Zinc

Amount of zinc in milligrams per 100 grams

Foods

10-25 milligrams

Oysters; wheat germ, wheat bran

5-10 milligrams

Edam, Swiss Emmental, chicken eggs; pork liver, beef; sunflower seeds, linseed, soy flour, cocoa powder

2,5-5 milligrams

Tilsiter, Gouda, Parmesan;
Rye, wheat, barley, millet, oats, quinoa;
Pea, lentils, beans;
Brazil nut, peanut; walnut, chia seed;

Modified according to: "Food table for daily use; The little Souci expert Kraut".

Your small intestine cannot absorb 100 per cent of zinc from food. It absorbs 40 per cent from meat, milk and cheese, while the rate for vegetables and similar is 20 per cent ^[11].

Zinc deficiency - Causes

Zinc deficiency can be associated with various health problems and risks. Especially children have to be supplied with sufficient amounts of the mineral: A deficiency leads to diarrhoea and pneumonia - the most frequent causes of death among children under the age of five worldwide.^[12–15].

Climate change could have a negative impact on our zinc supply: Due to the high carbon dioxide emissions, the zinc content of our food is said to have declined significantly. Plant-based and animal foods imported from Southeast Asia or South Africa also contain smaller amounts of zinc because the soil there is lower in zinc.

What are the causes of zinc deficiency?

If you sweat a lot, be it during exercise or in hot weather, you will lose a lot of zinc by sweating - you should compensate for these losses with a balanced diet. A vegetarian or vegan diet can also lead to a deficiency, as the small intestine absorbs less zinc from plant-based foods. If you suffer from a chronic inflammatory bowel disease (ulcerative colitis, Crohn's disease), the absorption of nutrients in the bowel is impaired. Permanent stress can also cause a zinc deficiency^{[9, 16]}.

Did you know that people with diabetes mellitus have a high risk of developing zinc deficiency? High blood sugar levels lead to frequent urination: poorly adjusted diabetics excrete much more zinc in their urine^{[9, 11]}.

Anti-nutrients in plant-based foods 

Although cereals, nuts and pulses also contain zinc, they also contain so-called anti-nutrients. They prevent the intestines from properly absorbing zinc. This group of substances includes^[17]:

• Phytate in wholegrain cereals (exception: sourdough bread)
• Phosphate in cola, meat, fish
• Histidine in dairy products
• Oxalate in spinach, rhubarb, beetroot
• Tannins in wine, black and green tea

Phytate forms insoluble complexes with zinc so that zinc cannot act in the body. In order to reduce the phytate content, you can soak grain several hours before preparation^[4].

Good to know: The zinc requirement of people who eat a purely plant-based diet is increased by 50 percent. Vegetable foods contain the anti-nutrients, which is why they are less easily absorbed^[9].

What are the symptoms of zinc deficiency?

Zinc works all over the body, so a deficiency will cause discomfort in all possible areas. If the body lacks zinc, your hair may fall out and your nails may become brittle. Additional symptoms are^[4]:

• Decelerated wound healing
• Night blindness, impaired sense of smell
• Fatigue, depressive moods
• Increased susceptibility to infections, diarrhoea
• Severe weight loss, muscle cramps
• Erectile dysfunction

Zinc deficiency - Treatment

An optimal supply of zinc is a question of proper nutrition. You can control this if you know which foods contain zinc and which sources your body can absorb it from. It gets more complicated when it comes to consuming dietary supplements. There are big differences in the quality and consequently in how well the body absorbs the preparations.

Very important: Do not use preparations until you have a verifiable zinc deficiency. Otherwise, you run the risk of a zinc surplus^[4]!

Nutrients for better zinc absorption: 

Animal proteins support the absorption of zinc. Together they form a complex that the body can utilize very well. Other nutrients that promote zinc absorption are^[17]:

• Histidine in almonds, peanuts, beef and pork
• Methionine in quark, almonds, cod, mackerel, tuna fish
• Cysteine in almonds, peanuts, beef and pork
• Citric acid in apples, pears, berries and citrus fruits

   

Zinc preparations

If you have a proven zinc deficiency, zinc preparations may help. Zinc preparations can be found in every form imaginable: Effervescent tablets, powder, capsules, lozenges, drops or as ointments. What makes a good zinc preparation is not the type of preparation but the zinc compound it contains. Zinc only exists in combination with other substances which are supposed to improve zinc absorption.^[7].

Important: In addition to the usual preparations you can also buy nasal sprays containing zinc. They are not recommended, however. These zinc nasal sprays can lead to a deterioration or in the worst case to a loss of your sense of smell^[7].

Which zinc compound is the best one

Several studies suggest that the following zinc compounds have an optimized bioavailability^[18–25]:

• Zinc histidine - only compound with no known side effects
• Zinc picolinate
• Zinc bisglycinate
• Zinc gluconate
• Zinc sulfate - only effective when taken on an empty stomach

Bioavailability describes how well your body absorbs a nutrient and how well it can subsequently work in your body.^[4].

Interactions

Minerals compete with each other and can prevent each other from entering the bloodstream through the small intestine. Zinc preparations can thus impair the effect of antibiotics, rheumatic drugs such as penicillamines and diuretics such as thiazide diuretics. Therefore, it is recommended to use zinc preparations a few hours before or after taking these medications.^[7].

Zinc and Biotin

Zinc preparations are often added to biotin. This vitamin is also involved in hair growth, a biotin deficiency can lead to hair loss. Zinc also increases the activity of biotin, which is why it makes sense to take it together. Through your diet, you consume biotin in the form of wholegrain products, mushrooms and meat.^[3].

The body cannot ingest any number of minerals at once because they interfere with each other's absorption. Therefore you should not take the following preparations at the same time: Iron, calcium and copper. Researchers have found that iron is not absorbed over a long period of time if large amounts of zinc are ingested at the same time.^[11].

Zinc and dermatological disorders

Zinc is becoming very popular in dermatology (skin medicine). Dermatological studies have shown that zinc helps in the treatment of skin diseases such as warts, acne, rosacea and basal cell carcinoma. Zinc is used externally (topically), i.e. in the form of ointments and creams, or orally, i.e. as tablets.^[13].

Even the cosmetics industry uses zinc: Sunscreens and anti-dandruff shampoos contain zinc as additional UV protection and to suppress dandruff. The mineral also reduces oil production in the skin. Oily skin is the ideal breeding ground for bacteria, which can lead to infections - especially if the immune system is weakened by a zinc deficiency.^[26].

Good to know: Zinc ointments with zinc oxide can help with sunburn. Zinc oxide helps damaged skin regenerate^[7]!

Zinc surplus

Not only a zinc deficiency represents a risk to your health. Too much zinc can also harm you. An upper limit of 25 milligrams of zinc per day is considered safe. If you exceed this limit for several days, you may already experience initial symptoms. This usually happens because of the consumption of too many dietary supplements - it is unlikely to absorb too much zinc through your diet^[4].

If an amount between 225 and 450 milligrams is ingested at once, severe vomiting may occur. The possible consequences of excess zinc are gastrointestinal problems, kidney dysfunction, diarrhoea, hair loss and iron deficiency anaemia. Too much zinc hinders the absorption of iron, whereupon blood formation no longer takes place sensibly: Blood deficiency (anaemia) occurs.

The trace element of copper also loses its efficacy due to an excess of zinc. As a result of this copper deficiency, numbness and weakness occur in the limbs. The same applies to calcium and magnesium, with which zinc competes in the body: Calcium and magnesium deficiency can lead to bone loss, faulty stimulus transmission and significant performance weakness.^{[1, 3, 8, 27]}.

A zinc surplus can lead to a reduction of the HDL cholesterol. It is considered the healthy cholesterol. HDL cholesterol repairs damage to our cell membranes and removes the harmful LDL cholesterol that causes arteriosclerosis.^[9].

Zinc poisoning can occur in people who use dental glue on a daily basis. It usually contains zinc. You should not use more than 1.5 grams of the paste per day^[9]!

Zinc preparations and the common cold 

Many companies advertise zinc as a miracle cure for colds. According to the promotional promises, it reduces annoying complaints such as a runny nose, sore throat and constant sneezing. One thing is clear: Your immune system cannot function without zinc. This is why it is assumed that the mineral can chase away your cold.

According to the German Nutrition Society (DGE), however, the study situation regarding zinc and its effect on colds is far from clear. The DGE advises to resort to zinc preparations for colds only if you have a proven zinc deficiency. A study conducted by the Cochrane Collaboration in 2012 found that 75 milligrams of zinc per day reduced the time taken to recover from a cold by one day. However, this only happened if the study participants took the drug within 24 hours of the onset of the first symptoms.^{[7, 28]}.

Zinc test

Both a zinc deficiency and a zinc surplus will pose problems for your health. However, you can counteract both by testing whether you have an optimal zinc supply. You can test your zinc levels with a blood test, for example.

How can I measure my zinc levels?

You can also test your zinc levels yourself, for example with our cerascreen® Mineral Deficiency Test. All you need is a small finger prick to fill a tube with a little bit of blood. Your sample will then be evaluated in our laboratory and you will receive a result report. It will tell you whether you have an undersupply and how best to maintain your levels^[29].

Some suppliers measure the zinc levels by means of a hair analysis. A three-year study has concluded that this method can also provide information about the current mineral supply. Particularly in children who eat too little, this method has proved to be suitable for developing further therapeutic measures for them^[30].