Excellent Food Sources of Calcium—And How to Optimize Your Intake

You know calcium as the mineral that’s crucial for strong bones and teeth, but it also plays an important role in how muscles function, blood vessels carry blood, and nerves send messages between the brain and the rest of the body. 

When people don’t consume enough calcium, over time that deficiency can cause health issues including fatigue, muscle pain and spasms, cognitive issues, abnormal heart rhythm, brittle hair and nails, tooth decay, osteopenia (mild to moderate bone loss), and osteoporosis (severe bone loss).

Experts agree the best way to get calcium is from food and drinks, not supplements. We turned to Adam Ross, RD, a performance nutrition specialist at the Atria Health and Research Institute, to help break down which foods have the most calcium and are best absorbed by the body, and how to ensure your body is getting what it needs.

Why calcium is key throughout your life

When you’re young, calcium helps increase bone density and build the “bone bank” that your body will draw on for the rest of your life. You reach peak bone mass as a young adult, and as you get older, continuing to consume enough calcium helps maintain that bone and slow the bone loss that leads to osteoporosis and fractures. (See our guides to supporting bone density and bone health at every age here.)

How much calcium do you need?

The amount of calcium people need varies throughout their lives, and your physician or dietitian can help you pinpoint your own daily needs. That said, national guidelines recommend benchmarks by age and sex to get you started:

About 99% of the body’s calcium is stored in your bones and teeth, while just 1% is in your blood. A calcium blood test often looks normal even when your intake is low, explains Ross, because your body starts pulling calcium from your bones when it needs more. A more useful test is a bone density scan, such as DEXA, which uses very low dose X-ray. Your doctor can also run a calcium urine test or tests to check related blood levels such as vitamin D, magnesium, or parathyroid hormone (PTH).

When to consider a supplement

Food is the preferred method for getting calcium, Ross says, and supplements should be used only to fill the gap between what your diet provides and the recommended daily amount. But there are some groups that may be reasonable candidates for supplementation:

• People whose diets mean they can’t get enough calcium from food (those with lactose intolerance or other allergies, limited access to calcium-rich foods, and vegans).
• Postmenopausal women and older adults, particularly those with osteopenia or osteoporosis or those on osteoporosis drug therapy, for whom moderate calcium (1,000–1,200 mg/day) and vitamin D can reduce fracture risk. 
• Amenorrheic women (those not having periods).

Calcium carbonate is the cheapest and most concentrated form, but it’s best taken with meals and can sometimes cause bloating and constipation. Calcium citrate is absorbed with or without food and may be gentler on the gut. “Importantly, more is not better,” Ross says. “Intake above the recommended amounts has not not been shown to add benefit and may actually cause harm.”

Who should be cautious

For most people, total calcium (food + supplements) should not exceed an upper limit of around 2,000 mg per day for adults over 50 and 2,500 mg per day for younger adults. Excess calcium can cause constipation and interfere with iron and zinc absorption. 

People prone to kidney stones shouldn't restrict calcium, but they do need to be strategic. Dietary calcium protects against calcium-oxalate stones (the most common type of kidney stones) by trapping oxalate in the gut so it exits safely in stool. However, calcium supplements taken on an empty stomach can raise urinary calcium and increase stone risk. To minimize risk, prioritize food sources, take any required supplements directly with meals, and consider calcium citrate, which provides stone-inhibiting citrate.

People concerned about cardiovascular risk should also talk with their doctor because some research has suggested that calcium supplements (again, not dietary calcium) may cause a small increase in the risk of cardiovascular disease, though other studies have said they don’t increase risk and more research is needed.

Other groups who should be cautious include: anyone at risk of medical conditions such as hypercalcemia, primary hyperparathyroidism, certain cancers, sarcoidosis, or those taking high-dose vitamin D.

How to optimize the calcium in your food

Interestingly, knowing which foods have the most calcium doesn’t provide the full picture. Here is Ross’s top advice to ensure your body can use all the calcium you consume: 

• Spread your calcium intake throughout the day. Calcium is best absorbed in doses of less than 500 – 600 mg at a time, so it’s best to space out calcium-rich foods and supplements. 
• Pair calcium with adequate vitamin D, which is essential for absorption.
• Not all foods let your body absorb calcium in the same way. Compounds in certain foods called oxalates and phytates bind to calcium and reduce your body’s absorption even if the food contains lots of calcium.
  • High-oxalate foods include spinach, soy products, legumes, and almonds
  • High-phytate foods include wheat bran, some whole grains, nuts, and seeds
• Cooking can help reduce soluble oxalate in vegetables, but the more reliable move is to go for naturally low-oxalate, calcium-rich vegetables such as kale, broccoli, and bok choy.
• Fortified plant milks (almond, soy, and oat milk) can be useful, but absorption is lower than cow’s milk and they need to be shaken well to prevent calcium from settling.

Calcium content in everyday foods

Here are the calcium contents in many common foods.

Dairy milk

Plant-based milks

Yogurt and frozen dairy

Cheese

Beans and lentils

Vegetables

Starches

Nuts and seeds

Proteins

Fruits

Desserts

Serving sizes are based on typical portions, and calcium content is approximate.

The bottom line

Calcium is crucial for your bones and many bodily functions. Foods and beverages are the best way to get it. If you’re concerned you may not be getting enough calcium, speak with a doctor or dietitian who can help figure out the right daily amount for you and whether any other steps are necessary. There are many everyday foods that contain high levels of absorbable calcium, and learning which ones to prioritize can help keep your bones healthy for years to come.

Sources: UpToDate; Cronometer; Nutrition Coordinating Center Food & Nutrient Database; United States Department of Agriculture National Nutrient Database for Standard Reference; International Osteoporosis Foundation