All About Calcium
Calcium’s function in the body
Calcium is the most abundant mineral in our blood, and plays major roles in our bodies
ability to function. Mostly calcium’s function is making our bones hard and flexible. It
also makes up a component of blood and other tissues. Blood calcium plays an important
role in the blood ph balance of the body, and because of this, it is also necessary for nerve
transmission and muscle contractions.
When the blood becomes low in calcium, a hormone is secreted by the parathyroid gland.
This starts a calcium preserving sequence of events in order to increase blood calcium
levels. Vitamin D activation is stimulated, calcium is reabsorbed by the kidneys, and the
hormone causes cells to breakdown bone and put calcium back into the bloodstream.
Risk factors for calcium deficiency
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Caucasian or Asian race
Females after menopause
Males and females over the age of 50 (due to decreased bone density, decreased
estrogen and testosterone, and decreased amounts of stomach acid)
Reduced stomach acid as with chronic acid suppression therapy for GERD or
heartburn
People with a bypass of their intestine (as with history of gastric bypass, BPD,
Chron’s disease, short gut syndrome).
Family history of osteoporosis, or personal history of fractures or frequent falls
Alcohol abuse, smoking, low calcium intake, sedentary lifestyle
Signs and symptoms of deficiency
Most commonly, bloodwork results will show an increased parathyroid hormone level
(PTH). There are no other early detectable signs and without proper screening, the
diagnosis is not made until damage has already been done.
More obvious consequences of calcium deficiency later detected include:
 Osteoporosis (weakening of the bones in the body.) Bones most at risk are the hip,
knee and spine. One in 3 women and one in 5 men over the age of 50 develop
osteoporosis.
 Undetected or untreated osteoporosis leads to fractures of the major bones.
 Breaking of bones with normal daily activities
 Muscle twitching or spasms
 Dangerously low levels can cause convulsions and even death!
Dietary sources (in order of highest to medium rich foods)
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nonfat plain or greek yogurt
collard greens
fruit flavored non fat yogurt
ricotta cheese 2%
nonfat milk
swiss cheese
canned fish such as sardines or salmon
kale, bok-choy, tofu
Supplement recommendations
In people with low stomach acid and/or malabsorption, such as with a gastric bypass,
BPD, gastrectomy, or people over the age of 50, Calcium should be in a citrate form. This
type of calcium is more easily absorbed without large amounts of stomach acid. Many
over the counter supplements are NOT in this form, so check the label.
Depending on age, sex, and blood levels, the recommendation may be anywhere from
1200-2000 mg per day. These recommendations include calcium obtained from foods.
(see above)
Vitamin D levels must be normal for proper absorption of calcium. These levels should
be checked with bloodwork and a preventative supplement of 3000 mg per day is
recommended along with exposure to sun (without sunscreen) for 15 minutes three times
per week.
Calcium must be taken in a maximum of 500 mg at a time. This is the maximum that the
intestines can absorb.
 Do not take a multivitamin containing calcium and a separate calcium
supplement at the same time
 Do not take calcium and iron together (they negate each other)
 Do not take supplements and dietary forms together.
 2 hours apart for any of the above recommendations is advised.
Treatment for a deficiency
First, evaluate your dietary and supplement regimen and implement the
recommendations for supplements (see above) and as advised by your doctor, nurse, or
dietician.
For high PTH levels with supplementation adjustments, a bone density scan and
other specialized testing may be recommended and prescription medications may be
warranted per your primary care physician’s advice.
Of note:
Parathyroid hormone (PTH) is not part of standard bloodwork, but should be part of the
yearly bloodwork for someone who has risk factors (as discussed above). A blood
calcium level that is normal does not detect a deficiency, but rather another disease
process. PTH is the primary blood detector of calcium deficiency. It is important to note
that everyone has different risk factors for deficiency, calcium absorption, dietary intakes,
and compliance to supplementation. This emphasizes the need for regular bloodwork
including PTH level.
References:
Thompson, J., Manore, M. Nutrition An Applied Approach. 3rd edition. Pearson, 2012.
American Society for Metabolic and Bariatric Surgery guidelines. 2013.