Nutritional Doublethink
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Vitamin B12 - Cobalamin

Vitamin B12 Functions

Vitamin B12 works with folate to make methionine, an amino acid important in the creation of proteins. Vitamin B12 important in energy metabolism, particularly in the creation of energy from fat and protein. Vitamin B12 maintains nerve sheaths and protects nerve fibers.

Vitamin B12 Deficiency

The main cause of vitamin B12 deficiency is lack of absorption. Vitamin B12 requires intrinsic factor to be absorbed. Many elderly people don’t produce enough intrinsic factor, so even if they are eating food sources with Vitamin B12, they can become deficient because the B12 is not absorbed. In these cases, higher intakes of Vitamin B12 are recommended, and Vitamin B12 is injected. Most people have adequate intakes of vitamin B12, but vegans are at risk as well. This is because Vitamin B12 is the only vitamin found ONLY in animal sources. Vegans typically take supplements and have adequate intrinsic factor, so although they are at risk, they are not as likely to have B12 deficiency as the elderly. Vitamin B12 deficiency can cause Pernicious Anemia. Because vitamin B12 is important in maintaining nerve sheaths, deficiency can result in a lack of sensation of the toes and the fingers. This can further progress up the legs and the arms and result in difficulty with movement and walking as well as disorientation and dementia.

Recommended Intake of Vitamin B12

Adult males and females need 2.4 ug per day.
Age and Gender
Amount of Vitamin B12 per Day
Infants 0-6 mo
0.4 ug
Infants 6-12 mo
0.5 ug
Children 1-3 yr
0.9 ug
Children 4-8 yr
1.2 ug
Males 9-13 yr
1.8 ug
Males 14 and up
2.4 ug
Females 9-13 yr
1.8 ug
Females 14 and up
2.4 ug

Food Sources of Vitamin B12

Vitamin B12 only occurs in animal foods. Good sources include:
  • clams
  • mussels
  • crab
  • beef
  • pork
  • tuna
  • turkey
  • cheese
  • egg
  • milk

For individuals who are vegan who don't eat any animal products,  they should obtain B12 from supplements, fortified foods or nutritional yeast.
< Folate
Minerals >

References

  1. Brody, T. Molecules Important to Digestion and Absorption. In: Nutritional Biochemistry, 2nd ed. Academic Press. San Diego, CA. 1999: 81.
  2. Dietary Reference Intakes (DRIs): Recommended Dietary Allowances and Adequate Intakes, Vitamins. Food and Nutrition Board, Institute of Medicine, National Academies. United States Department of Agricultural. Last accessed April 2nd, 2016. https://fnic.nal.usda.gov/sites/fnic.nal.usda.gov/files/uploads/recommended_intakes_individuals.pdf
  3. Food Sources. Vitamin B12. Vitamins. Linus Pauling Institute Micronutrient Information Center. http://lpi.oregonstate.edu/mic/vitamins/niacin. Last updated January, 2014. Last accessed April 13, 2016.
Last updated on April 2nd, 2016

Nutritional Doublethink

Nutritional Doublethink™ is the simultaneous acceptance of two contradictory beliefs about a food, "unhealthy is healthy". This website explores these contradictions and their impact on health. The information on this website is not meant to replace the advice from your doctor or dietitian.

Copyright Nutritional Doublethink™, 2017

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  • Home
  • About
  • Blog
  • Chart
  • Gallery
  • Nutrition Topics
    • Nutrition Basics >
      • Food Label
      • Nutritious Diet
      • Whole vs Processed
      • Food Choices
      • Nutrition and Disease
    • Dietary Guidelines >
      • Determining Intakes
      • Portion Size
      • Food Groups
    • Digestive Tract >
      • Digestion & Absorption
    • Carbohydrates >
      • Carbohydrate Digestion
      • Carbohydrate Absorption
      • Sugar
      • Foods with Sugar
      • Fiber
      • Glucose Regulation
      • Carbohydrate Recommendations
    • Lipids >
      • Lipid Digestion
      • Cholesterol
      • Essential Fatty Acids
      • Trans Fatty Acids
      • Lipid Recommendations
    • Protein >
      • Protein Structure
      • Protein Functions
      • Protein Digestion
      • Protein Digestibility
      • Protein Recommendations
    • Vitamins >
      • Vitamin A
      • Vitamin D
      • Vitamin E
      • Vitamin K
      • Vitamin C
      • B-Vitamins
      • Vitamin B1: Thiamin
      • Vitamin B2: Riboflavin
      • Vitamin B3: Niacin
      • Vitamin B6: Pyridoxine
      • Vitamin B9: Folate
      • Vitamin B12: Cobalamin
    • Minerals >
      • Calcium
      • Sodium
      • Potassium
      • Iron