Vitamin and Mineral Supplementation for the Bariatric Patient: Why,What,When,and How?

Introduction

Bariatric surgery has emerged as the cure for morbid obesity and subsequent comorbid factors. With this cure, however, comes a lifetime of nutritional recommendations that must be followed. Each bariatric surgical procedure has its own set of recommendations based on physiology and the technique used to achieve the desired surgical weight-loss outcome. In order to provide a baseline knowledge level of the various procedure types and the physiology associated with each, we will explore the three classifications of the common bariatric surgical procedures performed in the United States. These include:

1. Malabsorptive procedures

Biliopancreatic diversion with duodenal switch (BPD/DS)

Malabsorptive

The biliopancreatic diversion with duodenal switch (BPD/DS) requires consistent long-term nutritional follow-up and monitoring as it is a purely malabsorptive procedure. A portion of the stomach is resected, creating a smaller stomach pouch. The distal small intestine, or ileum, is then connected to the pouch. The duodenum (first 10–15 inches of small intestine) and the jejunum (middle of the small intestine) are bypassed. This bypassed small intestine is the basis for the decreased absorption of calories, protein, vitamins, and minerals that occur post BPD/DS. Patients who undergo this procedure must have consistent follow-up lab studies performed in order to assure that nutritional requirements are within normal limits. There are far fewer BPD/DS procedures performed compared to other weight loss procedures due to the need for long-term follow-up and monitoring.

There is no restrictive component as with gastric bypass, thus patients can eat larger quantities during snack and mealtimes. As with all malabsorptive procedures, BPD/DS patients do not effectively absorb micronutrients such as iron, calcium, vitamin B12, and folate. Due to the bypass of the duodenum and the jejunum, these patients are especially vulnerable to deficiencies in the fat-soluble vitamins A, D, E, and K.

Restrictive

The vertical banded gastroplasty, or stomach stapling, is a purely restrictive procedure. A portion of the stomach is stapled to create a small pouch. A small, non-adjustable polyurethane band is placed below the pouch. Vomiting and severe discomfort occur when food is not properly chewed. Healthy, more fibrous foods can be difficult to digest, while highly refined foods cause little discomfort. This can easily promote ingestion of junk foods, as opposed to foods that are considered to be healthy choices. This procedure is rarely performed today, as adjustable gastric bands are less invasive and have better results. Furthermore, reversal of this procedure is considered very dangerous and should only be considered when there are major complications. The vertical banded gastroplasty is included in this section to promote awareness due to its popularity in the 1980s and 1990s.

The sleeve gastrectomy is a purely restrictive procedure in which the stomach is reduced to about 15% of its original size. Eighty-five percent of the stomach is removed, thus rendering the procedure irreversible. This reduced stomach is achieved via stapling along the major curve of the stomach, and the open edges are attached together with staples, sutures, or a combination of both. The new stomach resembles a banana in shape and thus appears as a tube or a sleeve. Despite the reduction in size, the stomach tends to function normally and enables the patient to consume most food items, as long as portions are smaller. The pylorus is preserved, thus dumping syndrome is greatly reduced. Since the bowel is not resected and there is no small intestine anastamosis or staple line, there is no ulcer formation. Preserving the duodenum allows for less anemia, osteoporosis, and protein and vitamin deficiencies. The sleeve gastrectomy, or gastric sleeve, is a more appealing option for patients with existing anemia, Crohn's disease, irritable bowel syndrome, or the need for chronic steroid or non-steroidal anti-inflammatory (NSAID) drug use.

The adjustable gastric banding procedure, also known as the LapBand^® or Realize^® Band, is also considered a restrictive procedure. A silastic, adjustable band is placed around the top portion of the stomach, creating a small pouch just above the band. This band is connected to a port via silastic tubing. The port is placed just under the skin so that it can be accessed and saline can be added or removed in order to provide adequate restriction. This restriction results in decreased hunger and resultant weight loss. Patients with the LapBand do not have absorption issues but do have a decrease in food consumption. A daily multivitamin is important to assure that the recommended daily allowance of specific vitamins and minerals are being met. Eating foods that are gummy in consistency, such as bread or asparagus, may induce vomiting in the LapBand patient. Chronic vomiting may lead to a thiamine deficiency. Any multivitamin taken by this population of patients must have the recommended daily allowance of thiamine to assure thiamine levels are maintained.

Malabsorptive and Restrictive

By design, the gastric bypass Roux-en-Y is both a restrictive and malabsorptive procedure. A small stomach pouch is created with a stapler device, and then this pouch is connected to the distal small intestine, or jejunum. The upper part of the small intestine is then reattached in a Y-shaped configuration. This new configuration allows for a restrictive reservoir for food and liquids and a narrow outlet from which the food travels into the remainder of the digestive tract and out in the normal manner, bypassing the duodenum. This bypass impacts digestion as the duodenum is intricately involved in the digestive process. The primary role of the small intestine is absorption of vitamins and minerals, proteins (amino acids), carbohydrates, fats (lipids), enzymes, and water. Absorption is altered when digestion is incomplete. Thus patients having gastric bypass must take vitamin supplements for the rest of their lives. Furthermore, patients who have had this procedure will require 200% of the recommended daily allowances for vitamins and minerals.

In review, patients having a restrictive bariatric procedure such as laparoscopic gastric banding, vertical banded gastroplasty, and sleeve gastroplasty will benefit from one multivitamin daily with 100% of the recommended daily allowances (RDAs). Patients having a malabsorptive and/or restrictive procedure such as gastric bypass Roux-en-Y and biliopancreatic diversion with duodenal switch will benefit from two multivitamins per day or 200% of the recommended daily allowances (RDAs). See Table 1 for further explanation of daily requirements.

What, When, and How?

If we must recommend vitamin and mineral supplements to our patients, we must also have a basic understanding of how they function in the body. This next section will focus on various vitamins and minerals recommended for the bariatric patient and the key contributions they make to homeostasis. Water-soluble B vitamins are essential for energy production, immune system function, and heart health. They are absorbed quickly, are not stored in the fat cells, and therefore must be replaced every day. See Table 2 for the seven B vitamins (B-Complex) with their functions, food sources, and signs and symptoms of deficiency.

Interestingly, although the body can synthesize or make vitamins, it cannot manufacture one single mineral. Minerals must come from food sources or supplementation. Furthermore, vitamins are dependent upon minerals for adequate absorption. For example, vitamin D must be present in order for calcium to be absorbed. See Table 3 for a list of various minerals, their function, food sources, and signs and symptoms of deficiency.

In recent years, vitamin D has received a great deal of attention among healthcare providers and the media. Flanebaum et al. ¹ completed a retrospective analysis of 379 preoperative gastric bypass patients and found 68.1% were deficient in 25-hydroxyvitamin D. Ybarra et al. ² found 80% of a screened population of patients presented with similar patterns of low vitamin D levels. One mechanism for this deficiency is the decreased bioavailability of vitamin D due to enhanced uptake and clearance by adipose tissue. Thus the decreased availability of vitamin D is secondary to the preoperative fat mass. Reduced dietary calcium absorption increases a substance known as calcitrol, which in turn, causes metabolic changes that favor fat accumulation. Many bariatric centers now choose to preoperatively screen their patients for vitamin D deficiency. Certainly, vitamin D levels must be checked postoperatively to assure healthy levels are being achieved through supplementation. Continued research may prove that vitamin D contributes to a normal body weight, brain health, reduced symptoms of rheumatoid arthritis, and improved immune system function.

Supplementation for the bariatric patient is not just the responsibility of the dietician. Surgeons, advanced practice nurses, physician assistants, nurses, psychologists, and primary care providers must have a basic knowledge and understanding of vitamin and mineral therapy as it relates to various bariatric procedures. The American Society of Metabolic and Bariatric Surgeons has established nutrition guidelines for the bariatric patient, accessed via their website www.asmbs.org under Resources/Guidelines: Aills, L et al. ³ Lifetime nutritional support via vitamin and mineral therapy is critical for the continued health of all bariatric patients. Bariatric centers must continually use evidence-based research to establish guidelines for their respective practices. Education of healthcare providers must transfer to the individual patient to assure long-term compliance. Appropriate, ongoing nutritional education will empower patients to maintain their nutritional health long term.