
Zinc rarely gets the attention that calcium and protein do, but it was the discovery of zinc deficiency that first showed doctors a single mineral could hold back a child's growth. Today zinc shows up in many children's vitamins and "growth" formulas. Here's what zinc actually does for growth, what decades of research show about zinc and height, how much children need at each age, and when a supplement makes sense and when it doesn't.
Quick Answer
Zinc is essential for normal growth, and a shortage can slow it. The body needs zinc for protein and DNA synthesis and for cell division, the processes that build new tissue, and zinc deficiency causes slow growth in infants and children.[1][2]
Supplements help most where zinc is lacking. A meta-analysis of 33 trials found zinc supplements produced small but significant gains in height, with the biggest benefit in children who were already short or underweight.[5]
Extra zinc won't make a well-fed child taller. Most children in the U.S. get enough zinc from food,[1] and taking too much can cause side effects and interfere with copper.[2]
How Zinc Supports Growth
Zinc is a trace mineral, but it works in hundreds of enzymes throughout the body. It is needed for protein and DNA synthesis, cell signaling, and cell division, and it supports healthy growth and development through infancy, childhood, and adolescence.[1] Growth at the growth plates depends on exactly those processes: cartilage cells multiply, mature, and are replaced by new bone.
Absorbed best from meat, seafood, eggs, and dairy
Powers hundreds of enzymes, including those for protein and DNA synthesis
Supports the cell growth that lengthens bones at open growth plates
Enough zinc lets growth follow its course; extra zinc doesn't extend it
Like protein, zinc is a "permission" nutrient rather than a "booster": enough of it allows normal growth, while a shortage holds growth back. Genetics still sets the range for adult height. See growth plates and their role in height development and our guide to whether protein helps you grow taller.
What the Research Shows
The link between zinc and height was first noticed in the 1960s, when Dr. Ananda Prasad described young men in Iran and Egypt with severe growth failure and delayed puberty who turned out to be zinc deficient.[3] Since then, dozens of trials have tested zinc supplements in children.
| Study | Who was studied | What it found |
|---|---|---|
| Prasad's discovery (1960s, reviewed 1991)[3] | Young men in Iran and Egypt with severe growth failure | Identified human zinc deficiency as a cause of stunted growth and delayed sexual development. |
| Southern Ontario study (1989)[4] | Boys with low height percentiles in Canada | Described a mild, growth-limiting zinc deficiency in some of these boys, showing it can occur outside low-income countries. |
| Meta-analysis of 33 trials (2002)[5] | Children from birth to 10 years in Latin America, Asia, Africa, North America, and Europe | Zinc produced small but significant gains in height and weight, with the greatest benefit in children who were initially stunted or underweight. |
| Meta-analysis of 36 studies (2011)[6] | Children under 5 in developing countries | Zinc had a small positive effect on linear growth, stronger when given alone rather than combined with iron. |
| Meta-analysis (2009)[7] | Children under 5 | Found no significant effect of zinc on linear growth, one reason experts describe the overall effect as modest and dependent on zinc status. |
Most zinc trials were run in children with low zinc intake or high rates of stunting. Results can't be assumed to apply to children who already get enough zinc.
Reading the evidence in context: zinc reliably helps where it fills a real gap, in children who are zinc deficient, stunted, or underweight.[5][6] The effects are modest even then, and some reviews found no significant benefit.[7] No trial shows that giving extra zinc to a well-nourished child adds height.
How Much Zinc Kids and Teens Need
The Recommended Dietary Allowance (RDA) covers the needs of nearly all healthy people. The Tolerable Upper Intake Level (UL) is the most a person can take daily, from food, drinks, and supplements combined, without likely side effects.[1][2]
| Age | RDA per day | Upper limit per day |
|---|---|---|
| 7–12 months | 3 mg | 5 mg |
| 1–3 years | 3 mg | 7 mg |
| 4–8 years | 5 mg | 12 mg |
| 9–13 years | 8 mg | 23 mg |
| Girls 14–18 years | 9 mg | 34 mg |
| Boys 14–18 years | 11 mg | 34 mg |
| Adult women / men | 8 mg / 11 mg | 40 mg |
Source: NIH Office of Dietary Supplements, based on the National Academies Dietary Reference Intakes.[1][2] The upper limits don't apply to zinc prescribed by a doctor for a medical reason.
Notice how narrow the gap is for young children: a toddler needs 3 mg a day and should stay under 7 mg. Check your child's needs with our Zinc Intake Calculator.
Signs of Low Zinc and Who's at Risk
Zinc deficiency causes slow growth in infants and children and delayed sexual development in adolescents. Other signs include loss of appetite, hair loss, diarrhea, frequent infections, skin and eye sores, and slow wound healing.[2] Many of these signs have other causes too, so they point to a doctor's visit, not a diagnosis.
Most U.S. children get enough zinc from food.[1] The groups most likely to fall short are:
- Children on vegetarian or vegan diets: beans, nuts, and whole grains contain zinc, but phytates in these foods reduce how much the body absorbs.[1] See height-boosting foods for vegetarians.
- Older breastfed babies: from about 7 months, breast milk alone may not meet zinc needs, so zinc-rich complementary foods matter.[2]
- Children with digestive conditions that affect absorption, such as inflammatory bowel disease.[1]
- Children with sickle cell disease, who may have low zinc levels.[2]
- Very picky eaters who avoid meat, seafood, eggs, and dairy.
Can Kids Get Too Much Zinc?
Yes, and mainly from supplements. Too much zinc at once can cause nausea, vomiting, stomach cramps, diarrhea, and headaches. Taking too much over a long time can lower copper levels, which can lead to neurological problems such as numbness, weakness, and loss of coordination.[2]
Watch for "stacking": zinc appears in multivitamins, gummies, growth formulas, fortified cereals, and cold remedies. A child taking two products with zinc on top of fortified foods can approach or pass the upper limit. Add up every source before adding another, and keep supplements out of reach of young children.
Zinc also interacts with iron. Iron supplements of 25 mg or more taken at the same time as zinc can reduce zinc absorption,[1] so if your child takes both, ask your pediatrician about timing.
Best Zinc Foods for Growing Kids
Animal foods supply most of the zinc in American diets and are absorbed best. Beef alone provides about 20% of the zinc Americans get from food, and fortified breakfast cereals are another major source.[1]
| Food | Serving | Zinc |
|---|---|---|
| Oysters, cooked | 3 oz | 28.2 mg |
| Beef, sirloin, roasted | 3 oz | 3.8 mg |
| Blue crab, cooked | 3 oz | 3.2 mg |
| Breakfast cereal, fortified with 25% DV zinc | 1 serving | 2.8 mg |
| Oatmeal, cooked | 1 cup | 2.3 mg |
| Pumpkin seeds, roasted | 1 oz | 2.2 mg |
| Pork chop, broiled | 3 oz | 1.9 mg |
| Cheddar cheese | 1.5 oz | 1.5 mg |
| Lentils, boiled | ½ cup | 1.3 mg |
| Milk (1%) / Greek yogurt | 1 cup / 6 oz | 1.0 mg |
| Egg | 1 large | 0.6 mg |
Source: NIH Office of Dietary Supplements, based on USDA FoodData Central.[1] Fruits and vegetables contain very little zinc.
- Easy daily wins: a bowl of fortified cereal with milk and a small serving of beef or pork already covers most of a school-age child's 5 to 8 mg.
- For plant-based diets: lean on fortified cereals, oats, pumpkin seeds, lentils, and beans, and include dairy or eggs if the family eats them.
- Think of the whole plate: zinc works alongside protein, calcium, and vitamin D. See the nutrition and height connection and the importance of calcium for bone growth.
- Supplements only for a real gap: if a doctor confirms low zinc or a high-risk diet, a supplement within the age-appropriate upper limit is reasonable. Otherwise, food is enough.
When to Talk to a Doctor
Blood zinc tests have limits, so doctors look at diet, growth, and symptoms together.[1] Track growth between visits with our Growth Chart Tracker, and read about other common causes in factors that stunt growth in children.
FAQs
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References
- [1] NIH Office of Dietary Supplements. Zinc: fact sheet for health professionals. ods.od.nih.gov
- [2] NIH Office of Dietary Supplements. Zinc: fact sheet for consumers. ods.od.nih.gov
- [3] Prasad AS. Discovery of human zinc deficiency and studies in an experimental human model. American Journal of Clinical Nutrition. 1991;53(2):403-412.
- [4] Gibson RS, Vanderkooy PDS, MacDonald AC, Goldman A, Ryan BA, Berry M. A growth-limiting, mild zinc-deficiency syndrome in some Southern Ontario boys with low height percentiles. American Journal of Clinical Nutrition. 1989;49(6):1266-1273.
- [5] Brown KH, Peerson JM, Rivera J, Allen LH. Effect of supplemental zinc on the growth and serum zinc concentrations of prepubertal children: a meta-analysis of randomized controlled trials. American Journal of Clinical Nutrition. 2002;75(6):1062-1071.
- [6] Imdad A, Bhutta ZA. Effect of preventive zinc supplementation on linear growth in children under 5 years of age in developing countries: a meta-analysis of studies for input to the Lives Saved Tool. BMC Public Health. 2011;11(Suppl 3):S22. pmc.ncbi.nlm.nih.gov/articles/PMC3231896
- [7] Ramakrishnan U, Nguyen P, Martorell R. Effects of micronutrients on growth of children under 5 y of age: meta-analyses of single and multiple nutrient interventions. American Journal of Clinical Nutrition. 2009;89(1):191-203.

