You may have heard about zinc's role in fighting off colds and the flu and wonder if you should be taking a zinc supplement. While zinc is essential for your immune system, too much can be harmful. Below, Rachel Johnson, MD, board-certified internal medicine physician and pediatrician, discusses what you need to know before taking a zinc supplement.

What are the benefits of zinc?

Zinc is an essential nutrient found in a variety of foods as well as supplements. It helps the body by:

1. Playing a key role in skin health.
2. Helping your immune system function.
3. Tissue repair and cell growth.
4. Protecting your eyes against macular degeneration and night blindness.

How much zinc do I need?

The recommended dietary allowance for zinc is:

• 11 mg for adult men 
• 8 mg for adult women (nursing or pregnant women need a little more)
• 3 mg for children

With a varied diet, you should meet your daily zinc needs. Foods that are rich in zinc include:

• Meat
• Fish and seafood, particularly oysters
• Eggs
• Dairy products
• Chickpeas or legumes
• Fortified breakfast cereals and whole grains

Since most Americans have access to the foods above, we don't see a lot of zinc deficiency in the U.S. However, vegetarians and vegans need to monitor their zinc levels closely, as zinc is limited in – and less absorbed from – plant-based foods. It's highest in animal products like meat, seafood and eggs.

Are zinc supplements safe and effective?

Oral supplements can sometimes benefit people with low zinc levels. When taken within the first 24 hours, zinc supplements – particularly throat lozenges and syrup – may also help decrease symptoms of a cold or the flu. However, zinc nasal sprays are not recommended because they can cause loss of smell. Additionally, too much zinc can be harmful and lead to other health problems.

What happens if I get too much zinc?

Signs you may be getting too much zinc include: 

1. Nausea, vomiting or an upset stomach
2. Diarrhea 
3. Dizziness
4. Headaches

If you take too much zinc for a long time, you may also experience lower immunity, HDL or "good" cholesterol and copper. Copper is a mineral found throughout the body. It helps make red blood cells and keeps your immune system healthy. It also helps form collagen, a key part of bones and connective tissue. Copper may also act as an antioxidant, reducing free radicals that can damage your cells and DNA. Although rare, some individuals, such as those with a history of stomach surgery or prolonged intravenous nutrition, may be at an increased risk for copper deficiency. If you fall into this category, you should avoid taking a zinc supplement because it could decrease your copper levels even more. If your doctor suspects you have a copper deficiency, they can order a vitamin deficiency test to make sure you're not getting too much zinc.

How does zinc interact with other medications?

Some medicines can lower the zinc in your body. Zinc can also interfere with certain medications, such as:

1. Antibiotics – Using oral zinc supplements while taking certain antibiotics can interfere with their ability to fight bacteria. 
2. Rheumatoid arthritis medication – Using oral zinc supplements with rheumatoid arthritis medication can reduce the drug's ability to ease arthritis symptoms. 
3. Diuretics – Certain blood pressure drugs can increase the amount of zinc lost in urine.

The bottom line: Zinc is an essential mineral that plays a key role in your health. Eating a well-rounded diet should give you all the zinc you need. If you think you're deficient, consult your doctor – either in person or through a telehealth visit – before starting a supplement to make sure it's right for you. For more information or to schedule an appointment, call 800.922.0000.