Zinc Supports Healthy Immune System

(National Institutes of Health, Facts about Zinc)

Zinc: What is it?

Zinc is an essential mineral that is found in almost every cell. It stimulates the activity of approximately 100 enzymes, which are substances that promote biochemical reactions in your body. Zinc supports a healthy immune system, is needed for wound healing, helps maintain your sense of taste and smell, and is needed for DNA synthesis. Zinc also supports normal growth and development during pregnancy, childhood, and adolescence.

What foods provide zinc?

Zinc is found in a wide variety of foods. Oysters contain more zinc per serving than any other food, but red meat and poultry provide the majority of zinc in the American diet. Other good food sources include beans, nuts, certain seafood, whole grains, fortified breakfast cereals, and dairy products. Zinc absorption is greater from a diet high in animal protein than a diet rich in plant proteins. Phytates, which are found in whole grain breads, cereals, legumes and other products, can decrease zinc absorption.

When can zinc deficiency occur?

Zinc deficiency most often occurs when zinc intake is inadequate or poorly absorbed, when there are increased losses of zinc from the body, or when the body's requirement for zinc increases. Signs of zinc deficiency include growth retardation, hair loss, diarrhea, delayed sexual maturation and impotence, eye and skin lesions, and loss of appetite. There is also evidence that weight loss, delayed healing of wounds, taste abnormalities, and mental lethargy can occur. Since many of these symptoms are general and are associated with other medical conditions, do not assume they are due to a zinc deficiency. It is important to consult with a medical doctor about medical symptoms so that appropriate care can be given.

Who may need extra zinc?

There is no single laboratory test that adequately measures zinc nutritional status. Medical doctors who suspect a zinc deficiency will consider risk factors such as inadequate caloric intake, alcoholism, digestive diseases, and symptoms such as impaired growth in infants and children when determining a need for zinc supplementation. Vegetarians may need as much as 50% more zinc than non-vegetarians because of the lower absorption of zinc from plant foods, so it is very important for vegetarians to include good sources of zinc in their diet.

Maternal zinc deficiency can slow fetal growth. Zinc supplementation has improved growth rate in some children who demonstrate mild to moderate growth failure and who also have a zinc deficiency. Human milk does not provide recommended amounts of zinc for older infants between the ages of 7 months and 12 months, so breast-fed infants of this age should also consume age-appropriate foods containing zinc or be given formula containing zinc. Alternately, pediatricians may recommend supplemental zinc in this situation. Breastfeeding also may deplete maternal zinc stores because of the greater need for zinc during lactation. It is important for mothers who breast-feed to include good sources of zinc in their daily diet and for pregnant women to follow their doctor's advice about taking vitamin and mineral supplements.

Low zinc status has been observed in 30% to 50% of alcoholics. Alcohol decreases the absorption of zinc and increases loss of zinc in urine. In addition, many alcoholics do not eat an acceptable variety or amount of food, so their dietary intake of zinc may be inadequate.

Diarrhea results in a loss of zinc. Individuals who have had gastrointestinal surgery or who have digestive disorders that result in malabsorption, including sprue, Crohn's disease and short bowel syndrome, are at greater risk of a zinc deficiency. Individuals who experience chronic diarrhea should make sure they include sources of zinc in their daily diet (see selected table of food sources of zinc) and may benefit from zinc supplementation. A medical doctor can evaluate the need for a zinc supplement if diet alone fails to maintain normal zinc levels in these circumstances.

What are some current issues and controversies about zinc?

Zinc, infections, and wound healing

The immune system is adversely affected by even moderate degrees of zinc deficiency. Severe zinc deficiency depresses immune function. Zinc is required for the development and activation of T-lymphocytes, a kind of white blood cell that helps fight infection. When zinc supplements are given to individuals with low zinc levels, the numbers of T-cell lymphocytes circulating in the blood increase and the ability of lymphocytes to fight infection improves. Studies show that poor, malnourished children in India, Africa, South America, and Southeast Asia experience shorter courses of infectious diarrhea after taking zinc supplements. Amounts of zinc provided in these studies ranged from 4 mg a day up to 40 mg per day and were provided in a variety of forms (zinc acetate, zinc gluconate, or zinc sulfate). Zinc supplements are often given to help heal skin ulcers or bed sores, but they do not increase rates of wound healing when zinc levels are normal.

Zinc and the common cold

The effect of zinc treatments on the severity or duration of cold symptoms is controversial. A study of over 100 employees of the Cleveland Clinic indicated that zinc lozenges decreased the duration of colds by one-half, although no differences were seen in how long fevers lasted or the level of muscle aches. Other researchers examined the effect of zinc supplements on cold duration and severity in over 400 randomized subjects. In their first study, a virus was used to induce cold symptoms. The duration of illness was significantly lower in the group receiving zinc gluconate lozenges (providing 13.3 mg zinc) but not in the group receiving zinc acetate lozenges (providing 5 or 11.5 mg zinc). None of the zinc preparations affected the severity of cold symptoms in the first 3 days of treatment. In the second study, which examined the effects of zinc supplements on duration and severity of natural colds, no differences were seen between individuals receiving zinc and those receiving a placebo (sugar pill). Recent research suggests that the effect of zinc may be influenced by the ability of the specific supplement formula to deliver zinc ions to the oral mucosa. Additional research is needed to determine whether zinc compounds have any effect on the common cold.

Zinc Deficiency Overview from http://www.ctds.info/zinc1.html

Zinc Links to Connective Tissue Disorders

Humans with connective tissue disorders commonly have stretch marks, scoliosis, hypermobile joints, delayed wound healing, reduced collagen, and frequent infections. In fact, these features are often used as diagnostic criteria for many of the connective tissue disorders. But are they really signs of incurable connective tissue disorders, or, at least in some cases, are they signs of zinc deficiencies that may have an inherited component?

Interesting Facts About Zinc

Zinc levels are lower in gymnasts, and lower in female gymnasts than males. Rhythmic gymnasts have unusually high rates of scoliosis, delayed puberty, and hypermobility. As noted above, zinc deficiencies can cause delayed puberty. Zinc deficiencies in monkeys can cause soft bones similar to rickets in humans, which in turn can cause scoliosis and hypermobility. Perhaps a factor in why gymnasts have scoliosis, delayed puberty and hypermobility is because they tend to be low in zinc.

Zinc is important to male sex organ function and reproductive fluids. Oysters have the highest zinc content of any food. So there's more than just rumors to the old sayings about oysters and romance.

Celiac disease can cause zinc deficiencies.

A pilot study conducted by researchers at Louisiana State University Medical Center School of Medicine found that oral zinc administration given to subjects with drusen or macular degeneration had significantly less visual loss than the placebo group after a follow-up of period of twelve to twenty-four months.

In a study of fish, it was concluded that zinc is essential for normal eye development in juvenile Chinook salmon.

Phytic acids, which are found in high amounts in whole grains, can reduce zinc absorption. Emerging Marfan Syndrome or Progressing Zinc Deficiency?

Some patients with Marfan syndrome have what geneticists like to call "emerging Marfan syndrome". They don't have Marfan syndrome when they are born -- it "emerges" as they get older. Developing pectus excavatum or carinatum around puberty is a feature linked to Marfan syndrome. If Marfan syndrome was truly due only to an inherited mutated fibrillin gene, then why would it "emerge" at puberty or right before? Why would a mutation in the gene for fibrillin cause Marfans to be underweight? Why wouldn't the disorder show up right away if it was really caused only by genes? A zinc deficiency as a factor in Marfan syndrome and related connective tissue disorders would provide a logical explanation of why Marfans:

are often underweight

get features of rickets ( bowed limbs, scoliosis, pectus excavatum) and why they often get these features at puberty, as opposed to other times in their lives

get stretch marks (striae)

have defects in their connective tissue

have hyaluronic acid abnormalities in their urine

mitral valve prolapse (MVP has been linked to hyaluronic acid (HA) abnormalities in heart valves. HA is a zinc dependent biochemical.)

develop myopia (nearsightedness), macular degeneration, glaucoma cataracts and retinal detachment Perhaps "emerging Marfan syndrome" is really due to a treatable pre-puberty deficiency of zinc and other nutrients, with a genetic predisposition, rather than an incurable genetic disorder. If a zinc deficiency were a factor, then all of these unusual findings regarding emerging Marfan syndrome would have a completely logical explanation.

Mitral Valve Prolapse Syndrome and Zinc Deficiency

Mitral valve prolapse syndrome is another connective tissue disorder with possible links to zinc deficiencies. Some researchers feel MVP syndrome is a mild form of Marfan syndrome. MVP syndrome is more common in women than men. The characteristic features of the disorder include:

low body weight

mitral valve prolapse (which has been linked to hyaluronic acid abnormalities in heart valves, a zinc dependent biochemical)

small breasts

hypermobility

myopia

stretch marks

poor wound healing

scoliosis

defective connective tissue

pectus excavatum

TMJ All of the above conditions associated with MVP syndrome have also in some way been linked to zinc deficiencies. Mitral valve prolapse is an age dependent condition, which interestingly, also usually first appears in women around puberty or a few years later, the same time that zinc requirements increase to support sexual development.

Inherited Connective Tissue Disorder or Zinc Deficiency?

I had finger nails completely riddled with white spots growing up and so did other members of my immediate family. My husband's mother told me she had lots of white spots on her finger nails growing up. Her mother called them her "little friends". Some friends! Like his mother, my husband's fingers were riddled with white spots. Our kids had a few white spots on their nails, too, until we changed their diets. Now they only get the white spots back around holidays or vacations, when they don't eat as healthy as they should.

My husband and I were both very thin as children. We both have pectus excavatum (a feature of rickets), stretch marks and we both had problems with facial blemishes until we were about 40, when we changed our diets to get more zinc. Then our faces suddenly cleared up completely. (We started getting more zinc after I read the book Super Nutrition for Women.)

I've been diagnosed with a few variations of incurable inherited connective tissue disorders, including mitral valve prolapse syndrome. My husband, with many of the same symptoms as me, had a genetic exam once, too, and was completely ruled out from having any connective tissue disorder at all. Yet, if my problems were caused by an incurable genetic disorder, and my husband doesn't have one, then how come my husband has so many of the same features as me? How did the doctors who diagnosed me know I had an incurable disorder when they never checked me for a zinc deficiency, which has many identical symptoms?

I don't think I ever really had any incurable disorder at all. I think I was low in zinc for much of my life until I changed my diet, and that a tendency to be low in zinc ran in my family and my husband's family. I just probably had more of a deficiency than he did. I do wonder how many other people have been given a diagnosis of an incurable disorder (or from my email, no diagnosis at all!) when perhaps what they really had was a correctable nutritional deficiency, with a genetic predisposition.

I went to an Ehlers-Danlos syndrome meeting once (and only once because none of the people there had any interest in nutrition). One thing I remember from that meeting is that one of the people there who had been diagnosed with EDS had acne and his finger nails were riddled with white spots, just like I used to have. I do wonder sometimes if, like me, he actually had zinc and other nutritional deficiencies and not an incurable genetic disorder

Zinc and Pectus Excavatum

Zinc and other nutritional requirements rise as children begin puberty in order to support sexual development. This is especially true for males, as sperm contains high amounts of zinc. A diet that provided sufficient calories and nutrients during childhood may no longer be sufficient for a child beginning puberty.

Many people who develop pectus excavatum or pectus carinatum have their deformities occur at puberty or just before, the same time they are susceptible to zinc deficiencies. As noted above, in monkeys, zinc deficiencies can cause rickets, which can cause pectus excavatum or pectus carinatum. A zinc deficiency occurring around puberty would logically explain why children often develop pectus deformities at this time. It would also explain why pectus deformities often occur along with stretch marks and other signs of zinc deficiencies such as poor wound healing. It would also explain why people with chest deformities have been found to have zinc deficiencies in their rib cartilage, as noted in the abstract excerpt below:

"In 71 patients with chest deformity, cartilage of the ribs was removed intraoperatively. Analyses of trace elements showed a highly significant decrease in zinc....". The study also showed that the ribs also had abnormalities of collagen. As noted in the study above on chicks, zinc deficiencies were shown to cause abnormalities of collagen.

So if we look at zinc deficiencies as a possible factor in some cases of pectus excavatum, then there are logical explanations of why:

Males develop pectus deformities more often than females (8:1). It's probably because males are more likely to develop zinc deficiencies than females because of the need for zinc in male reproductive functions.

Pectus excavatum often occurs at puberty or just before, when the body's zinc needs increase to support sexual development.

Analysis of trace elements of patients with chest deformities show significant decreases in zinc.

Pectus excavatum and hypermobile joints occur together. Perhaps it is because a zinc deficiency negatively impacts both the rib cartilage and the connective tissue in joints. This may cause chests to sink in or protrude out and joints to weaken or, hyperextend.

Pectus excavatum and stretch marks frequently occur together. A zinc deficiency causes abnormalities in the skin, which prevent it from stretching normally during periods of growth.

Pectus excavatum is closely linked to collagen disorders like Ehlers-Danlos syndrome and osteogenesis imperfecta. Perhaps defective collagen and pectus deformities may occur together because they share a root causative factor -- a zinc deficiency.

Zinc deficiencies in monkeys can cause rickets, which in turn may cause pectus deformities. It would be logical to consider the possibility that zinc deficiencies in humans may cause similar rachitic conditions.

Zinc deficiencies in monkeys can be passed down from earlier generations, so this may explain why parents with pectus deformities often have children with pectus deformities. Maybe they aren't passing down a defective gene per se, maybe they are passing down a zinc deficiency.

According to one study, "... the rib is more sensitive to diagenetic processes that alter elemental proportions than is the femur." In other words, if you have a mineral imbalance such as a zinc deficiency, it's more likely to show up in your ribs than in another place in your bones such as your legs.

A surgeon who did her internship in pediatric surgery once commented to me that she noticed that many of the girls in the hospital for pectus excavatum surgery were abnormally flat chested for their ages, i.e. their breasts never really developed. If zinc deficiencies were a factor in pectus excavatum, then it would make sense that girls with the condition would also have underdeveloped breasts, since, as noted above, zinc deficiencies are known a known cause of lack of sexual development.

People with pectus deformities also frequently are myopic (nearsighted). It may be because both conditions may have zinc deficiencies as factors.

Many of the features of common chronic disorders, especially connective tissue disorders, are identical to the symptoms of zinc deficiencies. Is this a coincidence, or could zinc deficiencies be an often overlooked factor in many disorders currently attributed to genes or other causes?

If zinc deficiencies can carry over from generations in mice, as noted above, could the same be true for humans? Perhaps some of the conditions in humans we currently attribute to genetic defects were actually caused by deficiencies of zinc or other nutrients occurring in past generations.

Symptoms of Zinc Deficiency

Deficiencies of zinc have been linked to:

Delayed skeletal maturation and defective mineralization of bone (monkeys)
Weight loss
Intercurrent infections
Hypogonadism in males
Lack of sexual development in females
Growth retardation
Dwarfism
Delayed puberty in adolescents
Rough skin
Poor appetite
Mental lethargy
Delayed wound healing
Short stature
Diarrhea
Pneumonia
Stretch marks (striae)
White spots on fingernails
Reduction in collagen turnover and synthesis (in chicks)
Reduction in collagen (in humans)
Poor Immune system
Acne
Cross-linking of collagen
Hyaluronic acid abnormalities (in swine)
Defective connective tissue
Macular degeneration
Cataracts (in salmon)
Teeth with black plaque like deposits (rats)