by Andrew Magill
Featured, Health & Fitness, Healthy Eating

Feed Your Body Friday: Calcium

Exploring Micronutrients Series #2- Calcium

What is Calcium?
Per the National Institute of Health, Calcium is the most abundant mineral in the body. 99% of the Calcium in our body is found in the bones and teeth; the remaining 1% is utilized to support metabolic functions. The recommended daily allowance (RDA) of Calcium is between 1,000 and 1,200 mg for adult males and females. Children need more Calcium proportionally than adults, to support their growing frames. Calcium is naturally abundant in foods common in the Standard American Diet; and many other foods are fortified with Calcium.

by Brian Chow

Role in our bodies:
Calcium performs many critical roles in our bodies. A partial listing of the many functions Calcium serves in our bodies:

Supports bone structure and function
Vascular function and vasodilation
Muscle functioning (contraction and relaxation)
Nerve transmission
Intracellular signaling
Hormonal secretion
Fibrin stabilization (required for blood clotting)
Plays a key role in maintaining regular heartbeat


Calcium is one of several minerals required for bone health

Deficiency symptoms:
There are typically no symptoms in the short run associated with a Calcium deficiency. In the long run, a Calcium deficiency can cause osteopenia, which can lead to osteoporosis. Other possible symptoms of a Calcium deficiency include muscle cramps, high blood pressure, convulsions, tremors, tooth decay, poor appetite, lethargy, bone and joint pain and abnormal heart rhythm.

Calcium Excess:
It is possible to have too much Calcium in the body, typically from supplementation, which can result in constipation, kidney stones, renal insufficiency, vascular and soft tissue calcification and high levels of Calcium in urine. In addition, Dr. Carolyn Dean lists a host of other issues from allowing Calcium levels to remain unchecked by Magnesium levels in The Magnesium Miracle.

There are certain other vitamins and minerals that are critical to the absorption of Calcium, as well as the optimization of the levels of Calcium in the body. Vitamin D is the most widely touted cofactor, but others include Magnesium, Vitamin K2, Boron and Phosporus.

Food Sources:
Not surprisingly, dairy products are the richest sources of naturally-occurring Calcium. Other sources of Calcium include salmon, leafy greens, broccoli and certain legumes. In addition to naturally-occurring Calcium sources, many foods have been fortified with Calcium, including orange juice and cereals. Certain components in food, such as phytic acid (found in whole grains, nuts, seeds, legumes) and oxalic acid (found in spinach, turnip greens, sweet potatoes and legumes) can bind to the Calcium and inhibit absorption in the body. It is estimated that adults absorb 15-30% of the Calcium in foods, depending on the type of food.

by Andrew Magill

Dairy is one of the richest sources of dietary Calcium

How to Supplement:
While Calcium is available in many foods, some people are at risk for Calcium deficiency based on their diet. For instance, many people cannot tolerate dairy products or choose not to consume dairy for other health reasons. Vegans may need to pay careful attention to Calcium intake and possibly supplement, as the richest sources of Calcium are animal products. (however, it is possible for a Vegan to get all his/her Calcium from food sources!). Many multivitamins contain some amount of Calcium as well.

Many Calcium supplements come with Vitamins D3 and often Magnesium and Zinc to optimize absorption and usage in the body. The most common forms of Calcium in supplement form include carbonate and citrate. Calcium carbonate is a higher percentage of elemental Calcium (40%) than the citrate form (21%); however, the carbonate form is associated more with the gastrointestinal side effects that some may experience. Research shows that Calcium, regardless of form, is best absorbed in dosages under 500 mg at one time.

I personally get 325 mg of Calcium in my multivitamin. I do not feel I need to supplement beyond that, as I likely get plenty of Calcium in my diet and I have read enough to convince me that Calcium excess is more likely a concern than deficiency in my situation. Thus, I have chosen to supplement Magnesium to help keep my Calcium in check.

Other considerations:
If you think you may be deficient and would like to supplement with Calcium, please consult with your doctor first, particularly if you are on other medications or have any medical conditions.

Recommended reads:
This is meant to be an overview of Calcium, not a comprehensive article. For additional information, there is so much great information out there available and I highly recommend you research it further for yourself. I particularly think it is important to research Calcium in terms of its cofactors and optimal balance/ absorption. Here are some great book resources, in addition to the abundant information available over the internet:

   Vitamin K2 and the Calcium Paradox  by Kate Rheaume-Bleue

   The Calcium Lie II  by Robert Thompson and Kathleen Barnes


Photo credits: Brian Chow, woodleywonderworks, Andrew Magill