Recent diet and nutrition studies have shown a decrease in the levels of zinc provided by food, with values falling below the recommended Recommended daily allowance (RDA). This is concerning as zinc is responsible for the proper functioning of over a hundred key enzymes, regulating important processes such as DNA and RNA functioning. Additionally, maintaining a proper level of zinc can help prevent and combat diseases such as acne, some immunological disorders, or peptic ulcer disease. Zinc supplementation has been found to strengthen immunity, improve the condition of hair and nails, and have a positive effect on appetite and concentration. The recommended daily intake is 11 mg for men and 8 mg for women; for pregnant or breastfeeding women, it increases to 11 mg. It’s important not to exceed a dose of 40 mg/day.
Bioavailability refers to the percentage of a given substance that is absorbed in the digestive system and then detected in the bloodstream. This directly impacts how effective the supplementation with the substance will be. The higher the bioavailability, the more of the substance is absorbed, leading to potential positive effects in the body. While the concept of bioavailability is typically used in drug studies, scientists are now using this measure to determine the effectiveness of dietary supplements as well.
A study conducted by scientists from a French university compared the bioavailability of zinc chelate (zinc bisglycinate) and zinc gluconate. The study involved twelve healthy women between the ages of 18 and 40 with a BMI between 18 and 28. One group took 15 mg of zinc in the form of zinc gluconate, while the other group received the same dose of zinc as zinc bisglycinate. The study was designed as a “crossover study,” so after the first phase, the groups switched supplements. This allowed for a comprehensive comparison of the two forms of zinc.
The conducted studies have confirmed that both zinc bisglycinate and gluconate are safe and well-tolerated by the human body. Data analysis indicates that the chelate’s bioavailability is significantly higher than that of gluconate by up to 43%. This is likely due to the unique chemical structure of the chelate. Glycine binds the zinc ion in the form of a stable complex, which is easily absorbed by intestinal cells, partly because of its low molecular weight (213 g for bisglycinate and 456 g for gluconate). Furthermore, its stability not only protects against decomposition in the stomach’s acidic environment but also guards against interactions with drugs, other dietary supplements, or food. Given the research indicating a rise in zinc deficiencies in our diet, zinc bisglycinate may be beneficial for effective supplementation.
Based on the article:
Gandia P, Bour D, Maurette JM, Donazzolo Y, Duchène P, Béjot M, Houin G.
A bioavailability study comparing two oral formulations containing zinc (Zn bis-glycinate vs. Zn gluconate) after a single administration to twelve healthy female volunteers.
Int J Vitam Nutr Res. 2007 Jul;77(4):243-8. doi: 10.1024/0300-9831.77.4.243. PMID: 18271278.