Why your body needs zinc—and what happens without it
Zinc is an essential trace element that is required for a wide range of functions in the human body. A deficiency in this important mineral can lead to numerous health problems. Read on to learn more about the role of zinc in the body, as well as the symptoms and causes of zinc deficiency.
Table of contents
- What is zinc and what is it good for?
- What functions does zinc perform in the body?
- How much zinc should you consume daily?
- Which foods contain zinc?
- What are the causes of zinc deficiency?
- What are the symptoms of zinc deficiency?
- What are the complications of zinc deficiency?
- How can I test my zinc levels?
- How is zinc deficiency treated?
- Are zinc supplements useful?
- Can you consume too much zinc and what are the side effects of an overdose?
What is zinc and what is it good for?
Zinc is a vital trace element that our body needs for a variety of functions. It is an essential micronutrient, which means that our body cannot produce it on its own, so we must get it through our diet. Zinc is primarily absorbed in the small intestine and distributed throughout the body to various organs and tissues, with the largest amounts stored in the muscles and bones. Unlike some other minerals, the body does not store zinc in large quantities, so it is important to regularly and sufficiently consume zinc through food or supplements.
Zinc deficiency is relatively rare in industrialized countries but can affect certain population groups, including older adults, vegetarians, vegans, and people with certain conditions that affect zinc absorption or requirements. A zinc deficiency can lead to a variety of health problems. Therefore, ensuring adequate zinc intake is essential for maintaining good health (Harvard Health, 2023).
What functions does zinc perform in the body?
Its diverse involvement in bodily processes makes zinc an indispensable mineral for our health. Here are some of the main functions zinc performs in the body:
- Immune system: Zinc plays a crucial role in our immune system. It helps the body fight infections and heal wounds.
- Cell growth and division: Zinc is essential for the growth and division of our cells. It supports DNA synthesis and is important for the development and function of many cell types, including immune cells and neurons.
- Metabolism: Zinc aids in digestion and nutrient absorption, which are part of metabolism. It is involved in many enzymatic reactions that convert food into energy.
- Hormone production: Zinc is involved in the production and function of several hormones, including insulin and testosterone.
- Sensory functions: Zinc is important for our senses, especially taste and smell.
- Skin health: Zinc plays an important role in wound healing and can help relieve skin conditions such as acne. It is often found in topical creams and lotions to soothe skin irritation and promote healing.
Source: Cleveland Clinic, 2023
Given its wide range of functions, it is important to get enough zinc. A zinc deficiency can cause a variety of health problems, from infections and skin issues to growth delays and hormonal imbalances.
How much zinc should you consume daily?
The recommended daily intake of zinc varies by age, gender, and health status:
| Age group | Gender | Recommended daily intake (mg) |
|---|---|---|
| 0–6 months | Both | 2 mg |
| 6 months–3 years | Both | 3 mg |
| 4–8 years | Both | 5 mg |
| 9–13 years | Both | 8 mg |
| 14–18 years | Male | 11 mg |
| 14–18 years | Female | 9 mg |
| 19+ years | Male | 11 mg |
| 19+ years | Female | 8 mg |
| Pregnant | n/a | 11–12 mg |
| Breastfeeding | n/a | 12–13 mg |
Various factors, including certain illnesses and life circumstances, can lead to an increased need for zinc (NIH, 2022).
Which foods contain zinc?
Zinc is found in a variety of foods. Here are some of the best food sources of zinc, with the amount of zinc listed per 100 grams of each food:
- Oysters: 78.6 mg per 100 g
- Beef steak: 6.31 mg per 100 g
- Pork chop: 2.93 mg per 100 g
- Chicken breast: 1.0 mg per 100 g
- Chickpeas: 3.43 mg per 100 g
- Lentils: 3.27 mg per 100 g
- Cashews: 5.6 mg per 100 g
- Quinoa: 3.1 mg per 100 g
- Oatmeal: 3.97 mg per 100 g
- Yogurt: 0.9 mg per 100 g
Source: Cleveland Clinic, 2023
Please note that the body can absorb zinc from animal sources more easily than from plant-based foods. This is due to antinutrients found in plant foods that inhibit zinc absorption in the body. These include phytates, found in whole grains and legumes, and oxalates, found in some vegetables such as spinach and rhubarb. A balanced diet that includes both animal and plant-based foods can help ensure sufficient zinc intake (Roohani et al., 2013).
What are the causes of zinc deficiency?
Zinc deficiency can be caused by a variety of factors:
- Inadequate diet: A diet low in zinc-rich foods can lead to deficiency. Many plant-based foods contain less zinc than animal products, and the zinc they do contain is often harder to absorb.
- Nutrient absorption issues: Some people are unable to absorb zinc effectively from their diet. This may occur with certain digestive disorders such as Crohn’s disease or celiac disease, or following gastrointestinal surgeries. Celiac disease is an autoimmune disorder in which the body reacts negatively to gluten. The resulting inflammation damages the lining of the small intestine and impairs the absorption of nutrients, including zinc.
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Increased zinc requirements: Certain illnesses and life circumstances can increase the body’s need for zinc, raising the risk of deficiency. People in these groups should pay particular attention to their zinc intake and consult a healthcare provider if in doubt. These groups include:
- Pregnant and breastfeeding women: They require additional zinc for fetal development and milk production.
- People with certain illnesses: Conditions such as diabetes, malabsorption syndromes, chronic liver or kidney disease, and those undergoing dialysis may increase zinc needs.
- Vegetarians and vegans: Because zinc from plant sources is less bioavailable than from animal sources, higher intake may be needed.
- People under high stress: Stress, whether physical (e.g., intense exercise) or psychological (e.g., work pressure, personal issues), can raise zinc requirements. This is because zinc plays a role in regulating cortisol, the so-called “stress hormone.”
- Antinutrients: Substances like phytates and oxalates can inhibit zinc absorption in the intestines.
- Alcoholism: Alcohol impairs the intestines' ability to absorb zinc and increases its excretion through the kidneys, which can lead to deficiency.
Sources: NIH, 2022; Roohani et al., 2013
What are the symptoms of zinc deficiency?
Symptoms of zinc deficiency can vary and often depend on the severity of the deficiency. The most common symptoms include:
- Impaired taste and smell
- Loss of appetite
- Hair loss
- Skin issues such as dry or rough skin, acne, or eczema
- Weakened immune system and increased susceptibility to infections
These symptoms are relatively non-specific and can occur with many other health conditions. Therefore, it is important to consult a doctor if a zinc deficiency is suspected.
Source: Plum et al., 2010
What are the complications of zinc deficiency?
Prolonged zinc deficiency can lead to serious complications, including:
- Growth retardation: In children and adolescents, zinc deficiency can impair normal growth and development, both physically and neurologically.
- Weakened immune system: The immune response may become less effective, increasing susceptibility to illness.
- Skin problems: Deficiency can lead to rashes, ulcers, and wounds that heal slowly.
- Loss of appetite: A reduced interest in food or loss of taste may occur.
- Eye and vision issues: In some cases, zinc deficiency may lead to night blindness or other vision disturbances.
- Fertility problems: In men, zinc deficiency can reduce sperm count and testosterone levels, contributing to fertility issues (Te et al., 2023).
Sources: Nall,2023; MedlinePlus, 2023
How can I test my zinc levels?
If you suspect a zinc deficiency, it's advisable to consult a doctor. Diagnosing a deficiency can be complex because symptoms are often non-specific and may resemble those of other conditions. A thorough medical history and physical examination are typically performed first. If a zinc deficiency is suspected, a blood test can be ordered to determine current zinc levels. Additional tests, such as urine or hair analysis, may also be considered depending on the individual situation and the doctor’s judgment.
Source: Prasad, 2004
How is zinc deficiency treated?
If a zinc deficiency is confirmed, it's important to take steps to correct it and address any underlying causes. Possible measures include:
- Dietary changes: A balanced diet rich in zinc-containing foods can help restore zinc status.
- Zinc supplements: In more severe cases or when diet alone is insufficient, your doctor may recommend zinc supplements. It is important to follow your doctor’s instructions regarding dosage and duration, as excessive intake can cause side effects.
- Treating the underlying cause: If the deficiency is due to a specific condition such as celiac disease, treating that condition may help improve zinc levels. Discuss the best treatment approach with your healthcare provider.
Regular check-ups are recommended to monitor progress and make adjustments to treatment if necessary.
Source: NIH, 2022
Are zinc supplements useful?
Zinc supplements have gained popularity for the prevention and treatment of colds. However, studies on this topic show mixed results, and more research is needed to draw clear conclusions. While zinc products are often marketed for relieving cold symptoms, it’s essential to pay attention to the correct dosage and usage. Excessive intake can cause side effects and impair the absorption of other nutrients. Zinc may also interact with certain medications, including some antibiotics and diuretics. Speak with your doctor or pharmacist before taking zinc supplements, especially if you are on other medications.
Possible side effects of zinc supplementation include nausea, vomiting, diarrhea, a metallic taste in the mouth, and stomach pain. These should be discussed with your doctor as they may also indicate excess zinc intake.
Sources: NIH, 2022; Mayo Clinic, 2020
Can you consume too much zinc and what are the side effects of an overdose?
Zinc overdose can occur when high doses of supplements are taken over a prolonged period. Excessive zinc can lead to various health issues, including a weakened immune system, neurological symptoms, anemia, and low LDL cholesterol levels. High zinc intake can interfere with the absorption of other essential minerals such as copper, iron, and possibly calcium and magnesium. This can result in secondary deficiencies. It is therefore crucial to take zinc supplements responsibly and only as directed by a doctor.
Sources: NIH, 2022; Niragu, 2007
Summary
Zinc is an essential mineral that plays a vital role in many bodily functions. A deficiency can cause a range of symptoms and requires medical diagnosis and treatment. It is important to maintain a balanced diet that provides adequate zinc, and to take supplements only under medical supervision if needed.
