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  • Writer's pictureDra. Andrea Pereira

Vitamin B12 and B1 Deficiency after Bariatric Surgery

Vitamin B12

Vitamin B12 is an essential cofactor in the functioning of the nerves, interfering in several biochemical reactions, responsible for the production of neurotransmitters and components of the central nervous system, in addition to influencing cell division, production of genetic material and red blood cells, in the functioning of the nervous system. Mitochondria and participating in the metabolism of amino acids and fatty acids. Therefore, its deficiency, in addition to causing megaloblastic anemia, also interferes in several areas, including the nervous system.

This deficiency in gastrointestinal tract surgeries can reach 62%. The mechanism is multifactorial, associated with reduced production of intrinsic factor, impairing its absorption in the ileum; reduction of stomach hydrochloric acid, reducing its bioavailability in food; food intolerances, especially red meat and other animal derivatives, reducing the consumption of foods with vitamin B12; and changes in enzyme production resulting from surgery, leading to changes in pepsin production and consequent impairment in protein digestion.

Symptoms of this deficiency can be weakness, depression, malaise, tingling in the legs, memory impairment, and imbalance.

The treatment of B12 deficiency should be the adequacy of consumption within the daily diet and supplementation by tablet or intramuscular.

Thiamine or Vitamin B1

Thiamine, a coenzyme for essential enzymes, is absorbed in the proximal duodenum, most efficiently in the acidic environment, and stored in skeletal muscle, brain, liver, and kidneys, whose storage lasts for 2 to 3 weeks. The anatomical change caused by the surgery, reduced production of stomach acid, restricted consumption of B1 in the diet, and vomiting are the leading causes of thiamine deficiency.

Deficiency can cause symptoms of dry and wet beriberi, which are the less severe conditions:

Wet or cardiac beriberi: increased or decreased heart rate, lactic acidosis, shortness of breath, swelling in the legs, and dilated heart ventricle.

Dry or neurological beriberi: convulsion, muscle weakness, pain in legs and/or arms, exacerbation of tendon and muscle reflexes.

This deficiency can lead to a severe condition, Wernicke's Encephalopathy, characterized by changes in several nerves, imbalance, involuntary eye movements, reduced eye movements, loss of recent memory, confusion, and coma. When associated with psychosis and hallucination, we have Wernicke-Korsakoff Syndrome. These conditions require urgent thiamine replacement due to the possibility of progression to coma and death.

As the clinical picture of thiamine deficiency can worsen, reaching coma and death, in suspected cases, we should take the exam and supplement the thiamine because the result takes an average of 14 days to come out.

Don't wait to have these symptoms to seek help. See your doctor and get tested annually after bariatric surgery. Follow-up is critical before and after surgery to prevent nutritional deficiencies and weight gain.

Dr. Andrea Pereira, MD, PhD


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