Calcium Sources and Functions

Calcium Sources and Functions

All of the nutrient minerals work together to keep you healthy and feeling good. Here is a summary of the role of calcium, a major mineral in your good health.

What it does Helps maintain healthy bones and teeth, normal blood pressure and clotting and proper muscle and nerve function
Daily needs
[Infants: 200-260 mg] [Children: 700-1300 mg] [Men: 1,000-1300 mg] [Women: 1,000-1300 mg] [Pregnant: 1,000-1,300 mg] [Lactating: 1,000-1,300 mg]
Not enough Stunted growth in children; Osteoporosis in adults
Too Much Frequent urination; constipation; nausea; thirst; abdominal pain Severe: delirium; coma
Foods Dairy products; greens (kale family); legumes; some tofu

*The lower value is for infants up to 6 mos., the higher value is for infants up to a year old.
† The first value is for children 1-3 with the amount increasing until age 18.
# Adequate Intake (AI) is the average amount a healthy person consumes; no RDA established.

Most abundant mineral

Not surprisingly, calcium is the most abundant mineral found in your body, with most of it being located in your bones and teeth. It allows your bones to have a rigid frame; without it, your bones would be frail and break easily.


In addition to helping provide a rigid structure for your muscles and tendons to attach to, the bones are also depositories for calcium, so that it is readily available to maintain your blood levels. Although calcium is also stored in your teeth, it is less available than from your bones.

Interesting Fact about Calcium Sources and Functions: Although bones appear to be solid and unchanging, they are actually constantly gaining and losing minerals. If your body detects that your blood calcium level is low, it can remove it from your bones to bring up the level in your blood. Conversely, when your blood levels are high enough, your body can replace the calcium in your bones.

In addition to bone health

The calcium that circulates in your body is important for (1) normal blood pressure and the (2) clotting of the blood. It also is involved in the (3) contraction of your muscles, (4) blood vessel dilation, (5) hormone secretion, (6) enzyme activity and (7) normal nerve function. There is also some evidence that calcium may have a role in (8) maintaining a normal body weight and in the (9) prevention of diseases such as hypertension (high blood pressure), colon cancer, and diabetes.

Good Calcium Sources

Calcium is found most abundantly in dairy products.

Milk… Yogurt… Cheese… Ice cream…

It is also found in some non-dairy sources.

Broccoli… Cauliflower… Kale… Parsley… Bok Choy… Tofu… Sardines and other fish eaten with their bones… Oysters… Almonds… Sesame seeds… White beans… Pinto beans… Sweet potatoes… Whole wheat bread…

Caveat for Calcium Sources: Although calcium is present in some foods, such as spinach and rhubarb, these foods also contain oxalic acid, which binds the calcium and makes it virtually unavailable to your body. However, you can still enjoy these dark, leafies for all of the other important nutrients they contain, and you will still get at least a small amount of absorbable calcium into the bargain!

Fortified products

Some products, such as orange juice, some fruit drinks, and some cereals, are fortified with calcium. It is important to note that the type of calcium used in fortification will affect its availability for absorption in your body. This means that it is possible that not all of the calcium listed on the label of the fortified food, will actually be accessible to your body.

Should I supplement with pills?

As always, it is better to get your nutrients from the foods you eat, especially because they work in concert with each other. However, if you are unable to get enough calcium in your diet, possibly due to lactose-intolerance or a vegan lifestyle, you can supplement your diet with pills.

Be aware that most calcium supplements should be taken with mealsand that for the sake of good absorption; you should limit your supplementation to 500 mg at one time. Accordingly, you may want to break up your supplementation, taking one in the morning and one in the evening.


Not surprisingly, when calcium is discussed, the subject of osteoporosis often comes up. Since bone loss and calcium deficiency are closely linked, it is important to get enough this important mineral in your diet, especially in the first three decades of your life, when your bone density is being established.

--Caveat for Calcium Sources: It is not easy to know if you are at risk for osteoporosis, since your blood calcium levels will not reflect bone loss. You can lose mineral from your bones for years, and it will not show up until the bone loss is in an advanced stage.

Who gets osteoporosis?

Risk factors associated with osteoporosis are well documented.

-Long-term calcium deficiency…

-Women more than men…

-Older people rather than younger…

-Frail people rather than sturdy…

-Cigarette smokers…

-Excessive alcohol consumption…

-Family history of osteoporosis…

-Sedentary lifestyle…

-Estrogen deficiency in women and Testosterone deficiency in men…

-Long-term Vitamin D deficiency…

Fun Fact for Calcium Sources: Weight bearing exercise, such as brisk walking, tennis or working out with weights can significantly reduce your risk of developing osteoporosis. This is because when you build heavier muscles, your body responds by building heavier, denser bones to support those heavier muscles.

Although your chance of developing osteoporosis is affected by some factors you cannot control, such as heredity, gender and age, your diet and lifestyle also have an effect on your bone health. 

The two periods of your life when calcium consumption most affects your bone health are the first part, when you are growing and developing and the last part, when your ability to absorb calcium and your stores may be compromised.

Upper Limit

The Upper Intake Level for adults that has been established for calcium is 2500 mg per day.

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