What is Zinc Deficiency?
Zinc is a vital nutrient for us humans and plays a significant part in many of our body’s functions such as protein, fat, DNA metabolism, and gene control. It’s heavily involved in reproduction, our immune system, and the healing of wounds. On a tiny, cellular level, zinc significantly affects the normal workings of various immune cells and enhances their activity. Despite being one of the most plentiful trace elements in our body, it cannot be stored in large amounts. That means we need to consume it regularly either through our diet or supplements.
Zinc is found in several foods including meat, fish, legumes, nuts, and many other edible sources, but how much our body can absorb depends on the type of food it’s present in. Lack of zinc or ‘zinc deficiency’ is a significant health issue all around the world, particularly in less developed countries. The World Health Organisation regards zinc deficiency as a major factor contributing to diseases.
People suffering from zinc deficiency may experience slowed growth, sexual problems, inflammation, digestive issues, or skin problems.
What Causes Zinc Deficiency?
Zinc is a crucial nutrient that our bodies don’t naturally produce, so it must be obtained through our diet. Children need about 3 mg of zinc per day while adult women require 8 mg and adult men need 11 mg. These requirements become even greater for pregnant women and breastfeeding mothers.
Zinc deficiency is typically seen in regions where malnutrition is prevalent but can also occur in developed regions due to aging or chronic illnesses. There are two types of deficiencies: one that is acquired and one that is inherited. Acquired deficiency can result from not eating enough zinc, not being able to absorb the nutrient well, having a condition that causes high metabolic demand, or losing a lot of zinc from your body. People with an acquired zinc deficiency usually have a mix of these factors. For instance:
* Nutritional reasons could include not eating enough meat, consuming too much phytate (found in legumes, seeds, soy products and whole grains) or oxalate (found in spinach, okra, nuts and tea).
* Chronic illnesses or infections such as gastrointestinal issues, diabetes, liver problems, kidney disease, excess alcohol intake, or HIV infection can influence zinc levels in your body.
It’s also important to note that the absorption of zinc can be reduced with the consumption of phytates, calcium, and phosphate. Deficient intake is often seen in those reliant on intravenous feeding, strict vegetarians, and those with anorexia nervosa. Inadequate absorption can occur in those with health conditions like Crohn’s disease, small intestine issues, hookworm infestation, and pancreatic insufficiency.
Certain medications, including the antibiotic penicillamine, various diuretics and sodium valproate, can interfere with the body’s absorption of zinc.
A greater demand for zinc occurs in certain situations, such as pregnancy and breastfeeding. As these periods increase zinc requirements, losing up to 2 mg of zinc each day can last for about two months after giving birth. Preterm babies require more zinc due to inadequate supplies, reduced gut absorption, and increased metabolism.
Zinc can be lost excessively from the body via burns, hemodialysis, hemolysis, diarrhea, or excessive urination due to alcohol use or diuretics. This loss can lead to zinc deficiency over several months. To make up for this loss, the body tries to increase intestinal absorption by using tiny reserves stored in skeletal muscle, bone, hair, liver, brain, and skin.
Acrodermatitis enteropathica is a genetic condition that results in zinc deficiency due to poor absorption. Although rare and estimated to occur in 1 out of every 500,000 people, it’s caused by a mutation of the SLC39A4 gene on chromosome 8q24.3, which hampers the Zip4 transporter responsible for zinc absorption.
Risk Factors and Frequency for Zinc Deficiency
Zinc deficiency is a problem that affects a significant part of the world’s population. Up to 17% of people worldwide may not get enough zinc in their diets, with the percentage climbing to as high as 30% in South Asia. Other regions where zinc deficiency is common include sub-Saharan Africa and Central America. The situation has remained largely unchanged globally, though some countries, like China, have managed to lower their zinc deficiency rates significantly.
Endemic, or locally widespread, zinc deficiency can be found in up to a third of people in various parts of the world. This problem is particularly common in countries like Iran, Egypt, and Turkey, likely due to high dietary intake of phytates that interfere with zinc absorption.
Zinc deficiency is also tied to the practice of eating clay, or ‘pica’, which is common among children in certain communities and regions. Clay binds to zinc and reduces its bioavailability, or the body’s ability to use it. This condition affects roughly two billion people, predominantly children and elderly adults, in developing regions worldwide.
- Up to 17% of the global population may not get enough zinc in their diets, with the rate reaching 30% in South Asia.
- Zinc deficiency is common in sub-Saharan Africa and Central America.
- While global rates have been stable, China managed to reduce its zinc deficiency prevalence from 17% to 8% in 2005.
- A third of the population in countries like Iran, Egypt, and Turkey may suffer from zinc deficiency due to a high intake of phytates.
- Zinc deficiency can also result from the practice of eating clay among children in specific areas, affecting roughly two billion people, especially children and elderly adults, in developing regions.
Signs and Symptoms of Zinc Deficiency
Zinc deficiency can either be acquired through factors like lack of supply, regional and geographical risks, excessive loss, or high demand, or it can be inherited and usually shows symptoms early in life. Regardless of whether it is inherited or acquired, some symptoms are common to both. Surprisingly enough, zinc deficiency was first discovered when people noticed its link to stunted growth in the Middle East, likely linked to a diet high in Phytate.
Multiple body systems are affected when a person has a zinc deficiency. For example:
- In the reproductive system, zinc deficiency can lead to hypogonadism and reduced sperm count.
- In the central nervous system, it can cause mood swings, mental disturbances, impaired taste and smell, and sensitivity to light.
- The immune system is affected by making the individual prone to various infections.
- The digestive system shows symptoms like significant diarrhea.
The skin is also affected in a case of zinc deficiency, with symptoms appearing over several days. You might see these symptoms around the mouth, and on areas of the body that experience a lot of friction like elbows, knees, knuckles, ankles, and the sacrum. The skin might appear inflamed, bumpy or blister-like, and could break open. Spots of psoriasis may also form around these areas.
Inherited zinc deficiency, such as acrodermatitis enteropathica, is a rare condition that affects the body’s ability to absorb zinc. It usually becomes noticeable around 4 to 6 weeks after an infant is weaned off breastfeeding. Symptoms of this inherited condition can include behavioral changes, stunted growth, lack of appetite, night blindness, pica, and sensitivity to light. Kids might also show skin symptoms or have thinning hair and inflammation around the nails. Other signs could be delayed wound healing, inflammation of the eye, or frequent infections.
Testing for Zinc Deficiency
If you are at risk for Acrodermatitis enteropathica due to factors such as age or where you live, your doctor may be able to diagnose the condition using a combination of your symptoms, history, lab tests, and tissue biopsy.
Acrodermatitis enteropathica causes your body’s zinc levels to drop. A key sign of this condition can be a drop in blood tests related to zinc, like the serum alkaline phosphatase test and plasma zinc concentrations. However, these tests may not always be accurate if your zinc deficiency is not severe.
To get the most accurate results, your blood sample needs to be handled very carefully. This includes using special equipment that doesn’t contain any zinc, separating the blood cells from the plasma or serum quickly, and making sure the sample doesn’t hemolyze, or break down. Your doctor may ask you to fast overnight and then give the sample in the morning.
In adults, normal zinc levels fall between 70 to 250 μg/dl. When this falls to 40 to 60 μg/dl, you may start to show symptoms. Tests like zinc levels in urine or hair may not be reliable for detecting acute, or sudden, changes in zinc level.
Your doctor might also take a small tissue sample, or biopsy, from your skin. They’ll examine it under a microscope to look for certain changes that can suggest Acrodermatitis enteropathica. These can include cells losing their color, swelling, breaking down, or even dying off. This process, known as necrolysis, can show up in the top layers of your skin. However, keep in mind that these findings can also be seen in other skin conditions like pellagra and necrolytic migratory erythema, or even late-stage zinc deficiency, which can look like psoriasis.
Your doctor may give you zinc supplements to see if your symptoms improve. If they do, this could confirm that you have Acrodermatitis enteropathica.
Treatment Options for Zinc Deficiency
Zinc supplements have been shown in multiple studies to help decrease the risk of infection. For instance, a study conducted on children over six months old at risk of zinc deficiency found that zinc supplementation reduced the duration of diarrhea. Even in cases of mild zinc deficiency, blood tests may not be sensitive enough to detect it. Due to this, if typical symptoms of zinc deficiency are present, oral supplementation may be started regardless of the test results. Certain high-risk groups may be considered for routine supplementation.
The treatment for zinc deficiency usually begins with oral supplements. For adults, taking 20 to 40 mg of zinc daily often eliminates all symptoms within one to two weeks. Even for patients with malabsorption diseases (conditions where the gut doesn’t absorb nutrients properly), like Acrodermatitis Enteropathica, taking oral supplements is still the usual therapeutic approach.
For various age groups, the recommended daily intake of elemental zinc is as follows:
- 3 mg for children under 4 years of age
- 5 mg for children between 4 and 8 years old
- 8 mg for children between 9 and 13 years old
- 9 mg for women (not pregnant or lactating)
- 11 mg for men
- 11 to 12 mg for pregnant and lactating women
In patients with serious deficiency due to malnutrition or malabsorption disorders like Crohn’s disease or Short Bowel Syndrome, higher doses of zinc (more than 50 mg/day) might be needed temporarily. For premature infants with zinc deficiency, normal breastfeeding is typically enough for correction and any deficit usually gets better within weeks without any clinical symptoms. However, if the mother’s zinc stores are low or if there’s a genetic mutation affecting the breast milk’s zinc content, the infant may need additional zinc supplementation.
It’s worth noting that taking more than 50 mg of zinc daily may cause side effects like nausea, stomach discomfort, and diarrhea. Taking more than 150 mg per day can negatively impact the immune system and lipid profile. Higher doses could also interfere with the absorption of iron and copper, leading to potential genito-urinary problems. Consequently, when taking zinc for a long time and especially at high doses, it’s important to check copper levels in the blood.
Zinc supplementation can come in various forms including Zinc sulfate, Zinc acetate, Zinc aspartate, Zinc orotate, and Zinc gluconate. After beginning supplementation, patients should be monitored for their response to the therapy, and their zinc levels should be checked after three to six months. If there’s not enough improvement, the dose of zinc may be increased, but higher doses should be monitored closely for potential toxicity.
In the case of Acrodermatitis Enteropathica, patients have to take supplements for their entire life. In situations where long-term zinc supplementation may be required, the dose should be tailored to the individual’s needs and guided by regular checks of the patient’s serum zinc levels. Furthermore, regular checks of copper levels may also be necessary, as zinc and copper absorption compete with each other.
Last, it’s rarely needed, but for cases of intestinal failure or prolonged total parenteral nutrition (feeding a person intravenously), zinc might have to be administered into a vein.
What else can Zinc Deficiency be?
The differential diagnosis for this nutritional deficiency involves ruling out several other nutritional deficiencies. These include:
- Biotin deficiency
- Vitamin B2 (Riboflavin) deficiency
- Essential fatty acid deficiency
A deficiency in biotin can show similar skin symptoms and can also lead to muscle weakness, lack of coordination, seizures, and hearing loss. It’s detected by measuring the amount of biotin in the blood and the presence of a particular substance in the urine (3-hydroxyisovaleric acid). A Riboflavin deficiency can affect the eyes and is confirmed by checking the activity of a particular enzyme (erythrocyte glutathione reductase) in the blood. This deficiency can mimic the appearance of conditions like necrolytic migratory erythema, atopic dermatitis, psoriasis, and candidiasis. Necrolytic migratory erythema is tied to tumors that secrete glucagon, a hormone, and this can be checked by measuring glucagon levels in the blood.
In addition, when diagnosing zinc deficiency, other health issues should be considered, such as:
- Hypothyroidism
- Depression
- Iron deficiency
- Vitamin B12 deficiency
- Folate deficiency
- Vitamin D deficiency
- Vitamin A deficiency
What to expect with Zinc Deficiency
Zinc deficiency can typically be improved through the use of zinc supplementation and by addressing any dietary habits that might contribute to the situation. Treatment often brings quick relief from symptoms. Conditions like diarrhea may improve in as little as 24 hours, and skin problems often get better within 1 to 2 weeks.
Patients who have inherited zinc deficiencies should have their zinc levels checked, along with a protein called alkaline phosphatase. This should be done 3 to 6 months after beginning the replacement therapy. The dosage of the treatment may then be adjusted based on the results of these tests.
Possible Complications When Diagnosed with Zinc Deficiency
A severe and long-term lack of zinc can result in multiple health issues, including:
- Stunted growth – A prolonged lack of zinc is often associated with permanent problems in growth and development.
- Underdeveloped sexual organs
- Repeated infections – A lack of zinc can mean that both short-term and long-term infections are worse. These infections can also make the zinc deficiency worse. While it’s recognized that zinc is useful in the treatment of illnesses that cause diarrhea, its role in treating other infections like malaria and pneumonia is still being explored.
- Diarrhea
- Skin issues – Zinc deficiency can lead to skin diseases such as acrodermatitis enteropathica, cheilitis, and dermatitis.
Low zinc levels are also associated with higher risks for diabetes and obesity. Nevertheless, the exact link between zinc deficiency and these hormone-related disorders is still under investigation.
Other complications can include slow wound healing and low bone density – The impact of zinc deficiency on bone density isn’t clear yet. There is limited evidence showing that adding calcium to zinc supplements might be more beneficial than just taking calcium alone.
Preventing Zinc Deficiency
People who need more zinc in their diet should consider eating certain foods. Along with taking supplements, those lacking enough zinc might want to eat more of the following foods:
- Red meat
- Poultry
- Wheat germ
- Wild rice
- Seeds
- Nuts
If you’re vegetarian, you might find it harder to get enough zinc. However, you can get zinc from baked beans, peas, cashews, and almonds.
