Tricalcium Citrate Tetrahydrate
Also known as: Tricalcium citrate, calcium citrate, Tricalcium dicitrate tetrahydrate
Overview
Tricalcium dicitrate tetrahydrate, commonly known as tricalcium citrate, is a calcium salt of citric acid. It is a white, odorless crystalline powder primarily manufactured for use as a calcium supplement and for fortifying foods and pharmaceuticals. It contains approximately 21% elemental calcium by weight. Research indicates that tricalcium citrate offers superior bioavailability compared to calcium carbonate, making it an effective choice for supporting bone health and preventing osteoporosis. Its absorption is less dependent on stomach acid, which is particularly beneficial for individuals with reduced gastric acidity. The supplement is well-studied, with high-quality evidence from meta-analyses and randomized controlled trials supporting its efficacy and safety.
Benefits
Tricalcium citrate offers significant benefits primarily due to its superior calcium absorption. Meta-analyses have consistently shown that tricalcium citrate has approximately 20-27% higher calcium absorption than calcium carbonate, both when taken with meals and on an empty stomach. This enhanced bioavailability directly supports the maintenance of bone mineral density and aids in the prevention of osteoporosis. The 20-27% increase in absorption is statistically significant and clinically relevant for maximizing calcium supplementation efficacy. Furthermore, it is associated with fewer gastrointestinal side effects compared to calcium carbonate, which can improve patient tolerability and adherence to supplementation regimens. This makes it particularly beneficial for older adults and individuals with hypochlorhydria (low stomach acid), as its absorption is less reliant on gastric acidity. Long-term benefits for bone health require sustained supplementation, often in conjunction with vitamin D.
How it works
Tricalcium citrate functions by dissociating in the gastrointestinal tract, releasing calcium ions and citrate anions. The citrate acts as a chelating agent, which enhances the solubility of calcium and facilitates its absorption. Calcium ions are primarily absorbed in the small intestine through both active transport mechanisms, such as TRPV6 channels in enterocytes, and passive diffusion. The citrate complex helps maintain calcium in a soluble form, preventing its precipitation and thereby increasing its availability for absorption. This mechanism contributes to its higher bioavailability compared to calcium carbonate, as it requires less gastric acid for dissolution and absorption, making it effective across a wider range of stomach pH conditions.
Side effects
Tricalcium citrate is generally considered safe and well-tolerated. Common side effects, occurring in more than 5% of users, are typically mild gastrointestinal discomforts such as bloating or gas, which are less frequent than those associated with calcium carbonate. Uncommon side effects (1-5%) may include mild constipation or diarrhea. Hypersensitivity reactions are very rare, occurring in less than 1% of users. Tricalcium citrate can interact with certain medications; specifically, it may chelate with antibiotics like tetracyclines and fluoroquinolones, reducing their absorption. Therefore, it's advisable to take these medications at different times. Contraindications include hypercalcemia (high blood calcium levels) or a known hypersensitivity to calcium citrate. While generally safe for the elderly and those with reduced gastric acid, caution is advised for patients with renal impairment due to the potential for increased calcium load.
Dosage
The minimum effective dose of tricalcium citrate to support bone health is typically 500 mg of elemental calcium daily. The optimal dosage range is generally between 500–1000 mg of elemental calcium per day, often recommended in combination with 800–1000 IU of vitamin D for enhanced absorption and bone metabolism. The maximum safe dose from all sources, including diet and supplements, is generally considered to be 2000–2500 mg of elemental calcium daily to prevent hypercalcemia. Tricalcium citrate can be taken with or without food due to its efficient absorption profile, which is less dependent on gastric acidity. Dosing should be adjusted based on the elemental calcium content of the specific product, as tricalcium citrate tetrahydrate contains approximately 21% elemental calcium. Vitamin D supplementation is highly recommended as a cofactor to optimize calcium absorption and utilization.
FAQs
Is tricalcium citrate better absorbed than calcium carbonate?
Yes, meta-analyses indicate that tricalcium citrate has approximately 20-27% higher calcium absorption than calcium carbonate, both with and without food.
Can it be taken without food?
Yes, tricalcium citrate's absorption is effective both with and without meals, making it a flexible option for supplementation.
Are there cardiovascular risks associated with tricalcium citrate?
Some meta-analyses suggest a potential link between calcium supplements and cardiovascular risk, but the evidence is inconclusive and not specific to tricalcium citrate.
How soon will benefits on bone health appear?
Improvements in bone mineral density typically require several months to years of consistent and adequate calcium supplementation, often combined with vitamin D.
Is tricalcium citrate safe for elderly individuals?
Yes, it is particularly beneficial for the elderly due to its less dependence on stomach acid for absorption, which can be reduced in older age.
Research Sources
- https://utsouthwestern.elsevierpure.com/en/publications/meta-analysis-of-calcium-bioavailability-a-comparison-of-calcium- – This meta-analysis by Heaney et al. (1999) reviewed 15 acute absorption studies involving 184 healthy adults. It concluded that calcium citrate absorption is 20-27% higher than calcium carbonate, with consistent results across various meal conditions. The study highlights the superior bioavailability of calcium citrate.
- http://medcraveonline.com/JNHFE/JNHFE-06-00214.pdf – This MedCrave meta-analysis summary confirmed the superior absorption of tricalcium citrate compared to other calcium forms. It also noted better bone parameter outcomes in some studies, reinforcing the findings of Heaney et al. regarding its enhanced bioavailability.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC10861607/ – This randomized controlled trial involving 268 elderly subjects over several months assessed the tolerability and safety of calcium citrate. It reported good adherence and no major safety concerns, suggesting that calcium citrate is a well-tolerated option for long-term supplementation in older populations.