Bariatric surgery causes a reduction in appetite that often leads to low intake of essential nutrients such as calcium. Mostly deficiency is caused by reduced absorption from intestine that follows malabsorptive procedures. Statistics have shown that about half of patients after malabsorptive weight loss surgery will develop calcium deficiency by 24months after the surgery. With the unwanted consequences of calcium deficiency, supplement becomes an essential part of the post-op diet.
Functions of calcium
Calcium is a mineral element that is present in the body majorly in bones and teeth (99%). The remaining 1% is found in the blood and other body tissues where it plays a significant role in cellular functions.
- Calcium is required for bone and teeth development. Deficiency will result in osteomalacia (soft bones) in adults and rickets in children and tooth decay. Although adults are not actively growing bones and teeth, healthy bones and teeth require calcium. The progressive bone loss that accompanies aging and menopause can be minimized if calcium level is optimized. This will reduce the risk of fracture with minimal trauma
- Both skeletal and smooth muscle contraction requires calcium and deficiency may result in muscle cramps and twitch.
- Most clotting factors that are responsible for the formation of a blood clot after injury are calcium-dependent, and lack of calcium may result in prolonged bleeding following injury.
- Contraction of the heart, contraction, and dilatation of the blood vessels are all dependent on calcium concentration in the blood. Low calcium may, therefore, lead to abnormal heart rhythms and high blood pressure.
- Other functions of calcium in the body include hormone secretion from glands and neurological function. Reduction in the development of cancers of the colon and rectum.
Absorption of calcium
Calcium is absorbed from the lining of the entire length of the small intestine. This is aided by the active form of vitamin D known as calcitriol. However, the best sources of calcium are the dairy products, eggs, and fishes. Calcium of plant origin is often in complexes with organic acids that make the absorption difficult.
Effects of obesity on calcium
Most obese individuals have comorbid conditions such as hypertension, joint pain from osteoarthritis, heartburn from gastroesophageal reflux, etc. These make them use drugs that may further compromise the calcium level by either reducing absorption or increasing loss in urine. Some antacids used for heartburn impair calcium absorption while corticosteroid use in osteoarthritis increases the urinary loss.
Why calcium deficiency after bariatric surgery?
After bariatric surgery, the stomach is reduced in capacity, and the appetite is also reduced. The small intestine is refashioned in malabsorptive procedures leading to a reduction in the absorptive surface. These are responsible for reduced calcium intake and absorption respectively. Some patients may also want to move towards vegetable diets to accelerate weight loss and thus, take little or no dairy products that are rich in calcium.
Natural sources of calcium
The recommended daily allowance for calcium is 1000-1200mg. Rich sources of calcium include milk, cheese, fish (sardines), yogurt, okra, and almond.
Calcium comes in different forms. The most common over-the-counter calcium supplement is calcium carbonate but it is not easily absorbed following bariatric surgery as the stomach acid (necessary for absorption of calcium carbonate) is often reduced. A better supplement is calcium citrate which should be in chewable or liquid form.
Avoid taking calcium supplement with iron so as not to impair iron absorption. You should take about 1500mg of elemental calcium per day. This should be divided into three doses. The body can only absorb about 500mg at a time. Take the calcium citrate supplement with food to enhance intestinal absorption. Consult your doctor to assess your risk of kidney stone formation before you commence calcium supplement.