above that limit by itself. Add up zinc from every product you take. ### Why does zinc need a separate look from copper? Zinc and copper interact in the body. The NIH sets the zinc upper limit at the level where zinc begins to affect copper status, so the two minerals cannot be judged in isolation. Intake above the limit is the point where that interaction starts to matter. ### Did the lozenge trials prove that zinc shortens colds? No. The 2024 Cochrane review found that zinc may reduce the mean duration of ongoing colds by about 2.4 days across eight treatment trials, but it rated that evidence low certainty. It found little or no effect on preventing colds, also low certainty. A review with low-certainty ratings suggests a direction without settling the question. ### What did the 1961 study describe? It described a syndrome of iron-deficiency anemia, an enlarged liver and spleen, reduced sex-gland function (hypogonadism), short stature (dwarfism) and geophagia, the habit of eating earth. The report came from Shiraz, Iran, and its title does not name zinc. Later work by the same group linked the syndrome to zinc, and the 2013 review dates the essential role of zinc in humans to 1963. ### How is zinc connected to vitamin A? A 2000 study in rats describes zinc as "an important factor for the synthesis of" retinol-binding protein, the carrier that moves vitamin A out of liver stores. The study used a type I diabetes model in rats, so it shows how zinc status related to vitamin A transport in those animals. It does not show a human effect. ## Bottom line The zinc record has one clear human turning point, and it came in 1961 from a report about iron. For buyers, the lesson is about totals rather than history: the adult upper limit of 40 mg a day covers every source, and one 50 mg tablet already exceeds it. Read every label before adding one. ## Next reads - [The zinc monograph](/ingredients/zinc): what zinc does in the body and where it appears in food. - [The history of iron supplements](/blog/history/history-of-iron-supplements-and-the-ferritin-test): the iron story behind the 1961 syndrome. - [Quercetin + Zinc: What the Research Actually Shows](/health/immune-health/quercetin-zinc-research): a separate look at one zinc combination.