Wednesday, June 22, 2011

B vitamins

Deficiency of vitamin B12 (cobalamin) has been recognized as a
common problem in bariatric surgery patients for many years. Increased
provision of vitamin B12 is part of the supplementation plan for gastric
bypass patients due to decreased production of intrinsic factor. In the
gastric sleeve patient, the fundus of the stomach is removed, and it is
presumed that less intrinsic factor is made with this procedure.
Deficiency of vitamin B12 can cause pernicious anemia, nerve degeneration
and peripheral neuropathy. Pernicious anemia is a condition in which the
body does not make enough of a protein called “Intrinsic Factor,” which is
required for absorption of B12. Besides weight loss surgery, other common
causes of pernicious anemia include a weakened stomach lining (atrophic
gastritis) and autoimmune conditions where the body attacks the cells of the
stomach that make intrinsic factor. Provision of 500mcg or more oral or
sublingual B12 is usually sufficient to prevent deficiency; however, some
patients may require monthly injections of B12 to maintain desirable levels.
Stomach acid is required to absorb naturally occurring cobalamin; however,
forms that are added to foods or used in supplements do not require acid for

Thiamine (B1) can be deficient in weight loss surgery patients who have lost
weight very rapidly or who have frequent vomiting.Serious effects of
thiamine deficiency include Wernicke’s encephalopathy, affecting gait, and
peripheral neuropathy. If not caught quickly, repletion of thiamine levels
may not completely reverse the symptoms. It may take 3 to 6 months for
symptoms to resolve after repletion. Daily supplementation is advised as the
body has limited stores of thiamine. IV repletion is effective with doses of
100mg for 3 to 14 days followed by an oral supplement maintenance dose of
around 20 to 100mg per day to maintain adequate stores.

Most prescription and over-the-counter renal vitamin preparations contain B
vitamins at levels at or above the RDA. Some may also contain vitamin E,
iron, and trace minerals. These supplements do vary, so careful selection of
an appropriate product is desirable.

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