Postoperative Nutrition Monitoring

Monitoring of the food choices and nutrition supplement use is needed, especially postoperatively, for ensuring weight loss and identification of nutrient deficiencies. The medical literature suggests that several key nutrients need to be assessed after surgery—vitamin B12, folate, vitamin D, vitamin K, selenium, zinc, and copper [3].

Vitamin B12

Vitamin B12 is a group of cobalt containing compounds described by Alan R. Gaby, MD, in Nutritional Medicine called cobalamins.

Methylcobalamin is the coenzyme form of B12 that is critical for human health. Hydroxocobalamin is a more stable form of B12 but it first needs to be converted to an active form before it can be used in metabolism [7, pp. 89-96]. The most inexpensive form of vitamin B12 is cyanocobalamin, containing cyanide and found in most multivitamin formulas because of its cost effectiveness.

Vitamin B12 is important in DNA synthesis, red blood cell (RBC) formation, homocysteine (HCY) metabolism, and the production of S-adenosylmethionine (SAMe). Adequate B12 is essential for proper neurological and immune functioning.

The importance of vitamin B12 in health and anemia management was first realized during the Depression era when animal protein foods were limited in the American diet. Three physicians who reversed pernicious anemia in dogs were awarded the 1934 Nobel Prize for medicine. Drs. George Hoyt Whipple, George Richards Minot, and William Parry Murphy fed the dogs and humans 1/2 lb. of fresh liver per day as a means to control anemia [8].

Animal proteins—meat, poultry, fish, eggs—are the sources of vitamin B12 for humans. Plants do not need or produce B12. How B12 gets into your blood is a complex dance of stomach acids and intrinsic factors that starts with pepsin in the stomach splitting off the B12 from the protein compound to which it is bound. The intrinsic factor made by the parietal cells of the stomach attaches to the B12 to be shuttled to the ileum where receptors pull it into the blood [9]. Once in the blood, B12 is picked up by transcobalamin to be carried to cells throughout the body. Any excess is stored in the liver or excreted in the urine.

If inadequate intrinsic factor is available—loss from aging or proton pump inhibitor (PPI) use—B12 deficiency symptoms such as macrocytic anemia, neurological disorders, and psychiatric symptoms (memory loss, depression, confusion, paranoia) may occur. Severe B12 deficiency can result in intestinal damage, hyperpigmentation of the skin, hypotension, and immune dysfunction.

The Institute of Medicine (IOM) indicates that only 2-4 pg vitamin B12 is needed daily. The average American diet contains 5-15 pg per day according to the National Health and Nutrition Examination Survey (NHANES) studies [10]. Vegetarians and infants breastfed by vegan mothers are at greatest risk of developing B12 deficiency [11].

Despite the adequacy of IOM and NHANES data, other factors increase the risk of developing vitamin B12 insufficiency. Achlorhydria secondary to gastritis, gastric bypass surgery, and ileal resection for Crohn’s disease need assessment due to malabsorption [12]. Apathy abounds throughout the medical community despite the 2009 Centers for Disease Control and Prevention statistics indicating 1 out of every 31 persons over 50 years being B12 deficient [13]. With increasing numbers of gastric bypass patients, this deficiency could be significantly higher.

Adverse symptoms can first be noted with the complete blood count (CBC) test indicating large RBCs or macrocytosis—a folate and B12 deficiency. Other symptoms may include balance problems, numb hands and feet, leg pains, early onset dementia, pre-Parkinson’s-like disease, infertility, and depression.

Many physicians are poorly educated on vitamin B12 importance since it is a vitamin and easy to treat. Treatment with methylcobala- min injections with few definitive ways to test efficacy seems to be a primary factor. A complete medical history assessing for gut inflammation, celiac disease, gastroesophageal reflux disease (GERD), recent nitric oxide use in surgery, and genetic factors like methylene tetrahydrofolate reductase (MTHFR) should trigger a closer look at B12 adequacy even with a normal HCY plasma test [14]. According to Lewerin et al. high levels of B12 on standard blood analysis usually indicates poor absorption not intoxification of vitamin B12. Elevated B12 results >800 pg/mL frequently can indicate PPI use, low-stomach acid, or malabsorption. B12 lab results <350 pg/mL may still be inadequate for a patient with celiac disease, gluten enteropathy, or gastric bypass surgery so supplementation should be considered.

Medications matter when considering vitamin B12 status. Following are common drugs that impair absorption [8, pp. 30-31]: [1]

  • • Viagra, Cialis, Levitra
  • • Compazine, Haldol, Risperdal, Tegretal

Vitamin B12 supplementation is probably the safest medical treatment available and many bariatric patients may need B12 injections to show improvement in their symptoms. Effectiveness of injections depends more on frequency of administration than on amount given with each injection. Those who improve with injections rarely improve with oral or sublingual products no matter how large the dose because oral routes of administration are not capable of achieving high enough absorption levels [15].

Treatment with vitamin B12 may need to be continued for life. Until more research on efficacy and safety of oral B12 is available, intramuscular daily or weekly injections should be considered a standard of care, especially for those with gastric bypass surgery. Supplementation effectiveness can improve patient outcome as reviewed by Moore and Sherman [16].

Vitamin B12 is primarily found in animal protein foods—egg yolks, meat, fish, and yogurt with grass-fed beef liver as an excellent source. Tempeh, a fermented soybean product, and some sprouts may contain in modest amounts. Vitamin B12 in food is easily destroyed by microwave cooking.

  • [1] Antacids—maalox, milk of magnesia (MOM), Mylanta, Tums • Histamine blockers—Zantac, Tagamet, Axid, Pepcid • PPIs—Prevacid, Prilosec, Nexium, Omeprazole, Aciphex • Colchicine • Questran • Metformin, Glucophage • Celexa, Effexor, Elavil, Nardil, Paxil, Prozac, Zoloft, Wellbutrin • Ativan, Librium, Valium, Xanax
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