Download Vitamin B12 - Medical Nutrition Therapy Manual

Greyson, Ashley. Vitamin B12. KNH 413 – Medical Nutrition Therapy II. Miami University,
Oxford, Ohio, Spring 2013.
Vitamin B12
1. What is the nutrient?
Vitamin B12
2. What is the RDA/DRI for the nutrient?
Age
Male
Female Pregnancy
Lactation
0-6 months
.4 mcg
.4 mcg
7-12 months
.5 mcg
.5 mcg
1-3 years
.9 mcg
.9 mcg
4-8 years
1.2 mcg
1.2 mcg
9-13 years
1.8 mcg
1.8 mcg
14+ years
2.4 mcg
2.4 mcg
2.6 mcg
2.8 mcg
http://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/
3. How is the nutrient metabolized?
In contrast to other water-soluble vitamins, it is not excreted quickly in the urine,
but rather accumulates and is stored in the liver, kidney and other body tissues.
It is normally involved in the metabolism of every cell of the human body,
especially affecting DNA synthesis and regulation, but also fatty acid synthesis
and energy production.
http://pureherbalextracts.com/wholesale-supplements/vitamin-b12-supplements.html
4. What are food sources of the nutrient?
- Clams, Oysters and mussels
- Liver
- Caviar
- Octopus
- Fish
- Crab and Lobster
- Beef
- Lamb
- Cheese
- Eggs
http://www.healthaliciousness.com/articles/foods-high-in-vitamin-B12.php
5. What disease states alter the nutrients metabolism?
- Pernicious Anemia  condition in which the body can't make enough
healthy red blood cells because it doesn't have enough vitamin B12.
- Infections
- Surgery
- Medicines
- Crohn’s disease
- Short bowel syndrome
- Gastrointestinal disorders
http://www.nhlbi.nih.gov/health/health-topics/topics/prnanmia/printall-index.html
6. What are the tests or procedures to assess the nutrient level in the body?
- Complete Blood Count (CBC) The CBC is used as a broad screening test to
look for such disorders as anemia, infection, and a variety of other diseases
as well.
- Vitamin B12 Test to measure the level of this vitamin in the blood
- Homocysteine test and Methylmalonic Acid (MMA) test MMA primarily is
ordered, sometimes along with homocysteine, to help diagnose an early or
mild B12 deficiency. It may be ordered as a follow-up to a vitamin B12 test
for which the result is in the lower end of the normal range. Some
researchers have suggested using MMA as a screening tool, especially among
the elderly, who frequently have B12 deficiencies and may have few
recognizable symptoms. However, the use of MMA is still controversial in the
medical community and not used frequently for this purpose.
http://www.bami.us/Diet/VitB12.html
7. What is the drug –nutrient interactions?
Drug
Proton pump inhibitors (PPIs) are
used to treat gastroesophageal
reflux disease (GERD) and peptic
ulcer disease: Prilosec, Prevacid,
Nexium, and Aciphex
Potential Interaction
PPI medications can interfere with vitamin B12
absorption from food by slowing the release of
hydrochloric acid into the stomach. This is a concern
because acid is needed to release vitamin B12 from food
prior to absorption. So far, however, there is no
evidence that these medications promote vitamin B12
deficiency, even after long-term use.
H2 receptor antagonists are used to H2 receptor antagonists can interfere with vitamin B12
treat peptic ulcer disease. Tagamet, absorption from food by slowing the release of
Pepsid, and Zantac
hydrochloric acid into the stomach. This is a concern
because acid is needed to release vitamin B12 from food
prior to absorption. So far, however, there is no
evidence that these medications promote vitamin B12
deficiency, even after long-term use.
Metformin is used to treat diabetes. Metformin may interfere with calcium metabolism. This
may indirectly reduce vitamin B12 absorption because
vitamin B12 absorption requires calcium. Surveys
suggest that from 10% to 30% of patients taking
Metformin have evidence of reduced vitamin B12
absorption.
http://www.bami.us/Diet/VitB12.html
8. How is the nutrient measured?
Micrograms (ug) per serving (example below)
Food
Micrograms (μg) Percent
per serving
Daily Value
Mollusks, clam, mixed species, cooked, 3 ounces
84.1
1400
Liver, beef, braised, 1 slice
47.9
780
Fortified breakfast cereals, (100%) fortified), ¾ cup
6.0
100
Trout, rainbow, wild, cooked, 3 ounces
5.4
90
Salmon, sockeye, cooked, 3 ounces
4.9
80
Trout, rainbow, farmed, cooked, 3 ounces
4.2
50
http://www.bami.us/Diet/VitB12.html
9. What is the Upper Tolerable Limits?
None, as there is no toxicity
http://www.umm.edu/patiented/articles/what_vitamins_000039_1.htm
10.What are the physical signs of deficiency?
The consequences of vitamin B12 depletion -- anemia and potentially irreversible
nerve damage. Easy bone fractures are a sign, along with depression, memory
loss, instability, disorientation, decreased reflexes and possible hearing loss.
http://www.umm.edu/patiented/articles/what_vitamins_000039_1.htm
11.What are physical signs of toxicity?
No evidence of toxicity of this vitamin
http://www.umm.edu/patiented/articles/what_vitamins_000039_1.htm