Zinc is a particularly crucial trace element that the human body needs to maintain good health. Not having enough zinc can lead to various symptoms, including slow growth, poor immune resistance, increased fatigue, hair loss, deteriorating skin texture, and poor sleep quality.

Dr. Ou Hanwen, a physician specializing in integrative medicine and clinical nutrition at the University of Maryland, recently shared his insights on NTDTV’s “Health 1+1“ program about the role of zinc in maintaining good health, the symptoms of zinc deficiency, and how to obtain sufficient zinc from food.

Zinc is vital for hundreds of enzymes in the human body to maintain their functions, according to Ou. From pregnancy through infancy, childhood, and adolescence, zinc plays an indispensable role in supporting good health and growth.

Key Functions of Zinc

Zinc supports a wide range of physiological functions and is present in all body tissues.

1. Immune System Support

Almost all immune cells heavily depend on zinc for proper functioning. Both deficiency and excess can damage the immune system.

2. Protein and DNA Synthesis

Zinc is required for DNA synthesis, cell division and growth, protein synthesis, and macronutrient metabolism. It’s also crucial for the development and function of most body systems.

3. Wound Healing and Tissue Repair

Zinc plays a significant role in regulating various stages of the wound healing process, from membrane repair and coagulation to inflammation, immune defense, angiogenesis, and scarring.

4. Taste Enhancement

When we eat and smell, the organs need to send chemical signals to the brain to determine what they are eating and smelling. Zinc is involved in multiple levels of taste perception, including the taste buds, the nerves that transmit taste messages, and the brain.

5. Reproductive System Maintenance

Zinc plays a role in all stages of human reproduction, from spermatogenesis to childbirth. It’s particularly important during pregnancy, labor, and perinatal and neonatal periods.

Multiple studies have found strong associations between various indicators of maternal zinc status and important health outcomes, including fetal growth and development, birth outcomes, and maternal and perinatal morbidity.

6. Cancer Prevention

A 2023 study found that disruption of zinc homeostasis may lead to cancer development. While results from studies differ, they all indicate a link between the degree of zinc dysregulation in cells and several types of cancer.

Symptoms of Zinc Deficiency

Because of its many functions within the body, zinc deficiency can affect multiple body systems, organs, and tissues. For a normally healthy person who does not have enough zinc in their diet, common symptoms include:

• Hair loss
• Diarrhea
• Eye and skin problems
• Reduced sense of taste and smell

Children may experience slower growth, while adolescents may be undermined by delayed sexual development.

Zinc deficiency is also associated with an increased risk of sleep disorders. A 2023 cross-sectional analysis of 3,660 adults from the National Health and Nutrition Examination Survey (NHANES) found that serum zinc levels and zinc ratios with copper and selenium were inversely associated with the risk of self-reported sleep disorders.

Foods Rich in Zinc

Since the human body cannot store zinc, it needs to be continuously replenished through diet. According to Ou, foods high in zinc include:

• Raw oysters (highest zinc content at 39.3 mg/100 grams). The maximum daily dietary intake of adult men and pregnant women at just 11 milligrams (mg)
• Beef, lamb, chicken, pork
• Fish and shrimp
• Milk and dairy products
• Grains and nuts

As long as we have a normal diet, most of us will not have much problem, Ou said. However, some individuals may have insufficient zinc bioavailability, which could result in deficiency.

Groups Most at Risk for Zinc Deficiency

Zinc is an essential mineral that plays a crucial role in the body, but certain populations may face challenges in meeting their zinc needs because of specific health conditions or dietary factors.​ Here are some groups that often struggle with zinc intake and absorption:

• Patients with gastrointestinal diseases or bariatric surgery: Related conditions and inflammation can lead to poor dietary zinc intake, decreased absorption, or increased urinary excretion.
• Celiac disease patients: Caused by zinc malabsorption and mucosal inflammation.
• Vegetarians: Vegetarian diets contain lower amounts of zinc.
• Pregnant or lactating women: Demand for zinc increases during pregnancy and lactation. Pregnant women need to take 3 mg more zinc every day, while breastfeeding women need an additional 4 mg every day.
• Older infants exclusively breastfed: The zinc concentration of breast milk reaches a peak in the first month after birth and then gradually decreases. By six months, infants who are still exclusively breastfed will not have sufficient zinc intake per requirement.
• Children with sickle cell disease: A likely result of chelation therapy treatment that can affect zinc absorption
• Alcoholics: Alcohol consumption decreases zinc absorption and increases zinc excretion in urine.

Zinc Supplements

While zinc supplements can be beneficial, Ou warned that excessive intake may cause toxic reactions, including indigestion, nausea, vomiting, headache, fatigue, and immune function suppression. For adults 19 years of age or older in the United States, the recommended upper limit for daily intake is 40 mg.

Zinc supplementation should follow the advice of medical professionals or nutritionists and should not exceed the recommended daily intake limit. Long-term large doses of supplementation should also be avoided to prevent the occurrence of toxic effects. It is better to always ensure a balanced intake of dietary food rather than relying solely on supplements.