Efficiently, as your intake increases, it's best to take calcium in smaller doses throughout the day to facilitate absorption. You should not take more than 500 milligrams of calcium at a time and allow 4 to 6 hours between doses. To maximize calcium absorption, do not take more than 500 mg at a time. You can take a 500 mg supplement in the morning and another in the evening.
If you take a supplement that also contains vitamin D, it will help your body absorb calcium more efficiently. The higher the dose of calcium, the less it will be absorbed. For maximum absorption, no more than 500 mg of calcium should be taken in a single dose. If you need more than 500 mg as a supplement, take your doses at least four hours apart.
If you think you need a calcium supplement, ask your doctor or a dietician to recommend one. Taking calcium and vitamin D supplements along with thiazide diuretics may increase the chance of developing kidney stones. The amount of calcium the body will absorb from supplements depends on the form of the calcium in the supplement, how well the calcium dissolves in the intestines, and the amount of calcium in the body. Calcium supplements are also available in the form of gluconate, lactate, or phosphate, but they generally contain less absorbable calcium.
Calcium carbonate supplements dissolve better in an acidic environment, so they should be taken with meals. It can be difficult for some people to get enough calcium from their diet alone, especially if they don't eat dairy products. The best way to get enough calcium every day is to eat a variety of healthy foods from all food groups. Consuming much more than the recommended amount of calcium from foods and supplements increases the risk of side effects, so it's best to avoid taking too much.
Calcium can also decrease the absorption of some medications, such as osteoporosis medications, thyroid medications, and some antibiotics. Excess calcium can increase the risk of kidney stones, constipation, or even accumulation of calcium in the blood vessels, in addition to hindering the absorption of iron and zinc. Getting enough vitamin D every day from foods such as fortified milk or natural sunlight is important to help your body absorb and use calcium from food. Calcium helps blood vessels contract (narrow) and expand, causes muscles to contract, helps send messages through the nervous system, and helps glands secrete hormones.
Other organizations, such as the National Osteoporosis Foundation and the Institute of Medicine, recommend supplements if you don't meet your daily calcium needs through diet alone. Adults ages 19 to 50 should not consume more than 2500 mg of calcium in total per day (including food and supplements). If you're a woman over 50 and you don't take estrogen, you'll need to increase your calcium level up to 1000 to 1200 mg a day. People who follow a vegan diet or consume large amounts of protein and sodium may also not get enough calcium.