The range of absorption narrows further and increases percentage-wise when calcium is taken in smaller doses of 300 mg - 500 mg throughout the day, which is particularly helpful for people who are not able to absorb higher amounts of calcium in a single meal. However the largest single dose of the day is best taken in the evening, as calcium requirements are greatest during sleep, hence deficiency symptoms such as nocturnal leg cramps or insomnia. When supplemented with food, overall uptake of all types of calcium is up to 30% greater, and absorption between calcium citrate and calcium carbonate for instance becomes virtually identical. Inconsistencies are found only when calcium is supplemented in different forms, such as tablets versus gelatin capsules, where the gelatin itself may not dissolve properly in a low acid environment... Full Text