While it’s well known that calcium is needed for strong teeth and bones, we also need it for other reasons. This important mineral helps our blood vessels contract and dilate, aids with blood clotting, is needed for transmitting nerve signals, and assists with hormone secretion.1
As the most abundant mineral in our bodies, we store most of our calcium in our bones and teeth. When we need it for other functions, we’re able to take some from the bones where the bloodstream takes it to where its needed.1
Not getting enough calcium from the diet can cause too much leaching from our bones, which leads to weakened bones. Diseases like osteomalacia and osteoporosis are the result of chronic calcium deficiency.1,2
According to the Institute of Medicine, the current recommended dietary allowances (RDA) of calcium for adults are:2
|
Age |
Women |
Men |
|
19-50 Years |
1000 mg |
1000 mg |
|
51-70 Years |
1200 mg |
1000 mg |
|
70+ Years |
1200 mg |
1200 mg |
It’s wise to consume a wide variety of foods to maximize vitamin and mineral intake, and to supplement when needed to reach the RDAs.1 Calcium is found abundantly in dairy products and canned fish that have the bones included.1,3
Vegan calcium sources include leafy greens like broccoli, kale, and bok choy. Some cereals, juices, and soy products like tofu and soy beverages are also good vegan sources, but most of the calcium in these products comes from added fortification.1,3
While it may be best to get all the nutrients we need from food, it’s not always possible. Doctors and dietitians may recommend calcium supplementation for certain people.
People who may be at higher risk for calcium deficiency include:
- People who avoid dairy because of allergy, intolerance, or dislike.1,4
- Vegans or vegetarians who don’t consume dairy products.4
- Post-menopausal women.1
- People with intestinal diseases like celiac or inflammatory bowel disease.1,4
Keep in mind that all supplements should be taken with caution. Recent research shows that getting too much calcium can be harmful in the long term and that taking more than 500 mg at one time is not beneficial.1,6
It’s not considered safe for adults under age 50 to get more than 2,500 mg of total calcium per day, or more than 2,000 mg for adults over 50.1 It’s always best to talk to your doctor before taking any new medications or supplements.
There are so many choices when it comes to calcium supplementation that consumers can be overwhelmed and confused. In this section, we’ll compare the popular types of supplements: calcium lactate, calcium citrate, and calcium carbonate.
Elemental calcium isn’t chemically stable, so supplements are sold as compounds, not as the elemental mineral by itself. Each different compound contains a different percentage of elemental calcium.4,5
For example, calcium lactate contains 13% elemental calcium, calcium citrate contains 21%, and calcium carbonate contains 40%.4, 10, 11 This means that a 1000 mg tablet of calcium lactate will have 130 mg of elemental calcium, while a 1000 mg tablet of calcium citrate will contain 210 mg, and a 1000 mg table of calcium carbonate will have 400 mg.4
Calcium carbonate has been shown to have superior absorption when ingested with food, which is when we recommend taking a calcium supplement – i.e. take with meals.12, 13
Because the carbonate form has the highest content of calcium by weight, this allows less expense and a smaller pill size containing more calcium than citrate and other forms.14 Further, calcium citrate may inhibit absorption of non-heme iron while other forms including carbonate shows little to no effect.15
Once we swallow a supplement, our stomach acid breaks the compound down so that we can absorb the calcium from the digestive systems into our bodies. In theory, once the supplement is broken down, the calcium is the same.5
Lower stomach acid can be caused by age, medical conditions, or medications.4,5
How To Take Calcium Supplements For Best Absorption?
Like all nutrients, calcium is a team player and can’t work alone. Adequate intake of other vitamins and minerals are needed for calcium to do its job.1
For instance:
Vitamin D is needed to help calcium absorption through the intestines and into the bloodstream.7
It’s hard to get adequate vitamin D from food because humans are meant to make most of it with skin exposure to sunlight. Many of us have low levels, especially when we live in northern latitudes and if we have darker skin tones. For these people, doctors generally recommend a vitamin D supplement.7
Magnesium helps transport calcium over cell membranes and helps with creating our bone structure. Magnesium is rich in many plant sources including pumpkin seeds, chia seeds, spinach, peanuts, potatoes, and beans.8
Vitamin K is involved with calcium in bone metabolism and mineralization. Getting enough vitamin K has been associated with better bone density.9
Good sources of vitamin K include dark leafy green vegetables like collard greens, turnip greens, kale, and spinach. Broccoli, pumpkin, and soybeans are also good food sources.9
While research on calcium is ongoing, there’s no doubt that it’s important for bone health and quality of life during the later years. Falls and fractures can be debilitating and interfere with functional independence. Be sure to meet your daily recommended amounts consistently with calcium-rich foods and supplements if needed.
