Learn how zinc supports immune function, wound healing, and overall health—plus how to get the right amount safely through food and supplements.

As we enter cold and flu season, you may notice that some immune-support supplements contain zinc. That’s because zinc is essential for immune cell function and signaling. It’s a vital mineral that our bodies cannot produce on their own, so it must be obtained through diet. Zinc is the second most abundant trace mineral in the body after iron.

In addition to supporting immune function, zinc plays a key role in cell growth, gene expression, DNA synthesis, enzymatic reactions, and protein production. It’s also important for wound healing, skin health, and maintaining your senses of taste and smell.

Food Sources of Zinc

Most people who consume a varied diet—including animal and plant proteins, vegetables, fruits, whole grains, legumes, nuts, and seeds—get enough zinc.

Some of the highest food sources include:

• Shellfish, fish, meat, and poultry

• Legumes, nuts, and seeds

• Dairy and eggs

• Whole grains and vegetables such as mushrooms, peas, asparagus, kale, and beet greens

• Fortified foods such as cold cereals and snack bars

Recommended Daily Allowance (RDA) for Zinc

• Birth–6 months: 2 mg/day

• 7–12 months: 3 mg/day

• 1–3 years: 3 mg/day

• 4–8 years: 5 mg/day

• 9–13 years: 8 mg/day

• 14–18 years: Males 11 mg/day; Females 9 mg/day

• 19 years and older: Males 11 mg/day; Females 8 mg/day

• Pregnancy: 11 mg/day

• Lactation: 12 mg/day

Zinc Deficiency

Zinc deficiency is a major global health concern, particularly in developing countries. It’s estimated that about 17% of the world’s population is zinc deficient. Deficiency can lead to growth failure, impaired immune response, inflammation, gastrointestinal issues, and skin lesions.

Poor nutrition, malabsorption, chronic illness, excessive zinc losses, and certain medications can all contribute to deficiency. When dietary intake is low, the body draws on small zinc reserves stored in the hair, skin, bones, liver, brain, and muscle—eventually leading to depletion.

Zinc and Immune Function
Zinc may help inhibit viral replication and acts as an antioxidant, protecting cells from damage that could contribute to illness. Research also suggests that zinc lozenges may shorten the duration of respiratory infections, and combining zinc with vitamin C may help reduce the severity and duration of cold symptoms.

However, this doesn’t mean everyone should take extra zinc to prevent illness. While zinc supports immune function, evidence does not strongly support using zinc supplements to prevent colds or flu-like illnesses. More research is needed before general recommendations can be made.

Supplements should be used to fill nutritional gaps, not replace a healthy diet.

Zinc Toxicity

Consuming too much zinc can cause toxicity. Symptoms may include nausea, stomach pain, diarrhea, lethargy, nerve issues, hallucinations, reduced immune response, nose and mouth irritation, anemia, and zinc-induced copper deficiency.

In Summary

Zinc is a crucial mineral that supports immune health, wound healing, and overall body function. Most people can meet their zinc needs through a balanced diet that includes a variety of whole foods.

Before taking zinc or any other supplement, speak with your healthcare provider to ensure it’s safe and appropriate for you. A healthy diet, proper hydration, adequate sleep, and regular physical activity remain your best defenses for maintaining a strong immune system throughout cold and flu season.