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Zinc is a trace element that can be found in almost every cell of the human body. Most zinc is accumulated in bones, muscles, connective tissues, and red and white blood cells.
Zinc is involved in over 200 enzymatic reactions. Zinc levels below the norm can have a significant negative effect on overall health. Conversely, taking too much zinc can lead to equally serious health concerns.
The benefits of zinc
Zinc is crucial for numerous functions in your body, including:
Research: Zinc – Fact Sheet for Health Professionals
- DNA and protein synthesis;
- gene expression;
- enzymatic reactions;
- growth and development;
- normal immune system function;
- healing of wounds;
- hair loss prevention;
- processes regulating normal testicular and prostate function;
- healthy aging processes;
- prevention of cataracts and cancer;
- neutralization of the side-effects of alcohol consumption;
- absorption of vitamins A, C, and E.
The recommended dietary allowance (RDA)
| Age | RDA for infants |
| 0–6 months | 2 mg |
| 7–12 months | 3 mg |
| Age | RDA for children |
| 1–3 years old | 3 mg |
| 4–8 years old | 5 mg |
| 9–13 years old | 8 mg |
| Age | RDA for men |
| 14–18 years old | 11 mg |
| 19 and older | 11 mg |
| Age | RDA for women |
| 14–18 years old | 9 mg |
| 19 years old and older | 8 mg |
| Age | RDA for pregnant women |
| 18 and older | 11 mg |
| Age | RDA for breastfeeding mothers |
| 18 and older | 12 mg |
It is important not to exceed the recommended daily allowance. Prior to adding any supplementation to your diet, always consult your family doctor or nutritionist.
Top foods rich in zinc
- Pumpkin seeds – 7.6 mg per 100 g.
- Cashew nuts – 5.4 mg per 100 g.
- Sunflower seeds – 5 mg per 100 g.
- Pine nuts – 4.1 mg per 100 g.
- Almonds – 3.4 mg per 100 g.
- Pistachios – 2.2 mg per 100 g.
- Beans (cooked) – 4.1 mg per 1 cup.
- Lentils – 2.5 mg per 1 cup.
- Tofu – 1.6-4 mg per 1 cup.
- Rye flour – 6.4 mg per 1 cup.
- Wheat coarse flour – 3.6 mg per 1 cup.
- Oatmeal (cooked) – 1.2 mg per 1 cup.
- Rice (boiled) – 1.2 mg per 1 cup.
- Cooked wholemeal pasta – 1.3 mg per 1 cup.
- Ground beef (cooked) – 10.2 mg per 100 g.
- Chicken liver (boiled) – 4 mg per 100 g.
- Turkey liver (boiled) – 3.1 mg per 100 g.
- Oysters – 74 mg per 100 g.
- Roast beef – 7 mg per 100 g.
- Alaskan (king) crab – 6.5 mg per 100 g.
- Beef burger – 3 mg per 100 g.
- Lobster – 3.4 mg per 100 g.
- Pork chops – 2.9 mg per 100 g.
- Yoghurt – 1.3 mg per pack.
Zink deficiency
Zinc deficiency can have a negative effect on the immune and nervous systems. It can also lead to infertility in both males and females, and complications during labor and delivery.
Symptoms of zinc deficiency
Severe cases of zinc deficiency are relatively rare. However, according to nutritional surveys, the average zinc intake in Western countries is around 47-67% of the recommended daily allowance.
The most common symptoms of zinc deficiency are:
- Total or partial loss of taste and smell.
Research: Smell/Taste alteration in COVID-19 may reflect zinc deficiency
- Chronic diarrhea.
- Dry skin (dermatitis).
- Memory problems.
- Low sperm count and/or infertility.
- Decreased testosterone production and/or erectile dysfunction (impotence).
Research: Zinc status and serum testosterone levels of healthy adults
- Fatigue and irritability.
- Depression.
- Reduced resistance to infectious diseases.
- Slow healing of wounds.
Other symptoms indicative of zinc deficiency are poor night vision, delayed growth and development, testicular atrophy, mouth ulcers, and white plaque on the tongue.
Susceptibility to zinc deficiency
It is a well-known fact that the absorption of important minerals, including zinc, declines with age. As such, the older we get, the more care we should take to ensure that we maintain normal levels of zinc in our bodies.
In addition, a lack of foods containing zinc in the diet, and/or regular consumption of alcohol can also lead to chronically low levels of zinc.
Certain medical conditions and diets can also cause zinc deficiency:
- Acute infectious diseases and/or inflammatory processes.
- Cirrhosis and liver diseases.
- Anorexia nervosa.
- Burns.
- Post-traumatic stress disorder.
- Inadequate protein intake.
- Vegetarian diets.
- Fasting.
- Coeliac disease.
- Diabetes mellitus.
- Diarrhea.
- The excess fiber in the diet.
- Diets with a high calcium/zinc ratio.
- Diets with a high iron/zinc ratio.
- Pancreatic insufficiency.
Zinc toxicity
Zink toxicity is caused by excessive zinc intake. The symptoms include:
- nausea;
- vomiting;
- diarrhea;
- stomach ache;
- headaches.
Research: Zinc toxicity
Moreover, when in excess, zinc interferes with the absorption of other minerals, especially manganese, copper, and iron. High levels of zinc taken over long periods either through diets rich in zinc or through supplementation can cause anemia.
The tables below indicate the dosages at which zinc toxicity occurs:
| Age | Dosage associated with zinc toxicity in infants |
| 0–6 months | 4 mg |
| 7–12 months | 5 mg |
| Age | Dosage associated with zinc toxicity in children |
| 1–3 years old | 7 mg |
| 4–8 years old | 12 mg |
| 9–13 years old | 23 mg |
| Age | Dosage associated with zinc toxicity in men |
| 14–18 years old | 34 mg |
| 19 and older | 40 mg |
| Age | Dosage associated with zinc toxicity in women |
| 14–18 years old | 34 mg |
| 19 years old and older | 40 mg |
| Age | Dosage associated with zinc toxicity in pregnant women |
| 18 and older | 40 mg |
| Age | Dosage associated with zinc toxicity in breastfeeding mothers |
| 18 and older | 40 mg |
The take-home message
Zinc is an essential mineral and is crucial for the normal functioning of our bodies. A well-balanced diet rich in foods containing zinc is important to ensure adequate zinc levels in the blood and tissues. Zinc can be beneficial for a variety of health problems.
We recommend consulting a specialist who will test your zinc levels before prescribing the correct dosage because excessive zinc supplementation can be dangerous for your health.
The material is based on research:
- Zinc – Fact Sheet for Health Professionals
- Smell/Taste alteration in COVID-19 may reflect zinc deficiency
- Zinc status and serum testosterone levels of healthy adults
- Effect of vegetarian diets on zinc status: a systematic review and meta-analysis of studies in humans
- Zinc toxicity
