Zinc is an essential trace mineral that we need to consume through our food because our bodies can’t produce it or store it. Zinc is needed for a variety of processes in our body such as gene expression, DNA synthesis, enzyme reactions, immune function, protein synthesis, taste, smell, wound healing and growth. In fact, zinc is found in every single cell in our bodies and is the second most abundant trace mineral found in our bodies after iron. While zinc plays a role in a variety of different processes in the body, we’re going to take a closer look at some of the different ways zinc can help with immune response specifically.

Infections:

Zinc is essential for immune cell development, functioning and signalling, and keeping our immune responses strong. Zinc may help reduce oxidative stress and improve the immune response by boosting the activity of T-cells and natural killer cells, helping to protect your body from infection. Taking 80-92mg of zinc per day may reduce the length of the common cold by up to 33%.

Age-related diseases:

Zinc may reduce the risk of developing diseases such as pneumonia and others infections in the elderly. Zinc supplements have been shown to significantly reduce infection and promote an immune response in older adults as well as stimulate immune cells, reduce oxidative stress, reduce the risk of pneumonia and boost mental performance. Just 45 mg of zinc per day may decrease infection rates in older adults by nearly 66%.

Skin healing:

Our skin contains about 5% of our body's total zinc content and plays a vital role in collagen synthesis, immune function and inflammatory response. Because of this, zinc is commonly used in the treatment of burns, ulcers and injuries to the skin. While supplementing with zinc can speed the recovery of wounds, zinc deficiency can also slow recovery.

Inflammation:

Zinc has been shown to decrease levels of certain inflammatory proteins in the body and reduce oxidative stress which decreases chronic inflammation. Chronic inflammation contributes to a range of illnesses such as cancer and heart disease. One study showed that taking 45mg of zinc per day resulted in greater reductions in inflammatory markers than those who did not supplement zinc.

Food sources

Plenty of foods contain high levels of zinc naturally which means that most people are able to consume enough zinc to meet their daily requirements without much issue. However, zinc is absorbed differently depending on the source that you are getting it from. Animal products contain high levels of zinc which the body easily absorbs, whereas certain plant-based foods contain zinc that is absorbed less efficiently because other plant compounds within the food inhibit absorption.

Foods that are naturally high in zinc include :

Shellfish: Oysters, crab and mussels
Meat: Beef, pork and lamb
Poultry: Chicken
Fish: Flounder, sardines and salmon
Legumes: Chickpeas, lentils, black beans, kidney beans etc
Nuts and seeds: Pumpkin seeds, cashews, hemp seeds, etc
Dairy products: Milk, yogurt and cheese
Eggs
Whole grains: Oats, quinoa, brown rice, etc.
Certain vegetables: Kale, peas, mushrooms, asparagus and beet greens

Many foods are also fortified with zinc such as cereals, flours and snack foods. You can also take zinc supplements, multi-nutrient supplements, lozenges and other treatments for cold symptoms that contain zinc. 

RDI

The recommended daily intake (RDI) for zinc is:

• Adult men: 11/day
• Adult women: 8mg/day
• Pregnant women: 11mg/day
• Breastfeeding women 12mg/day

The recommended upper level of zinc is 40mg/day, however those with zinc deficiencies may need to take more. It is unlikely that you can get this amount of zinc from food alone, however, taking supplements can increase your zinc levels above this amount. This can also effect the absorption of other nutrients in your diet such as copper and iron. It is also not recommended that you take zinc supplements long-term ie more than 10-15mg 2-4 x per day for more than 4-6 weeks.

Deficiency

Unless you have a medical condition that inhibits your absorption of zinc, you should be able to consume enough through your diet which makes zinc deficiency relatively uncommon. However, zinc deficiency may occur in:

• Pregnant and breastfeeding women and breastfeeding infants whose mothers don’t have enough zinc
• Vegetarians and vegans
• People with gastrointestinal diseases like Crohn’s disease
• People with sickle cell anaemia
• People who are malnourished, including those with anorexia or bulimia
• People with an alcohol addiction
• People with genetic mutations
• People taking immune suppressant drugs
• People with chronic kidney disease

Our bodies control our zinc levels so zinc deficiency can be difficult to detect from blood tests alone. Doctor’s will consider other factors when determining zinc deficiency such as your diet and other risk factors named above. If you do need more zinc, doctor’s often recommend taking zinc supplements such as zinc citrate, zinc gluconate, methionine, glycine, acetate or sulfate which are easily absorbed.