Zinc is an essential mineral that plays many vital roles in the human body. Getting enough zinc in your diet is critical for maintaining overall health and wellbeing. Here is an overview of why zinc is so important.
Zinc’s Role in Immunity
One of zinc’s most important functions is supporting the immune system. Zinc aids in the development and activation of T-lymphocytes, a type of white blood cell that helps fight infection. Studies show that zinc deficiencies can weaken the immune system and increase susceptibility to pneumonia, malaria, and diarrhea infections in children. Zinc supplementation may help reduce the duration and severity of colds and other viruses. Overall, consuming enough zinc is vital for keeping your immune system strong and able to defend against pathogens.
Zinc for Growth and Development
Zinc plays a crucial role in growth and development, especially in children and during pregnancy. Zinc is needed for the activity of over 300 enzymes and 1,000 transcription factors involved in the synthesis of nucleic acids and proteins. Zinc deficiency during fetal development and infancy can result in stunted growth and impaired cognitive function. In children and teens, zinc supports proper growth and sexual maturation. Getting sufficient zinc is essential during pregnancy and childhood when growth rates are high.
Zinc’s Role in DNA and Protein Synthesis
Zinc plays a key role in nucleic acid metabolism involving DNA and RNA synthesis. Zinc is required by DNA and RNA polymerases, enzymes that assemble nucleic acids during gene transcription and replication. As a component of transcription factors, zinc helps regulate gene expression. In the cytoplasm, zinc aids in protein synthesis by activating amino acid transfer RNA. Overall, zinc is critical for building nucleic acids and proteins essential for cell growth and division.
Zinc for Brain Health
The brain contains high levels of zinc, particularly in the hippocampus, amygdala, cerebral cortex, and olfactory cortex areas. Zinc plays an important role in neurotransmission, synaptic plasticity, and cognition. Zinc deficiency has been linked to impaired learning and memory in animal studies. Human studies show supplemental zinc may benefit cognitive performance and behavior in children with ADHD. Overall, adequate zinc intake supports optimal brain health and cognitive function across all ages.
Zinc’s Antioxidant Functions
Zinc serves powerful antioxidant functions in the body. It is a cofactor of the antioxidant enzyme superoxide dismutase, which disarms free radicals. Zinc also helps maintain glutathione levels and the activity of catalase and glutathione peroxidase, other endogenous antioxidants. Through these mechanisms, zinc helps protect cells against oxidative damage from reactive oxygen species. Getting enough zinc is important for neutralizing free radicals and inhibiting oxidative stress.
Zinc for Fertility and Reproduction
Zinc plays critical roles in fertility and reproductive health for both men and women. In men, zinc supports testosterone synthesis and semen production. Zinc deficiency can lead to infertility and impaired sperm quality. In women, adequate zinc levels are needed for egg maturation and ovulation. Zinc deficiency may cause menstrual irregularities and infertility. During pregnancy, zinc supports fetal development, especially neurological function. For both men and women’s reproductive health, getting sufficient dietary zinc is essential.
Zinc’s Role in Vision
Zinc supports eye health due to its presence in high concentrations in the retina. It enables vitamin A to convert into its active form retinal for the synthesis of the visual pigment rhodopsin. Zinc deficiency may be associated with poor night vision and other visual abnormalities. Supplemental zinc may help slow the progression of age-related macular degeneration in high risk individuals. Consuming adequate zinc can help maintain healthy vision as you age.
Zinc Supports Wound Healing
Zinc assists in wound healing, especially following burns or surgery. Zinc is required for protein synthesis needed for re-epithelialization and tissue growth. It also supports the immune cells involved in wound repair. Low zinc levels can lead to chronic non-healing wounds. Research indicates supplemental zinc can help speed wound closure in deficient patients. Getting adequate zinc ensures your body can heal itself following injury.
Zinc Regulates Inflammation
Zinc helps regulate inflammation, as it is needed for the activity of over 300 enzymes involved in the inflammatory response. Mild zinc deficiency can result in chronic low-grade inflammation. Supplementation may reduce inflammation markers like CRP and IL-6 in those with deficiencies. Through its antioxidant activity, zinc also inhibits NF-kB signaling that drives pro-inflammatory cytokine production. Consuming enough zinc is vital for controlling inflammation.
Zinc and Taste Perception
Zinc is essential for normal taste buds and smell perception. Zinc-dependent enzymes help synthesize rhodopsin, a pigment needed for night vision, and gustin, a protein involved in taste. Without adequate zinc, loss of taste and smell can occur. Zinc deficiency is a common cause of hypogeusia (reduced ability to taste). Supplementing with zinc has been shown to help resolve taste disturbances in those deficient.
Zinc Supports Healthy Skin
Zinc is needed for proper structure and function of skin and connective tissues. It stimulates collagen and elastin synthesis to replace aged or damaged tissues. Topical zinc preparations may help treat inflammatory dermatitis, warts, acne, and wounds. Zinc also protects against UV radiation damage when applied topically. Consuming adequate zinc is important for maintaining youthful, healthy skin.
Zinc’s Role in Blood Clotting
Zinc aids in blood clotting by supporting coagulation factors. It assists in the activation of prothrombin, an essential clotting factor. Zinc also helps maintain the structure of fibrinogen, another clotting factor. During bleeding events, zinc is released from blood platelet storage sites to help form clots. Mild zinc deficiency can impair clotting function. Getting adequate zinc prevents bleeding complications.
Zinc Status in the Body
The total amount of zinc in the adult human body is 2-3 grams.muscle contains approximately 60% of total body zinc, while bone contains around 30%. The prostate and liver also store high concentrations. Plasma zinc levels are only about 0.1% of total body stores. Plasma zinc may decline with even minor deficiencies before tissue stores are depleted. Testing serum or plasma zinc levels can identify deficiencies before they become severe.
Zinc Absorption and Excretion
Zinc from animal foods is better absorbed than plant sources due to their phytate content. Absorption is also enhanced by protein foods. Only 20-40% of dietary zinc is absorbed. Excess zinc is primarily excreted in the feces. Minimal amounts are excreted in urine and sweat. Phytates, iron, calcium, and copper can inhibit zinc absorption when consumed in excess. Alcohol increases urinary zinc excretion.
Zinc Deficiency
Zinc deficiency affects around 17% of the global population, making it one of the most common micronutrient deficiencies. In developing countries, it may affect 30% or more. Causes include inadequate dietary intake, malabsorption disorders, liver and kidney disease, burns, and alcoholism. Symptoms can include impaired growth, increased infection risk, hair loss, diarrhea, impotence, eye lesions, and loss of appetite. Severe zinc deficiency can cause cell-mediated immune dysfunction.
Zinc Toxicity
Getting too much zinc from food sources is uncommon due to absorption limits. However, over-supplementing with zinc for long periods can lead to toxicity. Excess zinc competes with copper absorption, causing copper deficiency and neurologic symptoms. Nausea, vomiting, epigastric pain, headache, and lethargy can occur with extremely high intakes. Daily supplementation over 150 mg per day should be supervised by a doctor.
Zinc Interactions
Zinc can interact with several medications. Zinc can bind to tetracycline antibiotics, quinolone antibiotics, and penicillamine which reduces their absorption. Thiazide diuretics increase zinc excretion in urine. Zinc can decrease the absorption of antibiotics like ciprofloxacin, levofloxacin, and ofloxacin if taken together. There are also interactions with ACE inhibitors.
Food Sources of Zinc
| Food | Serving | Zinc (mg) |
|---|---|---|
| Oysters | 6 medium | 76.3 |
| Beef chuck roast | 3 ounces | 7.0 |
| Crab | 3 ounces | 6.5 |
| Lobster | 3 ounces | 3.4 |
| Pork chop | 3 ounces | 2.9 |
| Baked beans | 1 cup | 2.9 |
| Chicken | 3 ounces | 2.4 |
| Chickpeas | 1 cup | 2.5 |
| Milk | 1 cup | 1.2 |
| Almonds | 1 ounce | 1.1 |
Animal proteins including seafood, meat, eggs, and dairy are the richest sources of highly bioavailable zinc. Beans, nuts, some fortified cereals, and whole grains also provide zinc.
Zinc Supplements
The recommended daily intake is 8-11 mg per day for adults. Many supplements provide zinc in the form of zinc gluconate, zinc sulfate, or zinc acetate. Studies show zinc monomethionine, the form in oysters, may have enhanced absorption. Liquid zinc supplements are also highly bioavailable. Always take zinc with food to minimize side effects.
Zinc and Vegetarian Diets
Phytates in whole grains, beans, and nuts reduce zinc absorption. Soaking, sprouting, leavening and fermenting foods can reduce phytate content and increase bioavailability. Combining zinc foods with iron and protein also helps. Vegetarians should aim for 50% higher zinc intake than non-vegetarians. Those not meeting needs with diet alone may require supplements.
Maximizing Zinc Absorption
To maximize zinc absorption from your diet:
- Combine zinc foods with protein sources
- Avoid overcooking high zinc foods
- Soak beans, grains before cooking
- Choose sprouted grain breads
- Consume leavened whole grain breads
- Time calcium supplements away from meals
Following these simple tips can help optimize your zinc intake from meals.
Zinc for Cold and Flu
Due to its critical role in immunity, zinc lozenges, nasal sprays, and syrups are commonly used to prevent and treat cold symptoms. Meta-analyses show zinc helped shorten common cold duration, especially when taken within 24 hours of onset. However, large doses of zinc over long periods can cause toxicity. Short-term use of zinc for colds appears relatively safe.
Testing for Zinc Status
Zinc levels can be checked with blood, urine, or hair tests. Serum or plasma zinc is the most common, but levels can vary throughout the day. Low or deficient levels are under 70 mcg/dL. Hair mineral analysis can estimate long-term zinc status. Always work with your doctor for proper zinc testing and monitoring.
Increasing Dietary Zinc Intake
Here are some tips for increasing your daily zinc intake:
- Eat more zinc-rich proteins like beef, pork, chicken, fish, eggs, and dairy
- Have more nuts, seeds, legumes, and whole grains
- Choose fortified breakfast cereals with zinc
- Use zinc-fortified nutritional yeast
- Try sprouted breads and fermented grains
- Soak oats overnight before cooking
- Consider a multivitamin with zinc
Making a few adjustments to your diet can help provide sufficient zinc daily.
Conclusion
Zinc is an essential trace mineral that serves a diverse range of critical functions in the human body. From supporting immunity, growth, reproduction and DNA synthesis to regulating inflammation and protecting vision and cognition, zinc is indispensable for human health. Ensuring adequate intake through a balanced diet and supplementation when appropriate is key for optimal wellbeing at all life stages.