Counting on Calcium for Better Health

June 26, 2013

How Important is Calcium for WLS Patients?

Calcium is a mineral needed for healthy bones, nails, and muscle tissue and assists in blood clotting as well as heart and nerve functions.

Calcium (Ca) Levels- Absorption of Ca supplements is most efficient at several individual daily doses of 500 mg or less and when taken between meals. Ca also interferes with iron absorption. Iron absorption can be decreased by as much as 50 percent by many forms of Ca supplements or milk ingestion but not by forms that contain citrate and ascorbic acid, which enhance iron absorption. A study by bariatric surgeons recommends monitoring vitamin D and calcium intake in all patients following obesity surgery. The recommended 1200-1500 mg of Ca and 800 IU of vitamin D per day is difficult to achieve after gastric bypass without supplementation.

DEXA Bone Density Scan- Dual Energy X-ray Absorptiometry (DEXA) bone density scan is the single most useful tool to diagnose thinning bones. Combined with your medical history, DEXA allows your physician to determine if you are at risk. Men and women should receive a baseline DEXA prior to WLS surgery and should compare those levels to yearly post-operative DEXA scans.

Blood Tests- The level of calcium in your blood does not reflect how much is in your bones or how dense and strong they are.

Pre-menopausal- Before menopause, women need to focus on calcium intake. It is the intake prior to menopause that can affect bone loss during and after menopause.

Post-menopausal- After menopause, gastric acid secretion is often very low. Calcium citrate has the advantage of being absorbed with low gastric acid secretion. Post-menopausal women need good intake of this mineral, should participate in weight-bearing exercise, and should consider hormone (estrogen) therapy.

Men & Women- Men are far from immune to difficulties relating to calcium deficiency. This is even more true for male patients of weight loss surgery than for other men because WLS surgery can affect how your body absorbs the nutrient.

The Two C's: Citrate VS. Carbonate

As though muddling through minerals is not hard enough, getting through the essentials of calcium is additionally complex because there are two major types that provide different benefits.

Calcium Citrate:  Blood levels of calcium show that citrate is 2.5 times more bioavailable (easier for your body to use) than calcium carbonate. It has the advantage of being absorbed when gastric acid secretion is low. This is very common after menopause and in those taking acid-reducing medications. Additionally, the citrate form is protective against the formation of calcium-rich kidney stones. Calcium also needs vitamin D and magnesium to work. If your calcium does not have these in the tablet, then you must add magnesium and more vitamin D.

Calcium Carbonate:  Calcium carbonate has more calcium per gram than citrate, so it would take less volume (fewer pills or less liquid) of the carbonate to provide the same amount of absorbable calcium. However, this is the type often NOT recommended for WLS patients. Because calcium carbonate requires hydrochloric acid (a stomach acid) to be digested and absorbed, the type and extent of your gastric bypass will determine which calcium supplement is better for you. You should note that TUMS and other antacid tablets use calcium carbonate.

cathy wilson


Cathy Wilson, PCC, BCC, had RNY surgery in 2001 and lost 147 pounds. Cathy is a regular contributor to the OH Blog and authored the "Mind Matters" column in ObesityHelp Magazine. Cathy is a licensed pilot and loves flying. She is a member of the American Society for Metabolic and Bariatric Surgery (ASMBS) and the Obesity Action Coalition (OAC).

Read more articles by Cathy!