Those considering weight loss surgery or those who have already undergone it need to be aware of the nutritional deficiencies caused by this procedure. Nutritional deficiencies are common to all malabsorptive bariatric surgeries and occur in some restrictive types, too. However, they can often be prevented by standard multivitamin supplementation [1].
This article provides information on protein, vitamin, iron, and calcium deficiencies that can occur post-operatively and is based on a number of relevant studies including the scientific review study published in the journal of Obesity Surgery by Dr. Richard Bloomberg.
Why does nutritional deficiency occur after weight loss surgery?
The small intestine is the place where nutrients from the food are mainly absorbed. It is also the place where the pancreatic and bile enzymes mix with the food and facilitate absorbance of fat-soluble vitamins like A, D, E, and K.
In bariatric surgeries that work mainly through malabsorption like biliopancreatic diversion with or without duodenal switch (BPD-DS, BPD) and those that work with both malabsorption and restriction, like gastric bypass, a major part of the small intestine is bypassed. This is the major reason why deficiencies occur, apart from the fact that the overall intake of food is lowered post-surgery and that some people cannot tolerate certain types of nutrient-rich food like milk and other dairy products.
Types of nutritional deficiencies that may occur after Roux-en-Y, BPD, and BPD-DS
Protein deficiency
Protein deficiency, though occurring in gastric bypass patients, is seen at fairly high levels in BPD and BPD-DS patients. In a study in which questionnaires were answered by 858 BPD patients, it was found that protein deficiency was so severe in 3.7% of the patients that they had to be admitted to the hospital and 6% of them had to undergo revision surgery [2].
Dolan and colleagues examined patients that had undergone BDP with and without duodenal switch and found that both BPD and BPD-DS patients have 18% chance of presenting hypoalbuminemia [3], a condition where protein (albumin) levels in blood serum are too low. Fortunately, as several studies have shown, dietetic counseling and increased protein intake can lower the risk of protein deficiency.
Iron deficiency
Iron deficiency occurs in all bariatric surgeries, be it restrictive or malabsorptive. As shown in the illustration, the duodenum and the proximal jejunum are the main sites of iron absorption and bypassing these sites results in anemia.
RYGBP patients experience iron deficiency that tends to increase over the years, whereas in BPD and BPD-DS patients, conclusive evidence is yet to surface on whether the levels of serum iron and ferritin are affected over the years.
Vitamin B12 and Folate deficiency
A study by Halverson and colleagues demonstrated that a third of gastric bypass patients had vitamin B12 deficiency (<250 pg/ml) and 63% of them had folate deficiency (<3 ng/ml), despite being on a multi-vitamin regimen [4]. This can occur in patients even if they don’t have vitamin deficiency pre-operatively.
Rhode and colleagues experimented with different doses of B12 ranging from 100 ug to 600 ug and concluded that a dose of at least 350 ug needs to be administered to maintain a serum level of >150 pmol/L [5].
Calcium and Vitamin D deficiency
Calcium and vitamin D deficiencies are more frequently seen in malabsorptive weight loss surgeries than in restrictive. The duodenum and the proximal jejunum primarily absorb calcium, while vitamin D is absorbed by the jejunum and the ileum. Hence, bypassing these sites results in a lack of these nutrients.
When the body falls short of vitamin D, there is more production of the parathyroid hormone which results in release of calcium from bone, leading to bone loss and osteoporosis in the long term. Calcium and vitamin D deficiency occur at a rate of 10% and 51% respectively in distal Roux-en-Y patients [6]. There is a probability of postoperative metabolic bone disease developing in gastric bypass patients as a result of these deficiencies.
BPD patients too showed low levels of calcium and vitamin D: 57% of 170 patients studied showed a lack of vitamin D a year after surgery and 63% after four years [7].
Thiamine (Vitamin B1) deficiency
Thiamine deficiency is not a common nutritional consequence of bariatric surgery. However, the combination of reduced food intake, frequent vomiting, and malabsoption can sometimes cause this deficiency.
The resolution of thiamine deficiency is comparatively easy and quick. Intravenous or intramuscular thiamine doses of 50/100 mg/day have been shown to restore nutrient levels as early as one day after the administration. It is worth mentioning that administering glucose and other carbohydrates to a thiamine-deficient person can be dangerous, as thiamine is vital in carbohydrate metabolism [8].
Other fat-soluble vitamin (A, E, and K) deficiencies
While vitamin E and K deficiencies are not clinically significant in post-operative patients that receive supplementation, 61% of patients who had undergone either BPD or BPD-DS were found to have low levels of vitamin A [3], notwithstanding an 80% compliance rate with a multi-vitamin diet.
Other deficiencies
Zinc and magnesium deficiencies in gastric bypass patients have not been studied extensively. And in BPD patients with or without the duodenal switch, one study showed zinc deficiency in 50% of the patients in four years of follow-up. This level remained static and did not increase over the years [7]. But another study pinned zinc deficiency at only 10.8% of patients [2]. Magnesium, chromium, vanadium, and copper deficiencies are usually not seen in people going through bariatric surgery.
Specific signs and symptoms of protein deficiency:
Hair loss, fatigue, leg swelling
Specific signs and symptoms of common vitamin and mineral deficiencies:
· Calcium: bone pain
· Iron: fatigue
· Zinc: brittle nails
· Vitamin A: inability to see in the dark
· Vitamin E: poor wound healing
· Vitamin K: easy bruising
· Vitamin B1 (Thiamine): numbness and tingling in the hands and feet
· Vitamin B12 (Methylcobalamin): fatigue
Conclusion
Research on the full implications of these nutritional deficiencies and how they can be best resolved is still going on. In what form should a particular supplement be administered? How much of it should be recommended? These are some of the questions that need to be answered. Research has shown that multivitamin supplementation can greatly help in keeping important serum nutrients at acceptable levels. Patient education regarding vitamin supplementation is vital.
Morbidly obese individuals have nutritional deficiencies even before weight loss surgery and these can get further complicated if they are not prescribed the right supplements in the required doses post-surgery. But, in some cases, problems occur despite the individual following a multi-vitamin supplement regimen.
Hence, people thinking of opting for bariatric surgery should bear in mind the nutritional deficiencies and other complications that could face post-surgery. Strict compliance with a long-term multi-vitamin diet is required, and so are regular check-ups.
References
1. Nutritional deficiencies after Roux-en-Y gastric bypass can be prevented by standard multivitamin supplementation. Ledoux S, Larger E. Am J Clin Nutr. 2008 Oct;88(4):1176
2. Marinari GM, Murelli F, Camerini G et al. A 15-year evaluation of biliopancreatic diversion according to the Bariatric Analysis Reporting Outcome System (BAROS). Obes Surg 2004; 14: 325-8.
3. Dolan K, Hatzifotis M, Newbury L et al. A clinical and nutritional comparison of biliopancreatic diversion with and without duodenal switch. Ann Surg 2004; 240: 51-6.
4. Halverson JD. Micronutrient deficiencies after gastric bypass for morbid obesity. Am Surg 1986; 52: 594-8.
5. Rhode BM, Tamin H, Gilfix BM et al. Treatment of vitamin B12 deficiency after gastric surgery for severe obesity. Obes Surg 1995; 5: 154-8.
6. Brolin RE, LaMarca LB, Kenler HA et al. Malabsorptive gastric bypass in patients with superobesity. J Gastrointest Surg 2002; 6: 195-203; discussion 4-5.
7. Slater GH, Ren CJ, Siegel N et al. Serum fat-soluble vitamin deficiency and abnormal calcium metabolism after malabsorptive bariatric surgery. J Gastrointest Surg 2004; 8: 48-55; discussion 4-5.
8. Chaves LC, Faintuch J, Kahwage S et al. A cluster of polyneuropathy and Wernicke-Korsakoff syndrome in a bariatric unit. Obes Surg 2002; 12: 328-34.
Matt Papa works at Washington University as a biochemist. He has special interest in the field of obesity treatment and compassion for people who struggle with their weight. His website is about best weight loss programs and diet plans and provides practical information on wide range of diet topics including a review of the Realize My Success website and the cost of lap band at Strax rejuvenation in Florida.