What Is Calcium?
Calcium is a mineral that’s well-known for its key role in bone health. Calcium also helps maintain heart rhythm, muscle function, and more. Because of its health benefits, calcium is one of the best-selling supplements in the U.S.
Your body holds an abundance of calcium. Around 99% of this mineral is stored in your bones and teeth. The other 1% is in your blood and soft tissues.
Eating foods rich in calcium is important for growing and keeping your bones strong. It’s also an important nutrient for healthy cell function. Your body needs calcium to support muscle and nerve function and regulate blood pressure and hormone levels, as well as help with communication between cells.
Calcium Health Benefits
Calcium has many uses. It's an ingredient in antacids, and doctors use it to control high levels of magnesium, phosphorus, and potassium in your blood.
It may also ease PMS (premenstrual syndrome) symptoms and play a role in preventing certain cancers. For example, some research shows that calcium with vitamin D may help protect premenopausal women from breast cancer.
Further, calcium serves as an important nutrient for:
Your body maintains a certain level of calcium in your blood at all times so that your cells can work properly. A dip in calcium blood levels will signal your body to borrow calcium from your bones.
Your bones continually break down and rebuild. You can get osteoporosis when there's an imbalance between bone building and bone breakdown. Before age 30, you build bone at a faster rate than you break it down. After age 30, the rates reverse. This is why older people have more brittle bones that are at higher risk of breaking.
One way to prevent bone loss after age 30 is by getting enough calcium, which reduces the amount your body has to take from your bones. Calcium supplements are standard for treating and preventing osteoporosis and the condition that often comes before it, osteopenia (loss of bone density).
Blood pressure control
Calcium helps blood vessels contract and relax, so it's needed to maintain healthy blood pressure. Recent studies show that to get this benefit, you need to get the calcium from food rather than supplements.
Decreased risk of kidney stones
Calcium also prevents kidney stones from forming by decreasing your body's absorption of oxalates, which are found in many foods like spinach, beets, raspberries, and sweet potatoes. Oxalates are linked to a higher risk of kidney stones. Only calcium from food — not supplements — can help reduce this risk.
The U.S. Food and Nutrition Board has set dietary reference intake (DRI) and recommended daily allowance (RDA) standards for calcium. Getting this amount from the food you eat, with or without supplements, may be enough to keep your bones healthy. Doctors may recommend higher doses.
|1,200 milligrams/day for women; 1,000 for men
If you're pregnant or breastfeeding, you don’t need amounts higher than the recommendations above.
The tolerable upper intake levels (ULs) of a supplement are the highest amount that most people can take safely. For calcium, it's:
- Infants 0-6 months: 1,000 milligrams/day
- Infants 7-12 months: 1,500 milligrams/day
- Children 1-8 years: 2,500 milligrams/day
- Children/teens 9-18 years: 3,000 milligrams/day
- Adults 19-50 years: 2,500 milligrams/day
- Adults over 51 years: 2,000 milligrams/day
In general, it's best to take calcium supplements with food. For better absorption, don't take more than 500 milligrams at one time. Split up larger doses over the course of the day. For your body to make use of calcium properly, you also need to get enough vitamin D and magnesium.
Foods With Calcium
While many supplements are available, scientists recommend that at least half of your calcium intake come from your diet.
These five foods are some of the best sources of calcium:
1. Dairy products
Products like milk, yogurt, and cheese are rich in calcium and also tend to be the best-absorbed sources of it. Your body doesn't absorb calcium as well from plant-based foods.
2. Calcium-fortified foods
Cereals are often fortified with calcium. Some fortified cereals provide as much as 100 milligrams of calcium per serving.
3. Canned salmon
Aside from dairy products, canned salmon is one of the best dietary sources of calcium. Just 3 ounces of canned salmon provides 181 milligrams. Salmon also contains vitamin D, which helps your body absorb more calcium.
4. Flour tortillas
Good news for carb lovers: one 10-inch flour tortilla provides you with 90 milligrams of calcium.
5. Canned baked beans
Four ounces of canned baked beans contain about 126 milligrams of calcium. Beans also contain a lot of fiber.
Vegan sources of calcium
Dried figs make for a healthy, sweet, and calcium-dense snack. Two figs contain about 27 milligrams. As a natural sweetener, this fruit is also a healthier alternative to refined sugars.
2. Dark green, leafy vegetables
Cooked kale, spinach, and collard greens are all good calcium sources. Surprisingly, cooked kale has more calcium per serving than milk, at 177 milligrams per cup. This versatile leafy green also fights against heart disease, cancer, and inflammation.
Cooked collard greens have the highest amount: a cup provides 268 milligrams of calcium.
Foods made from soybeans are great sources of calcium. Some soy products include:
- Soy milk
One cup of dry-roasted soybeans has 130 milligrams of calcium, making them an excellent source for those who follow a vegan diet.
4. Bok choy
Bok choy — also called white cabbage, Chinese cabbage, or pak-choi — has about 74 milligrams of calcium in every cup.
Bok choy is also packed with vitamin A and vitamin C. One cup of the cooked leafy green provides more than 40% of the RDA for vitamin A and almost 2/3 of the RDA for vitamin C.
A cup of raw broccoli has about 35 milligrams of calcium. The same amount of cooked broccoli contains 76 milligrams.
One whole orange has around 60 milligrams of calcium, making it one of the most calcium-rich fruits.
For an added mineral boost, you can pick up calcium-fortified orange juice at the grocery store. Calcium citrate malate is a well-absorbed form found in some fortified juices.
While many seeds are excellent sources of calcium, the winners are poppy, pumpkin, sesame, celery, and chia seeds.
Two tablespoons of chia seeds contain about 14% of your RDA of calcium.
8. Winged beans
Winged beans, also called goa beans, grow in humid, tropical countries. A 44-gram serving gives you more than 4% of your recommended daily value of calcium.
If you're lactose intolerant or vegan, you may not get enough calcium from your diet, as dairy products are one of the most common sources of calcium.
You may want to talk to your doctor about calcium supplements and the best way to take them if you:
- Follow a vegan diet
- Can’t digest lactose (you’re lactose intolerant)
- Eat or drink a lot of protein or sodium, which can cause your body to lose more calcium
- Have thin, weak bones (osteoporosis)
- Take long-term corticosteroid treatments
- Have bowel or digestive diseases and can’t absorb calcium well
Studies suggest that calcium supplements may have some unwanted effects:
- Side effects. At normal doses, calcium supplements may cause bloating, gas, and constipation. Very high doses of calcium can lead to kidney stones. Some studies show that taking calcium supplements in addition to a diet high in calcium could raise your risk of heart attacks and strokes. But we need more research.
- Interactions. If you take any prescription or over-the-counter medicines regularly, ask your doctor if it's safe to use calcium supplements. Calcium can interact with drugs for heart disease, diabetes, epilepsy, and other conditions. High doses of vitamin D can result in dangerously high levels of calcium. High doses of calcium can also prevent your body from absorbing minerals like iron and zinc. In general, take calcium 1 to 2 hours apart from other supplements or medications. If you take them at the same time, calcium can bind to those products, and they’ll pass from your body without being absorbed.
- Other forms of calcium. There’s no need to use products known as "coral calcium." Claims made that coral calcium is better than regular calcium are unproven. Also, coral calcium products may have dangerous amounts of lead.
- Risks. If you have kidney disease, heart problems, sarcoidosis, or bone tumors, ask your doctor before you take calcium supplements.
- Overdose. High levels of calcium in your blood can cause nausea, dry mouth, belly pain, an irregular heartbeat, confusion, and death.