Zinc is an essential element for both plants and animals. Among its many other functions, zinc — along with folate and vitamin B12—is absolutely essential for DNA replication. Humans literally can’t even start to grow from an initial single cell without adequate zinc.
Plants get zinc from the soil, animals get it by eating plants, and humans get their zinc from eating both (except, of course, for vegetarians). If there’s not enough zinc in the soil, which appears to be a widespread problem in many countries, there likely won’t be enough in the plants or the animals and humans that eat them.
In 1969, the Department of Agriculture in the United States (USDA) published data showing that of the 50 states only 17 had what it considered adequate zinc in their agricultural soil. Since the very large majority of fertilizers used in agricultural regions since 1969 haven’t been ‘organic’ and contain little to no zinc, soil zinc depletion has only gotten worse since then.
It’s best to get as much zinc as possible from food; foods higher in zinc include seafood, meat, eggs, nuts, bran and oatmeal. However, there’s a problem; all zinc found in food (except for that in seafood) depends on soil zinc content, and soil is significantly lower in zinc in 2014 than it was in 1907 or 1807. So with the exception of seafood and some organically produced food, even ‘high-zinc’ foods contain less zinc than they ever did before.
Human zinc requirements for good health remain the same, so until zinc and other essential nutrients are restored to optimum levels in agricultural soil across the globe, there will be an increasing requirement for supplemental zinc to ensure better health.
The many health benefits of supplemental zinc
Prostate problems: Along with essential fatty acids, zinc can both prevent and treat benign prostatic hypertrophy (BPH), non-cancerous enlargement of the prostate gland. Unfortunately, most men don’t bother with trying to prevent BPH, but instead are notified of the need to ‘do something’ when there’s enough enlargement to affect the ease or frequency of urination.
In the only zinc and BPH research I’ve been able to find, reported by the head of the department of urology at Cook County Hospital, Chicago, 14 of 19 men with BPH who were treated with zinc experienced shrinkage of their prostates as confirmed by digital prostate examination (DRE), X-ray, and endoscopy. In addition, 140 of 200 men with chronic non-bacterial prostatitis had relief of all symptoms after two to 16 weeks of zinc treatment.1
Despite the paucity of research, hundreds of men over my more than 30 years of practice have told me that zinc supplementation (combined with essential fatty acids) has substantially reduced – or frequently eliminated – symptoms of BPH. Results are always better when zinc and essential fatty acid supplementation is started at the first sign of symptoms.
Always try zinc (and essential fatty acids) before using saw palmetto. If zinc and essential fatty acids are needed by your prostate, they’re needed elsewhere in your body too. Using saw palmetto first may help alleviate your prostate symptoms, but will not supply the zinc needed by all those other tissues, so your zinc deficiency in those tissues will just get worse.
Acne: Zinc supplementation for at least three months leads to a significant reduction in acne outbreaks, usually 50-60% or more. It’s effective for both teenagers and adults2 and can be combined with any other types of acne treatment, preferably natural ones.
Eczema: Much more common in smaller children than in teenagers and adults, eczema (also called ‘atopic dermatitis’) is significantly helped by zinc and essential fatty acid supplementation. Although I’ve seen literally hundreds of children improved by this combination of supplemental items, I’ve still not seen any published research.
Please don’t use only these supplements for this condition, as you won’t be treating the basic cause of eczema: food allergies. Always start by finding and eliminating any food allergies, if necessary having desensitisation done if there are too many food allergens to simply eliminate. After that, add the zinc and essential fatty acid supplements.
Colds: Zinc lozenges (usually containing 13-23mg of zinc each), dissolved in the mouth every two to three hours while awake, reduce the duration of colds by 50% or more.3 Zinc treatment is most effective when it’s used within 24 hours of symptom onset. Zinc acetate and zinc gluconate are the most effective forms; the effect is decreased by citrate/citric acid, sorbitol, or mannitol, so read zinc lozenge package labels carefully. So far, research has inexplicably demonstrated effectiveness for adults but not for children.
Wound healing and ulcers: Some of the earliest work about the healing-promoting effects of zinc was done at the Cleveland Clinic in the late 1960s and early 1970s. When compared with a placebo, zinc was found to significantly accelerate the healing of standardised wounds – identical surgical wounds created by identical surgeries done to remove ‘pilonidal cysts’, a type of benign birth defect.
Zinc induces wound and ulcer healing for the same reason it helps to prevent birth defects: stimulation of normal DNA replication, which is necessary to grow new cells of all types.
Macular degeneration: Along with selenium, zinc is a principal component of the successful macular degeneration treatment evolved at Tahoma Clinic since the early 1980s.4 (‘Successful’ means stopping the loss of vision or sometimes even improving vision in more than 70% of cases.) There’s more zinc in a normal retina than nearly anywhere else in our bodies except in the ‘hearing apparatus’, so it just made sense to try it – and it helps.
Immune system function: In both cancer5 and AIDS patients,6 zinc has been shown to improve immune function. In ‘normal’ individuals, the thymus gland (the ‘master gland’ of the immune system) shrivels to practically nothing by ages 70 to 80 – supplemental zinc has been found to restore a small fraction of thymic function even at these ages.
One of the most striking pieces of zinc research was done with pregnant experimental animals fed zinc-deficient diets. As soon as the baby animals were born, they were given diets with adequate zinc. Despite this, they experienced lifelong severe impairment of immune function, which could only be improved with extra, supplemental zinc.
When the female animals from this first generation became pregnant, they were given zinc-adequate diets; despite this, their offspring (the second generation after the pregnant ‘grandma’ animals given zinc deficient diets) had a moderate impairment of the immune system. And the third generation still had a small impairment of immune function. Not until the fourth generation did immune function return to normal – and remember that only the great-great-grandmas had experienced zinc deficiency during pregnancy!
Birth defect prevention: Folate is now well known to significantly reduce the risks of spinal bifida and related birth defects. It isn’t as well known that vitamin B12 and zinc have both been found to reduce the risks of these very same problems. Not a surprise – remember these three nutrients are key factors in DNA replication.
Tinnitus (ringing in the ears): Research has shown zinc to diminish tinnitus in 25-50% of individuals with low zinc levels, but it wasn’t helpful in individuals with normal zinc levels.7 (Note for your doctor: ‘serum zinc’ is less accurate as a measurement of body zinc levels than ‘white blood cell zinc’.
Childhood learning: In a double-blind, placebo-controlled trial, year 8 students who took 20mg of supplemental zinc daily for 10 weeks significantly improved performance on tests of learning, memory, and vigilance.8
Anorexia: My colleague, Alex Schauss, Ph.D., of Tacoma, Washington, specialised for several years in the very successful treatment of anorexia. He found that young women with anorexia routinely couldn’t taste a standard solution of zinc in water, while non-anorexics would usually react by immediately spitting it out in disgust.
As the anorexics improved with zinc treatment, they also became more and more able to taste the zinc solution. When their anorexia was gone or almost gone, they reacted with the same degree of distaste as did the non-anorexics.
He also observed that anorexic young women described their body shapes differently when looking in a mirror than they did after months of zinc treatment, even when weight gain was still small. He concluded that zinc deficiency might actually change perception.
Dr. Schauss pointed out that a successful 19th-century treatment programme for anorexia operating in the United Kingdom used as principal means of treatment a diet high in oysters – one of the best sources of zinc. Published research has also shown zinc to be of use in the treatment of anorexia nervosa.9
Rosacea: In a clinical study, after three months, zinc treatment improved rosacea by approximately 75%.10
‘Skin cracking’: Many people develop cracks in the skin of the heels, especially in the wintertime. Sometimes, the cracks deepen and start to bleed. Other people get small cracks along the edges of the fingers; these don’t usually proceed to bleeding. But in either case, zinc supplementation (along with essential fatty acids) always eliminates the cracking and much of the usually associated dry skin.
Even though the ‘heel cracks’ themselves usually disappear in two to three months, getting rid of often-associated heavy heel calluses usually requires six to eight months of extra vitamin A – 40,000-50,000 IU daily for non-pregnant adults.
Although there’s no research at all on these effects of supplemental zinc (with essential fatty acids), or on this effect of vitamin A, they work every time!
Warts: In a single-blind trial, 20 of 23 patients treated with a relatively large quantity of zinc sulphate (not recommended because of gastrointestinal side effects) had their warts disappear completely after two months.11 But several other people (not counted in the 23) had to drop out of the research project because of adverse gastrointestinal effects of zinc sulphate.
Types and quantities of zinc
From 1981-1992, I was a member of the Board of Trustees of Bastyr College of Naturopathic Medicine (now Bastyr University), the first fully accredited American college for naturopathic doctors (NDs). In the mid-1980s, I helped obtain Bastyr’s first-ever research grant (given by General Nutrition Corporation), which inaugurated Bastyr’s research department.
This research demonstrated that zinc picolinate is the best-absorbed form of zinc, with zinc citrate a close second. Both forms of zinc were well tolerated, with practically no side effects. The highest absorbability of zinc picolinate was no surprise, as at that time other researchers had reported zinc is absorbed by means of a ‘zinc-binding ligand’, picolinic acid.
Here’s how it works: After zinc is digested from our food, it’s then bound to picolinic acid, which is a metabolite of the essential amino acid tryptophan, produced in the pancreas. The combination of zinc and picolinic acid becomes zinc picolinate, which is a major form in which zinc is absorbed.
Following this research, zinc picolinate became the best-selling form of zinc supplementation.
If you want to try zinc supplementation for any of the conditions noted above, or any other application, please check with a doctor skilled in and knowledgeable about nutritional medicine to determine the quantities best for you. Also, be sure to read the safety information below.
In my own practice, for nearly all the applications for zinc noted above, I most often use a ‘starting’ quantity of 30mg (of elemental zinc, as picolinate) three times daily for adults and teenagers weighing over 120 pounds. Once the problem is eliminated or ‘levels out’ at a much lower level (acne, for example, which improves 60-80% with zinc supplementation, but rarely to 100% as other conditions can) then it’s important to taper to twice daily for a month or two, then once daily for ‘maintenance’.
For children weighing 60-120 pounds, 30mg twice daily is a good starting point, following the same schedule as above. For 30-60 pound children, a daily starting dose of 30mg is usually adequate, tapering to 15mg daily. At 30 pounds and under, it’s wisest to start with 15mg daily, increasing the dosage only if there’s no response after four weeks.
And about those essential fatty acids that accompany zinc for the treatment of several problems noted above: presently, I recommend a combination of high DHA/EPA fish oil (from 1½ tablespoonsful to 1 teaspoonful daily, depending on the severity of the problem and size of the person), and from 600 to 200mg daily of GLA (gamma-linolenic acid). Essential fatty acid supplementation should always be accompanied by vitamin E asmixed tocopherols.
How much zinc is safe?
Years ago, a medical journal article reported that the ‘upper limit’ of safety for adults was a total of 240mg daily. More recently, another expert has written that 100mg daily may be associated with an extra risk of prostate cancer (there are good theoretical reasons for this, too technical to be discussed here). Below 100mg daily, no extra risk was found.12
As you read above, I recommend a maximum 90mg daily for adults, total, for only as long as necessary to achieve results, and then tapering down.
Larger amounts of zinc taken for longer periods of time (yes, that’s indefinite, but both quantity and timing vary widely from individual to individual) can induce a copper deficiency (and vice versa, with large quantities of copper over prolonged periods of time possibly inducing zinc deficiency).
Most of the reported ‘side effects’ of ‘excess zinc’ actually result from a zinc/copper ‘imbalance’, rather than simply excess zinc. These side effects include benign cardiac palpitations, an increasing cholesterol/HDL cholesterol ratio, and ‘copper-deficiency anaemia’. My observations for more than 30 years have been that a 15:1 zinc/copper ratio, or close, will prevent these imbalance problems. However, there is no definitive research on this point.
Also, it’s been thought that zinc and copper ‘should be taken separately’ for maximum absorption, but there’s no research on this point, either, and my observation has been that for most of us, it doesn’t seem to matter whether they’re taken together or separately.
Theoretically, large quantities of zinc can induce folate deficiency, but this is easy to monitor with the ‘neutrophilic hypersegmentation index’, a sensitive and inexpensive test for folate adequacy.
Wishing you the best of health,
Dr. Jonathan V. Wright
Nutrition & Healing
Vol. 8, Issue 12 – December 2014
Full references and citations for this article are available in the downloadable PDF version of the monthly Nutrition and Healing issue in which this article appears.