ZINC

Zinc is a trace mineral which is present everywhere in our body. It regulates taste and appetite, improves metabolism, memory, and night vision. Like selenium, zinc is required in our body to produce superoxide dismutase (SOD). Together with vitamin B6 and magnesium zinc is needed to produce tryptophan and then serotonin which regulates our appetite and mood. Zinc is also necessary for optimal development and growth of human body or maintaining proper blood sugar level. It is believed that zinc may even work as an antioxidant preventing DNA damage and cancer. One of the new studies demonstrated that even relatively small zinc deficiency may lead to DNA damage thus contributing to cancer development.

Zinc deficiency is associated with insulin resistance, obesity, and often also with anorexia and bulimia nervosa. There are people who recovered from anorexia and bulimia after taking zinc supplements because in their case the main problem was zinc deficiency. Study conducted in obese children, demonstrated that zinc supplementation significantly reduced glucose and insulin levels. Zinc has important effects on metabolism, and on the thermoregulation of obese individuals. Obesity combined with zinc deficiency promotes the development of a chronic systemic inflammation. Obese individuals have an increased incidence of developing zinc deficiency, have lower dietary zinc intake and therefore exhibit more systemic inflammation. Zinc deficiency perturbs immune functions and promotes systemic inflammation. Recent studies have demonstrated that obesity can be associated with systemic inflammation which leads to atherosclerosis, asthma, and other health problems. In obese people, adipose tissue releases specific adipokines which lead to infiltration by macrophages thus promoting the production of inflammatory mediators.

Zinc is used in our body to produce stomach acid. Low stomach acid, therefore, can be a sign of zinc deficiency. That is why when the amount of zinc in our body is insufficient then the protein from food cannot be properly digested in the gastrointestinal tract. As a result, these undigested and too large protein molecules enter the bloodstream where they are recognized by the immune system as a potentially dangerous foreign bodies, thus inducing immune reaction and histamine secretion which, in turn, creates allergy symptoms.

Zinc helps our body to cope with obesity, infectious diseases, allergies, depression, prostate cancer, hair loss, chronic fatigue, insomnia, diabetes, anorexia and bulimia, psoriasis, acne, eczema, Alzheimer’s disease, AIDS, male infertility, erectile dysfunction, pyroluria, Lyme Disease, and even autism or autoimmune diseases. Zinc strengthens our immune system by stimulating antibody production and can be even directly toxic to certain types of virus. A study conducted at the Cleveland Clinic Foundation demonstrated that zinc gluconate “significantly reduced the duration of symptoms of the common cold.”

Researchers suggest that approximately 2 billion people around the world may suffer from zinc deficiency which may be associated with the following symptoms: sleep problems, hair loss, diarrhea, allergies, dry skin and skin lesions, lack of sex drive, mental lethargy, etc. Some experts such as Dr. Carl Pfeiffer also believe white spots on fingernails are often the result of a zinc deficiency.

Soil depletion is regarded as one of the main reasons why we can be zinc deficient, because if this mineral is not present in the soil then also plants will be deprived of it. Soil depletion has been well documented and even organically grown vegetables may not contain proper amount of minerals as organic farming usually only solves the pesticide pollution problem. It is, therefore, believed that the best way to receive vegetables high in zinc and other minerals is through the means of bio-dynamic farming, supplementing soils with natural compost, and through crop rotation.

Zinc deficiency is also exacerbated by certain drugs and eating too much of refined foods (all white flower products including white bread, refined sugar, sweets, pizza, spaghetti, etc.) which contain very little or no zinc. High sugar consumption leads to insulin surges which use up our zinc. IUDs (which are usually made of copper) and birth control pills (which may contain copper) may cause excess copper in the body, which can be toxic and contribute to zinc deficiency as these two minerals are antagonistic to each other. Mercury toxicity caused by using amalgam fillings, vaccines and fish consumption can block zinc and magnesium as mercury binds with these minerals. In this case it is suggested that even supplementing zinc and magnesium will not solve this problem without proper detoxification and removing mercury from the body.

If possible avoid iron and calcium supplements as they reduce zinc absorption. In case you have to take high doses of iron and calcium you should include zinc supplementation as well. Vitamin D and selenium, on the other, hand increases the bioavailability of zinc. Caffeine containing products inhibit absorption of not only zinc but also calcium, iron, manganese, and copper. Also alcohol contributes to zinc, calcium, and manganese or chromium deficiency.

Frequent sex and masturbation is often regarded as a one of the key causes of zinc deficiency. David Horrobin, M.D. and Ph.D. from Oxford University, declared that, “The amount of zinc in semen is such that one ejaculation may get rid of all the zinc that can be absorbed from the intestines in one day. This has a number of consequences. Unless the amount lost is replaced by an increased dietary intake, repeated ejaculation may lead to a real zinc deficiency with various problems developing, including impotence… It is even possible, given the importance of zinc for the brain, that 19th century moralists were correct when they said that repeated masturbation could make one mad!” Also Carl C. Pfeiffer, Ph.D., M.D., in his book on zinc stated: “In a zinc-deficient adolescent, sexual excitement and excessive masturbation might precipitate insanity.”

High amounts of zinc can be found in whole meal breads, whole grains, pumpkin seeds, garlic, mushrooms, nuts, and seeds. If you need zinc supplementation zinc gluconate is believed to be the best one (not more than 100 mg a day with meal). In case it causes nausea try to reduce the intake.

The Recommended Daily Allowance for zinc, is about 10 to 15mg. Some specialists, however, recommend 25mg to even 50mg of zinc per day, but not more than that. Overdoses of zinc lead to nausea, vomiting, and sometimes to stomach pain or diarrhea.

Unfortunately, it is often believed that meat products are better sources of zinc because plant foods which are high in zinc such as nuts, seeds (especially pumpkin seeds), whole grains, garlic, legumes, or mushrooms, contain much more phytate (phytic acid) which tends to reduce zinc absorption from these products. Some researchers, however, regard the ability of phytate to bind with metals as also beneficial because it does not allow our organism to absorb too much of the heavy metals which are toxic. Apart from that, phytic acid also binds with radioactive substances preventing their absorption and carrying them out of our organism. There is no doubt that if a plant-based diet is unrefined and consists of variety of products including whole grains, legumes, as well as some nuts, seeds, and mushrooms, it provides more than adequate amounts of zinc, while the phytic acid present in these products only prevents us from absorbing too much of this mineral. However, since we should avoid high intake of phytic acid it is better to reduce its possible negative influence in a very simple way: Soaking grains, legumes (beans), seeds, and nuts in water overnight greatly reduces the amount of phytic acid. But in order to achieve this goal you need to remove the water in which these foods were soaked. Some believe that as soon as the amount of phytic acid is reduced in this way, also enzymes present in these foods will be able to improve digestion process in our gastrointestinal tract.

Many nutritionists encourage us today to consume oysters which are high in zinc but it is a very bad idea as shellfish such as oysters, mussels or clams consume decaying organic matter that sinks to the sea floor, including sewage. In addition, they are often contaminated with bacteria or virus and that is why we are warned to not consume raw or undercooked oysters. Our Creator who knows best our nutritional needs forbade us in Leviticus 11 to eat so called “unclean” animal foods including shellfish. In “Eating by the Book” nutritionist David Meinz suggests wisely that, “God, in His wisdom, created certain creatures (pigs, shellfish, crabs, etc.) whose sole purpose is to clean up after the others? Their entire ‘calling’ may be to act exclusively as the sanitation workers of our ecology. God may simply be telling us that it’s better for us not to consume the meat of these trash collectors”.

Unfortunately, zinc supplements often cause stomach upsets or nausea and for this reason should be taken immediately after meals and in the form of gluconate. Zinc gluconate is regarded as more soluble, easily absorbed and quickly assimilated in our body form of zinc. It is also usually better tolerated by the stomach. However, if you still experience nausea after taking zinc gluconate try to reduce the amount to not more than 30mg a day.

Concerning the influence of high in zinc foods (especially pumpkin seeds) on appetite, I have found an interesting experience described by Brian who wrote: “I tried a low fat, near vegetarian diet with lots of fruits and I had lots of energy. Later, my health relapsed and I was hungry all the time despite drinking 1.5 l of green smoothie per day. When I ate a few handfuls of pumpkin seeds and a cup of quinoa, the food cravings dropped… It is best to soak the seeds to absorb more minerals”.

Another person suggests that zinc supplementation was very helpful in coping with anxiety: “I’ve had great success ridding myself of anxiety by taking (in divided doses) 50-100mg zinc, 200mg B6, and GLA each day. From what I’ve researched stress depletes both zinc and B6 so people who are prone to stress may be greatly benefited from taking these”.

Studies investigating the relationship between zinc and leptin show that zinc may critically impact leptin secretion. Zinc supplementation to the obese mice increases leptin levels and restoration of obesity induced by sucrose. It means that low levels of this very important hormone and appetite suppressor as well as leptin resistance which occurs in obesity might have resulted from zinc deficiency. The relationship between zinc and leptin was examined also in humans who had zinc deficiency caused by refined diet. Zinc supplementation to these individuals resulted in significant increase in leptin secretion.

A deficiency of zinc, or magnesium allows sodium levels to rise, contributing to water retention. A magnesium, or zinc deficiency also results in impaired sugar metabolism which can lead to weight gain.

Sources

Suzuki, H.; Asakawa, A.; Li, J. B.; Tsai, M.; Amitani, H.; Ohinata, K.; Komai, M.; Inui, A. (2011). Zinc as an appetite stimulator – the possible role of zinc in the progression of diseases such as cachexia and sarcopenia. Recent Pat Food Nutr Agric. 2011 Sep; 3(3):226-31.

Su JC, Birmingham CL. Zinc supplementation in the treatment of anorexia nervosa. Eat Weight Disord 2002; 7:20-2.

David F. Horrobin, M.D., Ph.D., Zinc, St. Albans, Vt.: Vitabooks, Inc., 1981, p. 8.

Carl C. Pfeiffer, Ph.D., M.D. Zinc and Other Micro-nutrients, Keats: New Canaan, Conn., 1978, p. 45.

Jing MY, Sun JY, Wang JF. The effect of peripheral administration of zinc on food intake in rats fed Zn-adequate or Zn-deficient diets. Biol Trace Elem Res 2008; 124:144-56.

Birmingham CL, Gritzner S. How does zinc supplementation benefit anorexia nervosa? Eat Weight Disord 2006; 11:e109-11.

Safai-Kutti S. Oral zinc supplementation in anorexia nervosa. Acta Psychiatr Scand Suppl 1990; 361:14-7.

Selvais PL, Labuche C, Nguyen XN, Ketelslegers JM, Denef JF, Maiter DM. Cyclic feeding behaviour and changes in hypothalamic galanin and neuropeptide Y gene expression induced by zinc deficiency in the rat. J Neuroendocrinol 1997; 9:55-62.

Lee RG, Rains TM, Tovar-Palacio C, Beverly JL, Shay NF. Zinc deficiency increases hypothalamic neuropeptide Y and neuropeptide Y mRNA levels and does not block neuropeptide Y-induced feeding in rats. J Nutr 1998; 128:1218-23.

Kennedy KJ, Rains TM, Shay NF. Zinc deficiency changes preferred macronutrient intake in subpopulations of Sprague-Dawley outbred rats and reduces hepatic pyruvate kinase gene expression. J Nutr 1998; 128:43-9.

Jing MY, Sun JY, Wang JF. The effect of peripheral administration of zinc on food intake in rats fed Zn-adequate or Zn-deficient diets. Biol Trace Elem Res 2008; 124:144-56.

Birmingham CL, Gritzner S. How does zinc supplementation benefit anorexia nervosa? Eat Weight Disord 2006; 11:e109-11.

Safai-Kutti S. Oral zinc supplementation in anorexia nervosa. Acta Psychiatr Scand Suppl 1990; 361:14-7.

Selvais PL, Labuche C, Nguyen XN, Ketelslegers JM, Denef JF, Maiter DM. Cyclic feeding behaviour and changes in hypothalamic galanin and neuropeptide Y gene expression induced by zinc deficiency in the rat. J Neuroendocrinol 1997; 9:55-62.

Lee RG, Rains TM, Tovar-Palacio C, Beverly JL, Shay NF. Zinc deficiency increases hypothalamic neuropeptide Y and neuropeptide Y mRNA levels and does not block neuropeptide Y-induced feeding in rats. J Nutr 1998; 128: 1218-23.

Kennedy KJ, Rains TM, Shay NF. Zinc deficiency changes preferred macronutrient intake in subpopulations of Sprague-Dawley outbred rats and reduces hepatic pyruvate kinase gene expression. J Nutr 1998; 128: 43-9.

Mantzoros CS, Prasad AS, Beck FW, Grabowski S, Kaplan J, Adair C, et al. Zinc may regulate serum leptin concentrations in humans. J Am Coll Nutr 1998; 17:270-5.