Zinc Deficiency - Symptoms, Causes, Therapy
Zinc is an essential trace element that is involved in numerous catalytic, structural, and regulatory functions in the body. These include DNA formation, cell division, and numerous metabolic functions. The trace element is also required for the skin, immune system, digestive system, and hormone production. Since zinc is present in every cell and is concentrated in the organs, a deficiency can quickly have a negative impact on health. In medical terminology, a zinc deficiency is referred to as hypozincemia.
The risk groups for zinc deficiency include:
- Infants, children, adolescents, and adults in developing countries 3 4 5
- Pregnant and lactating women 6
- Elderly individuals
- Diabetics 7
- Patients with inflammatory bowel diseases such as Crohn's disease and ulcerative colitis
Patients with genetic disorders such as hereditary zinc deficiency syndrome and cystic fibrosis can be causative 8. Patients with inherited diseases like sickle cell anemia may be affected by a deficiency 9 10 11. In this condition, the blood cells do not have their healthy disc-like shape but rather a crescent moon-shaped form.
Even endurance athletes and individuals engaged in activities that cause significant sweating can indeed suffer from zinc deficiency.
A vegan diet also tends to be low in zinc. Vegans are potentially at a higher risk of zinc deficiency 12. In several studies, vegans had the lowest zinc intake compared to other dietary groups 13 14 15 16 17. Vegetarians can also be affected by a deficiency 18.
In patients receiving parenteral nutrition, bypassing the intestine, the risk of zinc deficiency is also increased 19.
Patients with chronic kidney disease and patients who undergo long-term hemodialysis also have lower zinc status. Zinc can be lost during blood washing 20.
Causes of zinc deficiency
A mild zinc deficiency typically occurs due to inadequate intake of zinc-rich foods. However, heavily processed foods like refined wheat products often contain only a fraction of their original zinc content. Additionally, certain diet forms, especially those for weight loss, can lead to a deficiency. On the other hand, a severe zinc deficiency is rarely caused by dietary factors.
Numerous plant-based foods such as legumes and whole grains contain acids like phytates 21 22 23. These acids restrict the absorption of zinc in the intestine. They bind to zinc and form a non-absorbable complex, leading to partial excretion of unused zinc. Other plant compounds that inhibit absorption include polyphenols found in teas and coffee.
Due to zinc loss through sweating, athletes and individuals who perspire heavily can develop a mild zinc deficiency.
Persistent diarrhea can also cause zinc deficiency.
An increased zinc loss through urine can be a possible cause, which can occur due to advanced age as well as disorders or diseases in the digestive tract.
Certain medications such as penicillamine can cause increased excretion of zinc 26. Other medications can negatively affect zinc absorption and utilization in the body.
Another cause of zinc deficiency can be reduced absorption capacity (malabsorption), which can be caused by conditions such as celiac disease and short bowel syndrome.
- increased susceptibility to illness (usually colds)
- rough and dry skin also associated with rashes (acne)
- loss of appetite
- hypogonadism in men (testicular dysfunction, reduced sperm count, associated with decreased testosterone levels)
- impaired wound healing
- neurosensory changes (such as taste and smell alterations, as well as decreased light-dark adaptation)
- Hair loss (such as alopecia areata)
- Fertility disorders
- Severe diarrhea
- Weight loss
- Blistering dermatitis
- Tongue inflammation (glossitis)
- Nail dystrophy (abnormal growth of fingernails and toenails)
Consequences of Zinc Deficiency
Since zinc is involved in a variety of metabolic processes, a deficiency can lead to serious consequences. Mainly, it results in growth delays, immune dysfunctions, and cognitive impairments 34.
In children, zinc deficiency can have fatal consequences. Zinc plays a crucial role in the early stages of life, including embryonic development and fetal life 35. A deficiency can lead to growth and developmental disorders 36 37. Pregnant women can experience complications during pregnancy. Even a mild deficiency can lead to increased morbidity, prolonged gestation, uterine atony, and severe central nervous system malformations in the fetus (unborn child during pregnancy) 38 39. Zinc deficiency in infancy may contribute to the development of autism 40.
In athletes, mild zinc deficiency can lead to appetite loss (anorexia), significant weight loss, latent fatigue with reduced endurance, and an increased risk of osteoporosis 41.
Since zinc is involved in the formation of white blood cells in the immune system, a deficiency inevitably leads to immune system disorders. 42 43. This results in reduced activity of natural killer cells and reduced activity of T-helper cells. 44. The consequence is increased susceptibility to diseases and infections. 45.
A zinc deficiency limits the bioavailability of vitamin A 48. Vitamin A is a component of the retina and is necessary for normal vision. In advanced zinc deficiency, there can also be visual impairments 49. A typical symptom would be night blindness. Age-related macular degeneration (reduced visual capacity) could also be a consequence of zinc deficiency. Scientists believe that a deficiency leads to increased oxidative stress and retinal damage 50 51.
A deficiency of zinc can lead to hyperammonemia, which is an increased level of ammonium in the blood. 52. An elevated level of ammonium can cause rapid breathing, lethargy, and reduced muscle strength.
Detecting Zinc Deficiency
Currently, there are no precise biomarkers for determining a deficiency. Especially the detection of mild zinc deficiency proves to be difficult 61 62. Low albumin levels (hypoalbuminemia), which commonly occur with zinc deficiency, complicate the interpretation of zinc levels 63. Currently, measuring zinc levels in the blood serum serves as the best indicator of a deficiency. Additionally, hair and urine can also be examined 64 65.
|Condition||Serum Zinc Concentration|
|Normal||11 to 18.8 μmol/l (72 to 117.7 μg/dl)|
|Mild to Moderate Zinc Deficiency||7.65 to 11 (50 to 72 μg/dl)|
|Severe Zinc Deficiency||<7.65 μmol/L (50 μg/dL)|
It is often mentioned, especially in natural medicine, that it is possible to perform a taste test with a mild zinc solution to determine if a deficiency is present or not:
- Grade 1 (severe zinc deficiency): taste of water
- Grade 2 (mild zinc deficiency): no distinct taste initially, but a dry, mineral, furry, or sweet taste gradually develops
- Grade 3 (moderate zinc status): mineral taste that intensifies over time
- Grade 4 (optimal zinc status): strong and immediate metallic taste that persists for a longer duration
However, such tests are often very inaccurate and do not provide precise information about zinc status in the body 70 71. Therefore, from a scientific perspective, such tests are generally discouraged.
Depending on the cause and in consultation with a physician, appropriate treatment can be administered.
The simplest way to treat zinc deficiency is by taking supplements. The dosage depends on the severity of the deficiency. One option is to take a zinc supplement that contains 2 to 5 times the daily recommended intake of zinc (depending on the severity) for a period of six months 72.
Good absorbable zinc compounds are zinc gluconate and zinc sulfate. Supplementation should be done with utmost care, especially for pregnant and breastfeeding women.
In cases of severe zinc deficiency or intestinal disorders, zinc can also be administered intravenously 73.
By sprouting and processing foods through methods such as fermentation and soaking, the phytate content is reduced, which increases the absorption rates of zinc 75. Consuming sourdough products (such as sourdough bread) can contribute to improved zinc intake. The acidification process breaks down phytates, resulting in enhanced zinc absorption from grain products. Additional factors that enhance zinc absorption and bioavailability can be found here.