Do you suffer from a zinc deficiency?

What is zinc deficiency?

Zinc deficiency means that your body cannot provide enough zinc to maintain vital functions such as immune defense, cell division or wound healing. A deficiency can result from an unbalanced diet, an intestinal absorption disorder or an increased requirement. A diet with few zinc-rich foods, chronic illnesses and phases of life such as pregnancy and growth increase the likelihood of a zinc deficiency.

What symptoms can occur with zinc deficiency?

The symptoms of zinc deficiency vary greatly and are usually unspecific, which makes diagnosis difficult. The immune system may be weakened, wounds may heal conspicuously slowly or skin changes may occur. The sense of taste and smell can also be impaired.

Here are the most common signs:

• Weak immune system: Persistent infections and colds can be an indication of zinc deficiency, as zinc plays an important role in the immune system.
• Skin problems: Skin rashes, acne, eczema and delayed wound healing can occur.
• Hair loss: Zinc is important for hair growth and a deficiency can lead to hair loss.
• Delayed growth: In children, zinc deficiency can lead to growth retardation and developmental problems.
• Altered sense of taste and smell: Zinc deficiency can lead to taste disorders and a reduced sense of smell.
• Decreased appetite: Zinc deficiency can lead to loss of appetite.
• Cognitive impairment: Difficulty concentrating or general memory problems may occur.

What are the causes of zinc deficiency?

Zinc deficiency can be caused by chronic inflammatory diseases in particular, but also by excessive alcohol consumption or the regular intake of medication. Or simply an increased need, for example during pregnancy or growth, can be the cause of zinc deficiency.

Which illnesses promote zinc deficiency?

The absorption and utilization of zinc in the body can be impaired in the following diseases in particular:

• Crohn's disease: This chronic inflammatory bowel disease impairs the ability of the intestine to absorb nutrients.
• Coeliac disease: Gluten damages the lining of the small intestine, which impairs the absorption of nutrients.
• Chronic kidney disease: These can lead to increased loss of zinc via the urine.
• Liver cirrhosis: Damage to the liver can impair zinc storage and utilization in the body.
• Diabetes: People with diabetes often have an increased loss of zinc via the urine.
• Alcoholism: Excessive alcohol consumption can reduce zinc absorption in the intestine and increase zinc loss via the urine.

Medications that can promote zinc deficiency

Certain medications can impair zinc absorption or increase the excretion of zinc, which can lead to a deficiency. These include:

• Diuretics (dehydrating agents): These drugs, which are often used to treat high blood pressure and heart failure, increase the excretion of zinc through the urine.
• ACE inhibitors: These are used to treat high blood pressure and heart failure and can reduce zinc levels in the blood.
• Proton pump inhibitors (PPI): These are taken to reduce stomach acid production and are used to treat heartburn and stomach ulcers. Reduced stomach acid can impair zinc absorption.
• Antibiotics: Some antibiotics such as tetracyclines and fluoroquinolones can interact with zinc in the gut and reduce its absorption. Examples are doxycycline and ciprofloxacin.
• Anticonvulsants: These drugs, which are used to treat epilepsy among other things, can affect zinc levels in the body. Examples are phenytoin and carbamazepine.

People who take these medications long-term should have their zinc levels tested regularly.

Why vegetarians and vegans should pay particular attention to their zinc supply

Vegetarians and vegans are somewhat challenged when it comes to their zinc supply, as zinc is mainly found in animal foods such as meat, fish, eggs and dairy products.

Although plant-based foods also provide zinc, the absorption (bioavailability) from these sources is often limited. The reason for this is so-called phytates, secondary plant substances that bind zinc and make it more difficult to absorb in the intestine.

Foods rich in phytates

Plant foods that are rich in phytates and at the same time potentially rich in zinc include

• Whole grain products (e.g. whole grain bread, oatmeal, wheat)
• Legumes (e.g. lentils, chickpeas, beans)
• Nuts and seeds (e.g. almonds, walnuts, sunflower seeds, pumpkin seeds)
• Soy products (e.g. tofu, soybeans)

Although these foods contain valuable nutrients, their phytate content hinders the absorption of zinc. To increase the bioavailability of zinc, the food should either be soaked, sprouted or fermented before consumption to reduce the phytate content and promote zinc absorption.

Possible effects of a zinc deficiency

A zinc deficiency can have far-reaching health consequences, as zinc is involved in over 300 enzymatic processes in the body. The immune system, skin health and wound healing are particularly affected. Typical symptoms of a zinc deficiency include

• Frequent infections due to a weakened immune system
• Poor wound healing
• Skin problems such as dry, irritated skin or acne
• Hair loss and brittle nails
• Tiredness and lack of concentration

For vegans and vegetarians, a targeted intake of zinc through diet or food supplements can therefore be useful to prevent deficiency symptoms in the long term.

How is a zinc deficiency detected?

Zinc is not usually tested routinely because zinc deficiency does not usually cause acute symptoms. In Switzerland, 700 study participants (>18 years) were recruited in 2019 as part of a study on selenium deficiency during routine screening of blood donors in four regional centers of the Swiss Red Cross. Serum zinc concentrations (SZC) were also measured in order to assess the zinc supply in Switzerland: “The SZC measured in the blood donors and the moderate percentage of low values reflect the range of usual zinc intake and do not indicate a general deficiency in the Swiss population. However, no reliable statement on the prevalence of pronounced zinc deficiency can be made for people who eat a vegan or vegetarian diet due to the small sample size.” [1]

As zinc is a trace element that only occurs in small amounts in the blood, the test can vary depending on the method and laboratory. A normal serum level is between 60 and 115 umol/l. However, a zinc deficiency can be difficult to diagnose, as zinc levels in the blood can also be affected by inflammation, stress or infections. Sometimes the zinc level in the hair or urine is also measured to get a more accurate picture, especially if chronic illness or inflammation could distort the blood value.

This is why many doctors also look for symptoms that could indicate a zinc deficiency, such as delayed wound healing, skin problems, hair loss, frequent infections or tiredness.

What is the daily requirement of zinc?

As already mentioned, the zinc requirement must be determined individually. The following recommendations apply in Switzerland [1]:

Children and adolescents:

• 7 to 11 months: 2.9 mg/day
• 1 to 3 years: 4.3 mg/day
• 4 to 6 years: 5.5 mg/day
• 7 to 10 years: 7.4 mg/day
• 11 to 14 years: 10.7 mg/day
• 15 to 17 years: 11.9 mg/day (girls), 14.2 mg/day (boys)

Adults:

• Women aged 19 and over: 7.5, 9.3, 11.0 or 12.7 mg/day (depending on phytate intake)
• Men aged 19 and over: 9.4, 11.7, 14.0 or 16.3 mg/day (depending on phytate intake)

Pregnant women: 9.1, 10.9, 12.6 or 14.3 mg/day (depending on phytate intake)

Breastfeeding women: 10.4, 12.2, 13.9 or 15.6 mg/day (depending on phytate intake)

Doesn't seem quite so simple. Or do you know the amount of phytates and zinc you have taken in with your food today? It gets even more confusing if you want to supplement zinc.

Zinc supplementation and the Swiss maximum quantity model

In Switzerland, the maximum quantity model [2] regulates the dosage of trace elements in food supplements or in fortified foods, for example for athletes. The maximum daily amount of a zinc supplement is 5.3 mg and 1.8 mg as an additive in special foods.

However, this is probably not enough for vegans, vegetarians and other people who may have an increased requirement. This means that despite a healthy diet and a supplement, deficiencies could occur.

You're probably wondering why the maximum amount for zinc was set so “low”? Probably because, on the one hand, they want to prevent overdosing and, on the other hand, they believe that the Swiss population is sufficiently supplied with zinc, as the 2019 study on selenium, in which 700 participants were also tested for zinc, showed [1].

Risks of taking too much zinc

While an occasional high dose of zinc is usually well tolerated, a long-term overdose can have serious effects on the body.

1. short-term overdose (acute toxicity)

A single high intake of zinc (e.g. more than 200 mg zinc) can lead to acute zinc toxicity. Symptoms include:

• Nausea and vomiting
• Abdominal pain and diarrhea
• Headache and fatigue

These symptoms often occur shortly after ingestion and subside as soon as the intake is reduced. Nevertheless, an acute overdose can be stressful and should be avoided.

Zinc can also irritate the stomach lining in smaller quantities, which can lead to nausea. It is therefore important to take zinc supplements with food if possible. However, even then a slight nausea cannot be ruled out, as certain foods interact with zinc and this can also lead to stomach irritation.

2. Long-term overdose (chronic toxicity)

Serious health problems can develop with a long-term high zinc intake that exceeds the recommended limits. According to the European Food Safety Authority (EFSA), the tolerable upper intake level for adults is 25 mg per day [3]. Doses above 40 mg per day over a longer period of time can lead to chronic side effects, including

• Copper deficiency: High zinc intake over a long period of time can inhibit the absorption of copper in the gut, as zinc and copper compete for the same transport mechanisms in the body. Copper is essential for the formation of red blood cells and for energy metabolism. A copper deficiency can lead to anemia, reduced immune function and neurological disorders such as numbness or weakness.
• Weakening of the immune system: Paradoxically, an overdose of zinc can weaken the immune system. Although zinc supports immune function, chronic overdose can disrupt the balance of immune cells and cause pro-inflammatory reactions.

How can you meet your zinc requirements?

For healthy omnivores under the age of 65, the zinc requirement can generally be met through a balanced diet. Animal products such as meat, fish, eggs and dairy products contain a lot of zinc and are well absorbed by the body. The situation is different with plant-based foods, as some of these also contain zinc, but cannot be absorbed as well. The phytates in cereals and pulses in particular inhibit absorption in the body.