To maintain health, nutrition is very important. Food not only provides energy but it is also important to maintain normal body function. Besides proteins, carbohydrates, fats, vitamins minerals are also very important. Zinc is an important trace mineral. Trace elements are those elements that are needed by a human in very minute quantities yet they are necessary for the body.
Zinc is present in a wide variety of foods. Oysters are considered the best source of zinc. Other non-vegetarian food items that contain zinc are Red meat, poultry, seafood such as crab and lobsters. The vegetarian source includes beans, nuts, whole grains, and dairy products. Zinc is present in almost all multivitamin or mineral dietary supplements. It is also available alone or combined with calcium, magnesium, or other ingredients in dietary supplements.
A person may suffer from zinc deficiency due to many reasons such as certain medical conditions (gastrointestinal surgery, such as weight loss surgery, or who have digestive disorders, such as ulcerative colitis or Crohn’s disease), vegetarian diet, breastfed babies, alcoholics, etc. Zinc deficiency causes slow growth in infants and children, delayed sexual development in adolescents, and impotence in men. It may also cause hair loss, diarrhea, eye and skin sores, and loss of appetite. Weight loss, problems with wound healing, decreased ability to taste food and lower alertness levels.
Functions of Zinc
Zinc is an essential mineral. It is found in cells throughout the body and needed to stay healthy. It helps the immune system to prevent infections. Zinc is required to make proteins and DNA and to grow and develop properly. Zinc also helps wounds heal and is important for proper senses of taste and smell. The amount of zinc required daily depends on age. Average daily recommended amounts for different ages differ slightly.
- Zinc is found in cells throughout the body.
- It is needed for the body’s immune system to work properly.
- It plays a role in cell division.
- It helps in cell growth.
- It helps in wound healing.
- It helps in the breakdown of carbohydrates.
- It helps inaction of insulin.
- It is needed for the senses of smell and taste.
- During pregnancy, infancy, and childhood the body needs zinc to grow and develop properly.
- It gives immunity to certain diseases like the common cold when taken for at least 5 months.
- If zinc supplements are taken within 24 hours after cold symptoms begin, it helps in making the symptoms of cold less severe.
- Zinc is a component of various enzymes that helps in the function of proteins.
- It helps in the regulation of gene expression.
- It fights bacteria and viruses.
- It also needs zinc to make proteins and DNA, the genetic material in all cells.
Catalytic function: Nearly 100 specific enzymes depends on zinc for catalytic activity. Zinc acts as an electron acceptor in the various catalytic activities of the body.
Regulator function:
- It acts as a regulator of gene expression.
- It is needed for healthy skin.
- It helps in blood clotting. It helps in thyroid function.
- It is essential for growth and development and testicular maturation.
- It helps in good neurological function.
Food Sources of Zinc
Oysters are the best source of zinc. Animal protein such as pork and lamb is a good source of zinc. Lamb contains more zinc than fish. The dark meat of a chicken has more zinc than the light meat.
Nuts, whole grains, legumes, and yeast. Red meat, poultry, seafood such as crab and lobsters, and fortified breakfast cereals contain Zinc.
- Beans
- Certain seafood
- Lentils
- Milk products
- Nuts
- Oysters
- Peanuts
- Pumpkin seeds.
- Wheat germ
- Whole grains
- Beans, nuts, whole grains, and dairy products
Fruits and vegetables are not good sources of zinc, as zinc available in plant proteins is not readily used by the body as that obtained from animal sources. Zinc taken from animal sources is more readily absorbed by the body.
- Zinc supplements like zinc gluconate, zinc sulfate, and zinc acetate.
- Zinc is found in some over the counter medicines like cold lozenges, nasal sprays, and nasal gels.
- Zinc is also present in some denture adhesive creams.
Symptoms of Zinc Deficiency
- Difficulty in seeing in the dark
- Frequent infections
- Loss of hair
- Poor appetite
- Problems with the sense of smell
- Problems with the sense of taste
- Slow growth
- Small testes and gonads
- Soreness of skin
- Wounds take a long time to heal
Older people and children can have a high risk of getting pneumonia and other infections as a result of zinc deficiency. It is helpful in the treatment of age-related macular degeneration. Age-related macular degeneration (AMD) is an eye disease that causes vision loss.
Risk Group
Gastrointestinal surgery
Such as weight loss surgery, ulcerative colitis, or Crohn’s disease. Both this condition decreases the amount of zinc that the body absorbs and increase the amount lost in the urine.
Vegetarians
Vegan does not eat meat, which is a good source of zinc. Also, beans and grains have certain compounds that keep zinc from being fully absorbed by the body.
Older infants
who are breastfed because breast milk does not have enough zinc for infants over 6 months of age?
Alcoholics
As alcohol beverages decrease the amount of zinc that the body absorbs and increase the amount lost in the urine. They also eat a limited amount of food.
Sickle Cell Disease
Patients with sickle cell disease can also suffer from zinc deficiency.
Daily Body Requirement of Zinc
Recommended Dietary Allowance (RDA) for adults is 8 mg/ day for women and 11 mg/day for men.
- Infants 0-6 months- 2mg/day.
- 7 to 12 months: 3.0 mg/day
Children
- 1 to 3 years: 3 mg/day.
- 4 to 8 years: 5 mg/day
- 9 to 13 years: 8 mg/day.
Adolescent
- Males, age 14 and over: 11 mg/day.
- Females, age 14 to 18: 9 mg/day
- Females, age 19 and over: 8 mg/day.
- Pregnant females, age 19 and over: 11 mg/day
- Lactating females, age 19 and over: 12 mg/day
- Teens 14–18 years (boys) 11 mg
- Teens 14–18 years (girls) 9 mg
- Adults (men) 11 mg
- Adults (women) 8 mg
- Pregnant teens 12 mg
- Pregnant women 11 mg
- Breastfeeding teens 13 mg
- Breastfeeding women 12 mg
The upper limit of Zinc Intake
The upper limits for zinc are listed below. These levels do not apply to people who are taking zinc for medical reasons under the care of a doctor:
Life Stage Upper Limit
- Birth to 6 months 4 mg
- Infants 7–12 months 5 mg
- Children 1–3 years 7 mg
- Children 4–8 years 12 mg
- Children 9–13 years 23 mg
- Teens 14–18 years 34 mg
- Adults 40 mg
Side Effects of Taking High Amount of Zinc
Zinc is required by the body for proper functioning. But too much of anything is bad. Excess of one mineral leads to a deficiency of other essential nutrients. It also affects the electrolyte balance of the body. Zinc overdosing may happen by taking excess or many supplements which contain zinc.
Overdose of zinc may cause:
- Iron deficiency
- Diarrhea
- Abdominal cramps
- Vomiting
These symptoms appear within 3-10 hours of swallowing the supplements. These symptoms go away within a short period of time after stopping the supplements.
People should try to get most of their nutrients from food and not from supplements. Vitamins, minerals, dietary fiber, and other substances present in the food help to improve overall health without causing any disbalance. In some cases, fortified foods and dietary supplements may provide nutrients that otherwise may be consumed in less-than-recommended amounts.