Zinc is an essential trace mineral and next to iron it is the most common mineral found in the body. It is necessary for the functioning of more than 300 different enzymes and plays a vital role in an enormous number of biological processes. Even though zinc is a trace mineral, it is needed for the proper growth and maintenance of the human body. It is found in several systems and biological actions and is needed for immune function, wound healing, blood clotting, thyroid function, synthesis of DNA and RNA and many more. Keeping normal zinc levels helps with the maintenance of these enzyme systems and acts as a hormonal and immune system aid. Zinc also has antioxidant properties, meaning it helps protect cells in the body from damage caused by free radicals.

Zinc is found in high concentrations in the eyes, liver, muscle, skin, hair, prostate and seminal fluid.

Although zinc deficiency is rare in modren well-nurished diets, low zinc levels are sometimes seen in the elderly, alcoholics, people with anorexia, people on very restricted diets, malabsorption syndromes, such as Crohn's disease or celiac disease, acrodermatitis enteropathica - inherited inability to absorb zinc properly, cirrhosis - liver disease and kidney disease. There are also some medications that can decrease the amount of zinc in the body. These are:
ACE Inhibitors - Blood pressure medication
Cisplatin (Platinol-AQ) - Chemotherapy
Penicillamine - Medication for Wilson's disease and Rheumatoid arthritis
Thiazide - diuretic (water pill)
Zinc is also lost in sweat, as are many minerals, making mineral supplementation almost a necessity for athletes.

Symptoms of zinc deficiency include slowed growth, low insulin levels, loss of appetite, irritability, generalized hair loss, rough and dry skin, slow wound healing, poor sense of taste and smell, diarrhea, and nausea. Recommended daily allowance of Zinc for adults is 8 - 11 mg. To treat certain health conditions a dosage of 40 mg a day is considered as a safe amount for long term use. Please also note that chronic intake of excessive amounts of zinc can interfere with your body's absorption of other minerals, especially copper. Therefore, it is suggested to supplement copper in 15-to-1 zinc-to-copper ratio. Do not give zinc supplements to a child and always talk to your Health care provider before starting any supplemental treatment.

Zinc participates in an impressive number of functions in the human body and can be used to treat the following conditions.

Its immune-enhancing activities include regulation of T lymphocytes, CD4, natural killer cells, and interleukin II. Due to its immune enhancing properties  zinc supplements reduce both the severity and incidence of common cold and infections. Taken within twenty-four hours of the onset of common cold symptoms, it can significant reduce in the duration and severity of cold symptoms and can also lower the risk of pneumonia. Zinc also possesses antiviral activity and studies show that HIV positive people who take zinc have fewer infections, gain more weight, and have a better immune system response.

Wound & Ulcer healing
Zinc helps maintain the integrity of skin and mucosal membranes and can cure wounds. It can help speed the healing of leg ulcers and stomach ulcers - it is known to repair the intestinal mucosa effectively.

Lower respiratory infections
Results from large clinical trials suggest that supplementation with zinc may reduce the incidence and severity of lower respiratory infections.

Gut permeability
Dysregulation occurs with intestinal zinc absorption during aging, and adequate dietary intake may in turn be metabolically insufficient due to poorer absorption. High levels of zinc intake (330mg daily) has been implicated in alleviating even leaky gut syndrome.

Approximately 30%–50% of alcoholics have low zinc status because ethanol consumption decreases intestinal absorption of zinc and increases urinary zinc excretion. It can also provide therapeutic-like benefit in treating alcohol-induced damage to the gut and liver. Zinc also controls the release of stored vitamin A from the liver.

Sickle cell disease
It is noted in studies that 44% of people with sickle cell disease have a low plasma zinc concentration.

Parasitic Infections
Studies suggest that zinc supplementation may reduce the number of stays in hospital and death rate due to Malaria (P. falciparum) infection. Recent high-quality study data suggest that supplementation with zinc and vitamin A may favorably alter infection rate and duration among children.

Depression & Anxiety
Link between zinc deficiency, depression and other mental health conditions is its important role as a neurotransmitter in the brain, connected with hormone production as hormone dopamine is partially regulated by zinc. A person with low zinc levels can also be affected with low testosterone levels in the body.

Diabetics tend to have increased excretion of zinc which leads to lower levels of zinc in the body. Studies have shown that people who use zinc have a statistically significant reduction in their fasting blood sugar levels.

High cholesterol
There is evidence that zinc may improve cholesterol ratio of HDL "good cholesterol" versus LDL "bad cholesterol".

Thyroid Health
Within the endocrine system, zinc has been shown to regulate insulin activity and promote the conversion thyroid hormones thyroxine to triiodothyronine.

Down's syndrome
In several studies, zinc supplements seemed to counteract hypothyroidism and slightly reduce the number of infections in children with Down syndrome.

Kidney function
Studies show potential improvement in uremic patients taking zinc supplements.

Anorexia nervosa
Reports of zinc's effectiveness in treating symptoms of anorexia nervosa observed in young adults.

Taking zinc by mouth or applying it to the skin in an ointment that also contains erythromycin seems to help clear up acne.

Many studies report beneficial results of zinc supplements on infertility, as expressed in improved sperm quality and number, although this effect may depend on the cause of infertility.

Taking a zinc supplement in combination with copper, manganese, and calcium might decreases bone loss in women who have passed menopause.

Age-Related Macular Degeneration
Zinc is used to treat this eye disease that occurs when the part of the retina that is responsible for central vision starts to deteriorate. Common supplementation is by taking zinc (40 mg), vitamin C (500 mg), vitamin E (400 mg), beta-carotene (15 mg), and copper (2 mg).

Fungal infections
Zinc pyrithione is an effective treatment for tinea versicolor (scalp) fungal infections.

Herpes simplex (Cold Sores)
Zinc oxide cream can reduce the symptoms while effectively healing herpes.

There is some evidence that suggests taking zinc may reducing hyperactivity, impulsivity, and impaired socialization in children affected with ADHD but change in attention deficit symptoms is not observed.

Other Uses
It is also used for boosting the recurrent ear infections, night blindness and cataracts, asthma, high blood pressure, skin conditions such as psoriasis, eczema, and acne, blunted sense of taste (hypogeusia), ringing in the ears (tinnitus), severe head injuries, alzheimer’s disease, hansen’s disease, benign prostatic hyperplasia (BPH), erectile dysfunction (ED), rheumatoid arthritis, and muscle cramps associated with liver disease, acrodermatitis enteropathica, thalassemia and Wilson’s disease. Some athletes use zinc for improving athletic performance and strength.

Food Sources
The best sources of zinc are oysters, red meats, poultry, cheese (ricotta, Swiss, gouda), shrimp, crab and other shellfish, legumes such as lima beans, black-eyed peas, pinto beans and soybeans, peanuts, whole grains, miso, tofu, brewer's yeast, cooked greens, mushrooms, green beans, tahini, pumpkin and sunflower seeds.

Possible Interactions
Immunosuppressant medications - corticosteroids (such as prednisone), cyclosporine, or other medications intended to suppress the immune system.
Amiloride (Midamor) - Duretic, Deferoxamine (Desferal) - Used to remove excess may increase the levels of Zinc in the body and supplementing zinc with these medications can be harmful.