From the Guidelines
Oyster shell calcium carbonate 1250 mg is equivalent to oyster shell calcium 500 mg in terms of elemental calcium content, as calcium carbonate is approximately 40% calcium by weight, providing around 500 mg of elemental calcium per 1250 mg dose. When considering calcium supplements, it's essential to look at the elemental calcium content, as this is what the body actually uses. According to a study published in the New England Journal of Medicine 1, calcium carbonate supplements contain about 40% elemental calcium. This means that 1250 mg of calcium carbonate would provide approximately 500 mg of elemental calcium. Some key points to consider when choosing a calcium supplement include:
- The formulation and dose of the supplement, with calcium carbonate being the least expensive and most commonly used option 1
- The importance of taking calcium carbonate with meals, as acidity improves absorption 1
- Potential side effects, such as constipation, associated with calcium carbonate supplements 1 It's crucial to check the label to confirm the amount of elemental calcium in any supplement, as this can vary between products. Additionally, factors like absorption and effectiveness can be influenced by when and how the supplement is taken, so following the instructions on the label or consulting with a healthcare provider is recommended for optimal use.
From the FDA Drug Label
Each chewable tablet contains: calcium 300 mg Active ingredient (in each chewable tablet) Calcium carbonate 750 mg
The calcium content in oyster shell calcium carbonate 1250 mg is not directly stated in the provided drug labels. However, based on the information from 2 and 2, we can see that calcium carbonate 750 mg contains an unspecified amount of calcium, and calcium carbonate is not equivalent to calcium. Since the labels do not provide a direct conversion or comparison between oyster shell calcium carbonate 1250 mg and oyster shell calcium 500 mg, The FDA drug label does not answer the question.
From the Research
Calcium Content Comparison
- Oyster shell calcium carbonate 1250 milligrams (mg) is not directly equivalent to oyster shell calcium 500 milligrams (mg) in terms of elemental calcium content 3, 4.
- The elemental calcium content in oyster shell calcium carbonate can vary depending on the source and processing method 4, 5.
- A study comparing calcium carbonate preparations found that a 1250 mg dose of calcium carbonate was an effective phosphate binder, but it did not specifically address the equivalence to oyster shell calcium 500 mg 6.
Bioavailability and Utilization
- Calcium derived from hydrolysed oyster shell may be absorbed and utilized more easily than calcium carbonate 3.
- The bioavailability of calcium from different sources, including oyster shell and calcium carbonate, can vary depending on factors such as the presence of other nutrients and the individual's nutritional status 3, 7.
Calcium Sources and Egg Production
- A study on laying hens found that extruded eggshell, limestone, and oyster shell were all effective calcium sources, but the study did not directly compare oyster shell calcium carbonate 1250 mg to oyster shell calcium 500 mg 7.