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Your Guide to Zinc

Find the best type of zinc for your needs.

Dr. Stephanie Rubino
Woman applying zinc sunscreen to nose

Zinc is considered one of the most important essential trace minerals for human health, but it doesn’t always get the attention it deserves. [1]

Found throughout the body, especially in the skeletal muscles and bones, zinc is a cofactor in more than 200 normal enzymatic reactions. Zinc is involved in many physiological processes, such as healthy DNA synthesis, normal cellular growth, and healthy carbohydrate, protein, and fat metabolism. It also helps support healthy antibody production and maintain normal insulin storage and secretion.* [2,3]

As you can imagine, not getting sufficient zinc daily can impact our overall health. While the recommended intake for zinc is 3 mg per day for children, needs increase to 8 mg per day for adult females and 11 mg per day for adult males. Pregnant and breastfeeding women require higher amounts to support the baby’s normal growth and development.* [3]

Insufficient intake, malabsorption, certain medications, and even chronic stress can lower zinc levels, impacting the health of the skin, and the gastrointestinal, central nervous, immune, skeletal, and reproductive systems. [4] Consumption of nutrients that reduce zinc’s bioavailability, such as phytic acid, iron, and calcium, may also be a cause.

Zinc levels can be assessed through blood, urine, or hair tests. So,if you are wondering about your zinc levels, speak to your health professional for a proper evaluation, especially if you are experiencing common signs and symptoms that may indicate a deficiency, including:

  • Loss of hair, taste, or smell
  • Brittle or white-spotted fingernails 
  • Loss of appetite 
  • Skin concerns 
  • Slow growth 
  • Suboptimal immune function 
  • Unintended weight loss 
  • Slow healing 

Unfortunately, zinc cannot be stored in the body in significant amounts. [3] Sufficient intake of zinc, either through diet and/or supplementation, can help maintain healthy zinc levels already within the normal range.* In addition, healthy amounts of zinc may help support healthy skin, maintain normal immunity, and support healthy vision.* [5]

Obtaining our nutrients from food sources is always key. When it comes to zinc, consume foods such as fish (oysters contain more zinc per serving than any other food!), plus red meat and poultry, beans and legumes, nuts and seeds, whole grains, and dairy products.

But did you know that only 20–40% of the zinc from our food is absorbed into the body? Low bioavailability of zinc from food sources plays an important role in our overall zinc levels. Therefore, using zinc supplements can often help support and maintain healthy zinc levels.*   

Zinc Supplements 

Zinc sulfate, zinc citrate, zinc gluconate, zinc bisglycinate…with so many available forms of zinc supplements, choosing one can often be confusing.

Why are they so many? As the body cannot efficiently absorb elemental zinc on its own, this mineral is typically attached to another substance to help increase its absorption.

Zinc may be attached to inorganic acids, organic acids, or amino acids. Inorganic forms (e.g., zinc sulfate or oxide) are known to be poorly absorbed, but chelated zinc, which is zinc attached to either organic acids (e.g., zinc picolinate, citrate, or gluconate) or amino acids (e.g., zinc bisglycinate or monomethionine), are more easily absorbed.  

We can find supplemental zinc in different formats such as lozenges, sprays, liquids, tablets, and capsules. Depending on the delivery method, a specific type of zinc will be used. For example, zinc gluconate is often found in throat lozenges, whereas zinc oxide is typically found in topical products, and zinc citrate and bisglycinate are found in supplements.

Learning more about the differences among the various zinc supplements can help you choose the best one for you and your family.   

Zinc sulfate and zinc oxide 

 Woman applying zinc sunscreen to nose

Supplements with zinc bound to inorganic acids, such as sulfate and oxide, are well known. Zinc sulfate has been used orally to support healthy skin.* Both zinc sulfate and oxide can also be found in topical agents to support and maintain healthy skin, particularly during diaper use.* [6]

Since these forms cause digestive upset and are poorly absorbed, they are generally not recommended in supplement form. Other zinc complexes are better suited due to their enhanced bioavailability. 

Zinc gluconate 

Zinc gluconate supplements are formed by combining zinc with the organic acid, gluconic acid. Zinc gluconate has been shown to be well absorbed and seems to be the best form of zinc for seasonal throat and respiratory support, using formats such as lozenges.* [7,8]  

 

Zinc citrate 

Zinc citrate supplements provide zinc chelated with the organic acid citrate, and are known to be well absorbed compared to other forms of zinc. One randomized, double-blind study compared the absorption of 10 mg of zinc citrate, zinc gluconate, and zinc oxide. [7,9] Zinc citrate was shown to have an absorption rate of 61.3%, while zinc gluconate and zinc oxide had absorption rates of 60.9% and 49.9%, respectively.

The researchers concluded that zinc citrate was as well absorbed as zinc gluconate, and was useful to maintain and support healthy levels of zinc.* Zinc citrate can be used as a daily zinc supplement to support overall intake.  

  

Zinc bisglycinate 

When zinc is chelated with two molecules of the amino acid glycine, zinc bisglycinate is formed. Zinc bisglycinate is absorbed more efficiently than free zinc ions because of its ability to transport through specialized peptide channels used for normal protein absorption from the digestive tract. [10]

Zinc bisglycinate is more easily absorbed than zinc gluconate.* [5] Similar to zinc citrate, zinc bisglycinate can be used to support zinc’s functions in the body and maintain healthy zinc levels.*  

  

Other Zinc Supplements 

Zinc picolinate supplements are formed by chelating zinc with the organic acid, picolinic acid. Zinc picolinate may be more easily absorbed than either zinc citrate or zinc gluconate.* [11] Finally, zinc can also be chelated with hydrolyzed vegetable protein (HVP), often sourced from rice. HVP is broken down into smaller peptides and amino acids to chelate not only with zinc, but with various other minerals, such as magnesium, chromium, and iron, for better absorption. Such supplements are often called Zinc Chelate. 

Vegans, vegetarians, older adults, people looking for digestive support, and people who consume alcohol long term may particularly benefit from zinc support.* [5,12] In addition to dietary sources, zinc supplements, available as capsules, tablets, lozenges, and liquid, can help support and maintain healthy zinc levels.*

The typical recommended usage for zinc is 15–30 mg per day. Higher amounts are only advised for short periods of time and for specific purposes that should be discussed with a health professional, as long-term consumption of high amounts of zinc can interfere with copper absorption.

Support and maintain your body’s zinc levels today for a healthy tomorrow.* 

ABOUT THE AUTHOR
Dr. Stephanie Rubino
Dr. Rubino is a licensed Doctor of Naturopathic Medicine.
References
  1. Institute of Food Technologists (IFT). “Eight ways zinc affects the human body [Internet].” ScienceDaily, 2014. Available from: www.sciencedaily.com/releases/2014/07/140718114541.htm 
  2. Grüngreiff K, Reinhold D, Wedemeyer H. Ann Hepatol. 2016; 15(1):7-16.  
  3. Maxfield L, Shukla S, Crane JS. Zinc Deficiency. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 [Updated 2021 Aug 13]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK493231/ 
  4. Roohani N, Hurrell R, Kelishadi R, et al. J Res Med Sci. 2013; 18(2):144-57. 
  5. Gandia P, Bour D, Maurette JM, et al. Int J Vitam Nutr Res. 2007; 77(4):243-8. 
  6. Gupta M, Mahajan VK, Mehta KS, et al. Dermatol Res Pract. 2014; 2014:709152. 
  7. Nutr Rev. 1997; 55(3):82-5. 
  8. Marshall S. Can Fam Physician. 1998; 44:1037-42. 
  9. Wegmüller R, Tay F, Zeder C, et al. J Nutrition. 2014; 144(2):132-6. 
  10. Zhang YY, Stockmann R, Ng K, et al. Compr Rev Food Sci Food Saf. 2021; 20(1):652-85. 
  11. Barrie SA, Wright JV, Pizzorno JE, et al. Agents Actions. 1987; 21(1-2):223-8. 
  12. Read SA, Obeid S, Ahlenstiel C, et al. Adv Nutr. 2019; 10(4):696-710.