From the Guidelines
The recommended dose of calcium carbonate with vitamin D3 is typically 1200 mg of calcium and 800-1000 IU of vitamin D3 daily, as suggested by the NCCN Bone Health in Cancer Care Task Force 1. This dose is recommended to maintain proper calcium levels in the blood and support bone health.
- The supplements should be taken with meals to enhance calcium absorption, with doses separated by at least 4-6 hours.
- For optimal absorption, calcium carbonate specifically should be taken with food since it requires stomach acid for proper dissolution.
- Many people benefit from taking one dose in the morning and another in the evening.
- If you're taking higher doses of calcium (over 500 mg at once), splitting the dose improves absorption since the body can only absorb limited amounts at one time.
- These supplements work together synergistically - vitamin D3 enhances calcium absorption in the intestines and helps maintain proper calcium levels in the blood, while calcium is essential for bone health, muscle function, and nerve transmission.
- Individuals with certain medical conditions or those taking other medications should consult their healthcare provider before starting this regimen, as calcium can interact with some medications including certain antibiotics and blood pressure medications. The USPSTF also recommends vitamin D supplementation to prevent falls in community-dwelling adults aged 65 years or older who are at increased risk for falls because of a history of recent falls or vitamin D deficiency 1. However, the most recent and highest quality study, which is the NCCN task force report, recommends a daily intake of 1200 mg of calcium and 800-1000 IU of vitamin D3 1.
From the Research
Dose and Frequency of Calcium Carb/Vit D3
- The recommended daily supplementation with vitamin D is 800 IU, as advocated in most guidelines 2, 3.
- Calcium supplementation should be tailored to the patient's need, with a usual requirement of 500 mg per day to achieve a total intake of 1,200 mg 2.
- The combination of calcium and vitamin D is effective in reducing the incidence of non-vertebral and hip fractures when administered at respective dosages of at least 1,200 mg and 800 IU per day 3.
- Calcium citrate is preferred over calcium carbonate due to its better absorption properties, with approximately 24% better intestinal absorption 2, 3.
- The maximum dose of elemental calcium that should be taken at a time is 500 mg, and it is recommended to spread out calcium intake throughout the day 4, 5.
- Vitamin D intakes of at least 600 IU per day (up to 1,000 IU/day) are recommended for individuals older than 70 years, in addition to the calcium requirement of 1,200 mg per day 5.
- Adding vitamin D to calcium supplements can increase calcium absorption, even in healthy women 6.