How to Take Calcium Supplements for Maximum Absorption

The word “calcium” might conjure an image of a tall glass of cow’s milk. While a cup of milk is an excellent source of calcium, the mineral is also abundant in yogurt, tofu, canned fish and fortified nondairy milk. Surprisingly, even leafy greens and broccoli contribute small amounts of calcium to the diet. However, if your intake of these calcium-rich foods is low, you may have been advised to take a calcium supplement to meet your daily needs and support bone health.

Getting enough calcium in the day goes beyond maintaining strong bones and teeth. “Calcium also plays an important role in blood clotting, helping muscles to contract and regulating heart rhythms and nerve functions,” says Kristen Hruschak, RDfounder of Aging Well Nutrition Services. The majority of calcium is stored in bones, and the body constantly pulls from and restocks its calcium stores to support these vital functions and maintain balance, she explains. Luckily, you can help your body replenish its calcium stores through dietary changes and supplementation. But to get the most out of your calcium supplement, it’s important to time it right. Keep reading to learn how to maximize absorption of your calcium supplement.

Factors Affecting Calcium Absorption
Age
The natural aging process diminishes our body’s ability to absorb calcium. Hruschak explains that calcium absorption in the intestines heavily depends on the presence of the active form of vitamin D, called calcitriol. Our kidneys play a pivotal role in converting vitamin D into calcitriol. However, as we age, the kidneys may become less efficient at this process, resulting in reduced calcium absorption and an increased risk of bone loss. Consequently, older adults need more calcium than other adult populations to prevent calcium deficiency and maintain bone health.

Hormonal Status
During menopause, estrogen levels drop, which is a problem for your bones. The hormone plays a crucial role in maintaining bone density and strength by enhancing calcium absorption, promoting bone formation and inhibiting bone breakdown. With lower estrogen levels, you may experience bone loss and an increased risk of osteoporosis. If you are in perimenopause or menopause, make sure you’re getting enough calcium in your diet.

Type of Calcium Supplement
While browsing the store shelves, you’ll find a wide selection of calcium supplements available in various forms. Some of the most common forms include calcium carbonate, calcium citrate, calcium gluconate and calcium lactate. Among the options, Hruschak says that calcium citrate, lactate and gluconate are more easily absorbed and tend to be more well tolerated compared to calcium carbonate.

Optimal Timing for Calcium Supplement Intake
Timing with Meals
Pairing your calcium supplement with or without a meal impacts how well it’s absorbed—and how effective it is. Calcium citrate, lactate and gluconate are well-absorbed at any time of day and can be taken with or without food, says Hruschak. On the other hand, if you’re using calcium carbonate, take it with food or immediately after eating to improve absorption. Doing so also reduces the likelihood of gastrointestinal side effects, like gas, bloating or constipation.

However, the types of foods you eat can also impact calcium absorption. For example, phytates are plant compounds found in bran, nuts, whole grains, dried beans and seeds that can bind to calcium and make the mineral difficult absorb, explains Hruschak. Similarly, oxalates found in rhubarb, spinach, nuts and teas can do the same. Soaking dried beans and cooking these foods can minimize their interference—or you can take your calcium supplement separately from meals high in these foods.

Timing Away from Medications
Certain medications can also interfere with calcium absorption. Notably, glucocorticoids, such as prednisone, can reduce calcium absorption. It’s generally recommended to take calcium supplements two to four hours apart from these medications for optimal absorption, says Hruschak. Other medications that may negatively interact with calcium supplements include lithium, quinolone antibiotics, dolutegravir and levothyroxine. If you’re taking both calcium and one of these meds, talk to your health care provider about whether you need to monitor your calcium levels.

Taking Calcium Supplements with Other Nutrients
To get the most out of your calcium supplement, take it in combination with vitamin D, magnesium and vitamin K. It’s already been established that vitamin D is a powerful duo with calcium—they’re like leading actors in a (bone-strengthening) film. Magnesium plays a supporting role—it helps activate vitamin D. We also can’t forget vitamin K, which has a role of its own in the mix. Vitamin K (specifically vitamin K2) activates proteins needed for bone mineralization. This process also helps prevent blood vessel calcification, which is linked to cardiovascular disease. Getting enough vitamin D, magnesium and vitamin K from your diet, along with calcium, can greatly benefit bone and overall health.

Tips for Enhancing Calcium Supplement Absorption
When it comes to maximizing the absorption of calcium supplements, Hruschak recommends the following:

Take no more than 500 to 600 milligrams of calcium at once. Smaller doses are easier to absorb. Space supplements at least four hours apart.
Pair calcium supplements with vitamin D supplements for better absorption.
Although calcium citrate, lactate and gluconate are typically well absorbed whether taken with a meal or not, there’s an added perk to taking calcium and vitamin D together with a meal. That’s because dietary fat from your food boosts the absorption of vitamin D. The result? Better calcium absorption.
Avoid high-oxalate and high-phytate foods, as well as high doses of caffeine at the time of taking calcium supplements.

The Bottom Line
To get the most out of your calcium supplement, think about the dose and the foods you take it with, as well as medications you’re on. While you can take calcium citrate, lactate and gluconate with or without a meal and at varying times of day, you’ll get the most out of your calcium supplement if you take it with food, especially foods that contain vitamin D, and make sure you get enough magnesium and vitamin K in your diet. If you’re taking a calcium supplement, check in with your health care provider for any guidance specific to your health needs.