Zinc has so many health benefits that it’s almost impossible to cover them all in one post. This mineral has potent antioxidant and anti-inflammatory effects; it’s essential for immunity, reproduction, mental health, skin health, cognitive function, and so much more! Read on to learn the amazing benefits of zinc.
What is Zinc?
Zinc is an essential mineral found in all organs, tissues, and fluids in the body .
Zinc is required for the catalytic activity of more than 300 enzymes involved in the synthesis and metabolism of carbohydrates, fats, proteins, nucleic acids, and other nutrients .
Zinc also plays roles in stabilizing cell and organ structures, immune function, wound healing, cell division, growth, blood clotting, thyroid function, vision, taste, smell, and more .
Zinc in a Diet: Food Sources and Deficiency
Despite having such critical functions, it is not stored in the body and requires a regular dietary intake .
Good dietary sources of zinc include :
- Red meat
- Dairy products
- Whole grains
- People with digestive disorders
- Pregnant and lactating women
- People with sickle cell disease
Health Benefits of Zinc
The benefits of optimal dietary zinc intake may not imply the same benefits of zinc supplementation for individuals who are not deficient.
1) Zinc Deficiency
- Severe diarrhea
- Liver cirrhosis
- Renal failure
3) Wilson’s disease
Zinc supplementation is likely effective in treating Wilson’s disease, a disorder in which copper accumulates in tissues. It blocks copper absorption and increases copper elimination in the stool. Zinc acetate is an FDA-approved drug for Wilson’s disease [21, 22, 23].
4) Acrodermatitis Enteropathica
People with acrodermatitis enteropathica (a genetic disorder affecting zinc absorption), experience skin irritation, hair loss, diarrhea, and high rates of infection. Zinc supplementation in therapeutic doses usually results in complete recovery [24, 25].
5) Heart Disease
One study found that a higher rate of heart failure was associated with zinc deficiency .
According to one clinical review, high doses of zinc are able to prevent and treat angina (chest pain) in patients with atherosclerosis .
In a meta-analysis of 24 studies and 14,515 participants, zinc supplementation significantly reduced total cholesterol, LDL, and blood lipids. A reduction in these markers may lower the risk of heart disease [31, 32].
Scientists observed the potential of supplemental to protect the heart from stroke-related injuries in rats and mice .
6) Insulin Resistance and Diabetes
A meta-analysis of 22 clinical trials confirmed significant benefits of zinc supplementation for blood sugar control and insulin function .
7) Skin Health: Acne, Warts, Skin Damage
Zinc, both oral and topical, can benefit a variety of skin conditions (e.g., acne, warts, rosacea, eczema, psoriasis, melasma, and dandruff) .
A study in people with rosacea (a chronic inflammatory disease characterized by flushing, small blood vessels, and red bumps on the face) showed that oral zinc was able to reduce disease symptoms [55, 24].
Zinc supplementation exhibits similar efficacy in treating other inflammatory skin disorders such as psoriasis and eczema, likely owing to zinc’s anti-inflammatory and antioxidant properties. However, the results are less convincing [56, 57, 24].
Zinc may also treat seborrhoeic dermatitis (dandruff). Studies show that shampoos containing zinc can significantly reduce the scaling and inflammation associated with dandruff .
Zinc also protects against sun damage to the skin, which can cause skin aging and cancer. A study in humans found that a sunscreen containing zinc was more superior than titanium oxide in providing protection against ultraviolet (UV) irradiation [59, 60].
In a meta-analysis of 17 trials and 2400 participants, low blood levels of zinc were associated with more severe depressive symptoms .
Dietary intake of zinc was inversely associated with depression rates in another meta-analysis of nine studies .
When given to 30 young women with impaired mood, zinc significantly reduced anger and the symptoms of depression .
9) Appetite and Anorexia Nervosa
One of the earliest signs of a zinc deficiency is a loss of appetite .
10) Immunity & Infections
Zinc is essential for the normal development and function of many immune cells .
Because of the critical role it plays in the immune system, even a mild deficiency can impair immune function and increase the risk of bacterial, viral, and parasitic infection .
In clinical states associated with immunodeficiency (e.g., sickle cell disease, human immunodeficiency virus (HIV) infection) and in the elderly, zinc supplementation can restore natural killer cell activity, lymphocyte production, and resistance to infections [81, 82, 83, 84].
Studies in HIV patients with low blood zinc levels reveal that chronic supplementation is associated with lower opportunistic infections and a reduced risk of immunological failure [85, 86]. However, supplementation must be exercised with caution as excessive zinc may worsen disease symptoms [87, 88].
On the other hand, excessive levels may suppress immunity. A study in healthy young men revealed that high doses of zinc reduced several immune functions, including activation of lymphocytes and phagocytosis of neutrophils .
11) Common Cold
Owing to its immune-boosting properties, zinc is among the most popular supplements for a common cold.
Indeed, most clinical trials and reviews show a significant decrease in the duration of symptoms in adults. Zinc gluconate or zinc acetate supplements with 9-24 mg of elemental zinc per dose have shown the best results, when initiated within the first 24 hours [93, 94, 95].
According to a study of 48 children, low serum zinc levels may be associated with the symptoms of ADHD .
In a trial of 400 children with ADHD, zinc supplementation was “significantly superior to placebo in reducing symptoms of hyperactivity, impulsivity and impaired socialization” .
In combination with standard treatment, zinc supplementation reduced hyperactivity and impulsivity in 44 children with ADHD .
Zinc was particularly effective in obese children with zinc deficiency. The potential benefits for children with adequate zinc status are less clear .
Age-related macular degeneration, a major eyesight issue in the elderly, is believed to be caused by oxidative stress. Clinical studies have found that zinc supplementation can slow the progression of the disease, possibly by preventing oxidative damage to the retina [101, 102, 103, 104].
Most studies used zinc in combination with other antioxidants such as vitamin C and vitamin E, which likely contributed to the results.
Preliminary research suggests that zinc may protect against diabetic retinopathy. This is because of zinc’s ability to reduce oxidative stress and inflammation (through inhibition of NADPH oxidase and NF-κB) .
Night blindness is one of the earliest symptoms of vitamin A deficiency. A study found that zinc was able to enhance the effect of vitamin A in restoring the night vision of pregnant women with low zinc levels .
Zinc supplementation was able to enhance cognitive recovery in 26 zinc-deficient stroke survivors .
Zinc supplementation resulted in superior neuropsychological performance, particularly attention and reasoning skills in a study of 372 children .
On the other hand, zinc supplementation improved growth but failed to improve cognition in 16 zinc-deficient children .
Maternal zinc supplementation enhanced spatial learning and memory in rat pups .
Further well-designed clinical trials should investigate the benefits of zinc supplementation for cognitive development in infancy and childhood.
15) Allergy and Asthma
A study showed that zinc supplementation improved symptoms (e.g., cough, wheezing, and shortness of breath) in 284 children with asthma .
Low blood zinc levels may be linked to more severe asthma symptoms in some children .
In response to grass pollen, zinc increased regulatory T-cells and decreased proliferation in peripheral blood mononuclear cells (PBMCs) isolated from allergic subjects .
More research is needed before proclaiming zinc a safe and effective supplement for asthma and allergies.
16) Wound Healing
Zinc deficiency is linked to delayed wound healing in some patients .
Adhesive tape with zinc enhanced the repair of skin ulcers in a study of 44 diabetic patients .
17) Bone Health
Prenatal zinc supplementation in 240 pregnant women from a poor region significantly improved bone development in their babies .
18) Hair Loss
In a clinical study of 200 bald men, topical zinc was able to improve hair growth. Additional research suggests that zinc’s antimicrobial, anti-inflammatory, and antioxidant effects on the scalp are potentially involved in the increase of hair density [134, 135, 136, 137, 138].
Another study in women with polycystic ovarian syndrome (PCOS) showed that zinc supplementation had beneficial effects on a number of symptoms, including alopecia (hair loss) .
Zinc treatment also reversed hair loss in patients who underwent vertical gastroplasty (stomach stapling), a surgical operation that can result in zinc deficiency .
19) Kidney Disease, Hemodialysis
Restoring zinc levels in chronic kidney disease patients on hemodialysis can improve overall kidney function and reduce many complications associated with the disease (e.g., heart disease, anemia, infections, and sexual dysfunction) [141, 142, 143].
The effects are likely achieved by reducing inflammation, oxidative stress, and cholesterol, as well as by enhancing hemoglobin, sex hormones (i.e., testosterone and LH), and immune function [144, 145, 146].
20) Pregnancy Outcomes
A study found that Indian mothers receiving supplemental zinc had longer gestational periods (pregnancy times) and babies with healthier weights .
Another study in pregnant women (with low blood zinc levels) found that zinc supplementation (25 mg/day) during the second half of pregnancy significantly increased infant birth weights and head circumferences .
It is proposed that these beneficial effects are a result of its ability to inhibit embryonic cell death, increase growth factors (e.g., IGF, PDGF, and FGF), and reduce oxidative damage, all of which help promote healthy fetal development [147, 153, 154].
Most studies included malnourished and zinc-deficient mothers. It’s not clear whether zinc supplementation would provide the same benefits in mothers with normal zinc status.
21) Stunted Growth
In a number of studies, zinc supplementation produced significant beneficial effects on both height and weight measures of children, especially in underweight, malnourished children suffering from stunted growth [155, 156, 157].
A dose of 10 mg of zinc daily for 24 weeks increased net growth around 0.37 cm (in height), compared to children treated with placebo .
22) Women’s Health
Zinc deficiency is associated with hormonal imbalances that can lead to ovarian function problems, menstruation irregularities, and infertility .
Women with endometriosis (a condition where the tissue inside the uterus grows outside of the uterus) exhibit low blood zinc levels .
One study reported that an intake of antioxidants (i.e., vitamin C, vitamin E, selenium, and zinc) was inversely correlated with the severity of endometriosis progression in women, indicating that zinc may slow the development of this disorder .
23) Liver Protection
In 60 patients with non-alcoholic liver cirrhosis, supplemental zinc improved liver function and prevented excessive copper accumulation, which can damage the liver .
It was able to improve liver function, based on alkaline phosphatase and bilirubin levels, in 30 patients with alcoholic liver cirrhosis .
Zinc supplementation in animal models of alcoholic liver disease (ALD) protected the liver by blocking most mechanisms of liver injury (i.e., gut leakage, endotoxemia, oxidative stress, excess inflammatory cytokine production, and liver cell death) [167, 168, 169, 170].
24) Hearing Disorders
In a trial of 41 participants, zinc supplementation (50 mg/day for two months) was able to reduce the severity of tinnitus in 82% of patients .
In another study, the addition of zinc to oral corticosterone was associated with a greater improvement in symptoms in 66 people with a sudden hearing loss (from unknown reasons) than by corticosterone alone .
Otitis media (OM) is an infection of the middle ear. The effects of zinc supplementation on OM are mixed; the benefits may be limited to malnourished children with zinc deficiency .
Zinc deficiency is linked to impaired hearing in mice and rats, which can be improved with zinc supplementation. This is likely a result of zinc’s protective effects against toxins in ear structures [177, 178, 179, 180, 181].
25) Oral Health
Zinc-based mouthwashes were found to be effective in reducing plaque growth .
Similarly, a study in children from low-income areas found that a daily intake of 15 mg of zinc for ten weeks was associated with reduced plaque formation on the teeth .
26) Body Odor
Bromhidrosis (body odor) is usually associated with an increased bacterial flora in the armpit region, mainly consisting of Staphylococcus and Corynebacterium species .
No valid clinical evidence supports the use of zinc supplements for any of the conditions in this section. Below is a summary of up-to-date animal studies, cell-based research, or low-quality clinical trials which should spark further investigation. However, you shouldn’t interpret them as supportive of any health benefit.
27) Alzheimer’s Disease
In 30 Alzheimer’s disease patients, zinc supplementation protected against cognitive decline by lowering blood copper levels and improving zinc nutritional status. According to the authors, copper toxicity may play a role in the development of Alzheimer’s [190, 191].
In a mouse model of Alzheimer’s disease, zinc supplementation reduced pathological factors associated with progression of the disease (i.e., β-amyloid and tau protein loads). It also improved mitochondrial function and brain-derived neurotrophic factor (BDNF) levels in the hippocampus .
28) Male Fertility
This is likely because of zinc’s role in stabilizing the cellular membranes and DNA (by reducing oxidative damage) of sperm cells and enhancing spermatogenesis (formation of new sperm cells) [200, 201, 202].
Low to moderate doses (12 – 120 mg/kg) of zinc intake appeared to enhance reproductive function in rats .
In rats, zinc was able to preserve testicular function (as measured by testicular weight, sperm concentration, and testosterone levels) in response to oxidative stress induced by cigarette smoke .
One study found that blood zinc levels were significantly lower in chronic fatigue syndrome (CFS) patients and that symptom severity was negatively correlated with blood zinc levels. The study concluded that zinc may be effective in attenuating CFS symptoms because of its antioxidant and anti-inflammatory properties .
Gut inflammation (caused by a leaky gut) is common in people with CFS .
A study found that treating leaky gut with a mixture of anti-inflammatory and antioxidant substances including zinc in CFS patients resulted in a significant improvement of symptoms .
30) Blood Clotting
Hyperzincemia (high levels of zinc in the blood) can cause blood clotting while hypozincemia (low levels of zinc in the blood) leads to prolonged blood clotting times. Both conditions cause impairments in platelet aggregation and abnormal bleeding .
One study revealed that restoring zinc levels in zinc-deficient men led to normalized platelet aggregation and blood clotting time .
31-32) OCD and Schizophrenia
A study in schizophrenic men found that zinc in combination with risperidone improved many symptoms associated with the disorder (e.g., aggression, hallucinations, and delusions). This effect is in part attributed to its antioxidant and antidepressant properties .
The available evidence for the effects of zinc supplementation on OCD and schizophrenia is far from conclusive.
33) Digestive Disorders
Zinc deficiency has detrimental effects on the gut lining of animal models and humans in a variety of gastrointestinal diseases (e.g., inflammatory bowel disease, diarrhea, cancer, alcohol toxicity, and colitis). In most cases, zinc supplementation can provide improvement .
Zinc also protected the intestinal mucosa from alcohol-induced damage in rats and mice. It can prevent gut leakiness, which may reduce the risk of developing inflammatory bowel disease [220, 221, 222, 223, 224, 225].
In one study, zinc therapy significantly reduced the frequency of seizures in 31% of the treated children .
Scientists examined the potential of zinc supplementation to reduce seizure frequency in rats .
35) Thyroid Function
In 134 disabled hypothyroid patients under anticonvulsant therapy (with mild to moderate zinc deficiency), zinc supplementation was able to normalize thyroid hormone levels in the blood (i.e., T3 and FT3) and restore thyroid function .
A study on 25 children with Down’s syndrome suggested similar effects of supplemental zinc
Zinc supplementation was also to reverse the damaging effects of computer monitor-emitted radiation on the thyroid hormone levels of computer workers .
More research is needed to determine the effects of zinc supplementation on thyroid function in a general population.
36) Chemotherapy Side Effects
Mucositis (ulceration of mucous membranes) is a common side effect of chemotherapy and radiotherapy .
Dysgeusia (distortion of taste) and dysosmia (distortion of smell) can also occur during chemotherapy .
A study found that a daily intake of 100 mg of zinc for 4-6 months improved dysgeusia and dysosmia symptoms in patients with carbonic anhydrase VI (gustin) deficiency .
Zinc can stimulate the production of carbonic anhydrase VI, an enzyme in the saliva that is involved in taste bud growth .
37) Developmental Disorders
In a study of 79 autistic children, the severity of symptoms (i.e., awareness, hyperactivity, receptive language, focus and attention, eye contact, sound sensitivity, tactile sensitivity, and seizures) decreased after zinc and vitamin B6 supplementation. The children had high copper levels which reduced upon supplementation .
The lack of placebo control makes the results of this study questionable.
Prenatal zinc treatment prevented autism-like behaviors (e.g., induced social deficits, repetitive behaviors, and cognitive inflexibility) in rat offspring, indicating a possible link between its deficiency and autism development [244, 245].
In one study on adult mice, scientists observed the potential of zinc supplementation to prevent the development of autism-related behavior .
The available evidence is far from conclusive and doesn’t suggest the use of zinc supplements for developmental disorders. Further research should examine the connection between zinc and copper status, zinc supplementation, and ASD.
38) Metabolic Syndrome
A study in 60 children with metabolic syndrome found that zinc supplementation decreased insulin resistance, oxidative stress, inflammation, blood sugar, cholesterol, and body mass index .
The results warrant further investigation.
39) Sleep Quality
Two studies in infants revealed that zinc supplementation was able to prolong sleep duration. However. ⅓ of the children had stunted growth and were likely zinc-deficient .
More research should determine the relationship between zinc status and sleep quality.
40) Opioid Addiction
Based on these results, a literature review article suggested that zinc supplementation may reduce the risk of addiction in humans taking opioids for chronic pain, because of zinc’s pain-relieving effects and low toxicity. Clinical trials are needed to confirm this .
41) Physical Performance
A study in 10 wrestlers found that heavy exercise can significantly deplete thyroid hormones and testosterone levels, which can lead to exhaustion. However, zinc supplementation was able to prevent this loss and benefit athletic performance .
We can’t make any reliable conclusions based on a single small trial like this one.
Animal and Cellular Research (Lacking Evidence)
No clinical evidence supports the use of zinc supplements for any of the conditions listed in this section. Below is a summary of the existing animal and cell-based research, which should guide further investigational efforts. However, the studies listed below should not be interpreted as supportive of any health benefit.
In animal studies and test tubes, researchers have been investigating the potential benefits of zinc supplementation and optimal zinc levels for:
- Bacterial infections [260, 261, 262, 263, 263, 260]
- Transplant rejection and autoimmunity [264, 265, 266, 267, 265, 268]
- Radioprotection [269, 270, 271, 272, 273, 274]
- Pain relief [275, 276, 277, 278, 279, 278]
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