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Vitamin B12 Effects on Weight Reduction, Cravings and Diabetes in GLOBESITY Bootcamp for the Obese

FG 8 PR - Vitamin B12 Effects On Weight Reduction, Cravings And Diabetes in GLOBESITY Bootcamp for the Obese

Authors: Marcus Free MD, Rouzbeh Motiei-Langroudi MD, Waqar Ahmad PhD, Kelly Daly RDN, and Don Juravin (Don Karl Juravin).

Abstract (Research Summary)

  • Vitamin B12 and Folate promotes a healthy central nervous system, promoting metabolism of neurotransmitters (serotonin and dopamine), which prevents depression and emotional eating (Mansouripour, 2020). 
  • Vitamin B12 (aka: Cobalamin) is a water-soluble vitamin, primarily used to prevent weight gain (Nachtigal, 2005). It helps the body convert food into fuel which is used as energy. It is also involved in DNA and red cell synthesis, iron function, and works with folate to produce SAMe, a compound involved in immune function and mood (UMMC, 2015).
  • Vitamin B12 reduces weight gain (Nachtigal, 2005). Long-term use of Vitamin B12 (as well as multivitamins, B6, and chromium) was significantly associated with lower levels of weight gain among overweight men and women (Nachtigal, 2005).
  • Vitamin B12 deficiency in women is associated with a higher BMI and greater insulin resistance and results in a greater risk of gestational diabetes (Krishnaveni, 2009).
  • Vitamin B12 absorption is reduced by Metformin because of a calcium-dependent ileal membrane antagonism (Bauman, 2000; Wulffele, 2003). It is therefore crucial that Vitamin B12 is supplemented in diabetics using Metformin.
  • Vitamin B12 decreases cravings by increasing the synthesis of serotonin and dopamine, improving erythrocyte count and associated nutrient transportation, and by enhancing the cell repair process of brain centers (Coppen, 2005; Stabler, 2013; Asberg, 1976; Deana’ 1976; Penninx, 2006).


Vitamin B12 (Cobalamin) is a water-soluble vitamin, found naturally in a wide variety of animal foods (meats, fish, poultry, eggs, and dairy). Vitamin B12 helps convert food into glucose, which gives energy. Vitamin B12 increases the metabolism of fats and glucose, boosting energy production, which in turn decreases weight gain by muscle production and fat loss. It also helps in the production of red blood cells and DNA, as well as the proper functioning of the central nervous system. It promotes high levels of neurotransmitters such as serotonin and dopamine, preventing depression and emotional eating. 

Vitamin B12 Effects on Weight Reduction

Vitamin B12 is significantly associated with lower levels of weight gain and deficiency is associated with a higher BMI.

  • Vitamin B12 reduces weight gain. Long-term use of Vitamin B12 (as well as multivitamins, B6, and Chromium) is significantly associated with lower levels of weight gain among overweight men and women (Nachtigal, 2005).
  • Vitamin B12 increases the metabolism of fats and glucose and accelerates energy production as it increases the amount of healthy erythrocytes which transfer oxygen and nutrients to all the cells. Increased metabolism and energy production decreases weight by promoting muscle production and fat loss (Stabler, 2013).
  • Vitamin B12 helps a weight reduction regimen be successful. Deficiency leads to anemia and pernicious anemia (NIH, 1998; Stabler, 2013). Anemic symptoms include diminished energy and exercise tolerance, making it difficult to follow a weight loss regimen.
  • Vitamin B12 deficiency in women is associated with greater insulin resistance and a higher BMI (Krishnaveni, 2009). It is therefore important for Vitamin B12 to be supplemented for those at risk of deficiency.

Vitamin B12 Effects on Cravings

Vitamin B12 decreases cravings by improving the cell repair process of brain centers resulting in improved serotonin and dopamine sensitivity and synthesis. As Vitamin B12 also improves nutrient transportation, all body cells receive adequate energy and nutrition to complete their tasks, therefore decreasing the body’s need for additional nourishment resulting in diminished cravings.

  • Vitamin B12 deficiency is associated with low levels of serotonin resulting in depressed moods (Coppen, 2005; Asberg, 1976; Deana, 1976; Penninx, 2006). Serotonin, a hormone that brings happiness, is secreted when carbohydrate-rich foods, such as cakes and pastries, are consumed (Wurtan, 1995). Individuals with depressed moods therefore crave carbohydrate-rich foods to make themselves feel better (Wurtan, 1995).
  • Vitamin B12 improves the cell repair process of the brain reward center making it more sensitive to serotonin and dopamine resulting in decreased cravings (Coppen, 2005; Asberg, 1976; Penninx, 2006).
  • Vitamin B12 accelerates fat and glucose metabolism by increasing the amount of erythrocytes and improving nutrient transportation to cells resulting in decreased cravings (Stabler, 2013).

Vitamin B12 Effects on Diabetes

Vitamin B12 deficiency is linked to insulin resistance and increases the risk of diabetes. Metformin is also associated with decreased Vitamin B12 absorption, increasing the risk of deficiency and insulin resistance. 

  • Vitamin B12 deficiency in women is associated with a higher BMI and greater insulin resistance and results in a greater risk of gestational diabetes (Krishnaveni, 2009).
  • Vitamin B12 absorption is reduced by Metformin because of a calcium-dependent ileal membrane antagonism (Bauman, 2000; Wulffele, 2003). It is therefore crucial that Vitamin B12 is supplemented in diabetics using Metformin.
  • Vitamin B12 deficiency in pregnancy is related to gestational diabetes and the onset of diabetes later in life (Krishnaveni, 2009).
  • Vitamin B12 deficiency is common in elderly diabetic individuals is associated with neuropathy, and is responsive to Vitamin B12 supplementation (Solomon, 2011).

Benefits, Side Effects, Drug Interactions


  • Vitamin B12 deficiency causes anemia. Anemic patients are unable to cope with physical and mental stress resulting in loss of exercise and mental motivation towards their daily routine (Clarke, 2003). Vitamin B12 supplementation will alleviate this condition.
  • Vitamin B12 supplementation improves cognitive function and memory (Agarwal, 2011).


Vitamin B12 is Generally Recognized As Safe (GRAS) according to FDA.

Side effects

  • Allergic reactions: Vitamin B12 may cause allergies in individuals allergic to cobalt or cobalamin.

Drug interactions

  • Metformin (Glucophage): Long term use of Metformin leads to reduced Vitamin B12 levels in patients.
  • Chloramphenicol and proton pump inhibitors (omeprazole, lansoprazole, etc.) can reduce Vitamin B12 absorption.


  • Pregnancy and breastfeeding: Vitamin B12 is safe for pregnant and breastfeeding women in recommended doses (2.6 μg to 2.8 μg daily).
  • Post-surgical stent placement: Vitamin B12 supplementation should be avoided after receiving a coronary stent.
  • Leber’s disease: Vitamin B12 supplementation is not recommended for patients suffering from Leber’s disease.
  • High numbers of red blood cells (polycythemia vera): The treatment of Vitamin B12 deficiency may hide the symptoms of polycythemia vera.


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This research was sponsored by GLOBESITY FOUNDATION (nonprofit organization) and managed by Don Juravin. GLOBESITY Bootcamp for the obese is part of GLOBESITY FOUNDATION which helps obese with 70 to 400 lbs excess fat to adopt a healthy lifestyle and thereby achieve a healthy weight.

Tags: Vitamin B12, healthy gut bacteria, weight loss, weight reduction, healthy weight, diabetes, food craving, cravings

DOI: 10.5281/zenodo.3974702