Is your cat becoming weak, confused, ill, or diabetic?

House cats, like humans, are often deficient in vitamin B12 (also known as “cobalamin”) — despite the fact that commercial cat foods generally supply adequate amounts of this vitamin. Such deficiencies usually develop gradually, and are difficult to diagnose in both cats and humans because reliable B12-testing methods have become unavailable to veterinarians and physicians.

Vitamin B12 deficiencies are usually caused by feline medical problems that interfere with B12 absorption, or that deplete the body of B12. Such medical problems include:

  • damage to tissues that assist in absorption of B12 — for example, damage by diabetes or lymphoma
  • gastrointestinal illnesses that reduce the ability to absorb B12 — illnesses such as pancreatitis, exocrine pancreatic disease (EPI), bacterial infections, and inflammatory bowel disease (IBD)
  • diseases that cause cats to urinate and drink to excess, thereby depleting the body’s B12 stores — diseases like diabetes and hyperthyroidism)
  • genetic disorders that interfere with B12 absorption
  • disruption of digestion due to bile duct obstruction, as in cholangitis
  • chronic dietary shortage of B12 due to malnutrition.

All of these medical problems exist in humans, as well as in cats. Although far less medical research has focused on B12 deficiencies in cats than in humans, most of the human research is relevant to felines as well as to people.

If your cat is becoming weak, confused, or ill, you would be wise to consult with a veterinarian — various different factors can cause these same symptoms. But such symptoms are often caused by vitamin B12 deficiency, and there’s no harm in providing your cat with adequate B12 in addition to whatever other treatment your vet prescribes.

Consequences of B12 deficiencies

Vitamin B12 deficiencies are a very serious matter, but the symptoms are not unique and may not be immediately recognized for what they are. Common symptoms include:

  • Gastrointestinal disruption: vomiting, diarrhea, anorexia, weight loss
  • Neurological problems: lethargy, confusion, muscular weakness, neuropathy, difficulty walking or jumping; metabolic encephalopathy, blindness
  • vascular damage
  • Low red and white blood cell counts, anemia.

The symptoms of B12 deficiencies are usually reversible if corrected promptly. But if treatment is delayed too long, the damage can be permanent.

Correcting B12 deficiencies

Feline B12 treatments are available in several forms:

  • Subcutaneous injections of B12 (formulated as cyano-, hydroxo-, or methyl-cobalamine)
  • Oral high-dose cyanocobalamin supplementation
  • Oral high-dose methylcobalamin supplementation

Whichever method is used, the treatment will need to be continued for many weeks, even in otherwise healthy cats. For cats whose low B12 levels are due to permanent conditions — such as pancreatic disease, genetic disorders, or tissue damage — the treatment will be needed for life.

Which of these three treatments is the best one? If your budget and your time are of no concern, then you can take your cat to the vet every week for an injection. Problem solved. But if your resources are limited, or if your cat doesn’t appreciate being “needled” every week, then your best option will be oral high-dose cobalamin supplementation.

Injection versus high-dose B12

Are oral high-dose supplements as effective as injections? Studies have shown this to be so for humans. Similar studies have not been performed for cats. Cats and humans, however, share the same system for absorbing and processing B12; so it makes sense to use human treatments as a guide.

In humans, clinical trials have proven that injections are not necessary — oral B12 supplements are just as effective as injections — if the oral dosage is high enough.

How much is “high enough”? Actually, not very much. A “large dose” of B12 amounts to just a few milligrams. The typical daily loss of B12 by the body (human or feline) is only a microgram or so. But when a B12 supplement is taken orally, most of the dose is either damaged by stomach acid or simply passes through the digestive tract unabsorbed — especially if the patient already has absorption problems. Only about 1% of a “large” oral dose actually reaches the bloodstream — the rest is never absorbed and gets wasted. Therefore, to replace the typical daily loss of B12 in the (feline or human) body, one needs at least a hundred times the replacement amount. But this still amounts to only a few milligrams.

For years, cat owners have been using oral B12 supplements to treat their cats, and it is clear from their reports that this treatment works well. Since the toxicity of B12 is essentially zero, the same dosages can be used in cats as in humans.

Methyl vs cyano B12

If you have opted for oral supplements for your cat, the question becomes which form of B12 to use: methylcobalamin or cyanocobalamin? Both forms are safe — but only one form is effective.

Users of LifeLink’s Zobaline have reported that their cats with diabetic neuropathy respond quickly to Zobaline (methylcobalamin) treatment whereas they did not respond well to previous treatment with cyanocobalamin. Their Zobaline-treated cats, they say, recover their strength after just a few weeks of treatment. This major difference in the effectiveness of cyano- and methyl-cobalamine may at first glance seem puzzling. But careful consideration of how these substances are processed in the body reveals three likely reasons for the difference:

  • Loss of B12 in the stomach. Both cyano- and methyl-cobalamin are sensitive to the acid conditions of the stomach. This is why the body produces transport proteins to protect B12 as it passes through the stomach. But only a limited amount of these transport proteins are available — enough to protect the tiny amounts of B12 found in food, but not enough to protect the much larger amounts of B12 in high-dose B12 supplements. This is one reason why most of the B12 in high-dose supplements never gets absorbed — much of it is destroyed in the stomach. But the cyano form is more susceptible to this destruction than is the methyl form.
  • Dwell time in the body. When a dose of either methyl- or cyano-cobalamin is consumed and absorbed into the blood, the kidneys immediately set to work removing the compound from the blood and from the body. For methylcobalamin, this removal process is takes place considerably more slowly than for cyanocobalamin. Thus, methylcobalamin is a more efficient source of B12, since it stays in the body longer.
  • Conversion to active B12. The methyl form is an active form of B12, whereas the cyano form requires biochemical processing in the body to convert it to an active form. This extra processing — to remove the cyano component and replace it with a methyl component — is an additional burden on the body’s cells. It requires the production of enzymes to carry out the process, and it requires the expenditure of biochemical energy. Worse yet, some individuals have defective enzymes for performing this task, leaving the patient completely unable to utilize the cyano supplement at all.

For these reasons, the methyl form of B12 is by far the superior choice for supplementation.

(Some misguided nutritional websites try to make an issue out of the notion that cyanocobalamin is synthetic, whereas methylcobalamin is “natural”. This argument is complete nonsense. Most of the methylcobalamin on the supplement market is made synthetically from cyanocobalamin. The rest (as well as cyanocobalamin itself) is made by chemically extracting cobalamine from genetically modified bacteria. There is nothing wrong with either of these methods — the real advantage of methylcobalamin is not its source, but rather how well it performs in the body.)

How to administer a Zobaline tablet to a cat

Sublingual lozenges are designed for human use, but are often used for cats, as well. Humans use them by holding them under their tongues until they dissolve and are absorbed — or until the dose is inadvertently swallowed.

Of course, cats cannot be expected to hold the lozenges under their tongues. Instead, the lozenges are administered by standard “cat pilling” methods.

Zobaline tablets are quite easy to prepare for cats: crush the tablet to a powder with the back of a spoon and mix it with any moist cat food. Most Zobaline users find that their cats don’t even notice anything different about the medicated food. And after all, why should they? Cats do not object to medicines that they cannot detect.

The doses involved in B12 supplementation are small — even “high” doses contain only a few milligrams of B12. Furthermore, B12 itself is virtually tasteless and has no aroma. Even if cats were able to detect its presence, they would probably not find it unappetizing — after all, B12 is present in all meats, which cats generally consider to be quite tasty.

More information

If you are interested in knowing more about how the body transports, absorbs, and utilizes vitamin B12, see LifeLink’s website article “How the body acquires and uses Vitamin B12 — like a Rube Goldberg machine”.