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Calcium Supplementation in Post-op WLS Patients

By Emily Wong-Swartz, MS, R.D.

Most people do not consume an optimal amount of all vitamins by diet alone according to the USDA National Food Consumption Survey. Vitamin and mineral deficiencies often occur in obesity and needs to be addressed before a weight loss procedure.

The Roux-en Y gastric bypass procedure is both a restrictive and malabsorptive procedure. Ingested food bypasses the gastric fundus, body, antrum, duodenum and a variable length of proximal jejunum. In consequence, patients are at risk to develop vitamin B12, Vitamin B1, iron and calcium deficiencies. Vitamin D and calcium absorption are reduced since the duodenum and proximal jejunum, which are the preferential sites of absorption, are bypassed by this procedure. Life long supplements of multivitamins, vitamin B12, Vitamin B1, iron and calcium are mandatory following this procedure. Careful long-term nutritional supplementation, biochemical monitoring and clinical follow-up is essential.

Good nutrition is important to maintain good health after weight loss surgery. It may be difficult to meet nutritional needs from diet alone after gastric bypass surgery, as both reduced food portions and dietary restrictions allow fewer nutrients to be consumed. Nutritional supplementation becomes important with restrictive and malabsorptive procedures since the Roux-en-y gastric bypass can affect the absorption of some critical nutrients. Choosing quality nutritional supplements can help meet nutritional needs to promote lifelong health following RNYGB. It is important to keep in mind that taking vitamins after WLS should become part of a daily routine.

Calcium is an important mineral and supplementation over the long term with a restrictive and malabsorptive procedure and may be necessary to help prevent osteoporosis. Calcium intake may be inadequate in the diet and absorption of calcium from foods may be impaired. Due to the acidic environment in the stomach being reduced from the bypass surgery, the form of supplemental calcium is vital. Calcium is actively transported in the duodenum and upper jejunum and dependent on active vitamin D. Vitamin D is a fat-soluble vitamin and a major regulator of calcium absorption in the intestine. WLS procedures that are malabsorptive may decrease absorption of Vitamin D.

Calcium is the most abundant mineral in the human body and has several important functions. More than 99 % of total body calcium is stored in the bones and teeth where it functions to support their structure. The remaining 1 % is found throughout the body in blood, muscle, and the fluid between cells. Calcium is needed for muscle contraction; blood vessel contraction and expansion; the secretion of hormones and enzymes; and sending messages through the nervous system. A constant level of calcium is maintained in body fluid and tissues so that these vital body processes function efficiently.

Bones undergo continuous remodeling, with constant resorption and deposition of calcium into newly deposited bone. The balance between bone resorption and deposition changes as people age.  During childhood there is a higher amount of bone formation and less breakdown. In early and middle adulthood, these processes are relatively equal. In aging adults, particularly among postmenopausal women, bone breakdown exceeds its formation, resulting in bone loss, which increases the risk for osteoporosis.   Estrogen is a hormone that plays an important role in helping increase calcium absorption. After menopause, estrogen levels drop and so may calcium absorption.  

Osteoporosis or ?porous bone? is characterized by a decrease in bone mineral density, bone calcium content and an increased risk of fractures. It can strike at any age. Osteoporosis is a major public health threat for 44 million Americans, 68 percent of whom are women. One out of every two women and one in four men over 50 will have an osteoporosis-related fracture in their lifetime. Osteoporosis is often the cause of many health complications, as it progresses silently unnoticed for years. Only after years of bone loss do signs and symptoms appear such as pain, spine deformity and fractures.  A calcium deficient diet is one of the causative factors of osteoporosis. Risk factors for osteoporosis that cannot be changed are: being female, post menopausal, having a small skeletal frame, being Caucasian/Asian, a family history of osteoporosis and fractures and advanced age. Osteoporosis risk factors that can be changed are: medications with negative affects on bone, inadequate or excessive intake of nutrients, sedentary-non weight bearing activity, excessive exercise, low body weight, cigarette smoking and high alcohol consumption.  One way to help reduce risk for the WLS patient is to supplement adequately with calcium supplements. Since WLS patients may become lactose intolerant after WLS, or have decreased calcium absorption with the combined restrictive and malabsorptive procedure, calcium supplementation is required to achieve adequate calcium intake.

 Dietary Reference Intake (DRI) for calcium intake varies between 1,000-1,300 mg/d for an adult depending on age and gender. One serving of dairy product provides approximately 300 mg of calcium. Individuals who do not consume enough calcium from food sources will need calcium supplements to meet the daily requirements. To avoid calcium toxicity, it is not recommended to take more than 2,500 mg of calcium per day. High calcium intake can lead to constipation, an increased chance for developing calcium kidney stones and may inhibit the absorption of iron and zinc from food.

Calcium consumed via diet or supplement is absorbed by the body in the small intestine. Not all calcium consumed will be absorbed; some passes through the body and is excreted as waste. How much the body absorbs calcium depends on the type of calcium consumed, how well the calcium dissolves in the intestines, and the amount of calcium in the body. Dietary supplements may contain one of several different forms of calcium. Calcium consumed in foods and supplements occurs in a compound form with carbonate or citrate. A compound is a substance that contains more than one ingredient. Calcium carbonate is alkaline based and calcium citrate is acidic based. Choosing the right calcium supplement really depends on individual needs. The calcium in a compound is called elemental calcium. During digestion, the calcium compound dissolves and the elemental calcium becomes available to be absorbed into the blood. The most important factor when purchasing a calcium supplement is the elemental calcium content, not the total content. A greater percentage of elemental calcium means that fewer tablets are needed to achieve the desired calcium intake. On the nutritional/supplemental facts label a % recommended daily value (RDA) is listed. The RDA recommends the average daily intake that is sufficient to meet the nutrient requirements of nearly all (97-98 %) healthy individuals in each age and gender group. This is based upon a 1000 mg recommended daily value for calcium. Therefore a supplement with a 25 % daily value for calcium has 250 mg of elemental calcium. Serving size should also be noted, that is the number of tablets, pills etc required to obtain that level of elemental calcium.

Calcium Carbonate

Calcium carbonate is the most prevalent calcium supplement on the market. It provides more elemental calcium than calcium citrate that reduces the number of pills required. The pills are usually bigger tablets that some individuals find hard to swallow. A tablet containing 500 milligrams of calcium carbonate contains only 200 milligrams of elemental calcium. This is because only 40 % of the calcium compound is elemental calcium. The other 60% or 300 milligrams is from the carbonate ingredients. Most calcium supplements list the elemental calcium content on the label. Tums®, Viactiv® and Caltrate® are brand name calcium carbonate products. Calcium carbonate is alkaline based, and requires extra stomach acid for better absorption. It is best taken directly after meals or with a glass of acidic juice such as orange juice.

Dolomite, oyster shell, coral and bone meal are naturally occurring calcium carbonate sources that may contain heavy metals including lead and/or aluminum. Minimizing lead intake is important for pregnant and nursing women and children. Calcium supplements are not tested by a regulatory agency for lead content before they are placed on the market therefore it is up to the manufacturer to assure that the lead content of their calcium supplement meets the FDA standards.

Many physicians recommend calcium carbonate because it requires the fewest pills to reach a given level of calcium and it is readily available and inexpensive. For people concerned with cost and only willing to swallow two to three calcium pills per day, calcium carbonate is a sensible choice. The disintegration of calcium carbonate pills can be easily evaluated by putting a tablet in a half cup of vinegar and stirring occasionally. After half an hour, the tablet should be completely dissolved. Calcium carbonate requires an acidic environment in order to be dissolved in the intestine and absorbed into the blood. Stomach acid production increases in the presence of food, creating an acidic environment. Calcium carbonate supplements should be taken with meals and is an appropriate choice for an individual with a restrictive procedure.

Calcium Citrate

Calcium citrate is the most absorbable supplemental form of calcium. It does not require extra stomach acid for absorption, may be taken anytime during the day and on an empty or full stomach. It provides less elemental calcium (21%) than calcium carbonate, therefore more pills per day are required to meet the need. It is usually a small capsule form but can also come in colloidal form, a liquid form that is less irritating to the intestine. Liquid calcium has a very short shelf life (as do all liquid vitamins), therefore, they lose their potency. It is the preferred form of calcium for an individual with a restrictive and malabsorptive procedure. Citracal® and Solgar® are brand name calcium citrate products.

Vitamin D

 Calcium absorption is dependent on an adequate level of the active form of vitamin D. Vitamin D supplements are usually not necessary because vitamin D is available from vitamin D fortified milk, foods such as fish, egg yolks and exposure to sunlight by the skin. In general, 15 minutes of sunlight exposure is adequate to maintain vitamin D levels. However, the amount of sunlight your skin absorbs is dependant on the weather, latitude, time of year, the amount of skin exposed and sunscreen use.

 Calcium and magnesium should be present in supplements in a ratio of 2:1. Magnesium taken in a 1:1 ratio to calcium could cause diarrhea in susceptible individuals. Magnesium is helpful in relieving the constipating effect of calcium. As our calcium intake increases, our body absorbs calcium less efficiently. It is best to take calcium in smaller doses throughout the day to aid absorption. No more than 500 milligrams of calcium at one time should be taken and 4 to 6 hours should be allotted between dosages.  When the calcium level in the blood is low, parathyroid hormone (PTH) is released and increases the production of vitamin D. Vitamin D helps increase calcium absorption, returns the amount of calcium in our blood to normal levels, and makes calcium available to be deposited in the bones.

Calcium phosphate, calcium lactate and calcium gluconate have very small percentages of elemental calcium in each supplement tablet. Therefore it is necessary to take a large number of tablets to consume an adequate amount of daily calcium. 

One factor affecting calcium absorption for supplement tablets is how well the calcium tablet dissolves. To ensure the supplement will dissolve in the intestine, one that meets the U.S. Pharmacopeia?s (USP) standards for dissolution (and stamped with the USP label) should be chosen. According to USP standards, a calcium tablet must contain 90-110 % of the amount of elemental calcium listed on the supplement label and must dissolve in 30 to 40 minutes.  

Osteoporosis may be a long-term complication due to inadequate intake and absorption issues. It is best for the WLS patient to use forms that are highly soluble and well absorbed such as citrate/citrate-malate. Calcium requires an acidic environment for good uptake and utilization. Signs and symptoms of osteoporosis do not usually appear until later in life. In America, osteoporosis affects seniors over age 70. Osteoporosis progresses slowly and silently and as bones become porous and fragile most people do not realize they have osteoporosis until bone is fractured.

Gastric bypass patients are more susceptible to lactose intolerance as the lactase enzyme required to break down milk sugars is secreted at the distal bypassed portion the stomach. This may result in decreased intake of dairy products, further worsening calcium deficiency

Insufficient calcium intake, poor calcium absorption, and/or excessive calcium losses through the urine and feces can cause calcium deficiency. In children, calcium deficiency can cause improper bone mineralization, which leads to rickets, a condition characterized by bone deformities and growth retardation. In adults, calcium deficiency may result in osteomalacia, or ?softening of the bone?. Calcium deficiency, along with other contributing factors, can also result in osteoporosis. Low levels of calcium in the blood may cause a condition called tetany, in which nerve activity becomes excessive. Symptoms of tetany include muscle pain and spasms, as well as tingling and/or numbness in the hands and feet

It is important for WLS patients to supplement adequately with enough calcium to maintain adequate blood and bone calcium levels.  Bypassing the duodenum may result in metabolic bone disease in some patients, resulting in bone pain, loss of height, humped back and fractures of the ribs and hipbones. Alterations in bone metabolism and vitamin D deficiency have been described in morbidly obese individuals even before bariatric surgery.  Serum calcium measurements are not good markers of postoperative calcium deficiencies. These levels are maintained stable at the expense of mobilization from bone.

All of the deficiencies mentioned above can be managed through proper diet and vitamin supplements. A patient?s commitment to the required follow-up care is essential for success. Adequate calcium intake with restrictive procedures is unlikely to cause metabolic bone disease. Metabolic bone disease is likely to occur following biliopancreatic diversion if supplementation of vitamin D and calcium are inadequate. Metabolic bone disease presents late and with nonspecific symptoms. Monitoring of calcium, alkaline phosphatase, 25 OH vitamin D and parathyroid hormone (PTH) levels for metabolic bone disease is important after any restrictive and malabsorptive procedures. A rise in Alk-phos and PTH are the first indications of metabolic bone disease and indicates a need to increase vitamin D and calcium supplementation.

The best way to check for calcium deficiency is a DEXA scan or PTH level. Serum vitamin D levels should be monitored if calcium deficiency or bone loss is suspected. Supplements taken after bariatric surgery, especially after a restrictive and malabsorptive procedure, should have the USP designation. Regardless of which surgery a patient undergoes, there is a significant decrease of food intake that also minimizes vitamin and mineral intake. Daily calcium supplementation is essential to prevent osteoporosis. The dosage and form depends on the type of bariatric surgery a patient has undergone. Although low nutrient levels are discovered following surgery, there is a lack of consensus in the dosing and form of supplements.  General recommendations are 1500-2000 mg Calcium/day. Calcium Citrate with Vitamin D in doses of 500 mg three times is recommended. Compliance with long-term follow-up is vital as nutritional and metabolic problems can be easily treated or avoided. 

Emily Wong-Swartz, MS, R.D. is the program coordinator for the Bariatric Institute at Cleveland Clinic Florida.  She is Certified in Adult Weight Management and has a M.S. in Health Service Administration and a B.S. in Dietetic. For more information, please visit: http://publish.www.ccf.org/florida/departments/bariatric/