Zinc Bisclycinate
Also known as: Zinc bisglycinate, zinc glycinate, zinc bisglycinate chelate
Overview
Zinc bisglycinate is a synthetic chelated form of zinc, where a zinc ion is bound to two glycine molecules. This chelation is specifically designed to enhance the bioavailability and absorption of zinc in the body compared to traditional inorganic zinc salts. While not naturally occurring, it is manufactured as a nutritional supplement to prevent or treat zinc deficiency. Its primary applications include supporting immune function, cognitive health, and metabolic regulation. A key characteristic of zinc bisglycinate is its improved gastrointestinal tolerability, as the chelated form reduces the stomach upset often associated with other zinc supplements. Research on zinc bisglycinate specifically is growing, with studies demonstrating its superior absorption, though broader clinical outcome data often extrapolate from general zinc supplementation research. It is categorized as a mineral supplement and a trace element chelate.
Benefits
Zinc bisglycinate primarily offers improved zinc status and plasma zinc levels due to its superior absorption. Research, including a randomized controlled trial (RCT), has shown that zinc glycinate significantly increases plasma zinc compared to placebo and other forms like zinc gluconate. This enhanced absorption is a major benefit, ensuring more effective zinc delivery to the body. Secondary benefits, often extrapolated from general zinc supplementation studies, include potential improvements in cognitive function, particularly in overweight/obese women, and an inverse association between dietary zinc intake and metabolic syndrome risk. While the cognitive improvements observed were modest, they suggest a broader role for adequate zinc. Populations at higher risk of zinc deficiency, such as women of reproductive age and overweight/obese individuals, may particularly benefit from this highly absorbable form. The evidence for improved zinc status is strong, supported by RCTs, while clinical outcome data for specific conditions are emerging and often rely on broader zinc research.
How it works
Zinc bisglycinate functions by providing highly bioavailable elemental zinc to the body. Zinc is an essential trace element crucial for over 300 enzymatic reactions, immune system function, protein synthesis, DNA synthesis, and cell division. The chelation of zinc with two glycine molecules protects the zinc ion from inhibitors in the gut and allows it to be absorbed via amino acid transporters, which are more efficient than the transporters for inorganic zinc. This mechanism enhances intestinal absorption and bioavailability. Once absorbed, zinc supports various biological pathways, including those involved in immune cell development and function, neurological signaling, and metabolic regulation. It interacts with numerous zinc-dependent enzymes, transcription factors, and signaling pathways to maintain cellular homeostasis and overall physiological function.
Side effects
Zinc bisglycinate is generally considered safe when taken at recommended doses, and its chelated form tends to reduce the gastrointestinal side effects commonly associated with inorganic zinc salts. However, mild gastrointestinal discomfort, such as nausea or a metallic taste, can still occur, though less frequently than with forms like zinc sulfate or gluconate. Allergic reactions are very rare. It is important to be aware of potential drug interactions: zinc may interfere with the absorption of certain antibiotics (e.g., tetracyclines and fluoroquinolones) and penicillamine, and it can also interfere with copper absorption, potentially leading to copper deficiency with long-term, high-dose use. Contraindications include known hypersensitivity to zinc or glycine compounds. Caution is advised for special populations such as pregnant or breastfeeding women, where dosing should strictly follow clinical guidelines to ensure safety for both mother and child. The upper tolerable intake level for adults is 40 mg elemental zinc per day to prevent toxicity.
Dosage
The typical recommended daily dosage for zinc bisglycinate for general supplementation ranges from 15 to 30 mg of elemental zinc. For individuals with confirmed zinc deficiency or specific clinical indications, dosages may range from 15 to 50 mg elemental zinc per day, under medical supervision. It is crucial not to exceed the established upper tolerable intake level (UL) for adults, which is 40 mg of elemental zinc per day, to avoid potential toxicity and adverse effects such as copper deficiency. Zinc bisglycinate is generally best absorbed on an empty stomach, ideally between meals, as food can sometimes interfere with absorption. However, if gastrointestinal discomfort occurs, it can be taken with a small meal. The bisglycinate form is preferred due to its superior absorption and reduced likelihood of causing stomach upset compared to other zinc forms. To optimize absorption, it is advisable to avoid co-administration with phytates (found in grains and legumes) or high-calcium meals, as these can inhibit zinc uptake.
FAQs
Is zinc bisglycinate better absorbed than other forms?
Yes, randomized controlled trials (RCTs) have demonstrated that zinc bisglycinate has superior bioavailability and absorption compared to other common forms like zinc gluconate and zinc oxide.
Is it safe for long-term use?
Generally, zinc bisglycinate is safe for long-term use within recommended daily doses (up to 40 mg elemental zinc). However, prolonged high doses can potentially lead to copper deficiency.
When is the best time to take zinc bisglycinate?
It is preferably taken on an empty stomach, between meals, for optimal absorption. If gastrointestinal upset occurs, it can be taken with a light meal.
How quickly can I expect to see results?
Improvements in plasma zinc levels can be observed within a few weeks of consistent supplementation. Clinical benefits, such as immune support or cognitive improvements, may take longer to manifest.
Does zinc bisglycinate cause stomach upset?
Zinc bisglycinate is less likely to cause stomach upset compared to inorganic zinc forms due to its chelated structure, but mild discomfort is still possible in sensitive individuals.
Research Sources
- https://pmc.ncbi.nlm.nih.gov/articles/PMC11677333/ – This randomized controlled trial (RCT) involving 30 young adult women found that zinc glycinate significantly increased plasma zinc levels compared to zinc gluconate and placebo over 6 weeks. The study supports the superior bioavailability of zinc glycinate.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC10609714/ – This RCT investigated the effects of zinc supplementation on cognitive scores in overweight/obese women over 12 weeks. It reported modest improvements in certain cognitive parameters, suggesting a potential benefit of zinc, though the specific form of zinc was not always specified.
- https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2022.798078/full – This umbrella review and meta-analysis assessed the impact of zinc supplementation on maternal zinc status. It concluded that zinc supplementation generally improves maternal zinc status but highlighted the heterogeneity and often low-to-moderate quality of included studies, emphasizing the need for more robust research.
- https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2022.825913/full – This research explores the relationship between dietary zinc intake and metabolic syndrome risk. It suggests an inverse association, indicating that adequate zinc intake may play a role in reducing the risk of metabolic syndrome, though causality requires further investigation.