Among the various nutritional deficiencies, low levels of zinc are usually not a concern for most people in developed nations. Studies have shown that there is no significant deficiency of zinc among vegetarians despite the mineral being more abundant in meat, poultry and seafood.
However, in developing nations there may be a problem with zinc levels. This is not only due to poor nutrition but also due to problems with the digestion of zinc-rich foods and the subsequent absorption of zinc.
Sources of Zinc
The human body cannot produce zinc. It has to be sourced from food. Sometimes zinc enters the body through inhalation and skin contact. This is not common and is more likely to occur in the occupational setting. It may lead to zinc toxicity in some individuals. Zinc is found in a host of different plant and animal foods.
These are the 10 best food sources for zinc:
- Beef chuck
- Alaskan crab
- Beef patty
- Fortified breakfast cereal
- Pork chop
- Baked beans
- Chicken (dark meat)
This based on the milligrams per serving. It is important to note the serving size of each food. Refer to the NIH website on sources of zinc¹.
Causes of Zinc Deficiency
There are various causes of zinc deficiency. While it is uncommon in developed nations due to dietary availability, there are several other causes of zinc deficiency that can affect any person of any age and socioeconomic status. It may also affect people who eat zinc-rich foods on a regular basis, even in developed countries.
Low Zinc Intake
Consuming a diet that is low in zinc is one of the leading causes of zinc deficiency globally. Malnutrition is not only about eating too little zinc-rich foods. Zinc can be found in many different plant and animals foods, albeit in much small quantities that the foods mentioned above. Instead zinc deficiency may be due to an insufficient intake of all food due to unavailability (famine, poverty).
Poor Absorption of Zinc
One of the common causes of zinc deficiency is malabsorption of the mineral. This means that sufficient zinc cannot be absorbed from the digestive tract despite consuming sufficient food. A zinc deficiency due to malabsorption is more likely to occur with small intestine diseases since most absorption occurs in this part of the gut. These conditions may include celiac disease, Crohn’s disease (IBD), alcoholism and any cause of chronic diarrhea.
Zinc deficiency may also arise with a host of chronic diseases. This may be a result of several possible mechanisms that can affect the absorption, assimilation and utilization of zinc. These diseases may include cancer, chronic kidney disease, liver disease, diabetes, pancreatic disease as well as the diseases mentioned above under poor absorption of zinc. Acrodermatitis enteropathica is a rare genetic disorder where the body’s ability to absorb zinc is impaired.
Vegetarians and Vegans
Vegetarians and vegans may have lower levels of zinc than meat eaters. Zinc from meat is absorbed more efficiently by the human body than zinc from plant foods. However, this does not mean that all vegetarians and vegans will have a zinc deficiency. It depends on overall nutrition and a balanced vegan or vegeatrian diet may provide sufficient zinc for the body’s needs. Furthermore, a zinc deficiency can also occur in meat eaters.
Certain drugs can affect zinc absorption. This is not common but can occur with thiazide diuretics. However, these drugs should not be discontinued unless otherwise advised by a medical professional. It is important to note that a zinc deficiency is more common among the elderly but this is usually not due to chronic medication which is common in the senior years. Instead zinc deficiency in the elderly is more likely due to poor nutrition.
Symptoms of Zinc Deficiency
As with any nutritional deficiency, the signs and symptoms of zinc deficiency are usually related to the functions of the micronutrient. Zinc is important for healthy skin and hair, immune activity, growth and development, healing and sexual function. A mild zinc deficiency may not cause any noticeable signs and symptoms.
Repeated infections like a recurent cold or stomach bug, persistent flu and other infections are usually a sign of a weakened immune system which can be a sign of a zinc deficiency. Wounds may not heal properly and be prone to infections.
Read more on immune boosting foods.
Skin and Hair
Zinc is important for healthy skin and hair. It is therefore not uncommon for skin to become dry, for rashes to form and even for skin diseases like acne to worsen when there is a zinc deficiency. In severe zinc deficiency, hair loss may occur.
Growth and Development
Since zinc is one of the nutrients required for growth and development, there may be slower than expected growth when a zinc deficiency is present. This is not only a problem in young children. A zinc deficiency may delay the development of sexual characteristics at puberty.
Zinc also plays a role in male sexual function. It can cause hypogonadism in males which affect sexual reproductive function. In addition, a zinc deficiency can be a factor for impotence in men. Along with fatigue and other effects of a zinc deficiency, there may be a resulting loss of libido.
Other Signs and Symptoms
- Eye problems
- Skin lesions
- Unexplained fatigue and lethargy
- Unintentional weight loss
- Unusual tastes or ability to taste
It is important to note that most of these symptoms arise with a severe zinc dericiency.
Treatment and Supplementation
When a zinc deficiency is due to an underlying disease then treatment should be directed at this causative condition. Dietary change and supplementation without treating the underlying cause may not resolve a zinc deficiency. It is therefore important to seek professional medical advice when a zinc deficiency is suspected or verified.
However, most zinc deficiencies are due to poor nutrition. Although a mild zinc deficiency can be treated, managed and prevented with dietary change, supplementation may still be advised. For moderate to severe zinc deficiencies, supplementation is necessary along with dietary change.
Apart from a balanced diet, supplements should be taken to ensure that the Recommended Dietary Allowance (RDA) is met. The RDA varies by age as well as by gender.
- 0–6 months: 2 mg
- 7–12 months: 3 mg
- 1–3 years: 3 mg
- 4–8 years: 5mg
- 9–13 years: 8 mg
- 14–18 years 9mg (females) and 11mg (males)
- 19+ years: 8mg (females) and 11mg (males)
Pregnant and breastfeeding women may require higher doses as advised by a medical professional.