B12 is non-toxic, water soluble and has the largest and most complex chemical structure of all vitamins. The list
of benefits and symptoms of deficiencies are both long. There are no known side effects other than it can
produce occasional diarrhea, though rare and the benefits far outweigh the risks.
B12 helps to support adrenal function, maintain a healthy nervous system, aid in the production of DNA and
RNA, and the production of neurotransmitters. It affects the development and maintenance of red blood cells,
nerve cells and normal myelination (the fatty sheaths that cover and protect nerve endings). It’s needed to
prevent anemia, required for the proper digestion and absorption of food, and the metabolism of carbohydrates
and fats.
A B12 deficiency can cause poor cell formation in the digestive tract and lead to nausea, vomiting, loss of
appetite, poor absorption of food (malabsorption syndrome), constipation, gas, weight loss, fatigue, lethargy,
abdominal pain, and/or diarrhea. Absorption of B12 requires normal function of the stomach, pancreas and small
intestine. Sound familiar? These are the very symptoms that cats with IBD and other gastric disorders exhibit. A
b12 deficiency also inhibits and decreases the body’s ability to produce blood, increases blood cell destruction
and is very harmful to the nervous system which can cause neurological disorders and severe and sometimes
irreversible nerve damage. Because a healthy liver is able to store many years worth of B12, signs of deficiency
may not be obvious for a long time. Which may be why some cats seem to benefit even when they test negative
for deficiency.
To be absorbed in the body, B12 needs to combine with a substance called intrinsic factor. IF is produced by
your stomach lining where B12 from foods is released from its protein complex by hydrochloric acid and
enzymes. The secreted IF will bind to B12 and this combination will travel to the end of the small intestine which
then crosses the intestinal wall into the bloodstream. B12 is stored in the liver after being absorbed and excess
is excreted in the urine. If it’s not absorbed (ie due to malabsorption), it’s excreted in feces since it never leaves
the GI tract.
On PetPlace.com, they clearly state that a congenital B12 malabsorption syndrome has been reported in cats
(as well as some specific dog breeds). It also states that for dosing in cats, no good data is available and oral
treatment is unlikely to be of much benefit in malabsorption states (e.g. pancreatic disease interfering with the
production and release of pancreatic IF). This is why injections are used instead of pills. Injections will bypass
the stomach and go straight to the liver but the pills will have a long way to get there, will break down a lot
sooner and not have nearly the same affect.
http://www.petplace.com/drug-library/vi ... page1.aspx
Some risk factors for B12 deficiency are a weakened immune system and impaired white blood cells, gluten
allergies and/or sensitivities and helicobacter pylori infection (bacteria that can be common in IBD). Antacid, H2-
blockers, anticoagulants and potassium supplements can impair the absorption of B12, broad spectrum use of
antibiotics or anti-convulsants and parasites (specifically tapeworm). Large parasites like the beef tapeworm
compete for nutrients by robbing the body of micronutrients and vitamins.