Zinc deficiency is defined either as insufficient zinc (Zn) to meet the needs of the body or as a serum zinc level below the normal range. However, since a decrease in the serum concentration is only detectable after long-term or severe depletion, serum zinc is not a reliable biomarker for zinc status. Common symptoms include increased rates of diarrhea. Zinc deficiency affects the skin and gastrointestinal tract; brain and central nervous system, immune, skeletal, and reproductive systems. Conservative estimates suggest that 25% of the world’s population is at risk. Zinc deficiency is thought to be a leading cause of infant mortality. Siddha Spirituality of Swami Hardas Life System brings you out symptoms, causes, diagnosis, treatment, and best dietary sources for well-being.
What is Zinc deficiency?
A rare inherited condition called acrodermatitis enteropathica is an occasional cause of zinc deficiency. In this condition, there is an absence of a transport protein that normally allows zinc absorption, resulting in severe deficiency.
What are the Symptoms of Zinc deficiency?
Skin, nails, and hair
Zinc deficiency may manifest as acne, eczema, xerosis (dry, scaling skin), seborrheic dermatitis, or alopecia (thin and sparse hair). It may also impair or possibly prevent wound healing.
Zinc deficiency can manifest as non-specific oral ulceration, stomatitis, or white tongue coating. Rarely it can cause angular cheilitis i.e. sores at the corners of the mouth.
Vision, smell, and taste
Severe zinc deficiency may disturb the sense of smell and taste. Night blindness may be a feature of severe zinc deficiency, although most reports of night blindness and abnormal dark adaptation in humans with zinc deficiency have occurred in combination with other nutritional deficiencies e.g. vitamin A.
Impaired immune function in people with zinc deficiency can lead to the development of respiratory, gastrointestinal, or other infections, e.g. pneumonia. The levels of inflammatory cytokines in blood plasma are affected by zinc deficiency and zinc supplementation produces a dose-dependent response in the level of these cytokines. During inflammation, there is an increased cellular demand for zinc and impaired zinc homeostasis from zinc deficiency is associated with chronic inflammation.
Zinc deficiency contributes to an increased incidence and severity of diarrhea.
Zinc deficiency may lead to loss of appetite. The use of zinc in the treatment of anorexia has been advocated since 1979 by Bakan. At least 15 clinical trials have shown that zinc improved weight gain in anorexia. A 1994 trial showed that zinc doubled the rate of body mass increase in the treatment of anorexia nervosa. Deficiency of other nutrients such as tyrosine, tryptophan, and thiamine could contribute to this phenomenon of “malnutrition-induced malnutrition”.
Cognitive function and hedonic tone
Cognitive functions, such as learning and hedonic tone, are impaired with zinc deficiency. Moderate and more severe zinc deficiencies are associated with behavioral abnormalities, such as irritability, lethargy, and depression e.g. involving anhedonia. Zinc supplementation produces a rapid and dramatic improvement in hedonic tone i.e. the general level of happiness or pleasure under these circumstances. Zinc supplementation has been reported to improve symptoms of ADHD and depression.
Schizophrenia has been linked to decreased brain zinc levels. Evidence suggests that zinc deficiency could play a role in depression. Zinc supplementation may be an effective treatment for major depression.
Growth in children
Zinc deficiency in children can cause delayed growth and has been claimed to be the cause of stunted growth in one-third of the world’s population.
Zinc deficiency during pregnancy can negatively affect both the mother and fetus. A review of pregnancy outcomes in women with acrodermatitis enteropathica reported that out of every seven pregnancies, there was one abortion and two malfunctions, suggesting the human fetus is also susceptible to the teratogenic effects of severe zinc deficiency. However, a review on zinc supplementation trials during pregnancy did not report a significant effect of zinc supplementation on neonatal survival.
What are the risk factors for Zinc deficiency?
You may be at risk for zinc deficiency because of a number of factors. Not all people with risk factors will get zinc deficiency. Risk factors for zinc deficiency include:
- Chronic kidney disease (hemodialysis)
- Intestinal malabsorption
- Limited or no intake of animal protein
- Living in a region without access to proper nutrition
Reducing your risk of zinc deficiency
Fortunately, zinc deficiency is preventable. A health care provider can advise about steps one can take to reduce risk, including providing guidelines for required daily zinc intake.
You may be able to lower your risk of zinc deficiency by:
- Following the guidelines established by the Institute of Medicine’s Food and Nutrition Board
- Obtaining zinc from dietary sources, such as peanuts and beef or lamb
Taking zinc supplements if your diet does not provide sufficient zinc
What Causes Zinc deficiency?
Zinc deficiency can be caused by a diet high in phytate-containing whole grains, and foods that are grown in zinc-deficient soil. Processed foods also contain little or no zinc. Conservative estimates suggest that 25% of the world’s population is at risk of zinc deficiency.
Recent research findings suggest that increasing atmospheric carbon dioxide concentrations will exacerbate zinc deficiency problems in populations that consume grains and legumes as Staple foods. A meta-analysis of data from 143 studies comparing the nutrient content of grasses and legumes grown in ambient and elevated CO2 environments found that the edible portions of wheat, rice, peas, and soybeans are grown in elevated CO2 contained less zinc and iron.
Acrodermatitis enteropathica is an inherited deficiency of the zinc carrier protein ZIP4 resulting in inadequate zinc absorption. It presents as growth retardation, severe diarrhea, hair loss, skin rash (most often around the genitalia and mouth) and opportunistic candidiasis, and bacterial infections.
Exercising, high alcohol intake, and diarrhea all increase loss of zinc from the body. Changes in intestinal tract absorbability and permeability due, in part, to viral, protozoal, or bacteria pathogens may also encourage fecal losses of zinc.
Wilson’s disease, sickle cell disease, chronic kidney disease, chronic liver disease have all been associated with zinc deficiency. It can also occur after bariatric surgery, mercury exposure, and tartrazine.
What are the potential complications of zinc deficiency?
Although zinc deficiency is both preventable and treatable, potential complications of untreated zinc deficiency can be serious and even life-threatening in some cases. To help minimize your risk of serious complications, it is important to follow the treatment plan you and your health care provider design specifically for you. Complications of zinc deficiencies include:
Zinc deficiency Diagnosis
Any level below 70 mcg/dl is considered zinc deficiency. However, diagnosis is typically made based on clinical suspicion and a low level of zinc in the blood. There is a paucity of adequate zinc biomarkers, and the most widely used indicator, plasma zinc, has poor sensitivity and specificity.
How to Prevent Zinc deficiency?
Five interventional strategies include:
- Adding zinc to soil, called agronomic biofortification, both increase crop yields and provides more dietary zinc.
- Adding zinc to food, called food fortification. The Republic of China, India, Mexico, and about 20 other countries, mostly on the east coast of sub-Saharan Africa, fortify wheat flour and/or maize flour with zinc.
- Adding zinc-rich foods to the diet. The foods with the highest concentration of zinc are proteins, especially animal meats, the highest being oysters. Per ounce, beef, pork, and lamb contain more zinc than fish. The dark meat of a chicken has more zinc than the light meat. Other good sources of zinc are nuts, whole grains, legumes, and yeast. Although whole grains and cereals are high in zinc, they also contain chelating phytates which bind zinc and reduce its bioavailability.
- Oral repletion via tablets e.g. zinc gluconate or liquid e.g. zinc acetate.
- Oral repletion via multivitamin/mineral supplements containing zinc gluconate, sulfate, or acetate. It is not clear whether one form is better than another.
Zinc deficiency Treatment
The known treatments for zinc deficiency include:
- Increasing or introducing foods that are rich in zinc, and
- Zinc supplements
What can be done to improve Zinc deficiency
The recommended daily amount of zinc is 8 milligrams (mg) for women and 11 mg for adult men. Ensuring intake of the recommended amounts of zinc through:
- Obtaining zinc from dietary sources, such as peanuts and beef or lamb
- Using zinc supplements if your diet does not provide adequate levels of zinc
Which are the best dietary sources for Zinc deficiency?
It is an excellent source of zinc. Red meat is a particularly great source of zinc. In fact, a 100-gram (3.5-ounce) serving of raw ground beef contains 4.8 mg of zinc, which is 44% of the Daily Value (DV).
This amount of meat also provides 176 calories, 20 grams of protein, and 10 grams of fat. Plus, it’s a great source of many other important nutrients, such as iron, B vitamins, and creatine. It’s worth noting that eating large amounts of red meat, especially processed meat, has been linked to an increased risk of heart disease and some cancers.
However, as long as you keep your intake of processed meats to a minimum and consume unprocessed red meats as part of a diet rich in fruits, vegetables, and fiber, this probably isn’t something you need to worry about.
Shellfish are healthy, low-calorie sources of zinc. Oysters contain particularly high amounts, with 6 medium oysters providing 32 mg or 291% of the DV. Other types of shellfish contain less zinc than oysters but are still good sources.
In fact, Alaskan crab contains 7.6 mg per 100 grams (3.5 ounces), which is 69% of the DV. Smaller shellfish like shrimp and mussels are also good sources, both containing 14% of the DV per 100 grams.
However, if you are pregnant, make sure shellfish are completely cooked before you eat them to minimize the risk of food poisoning.
Legumes like chickpeas, lentils, and beans all contain substantial amounts of zinc. In fact, 100 grams of cooked lentils contain around 12% of the DV.
However, they also contain phytates. These antinutrients inhibit the absorption of zinc and other minerals, meaning zinc from legumes isn’t as well absorbed as the zinc from animal products.
Despite this, they can be an important source of zinc for people following vegan or vegetarian diets. Heating, sprouting, soaking, or fermenting plant sources of zinc like legumes can increase this mineral’s bioavailability.
Seeds are a healthy addition to your diet and can help increase your zinc intake. However, some seeds are better choices than others. For example, 3 tablespoons (30 grams) of hemp seeds contain 31% and 43% of the recommended daily intake for men and women, respectively.
Other seeds containing significant amounts of zinc include squash, pumpkin, and sesame seeds. In addition to boosting your zinc intake, seeds contain fiber, healthy fats, vitamins, and minerals, making them an excellent addition to your diet. To add hemp, flax, pumpkin, or squash seeds into your diet, you can try adding them to salads, soups, yogurts, or other foods.
Eating nuts such as pine nuts, peanuts, cashews, and almonds can boost your intake of zinc. Nuts also contain other healthy nutrients, including healthy fats and fiber, as well as a number of other vitamins and minerals.
If you’re looking for a nut high in zinc, cashews are a good choice. A 1-ounce (28-gram) serving contains 15% of the DV. Nuts are also a quick and convenient snack and have been linked to a reduction in risk factors for some diseases, like heart disease, cancer, and diabetes.
What’s more, people who eat nuts tend to live longer than those who don’t, making nuts a very healthy addition to your diet.
Dairy foods like cheese and milk provide a host of nutrients, including zinc. Milk and cheese are two notable sources. For example, 100 grams of cheddar cheese contains about 28% of the DV, while a single cup of full-fat milk contains around 9%. These foods also come with a number of other nutrients considered important for bone health, including protein, calcium, and vitamin D.
Eggs contain a moderate amount of zinc and can help you meet your daily target. For example, 1 large egg contains around 5% of the DV. This comes with 77 calories, 6 grams of protein, 5 grams of healthy fats, and a host of other vitamins and minerals, including B vitamins and selenium.
Whole eggs are also an important source of choline, a nutrient that most people aren’t getting enough of.
Wheat, quinoa, rice, and oats contain some zinc. However, like legumes, grains contain phytates, which bind to zinc and reduce its absorption. Whole grains contain more phytates than refined versions and will likely provide less zinc.
However, they are considerably better for your health and a good source of many important nutrients like fiber, B vitamins, magnesium, iron, phosphorus, manganese, and selenium.
In general, fruits and vegetables are poor sources of zinc. However, some vegetables contain reasonable amounts and can contribute to your daily needs, especially if you don’t eat meat. Potatoes, both regular and sweet varieties, contain approximately 1 mg per large potato, which is 9% of the DV. Other vegetables like green beans and kale contain less, at around 3% of the DV per 100 grams.
Although they don’t contain a lot of zinc, eating a diet rich in vegetables has been linked to a reduced risk of chronic diseases like heart disease and cancer.
Perhaps surprisingly, dark chocolate contains reasonable amounts of zinc. In fact, a 100-gram (3.5-ounce) bar of 70–85% dark chocolate contains 3.3 mg of zinc or 30% of the DV. However, 100 grams of dark chocolate also contain 600 calories. So while it provides some healthy nutrients, it is a high-calorie food.
While you may get some added nutrients with your treatment, it’s not a food you should be relying on as your main source of zinc.
Given the above, I am confident that you have learned about zinc deficiency, symptoms, causes, risk factors, complications, diagnosis, prevention, treatment, and best dietary sources.
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Frequently asked questions
Here are a few frequently asked questions regarding zinc deficiency. Before posting your query, kindly go through them:
|What is zinc deficiency?
A rare inherited condition called acrodermatitis enteropathica is an occasional cause. In this condition, there is an absence of a transport protein that normally allows zinc absorption, resulting in severe deficiency.
|What are the risk factors?
You may be at risk for zinc deficiency because of a number of factors. Not all people with risk factors will get it. Risk factors for zinc deficiency include Alcoholism, Chronic kidney disease (hemodialysis), Intestinal malabsorption, Limited or no intake of animal protein, Living in a region without access to proper nutrition, and Malnourishment.
|What are the best dietary sources?
Meat, shellfish, legume, seeds, nuts, dairy products, eggs, whole grains, some vegetables, and dark chocolate are the best dietary sources.