Zinc
Zinc is a cofactor for over two hundred in the human body and plays a direct role in RNA, DNA, and protein synthesis. Zinc also is a cofactor for enzymes involved in energy metabolism. As the result of its prominent roles in and energy metabolism, a zinc deficiency in infants and children blunts growth. The reliance of growth on adequate dietary zinc was discovered in the early 1960s in the Middle East where adolescent nutritional dwarfism was linked to diets containing high amounts of phytate. Cereal grains and some vegetables contain chemicals, one being phytate, which blocks the absorption of zinc and other in the gut. It is estimated that half of the world’s population has a zinc-deficient diet.[1]
This is largely a consequence of the lack of red meat and seafood in the diet and reliance on cereal grains as the main dietary staple. In adults, severe zinc deficiency can cause hair loss, diarrhea, skin sores, loss of appetite, and weight loss. Zinc is a required cofactor for an enzyme that synthesizes the heme portion of and severely deficient zinc diets can result in anemia.
Dietary Reference Intakes for Zinc
| Age Group | RDA (mg/day) | UL (mg/day) |
|---|---|---|
| Infant (0–6 months) | 2* | 4 |
| Infants (6–12 months) | 3 | 5 |
| Children (1–3 years) | 3 | 7 |
| Children (4–8 years) | 5 | 12 |
| Children (9–13 years) | 8 | 23 |
| Adolescents (14–18 years) | 11 (males), 9 (females) | 34 |
| Adults (19 + years) | 11 (males), 8 (females) | 40 |
| * denotes Adequate Intake |
Fact Sheet for Health Professionals: Zinc. National Institute of Health, Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/Zinc-HealthProfessional/. Updated February 11, 2016. Accessed November 10, 2017.
Dietary Sources of Zinc
| Food | Serving | Zinc (mg) | Percent Daily Value |
|---|---|---|---|
| Oysters | 3 oz. | 74 | 493 |
| Beef, chuck roast | 3 oz. | 7 | 47 |
| Crab | 3 oz. | 6.5 | 43 |
| Lobster | 3 oz. | 3.4 | 23 |
| Pork loin | 3 oz. | 2.9 | 19 |
| Baked beans | ½ c. | 2.9 | 19 |
| Yogurt, low fat | 8 oz. | 1.7 | 11 |
| Oatmeal, instant | 1 packet | 1.1 | 7 |
| Almonds | 1 oz. | 0.9 | 6 |
Fact Sheet for Health Professionals: Zinc. National Institute of Health, Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/Zinc-HealthProfessional/. Updated February 11, 2016. Accessed November 10, 2017.
Learning Activities
Technology Note: The second edition of the Human Nutrition Open Educational Resource (OER) textbook features interactive learning activities. These activities are available in the web-based textbook and not available in the downloadable versions (EPUB, Digital PDF, Print_PDF, or Open Document).
Learning activities may be used across various mobile devices, however, for the best user experience it is strongly recommended that users complete these activities using a desktop or laptop computer.
- Prasad, Ananda. (2003). Zinc deficiency. British Medical Journal, 326(7386), 409–410. doi: 10.1136/bmj.326.7386.409. Accessed October 2, 2011. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1125304/?tool=pmcentrez. ↵
A protein molecule that speeds up or accelerates specific chemical reactions without changing itself.
The branch of metabolism that synthesizes body compounds and promotes tissue growth.
An element used in the body to promote chemical reactions and help form body structures.
An iron-containing protein found in red blood cells that bind and transports oxygen throughout the body.
A set of values for the intake of energy, nutrients, and food components that can be used for planning and assessing the diets of healthy individuals in the United States and Canada.
