An interesting Mayo Clinic Study

January 12, 2004

I recently found an interesting Mayo Clinic article on the effects of

gastric bypass surgery, Mayo Clin Proc, July 2000, Vol 75, 673-680. It

will need to have Adobe Acrobat Reader installed on your computer to

read it. This can be downloaded free from http://www.adobe.com.

What struck me were the nutritional consequence findings, at 678.

" Another potential concern of gastric bypass is the possibility of

vitamin and mineral deficiencies. Cyanocobalamin (vitamin B12) requires

gastric acid, R-factor, and intrinsic factor for normal absorption

within the ileum. The altered anatomy of RYGB disrupts this necessary

interaction. 30 Nevertheless, with supplementation of free

cyanocobalamin, deficiencies are rare.31 Although we have no objective

data on which to base our recommendations of supplemental cyanocobalamin

(1000 mg intramuscularly monthly) other than the demonstrated decreased

absorption, 30 we believe that supplements prevent potential serious

neurologic and hematologic problems caused by vitamin B12 deficiency.

Similarly, bypass of the stomach and duodenum hinders normal absorption

of ingested iron; yet, significant iron deficiency in our experience and

that of others32 is unusual except in women with heavy menstrual losses

of iron. Oral supplementation is usually sufficient, but on occasion we

have administered intravenous iron dextran to attain satisfactory

levels. While we encourage use of calcium supplements (much of the oral

calcium is absorbed in the duodenum), we currently have little evidence

that RYGB predisposes to calcium deficiency or metabolic bone disease. "

The statement that " we currently have little evidence that RYGB

predisposes to calcium deficiency " is somewhat astounding. Equally of

interest, at least to me, was that they did not consider the possibility

of protein deficiency as being even worthy of consideration.

Ray Hooks

For WLS nutrition info, visit

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