MikronährstoffCoach®: Mikronährstoffe / mikronaehrstoffcoach.com

Sources and physiological effects

Dietary sources
Foods of animal origin are of particular importance for the supply of zinc to humans. They usually contain higher concentrations of zinc and have a higher bioavailability. The main reason for the poor usability of zinc of plant origin is its phytic acid content, which not only reduces the bioavailability of oral zinc, but also prevents reabsorption of endogenous zinc. This effect is further intensified by high calcium intake due to complex formation (Ca-Zn phytic acid). Simultaneous consumption of animal protein, on the other hand, improves the usability of zinc from foods containing phytic acid. Tannins (vegetable tannins) from wine, coffee and tea also impair the bioavailability of zinc. Good sources of zinc are meat, offal, oysters, dairy products, eggs and fish. Plant zinc sources include spinach, oat flakes, wheat germ and wholemeal products. Since zinc is contained in the surface layers of cereals, the zinc content of cereal products depends on their degree of processing. Vegetarians and vegans should pay particular attention to their zinc intake.
Physiological effects
Immune system	Differentiation of T-cells and transfer to the active form Influences the activity of T-helpers, TC-, NK-cells and lymphokines Stabilization of the cell membranes of the mucous membranes (barrier against germs)
Skin, hair and nails	Promotion of collagen synthesis and wound healing Cell differentiation Regulation of the cornification of the skin
Fertility	Cofactor of spermatogenesis and testosterone synthesis
Nervous system	Cofactor of neurotransmitter formation (dopamine synthesis)
Antioxidant	Cofactor of superoxide dismutase
Detoxification	Participation in alcohol degradation Support of ammonia decomposition by conversion into urea
Metabolism	Promotion of insulin storage in the pancreas Cofactor of the hormone metabolism of insulin, glucagon, thyroid and growth hormones

EFSA Health Claims

Health claims		EFSA opinion
Zinc	Contributes to a normal acid-base metabolism Contributes to normal cognitive function Contributes to normal fertility and reproduction Contributes to a normal fatty acid metabolism Contributes to a normal vitamin A metabolism Contributes to the preservation of normal bone Contributes to maintaining normal vision Contributes to maintaining a normal function of the immune system Has a function in cell division Contributes to a normal carbohydrate metabolism Contributes to normal DNA synthesis Contributes to maintaining normal testosterone levels Contributes to normal protein synthesis Contributes to the maintenance of normal hair Contributes to the preservation of normal nails Contributes to the maintenance of normal skin

Recommended intake

Reference values for nutrient supply D-A-CH (Reference values EFSA and NHI )
	Age	Zinc (mg/d)
Infants (months)
	0-4	1,5
	4-12	2,5
Children (years)
	1-4	3
	4-7	4
	7-10	6
	10-13	8
	13-15	10
Teenagers/adults (years)		Women	Men
	15-19	11	14
	19-25	11-16¹	7-10¹
	25-51	11-16¹	7-10¹
	51-65	11-16¹	7-10¹
	> 65	11-16¹	7-10¹
Pregnancy	9-13¹
Breast-feeding	11-14¹
Increased need	Alcohol abuse, sports (loss through sweating), vegetarian/vegan diet, chronic inflammatory intestinal diseases, intestinal resection, heavy metal pollution, etc.
	¹The absorption of zinc in adults is influenced by the phytate content of the food. The higher the phytate content of a food, the lower the zinc intake. Therefore, the recommended intake of zinc is given as a function of the phytate intake. 330 mg/day phytate (0.5 mmol/day) corresponds to a low phytate intake, thus the daily requirement of zinc is lower. This amount corresponds to a diet with a low proportion of whole grain products and a high proportion of animal proteins. 990 mg/day phytate (1.5 mmol/day) corresponds to a high phytate intake, which increases the daily requirement of zinc. This amount corresponds to a diet with a high proportion of whole grain products and a low proportion of animal proteins.

Recommended intake according to food labelling regulations		Zinc
(=100 % TB marking on label)		10 mg
Nutrient safety
UL	Long-term daily intake, where no adverse health effects are expected	25 mg/d (according to the EFSA)
NOAEL	Maximum intake, with no observed adverse effect.	50 mg/d (according to the Scientific Committee on Food)
Safety	European Commission has looked at the safety of zinc.

Detailed information

Insufficient zinc status in many population groups

Although a normal balanced diet should provide an adequate supply of zinc, a high prevalence of inadequate intake is assumed for school children in Austria. According to the Austrian Nutrition Report 2012, half of the children have a significantly reduced zinc status. Zinc intake by men is also considered to be in need of improvement. In vegetarians, the average intake is far below the DACH recommended intake levels (1). The latter can be explained by the low intake of animal food, but is further complicated by the fact that various components of plant foods additionally reduce the absorption of zinc by forming insoluble complexes.

Zinc and its tasks in metabolism

Zinc plays a key role in numerous biochemical processes. As an integral component of more than 150 zinc-dependent enzymes, it is found in many tissues. The concentration in the individual organs varies. Particularly high zinc contents are found in skin, hair and nails, in the liver, in the male reproductive organs as well as in the retina and iris of the eye and at the edges of wounds. This correlates with the biological functions that zinc performs in the organism. Zinc is generally necessary for protein synthesis, but it also has other specific areas of action. Due to its role in collagen synthesis zinc is needed for the skin and connective tissue metabolism. It influences spermatogenesis (2), insulin storage in the pancreas (3) and is essential for the maturation of T-lymphocytes (4).

Zinc – modulates and strengthens the immune system

An insufficient zinc supply impairs the formation and activity of phagocytes and natural killer cells. As a result, zinc seems to have a direct influence on the risk, duration and intensity of illnesses. It is also suspected that zinc inhibits the formation of inflammation-promoting cytokines and thus has a direct influence on the course of infection (5). Zinc supplementation can serve to strengthen immune functions, especially in older people (6). Since zinc can inhibit the release of histamine from mast cells, it is an important adjuvant in treatment of allergies and allergic reactions (7). Studies have also shown a clear link between food allergies in children and reduced zinc and selenium status (8)

Zinc and dermatological diseases

Differentiation processes in the stratum basale of the skin are a prerequisite for the formation of a layered epidermis and for controlled cornification processes. Since these processes are controlled by zinc-dependent enzymes, the zinc status has a direct influence on skin, hair and nail growth. Zinc also plays an important role in the metabolism of cysteine, the most important amino acid for hair growth. Thin, brittle hair, slowed hair growth and hair loss can be caused by a lack of zinc absorption. Zinc deficiency can also be seen on the nails due to the formation of transverse Beau grooves and in extreme cases due to the detachment of the nail plate from the nail bed (9). Clinical studies have shown the positive effects of therapeutic zinc supplementation in the treatment of acne. Here zinc is used mainly because of its anti-inflammatory properties in inflammatory forms of acne (10).

Zinc – an important component of wound management

Zinc has several functions in wound healing processes. It is an important cofactor for the activity of matrix metalloproteinases, which enable the formation of new tissue and the closure of wounds. Since it also has an effect on the cellular immune defense, zinc is involved in combating the infection process during the first phase of an injury. It has been proven that zinc is required for wound healing processes and that an undersupply leads to delayed or disturbed wound healing (11).

Zinc during pregnancy and lactation

During pregnancy, the recommended zinc intake increases by an average of 43%. It is also known that zinc levels during pregnancy continuously fall to around 35% of those of non-pregnant women (2). Since zinc influences fetal growth and there is a proven relationship between zinc status and birth weight, optimized zinc supply during pregnancy is particularly important for women with short intervals between pregnancies (12) and for vegetarians (13). The same applies to zinc requirements during breastfeeding.

Reference values

Parameter	Substrate	Reference values	Description
Zinc in the blood	Serum	0.8 - 1.4 mg/l	Zinc determination in serum is only of limited importance, since 90 % of zinc is found intracellularly.
	Whole blood	7.0 - 8.0 mg/l	Zinc is predominantly (90 %) erythrocytically bound. Hematocrit-correlated whole blood analysis enables the correct interpretation of the status.
Zinc in urine	24 h-urine	0.2 - 0.8 mg/l	Urine should be acidified to prevent zinc precipitation.
Interpretation
Low values		Indication of zinc deficiency
High values		Hyperthyroidism, essential hypertension, eosinophilia, polyglobulia and polycythaemia vera
Note on the measurement results
Increased values are often caused by analytical errors. Even slight hemolysis falsifies zinc values in the serum. Occupational exposure or the use of zinc ointments can also lead to increased values.

Deficiency symptoms

Impact on	Symptoms
General finding	Loss of appetite, fatigue
Skin, hair and nails	Wound healing disorders, hair loss, brittle, white spotted nails
Immune system	Increased susceptibility to infections Atrophy of the thymus
Nervous system	Concentration problems, hyperactivity, depression
Metabolism	Growth disorders, weight loss
Blood	Coagulation disorders, anemia
Fertility	Fertility disorders, ovulation disorders

Indications

Effect	Indication	Dosage
Physiological effects at a low intake	To cover an increased zinc requirement	10 - 15 mg/d
	Support during cold and flu infections	15 - 30 mg/d
	To ensure adequate zinc intake in vegetarians, in pregnancy, aging, and for high performance sports	15 mg/d
	Supportive therapy for wound healing disorders, skin, hair and nail diseases	15 - 30 mg/d
	Zinc deficiency detected by medical diagnosis	30 mg/d

Administration

General mode of administration
When	Zinc should be taken between meals (preferably in the evening) for optimal absorption. Practical experiences suggest a dependence of zinc compatibility with the daily rhythm. The zinc concentration in the plasma is also characterized by circadian fluctuations. For sensitive patients it is therefore recommended to take zinc in the evening or to take it with meals. High doses of zinc interfere with the absorption of iron, copper, calcium and magnesium. Therefore, a delayed intake of mineral supplements at intervals of at least 2 hours is suggested.
Side effects
Nausea may occur if taken in the morning or during the day. Overdose can cause metal taste, headaches and fatigue.
Contraindications
Renal insufficiency

Interactions

Drug interactions
Antacids (H₂-blockers)	Deterioration of absorption (exception: cimetidine)
Antibiotics (fluoroquinolones, tetracyclines)	Deterioration of absorption due to complex formation (intake interval 3-4 h) (exception: doxycycline)
ACE inhibitors (especially captopril, enalapril)	Complex formation, increases excretion
Corticosteroids (e.g. dexamethasone, prednisolone)	Increase excretion, decrease in serum concentration
Increase excretion, decrease in serum concentration	Increase excretion
Potassium-saving diuretics (amiloride, triamterene)	Amiloride can reduce renal excretion, triamterene leads to increased excretion
Östrogene (oral contraceptives, hormone replacement therapy)	Increase excretion, decrease in serum concentration
Psychostimulants (methylphenidate)	May improve effectiveness of methylphendiate
NSAIDs (e.g. diclofenac, ibuprofen, naproxen)	May cause increased excretion
Antidepressants (tricyclic, SSRI)	Zinc can improve the effect of antidepressants
Nutrient interactions
Trace elements	Calcium, magnesium, iron, manganese, copper and selenium can impair absorption
Amino acids	L-cysteine can form complexes with zinc L-histidine can improve zinc uptake
Vitamins	A vitamin B₂ deficiency reduces the absorption of zinc

Description and related substances

Description

Trace mineral
Formula: Zn
Ion: Zn²⁺

Related substances

Zinc acetate, zinc L ascorbate, zinc L aspartate, zinc bisglycinate, zinc chloride, zinc citrate, zinc gluconate, zinc lactate, zinc L lysinate, zinc monumentate, zinc mono L methionine sulphate, zinc oxide, zinc carbonate, zinc L pidolate, zinc picolinate, zinc sulphate

The bioavailability varies. Good bioavailability can be observed in organic compounds (citrate, acetate, lactate, gluconate and especially bisglycinate) (14).

References

(1) Bundesministerium für Gesundheit: Österreichischer Ernährungsbericht 2012.
(2) Mora-Esteves C. and D. Shin: Nutrient supplementation: improving male fertility fourfold. Semin Reprod Med, 2013. 31 (4): p. 293-300.
(3) Myers S.A., A. Nield and M. Myers: Zinc transporters, mechanisms of action and therapeutic utility: implications for type 2 diabetes mellitus. J Nutr Metab, 2012. 2012: p. 173712.
(4) Blewett H.J. and C.G. Taylor: Dietary zinc deficiency in rodents: effects on T-cell
development, maturation and phenotypes. Nutrients, 2012. 4 (6): p. 449-66.
(5) Prasad AS, Fitzgerald JT, Bao B, Beck FW, Chandrasekar PH: Duration of symptoms and plasma cytokine levels in patients with common cold treated with zinc acetate. Ann Intern Med. 2000; 133 (4): 302-3.
(6) Haase H, Rink L: The immune system and the impact of zinc during aging. Immun Ageing. 2009 Jun 12; 6:9.
(7) Toyran M et al: Trace element levels in children with atopic dermatitis. J Investig Allergol Clin Immunol, 2012. 22 (5): p. 341-4.
(8) Kamer B et al: Role of selenium and zinc in the pathogenesis of food allergy in infants and young children. Arch Med Sci, 2012. 8 (6): p. 1083-8.
(9) Biesalski HK (Hrg): Vitamine, Spurenelemente und Mineralstoffe. 2002.
(10) Degitz K, Plewig G: Adjunctive treatments for acne therapy. J Dtsch Dermatol Ges. 2005; 3 (2): 92-6.
(11) Zorilla P, Salido JA, Lopez-Alonso A, Silva A: Serum zinc as a prognostic tool for wound healing in hip hemiarthroplasty. Clin Orthop Relat Res. 2004, (420): 304-8.
(12) Rathi SS, Srinivas M, Grover JK, Mitra D, Vats V, Sharma JD: Zinc levels in women and newborns. Indian J Pediatr 1999; 66 (5): 681-4.
(13) Hronek M, Kudlackova Z: Deficient intake of nutrients and the resulting health complications in vegetarians in the course of pregnancy and lactation. Ceska Gynekol. 2005; 70 (2): 161-4.
(14) Lönnerdal B. Dietary factors influencing zinc absorption. J Nutr. 2000 May; 130 (5S Suppl): 1378S-83S.

References Interactions:
(1) Stargrove Mitchell Bebel, Treasure Jonathan, McKee Dwight L.: Herb, Nutrient, and Drug Interactions: Clinical Implications and Therapeutic Strategies. 2008
(2) Gröber Uwe: Mikronährstoffe. Metabolic Tuning – Prävention – Therapie. 3. Auflage, 2011
(3) Gröber Uwe: Arzneimittel und Mikronährstoffe. Medikationsorientierte Supplementierung. 2. Auflage, 2012