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Calcium Glycinate

Also known as: Calcium bisglycinate, Chelated calcium glycinate, Calcium glycinate

Overview

Calcium glycinate is a chelated form of calcium where calcium ions are bound to the amino acid glycine. This formulation is designed to enhance calcium bioavailability and minimize common gastrointestinal side effects associated with other calcium supplements, such as calcium carbonate or calcium citrate. It is primarily utilized to support bone health, prevent or treat calcium deficiencies, and maintain various physiological functions that rely on adequate calcium levels. While extensive research supports the general benefits of calcium supplementation for bone mineral density (BMD) and fracture risk reduction, specific high-quality studies focusing solely on calcium glycinate are limited. Most evidence is extrapolated from broader calcium supplement research, which includes numerous randomized controlled trials (RCTs) and meta-analyses. The chelation with glycine is hypothesized to improve absorption and reduce issues like constipation or gastric discomfort, making it a potentially more tolerable option.

Benefits

Calcium glycinate, as a source of calcium, significantly contributes to improved bone mineral density (BMD) and bone mineral content (BMC). This is particularly beneficial for individuals under 35 years old aiming to achieve peak bone mass and for postmenopausal women at risk of osteoporosis, thereby reducing fracture risk over time. Meta-analyses indicate statistically significant, albeit small to moderate, increases in BMD at critical sites like the femoral neck, lumbar spine, and total hip with consistent calcium supplementation. While the primary benefit is bone health, some research suggests calcium's influence on cardiovascular health, though findings are inconsistent; some meta-analyses report a modest increased risk of cardiovascular disease (CVD) with calcium supplements, particularly in postmenopausal women. Benefits on bone density typically require at least 18 months of consistent supplementation to become significant.

How it works

Calcium glycinate delivers elemental calcium, which is absorbed in the intestines through both active transport and passive diffusion. The chelation of calcium with glycine is believed to enhance its solubility and absorption efficiency by preventing calcium precipitation in the gut, thereby improving bioavailability and reducing gastrointestinal irritation. Once absorbed, calcium is crucial for numerous bodily functions, including bone mineralization, proper neuromuscular function, vascular contraction, and intracellular signaling pathways. Its absorption is significantly influenced by vitamin D status, gastric pH levels, and other dietary factors.

Side effects

Calcium glycinate is generally considered safe when taken within recommended dosages. The most common side effects of calcium supplements, affecting over 5% of users, are mild gastrointestinal issues such as constipation and bloating; calcium glycinate may exhibit a lower incidence due to its potentially improved tolerability. Uncommon side effects (1-5%) include hypercalcemia, which can occur with excessive intake or in individuals with impaired renal function. Rare side effects (less than 1%) include the formation of kidney stones, especially in predisposed individuals or when combined with high doses of vitamin D. Some meta-analyses have suggested a potential modest increase in cardiovascular risk with calcium supplements, though this remains a debated topic and may vary depending on the population and specific supplement form. Calcium can interact with certain medications, including antibiotics (e.g., tetracyclines, fluoroquinolones) and bisphosphonates, by interfering with their absorption. Contraindications include pre-existing hypercalcemia, severe renal impairment, and certain cardiac conditions. Pregnant women and the elderly should use calcium supplements under medical supervision.

Dosage

For bone health, a minimum effective dose of approximately 500-600 mg of elemental calcium daily is generally recommended, often in conjunction with vitamin D to optimize absorption. The optimal daily dosage typically ranges from 500 to 1200 mg of elemental calcium, adjusted based on individual dietary intake and specific needs. To avoid toxicity, the maximum safe dose is generally considered to be 2000-2500 mg of elemental calcium per day. To enhance absorption and minimize gastrointestinal side effects, it is advisable to take calcium glycinate in divided doses with meals. As a chelated form, calcium glycinate may offer superior absorption and tolerability compared to calcium carbonate. Adequate vitamin D status is crucial for calcium absorption, and simultaneous intake with high-oxalate or high-phytate foods should be avoided as they can hinder absorption.

FAQs

Is calcium glycinate better absorbed than other forms?

Evidence suggests chelated forms like calcium glycinate may have improved bioavailability and fewer GI side effects compared to calcium carbonate, but direct comparative RCTs are limited.

Is calcium supplementation safe for heart health?

Some meta-analyses report a slight increased risk of cardiovascular events with calcium supplements, but findings are inconsistent and may depend on population and supplement form.

How long before benefits appear?

Bone density improvements generally require at least 12-18 months of consistent supplementation to manifest significantly.

Can calcium glycinate cause kidney stones?

The risk is low but may increase with excessive calcium intake or in individuals with predisposing factors for kidney stone formation.

Research Sources

https://pmc.ncbi.nlm.nih.gov/articles/PMC7910980/ – This meta-analysis of randomized controlled trials investigated the effect of calcium supplements on cardiovascular disease risk. It found a modest increase in cardiovascular disease risk (approximately 15%) in healthy postmenopausal women taking calcium supplements, though findings varied across included studies. The study highlights the need for careful consideration of calcium supplementation in this population.
https://elifesciences.org/articles/79002 – This systematic review and meta-analysis, involving 7382 participants under 35 years old, concluded that calcium supplementation significantly improved bone mineral density (BMD) and bone mineral content (BMC) at sites like the femoral neck in younger individuals. The study provides strong evidence for calcium's role in bone health during critical developmental stages, though it did not specifically focus on calcium glycinate.