Research into nutritional deficiency shows even a small one — particularly of zinc, particularly in boys — can have a large effect on growth rates.
It's no secret that severe malnutrition stunts growth, but recent evidence suggests that even a marginal nutritional deficiency may also keep some children from reaching optimal heights.
In Ontario, when University of Guelph researcher Rosalind Gibson gave 10 mg of extra zinc daily for a year to eight boys marginally deficient in zinc, they grew faster than eight similarly zinc-deficient boys who did not receive the supplements.
Since zinc is essential for cell and bone growth, children and teens — especially boys — need more during growth spurts. If they don't get enough, the deficiency can create a vicious cycle.
"One of the first symptoms is impaired appetite," says Gibson. "So if a child is even moderately deficient in zinc, his food intake decreases, and he becomes even more deficient."
In an unrelated study, Cornell researchers have shown that iron supplementation significantly improves growth in mildly anemic children.
Certainly not all short children are deficient in zinc or iron, but it's something to be aware of. Fortunately, both zinc and iron are found in red meat and poultry. Whole grains, nuts, and legumes are also good sources, though zinc from vegetables is less readily absorbed than that from animal sources. Iron supplements, on the other hand, can inhibit the absorption of zinc, so make sure any iron and zinc supplements are taken in roughly equal amounts.