Diabetes in CatsNovember is National Pet Diabetes Month, so I decided to take a closer look at diabetes in cats. There's certainly a lot of information out there! I've compiled it into one overview that, while lengthy, looks at diabetes from all viewpoints.
Because it deals with the blood sugar, diabetes is also called diabetes mellitus or "sugar diabetes." It's a condition that was first recognized in the 1940s. One estimate stated that diabetes affects only up to 2% of all cats, but its incidence has been increasing since the 1980s. Here's the latest on it:
What Causes Diabetes in Cats?In a normal cat's body, the digestive system breaks down the proteins, fats, and carbohydrates in food into tiny components that can be used by the body's cells for fuel. One of these tiny components is glucose, also known as blood sugar or serum fructosamine.
When it senses a rise in blood sugar, beta cells in your cat's pancreas produce insulin to regulate the level of glucose in the bloodstream and its storage in tissues. Insulin allows glucose to enter the cells so they can use it for fuel.
The liver stores glucose as glycogen. When blood sugar declines, alpha cells in the pancreas produce glucagon that triggers the liver to convert glycogen back into glucose because the body's cells are hungry for fuel. Studies in the last decade have shown that the liver can produce insulin, as well, to process simple carbohydrates in the diet.
A cat's kidneys serve as filters that remove waste products from the bloodstream and return essential nutrients to the cat's body. Glucose is usually one of these returned nutrients. But when the glucose level becomes too high, the kidneys can no longer process it all. The excess sugar is passed into the bladder for excretion in urine. There, it attracts water, dehydrating the cat and driving thirst. Bacteria love sugar, too, so they are drawn to the now sugar-rich urinary tract, where they can cause secondary infections (UTIs).
Along with the sugar, the kidneys will pull out certain electrolytes that should have been passed back into the bloodstream. The cat's levels of sodium and potassium will drop, causing weakness and lethargy.
Both insulin and glucagon are necessary for normal metabolism. They work in tandem, regulating the bloodstream's glucose level so that all the body's cells are properly nourished. The pancreas and liver work together to control their relationship.
Blood glucose level is also affected by many other factors beyond insulin and glucagon, such as:
- enzymes secreted by the pancreas into the small intestines
- epinephrine (adrenaline)
- cortisol (cortisone)
- feline growth hormone
The feline body needs far less carbohydrates than do our human bodies. Cats are obligate carnivores, lacking a specific liver enzyme that allows for proper processing of carbohydrates. Their gastrointestinal tract is far shorter than a dog's or a human's. Designed to get most of their nutrition from protein, their bodies simply aren't efficient at metabolizing carbs from grains and actual sugar.
In nature, cats would eat a diet consisting of perhaps 2-3% carbs. Most dry cat foods contain 35-50% carbs. Is it any wonder our cats are becoming obese and developing diabetes with increasing frequency?
In some diabetic cats, beta cells in the pancreas do not produce enough insulin to regulate blood sugar. This is referred to as Type 1 diabetes. It is quite uncommon for cats to have this, but most commonly affects cats in middle age. It is always insulin-dependent. A cat with this type may be able to maintain enough insulin to be fine most of the time, but when put into a stressful situation, diabetic symptoms may start to appear.
Or the cat's cells may have developed some type of resistance to insulin -- this is more common in cats suffering from obesity. Fat cells produce a substance that decreases the cells' ability to respond to insulin. Cats with an overactive thyroid gland (hyperthyroidism) can also develop insulin resistance. This condition is known as Type 2 diabetes. Metabolism of carbohydrates, proteins, and fats will become abnormal. The organs will all be working harder to push all that excess sugar out of the body. Damage will eventually lead to lowered insulin production in Type 2 diabetes, as well. About 1% of all cats will get Type 2 diabetes, which works out to around 800,000 kitties in the United States alone. Stress can push some cats with Type 2 into Type 1 diabetes.
There is also a Type 3 of diabetes. It is usually due to other diseases that have damaged the cat's pancreas and is extremely rare. The cat's immune system attacks the beta cells in kitty's pancreas that generate insulin. Immune cells bring along a compound known as amyloid that is toxic to these beta cells.
When the brain's appetite center senses that blood sugar is low, it generates an urge to eat. In a normal cat's body, this would spur the cat to eat food that the body would then break down into glucose to feed the cells. But when insulin levels are decreased, this center cannot sense glucose in the blood, so it mistakenly thinks the cat needs to eat. Eating makes the blood sugar rise even more, giving the body excess sugar to process.
Before developing diabetes, cats -- just like people -- can go through a pre-diabetic state. During this time, their pancreas is working as hard as it can to produce insulin to combat all the carbohydrates in the diet. These persistently higher levels of blood sugar will finally exhaust the pancreas so that diabetes sets in. But if caught early, proper management of the cat's diet can completely reverse the damage.
Some cats also experience transient diabetes, in which they may be dependent on insulin for a while, then lose the need for it. This may come and go. The stretches where insulin is not required may be only days or can go on for months.
Because the glucose they need for fuel cannot enter the cells, it has to go somewhere else. The cat's liver and kidneys start working at their maximum capacity to eliminate this sugar. Excess glucose will be eliminated in the cat's urine. Once the liver has stored all the sugar it can and the kidneys are processing as much as they can, that sugar starts going into the bloodstream. Excessive sugar (glucose) in the bloodstream is known as hyperglycemia.
Many factors can come into play with diabetes:
- Diet, especially feeding dry cat food (kibble)
- Some viral diseases
- Autoimmune diseases
- Physical trauma
- The cat's exercise level
- Medications, especially steroids and beta blockers
How Does Diabetes Affect Cats?Cats with diabetes are suffering from having the fat and protein stores in their bodies broken down to use for energy. Their organs are either functioning at maximum capacity, or being broken down for fuel.
If left untreated, diabetes will shorten your kitty's life. With their fuel being diverted instead of absorbed, the cat's cells are not receiving proper nourishment. In essence, the cells are starving. Kitty's body begins breaking down its own fat and muscle protein to get the energy the cells need in an attempt to normalize metabolism.
High levels of ketones in the bloodstream will make a cat thirsty as normal metabolism is disrupted. Excessive thirst is also the result of vomiting caused by these ketones. They change the blood's pH balance and can lead to fatty liver disease. The cat's electrolytes get out of balance and kitty will go into a supplementary condition known as diabetic ketoacidosis. This is a medical emergency that can be fatal. More on it in the section on symptoms below.
Cats with diabetes can develop liver disease and secondary bacterial infections. When untreated, diabetes can also develop high blood pressure. The kidneys can become damaged from processing all that excess sugar.
Some diabetic cats will have diabetic neuropathy, just like humans. Some old-school vets will resort to amputating limbs affected by this rather than addressing the diabetes more aggressively.
Where cats differ from humans is that diabetes will not typically damage a cat's kidneys, blood vessels, or coronary arteries, nor do cats tend to have vision problems from diabetes. Another significant difference is that the beta cells in a cat's pancreas can sometimes be revived and actually start producing insulin again! We humans can't do that.
What Puts a Cat at Risk for Diabetes?
While no specific breeds of cats are more prone than others, there are several risk factors that can make a cat more susceptible to diabetes:
- Age: over 6 years
- Being male and neutered
- Chronic pancreatitis
- Various hormonal/endocrine diseases: acromegaly, Cushing's, hyperthyroidism
- Some medications: corticosteroids, beta blockers, megestrol acetate
- Being a Burmese cat in the UK, Australia, or New Zealand
- Chronic renal (kidney) failure
The one most prevalent risk factor for a cat developing diabetes is a diet consisting mainly of dry cat food (kibble). This is something that is completely controllable.
What Are the Symptoms of Feline Diabetes?Cats are good at masking symptoms of illness until they are almost dead, so watch carefully for any signs of diabetes. Earlier treatment is always better, as it will minimize the damage caused to your cat's body by excess glucose.
Your diabetic cat may eat more, but still lose weight. These cats may become almost ravenous. They will urinate more often and seem excessively thirsty. There may be more "accidents" of urination outside the litter box. You may notice problems with your kitty's skin becoming dry and flaky and the coat appearing dull and oily.
Some cats will lose their appetite. They may nap more. As their bodies consume existing stores of fat and then muscle tissue, they will become thin and bony through the back and in the back legs. Eventually, this process will start to attack cells in the brain, heart, and lungs. As the kidneys become clogged with ketones from the digestion of muscle tissue, they can clog and will eventually fail.
If your cat suffers from diabetic neuropathy, you may notice kitty walking differently to take pressure off the painful area of the paw pads. Their gait will become more flat-footed instead of walking on their toes like cats normally do. As the muscles of their back legs are broken down to feed the body's cells, they can become weak. You may notice the rear legs wobbling as kitty walks.
Cats who go into diabetic ketoacidosis (DKA) will lose their voracious appetite and begin to vomit and have diarrhea. It can be brought on if your diabetic cat has not had enough food, or enough insulin, or has developed a high insulin resistance due to other health problems. The cat may not eat for more than 12 hours. They will become lethargic and weak, unable to keep enough water in them to stay properly hydrated. They may walk into things or circle inexplicably. These cats may stagger as though drunk. Their breath may smell like fruit or nail polish remover. These cats may also start to shake or have fast, labored breathing. In severe cases, they may lapse into a coma. Obviously, cats exhibiting these symptoms need to be taken to the veterinarian immediately.
When your veterinarian checks for diabetes, this is done by examining the cat's symptoms and testing the levels of sugar in the blood and urine. This can be tricky, because many other conditions can cause cats to have higher than normal blood glucose levels -- even stress. A test for serum fructosamine, which shows sugars attached to proteins in the blood, can improve the chance of a correct diagnosis. Another test they can run is for glycosylated hemoglobin, which can reveal an average blood glucose level for the past 2-3 months. For optimal results, they will ask you to withhold food from your cat for 8-12 hours before taking samples to run these tests.
High sugar level in the urine is called glycosuria. In addition to high levels of sugar, your vet will look for ketones, the result of the cat's body digesting its own fat and muscle protein, in the urine.
How is Diabetes Treated in Cats?The first step is to work in tandem with your veterinarian. Managing diabetes is complicated and every cat's system is different. You need the help of a trained professional to do it correctly. While there are many online sources of information, some of them conflict and can be confusing to the layperson.
If your cat has developed ketoacidosis (DKA), hospitalization is necessary. It is considered to be a medical emergency. Your vet will administer fluids, electrolytes, and carefully regulated insulin injections until glucose and ketones are under control and kitty is stable enough to go home. The vet may also treat any secondary bacterial infections or other diseases that may have set in as a result of the condition.
Cats who are diagnosed earlier are treated in a variety of ways. Remission of the diabetes is always the goal. Each cat's system is unique and treatment will vary from individual to individual. A mere change of diet may put the diabetes in permanent remission in some cats. This should be the first course of treatment in most cases.
The cat's diet is the most critical thing that must be addressed, especially if obesity is a factor. Gradual weight loss is essential, no more than about 1% of the cat's body weight per week. Steer clear of kibble diets advertised as "weight control", as they tend to substitute carbohydrates for the protein kitty needs. Feed only wet foods (canned, pouched, or defrosted frozen). Keep a weekly log of your cat's weight. You may want to invest in a baby scale to get the most accurate numbers.
In the past, eating food higher in fiber and complex carbohydrates was recommended for overweight cats. A diet like this shifts the cat's digestion into a lower gear so that sugar is released more slowly into the system. This, however, typically works better on cats with Type 1 diabetes, which is quite rare. Remember, a cat's natural diet is very low in carbohydrates. Be wary of the high-priced "prescription" foods only available from your vet, as many of these are actually higher in carbohydrates than is healthy for a diabetic cat.
Especially in cats with Type 2 diabetes, vets are increasingly advocating an immediate change in diet and careful monitoring for 3-5 days to see if that alone can reverse the cat's diabetic state. Most recent studies point to a diet high in protein and low in carbohydrates. A grain-free food is essential. Especially avoid rice, corn, and potatoes. Cats do not need fruit or vegetables, either. Small meals 2-3 times per day are preferred instead of one large meal to stabilize blood sugar levels. A supplement containing Omega-3 fatty acids can be helpful if kitty's skin is dry and flaky, especially if you're feeding a low-fat diet.
This dietary change can quickly send diabetes into remission in many cats so that insulin will no longer need to be given. When switching a diabetic cat to a low-carb diet if you're also giving insulin, you'll need to carefully monitor blood sugar daily to avoid the dangerous condition of hypoglycemia (discussed below).
Underweight kitties may be given a high-calorie diet to get back up to optimal weight. It's preferred that you switch to timed feedings instead of allowing your diabetic cat to free-feed throughout the day. Feedings will need to correspond with insulin injections and should be given at the same time each day. Portions should also be controlled.
Homeopathic treatments for diabetes include administering tinctures including Belladonna 30C, Natrum muriaticum 6C, Phosphorus 6C, and Thuja 30C. One mixture we used to sell on Old Maid Cat Lady was GlucoEnsure by PetAlive. Its combination of homeopathic elements support the cat's pancreas to help it produce insulin.
Vets who use herbs have many herbal options for treating diabetic cats. These include fenugreek seed, gymnema sylvestre, bitter melon, and turmeric. Do not attempt these therapies on your own, however; they require the expertise of a professional to get the correct balance. Typically such treatments are used in conjunction with dietary changes and insulin treatment.
Acupuncture has also been used as supportive treatment for diabetes. It is said to work by clearing lactate from the kidneys and liver and increasing the production of cortisol. While not a substitute for conventional treatment, it can also have positive effects on the pain and inflammation associated with diabetic neuropathy. Acupuncture can also be quite effective for cats with transient diabetes.
Another supportive treatment for diabetes is massage. It can help with the tightness that sometimes accompanies diabetic neuropathy, but will not address the insulin insufficiency that causes diabetes.
Diabetic cats may need insulin that can be administered orally or via injection at home. Injections are typically given in a cat's side, where circulation is good. They are always given in conjunction with meals. Your veterinarian will show you how to give the injections. Thanks to tiny needles, many cats do not even notice that they're receiving them!
Current types of insulin being given for diabetic cats are Lantus® (Glargine insulin), ProZinc® (protamine zinc insulin, or PZI), and Vetsulin® (Lente insulin). PZI is developed from cow or pig insulin, which are closest to the type naturally produced by cats, so it is the preferred type of insulin for treating feline diabetes. The newest of these is the Glargine, which is also used for humans, but it is more unpredictable and difficult to manage when used for cats. It is also more expensive. And it can produce an allergic reaction in some cats. Lente use is increasing in cats. It is made from pig insulin. Some vets use Humulin® for cats, as well.
The type of insulin administered is important, as it can determine whether the cat will need insulin for the rest of its life, or just until glucose is normalized and the diabetes appears to be in remission. Each cat responds differently to each type of insulin, however, so your vet will be the best judge of which to prescribe for your kitty. A 1969 study revealed that insulin also increases by up to 250% the risk of heart attack and stroke. So it is nothing to be taken lightly.
If you must inject insulin, the cat will usually require two injections per day. You will also need to check kitty's blood sugar daily, usually about 6-8 hours after an insulin injection. This is done using the same type of equipment used to check blood sugar levels in humans. The Abbott Precision Xtra meter is commonly used. Urine sugar can be tested with Keto-Diastix strips. There are even some cat litters that now contain crystals that will change color in the presence of ketones in the urine.
Glipizide is a type of insulin that is given orally to lower blood sugar. It is not recommended for most cats, as the injections work better. Not only does this form cost more, it can take up to 10 weeks to become effective. There are also a few side effects of the oral medication: vomiting, appetite loss, and liver damage. But these are uncommon.
Monitoring blood sugar is important during treatment, as getting too much insulin can cause it to drop dangerously below normal. This condition is known as hypoglycemia. Cats suffering from it will grow weak and listless, appear uncoordinated, and possibly go into convulsions or coma. If you don't catch it in time, it can cause brain damage or even be fatal.
Most cats function normally, when relaxed at home, within a range of 60-100 blood glucose, even though a range of 80-130 is considered normal. In a stressful situation, a cat's blood sugar can temporarily spike to a level of 300-500. It's when this elevated level becomes consistent that problems occur.
If your cat's blood sugar check shows a level lower than normal, immediately feed the cat a small meal of wet food high in protein. Cats who have progressed to the stage of hypoglycemia to the point that they are unable to eat are even more critical. Some vets advise to rub a little corn syrup on their gums or give it directly into the mouth by syringe, while others say never to do this. Because of this uncertainty, it's far better to manage your cat's diabetes responsibly so this condition does not occur. Obviously, hypoglycemic cats who are unable to eat need to get to the vet immediately.
Once your cat is diagnosed with diabetes, you'll need to carefully watch for the warning signs that initially alerted you to the condition. Blood sugar consistently above 150 is a problem. Check with your vet if you see these symptoms again, as they could indicate a need to adjust kitty's insulin dosage.
A new therapy being tried by naturopathic veterinarians involves using animal tissues and pancreas extracts to repair damage to your cat's organs and glands. Since cats in the wild would consume whole prey, they would get these nutrients naturally. In our highly processed commercial pet foods, however, some of the organs present in whole prey are removed. Results of this therapy are few, but promising.
You will need to visit your vet about every 3-4 months for follow-up testing. When managed properly, cats with diabetes can live for many more years and enjoy a good quality of life.
How Can I Prevent Diabetes in My Cat?Prevention really is far preferable to going through an exhausting and expensive course of treatment! Diabetes is not curable, per se, but the more common Type 2 diabetes can go into remission when successfully managed. Since weight plays such a large role in diabetes, keeping your cat at an optimal weight is a great way to keep from having to give injections and do blood tests!
Stop feeding your cat dry food (kibble). It may be convenient, but it's unhealthy. Since all dry cat food contains carbohydrates your cat's body can't process, it's safer to stick to a wet (canned) or raw diet to keep your cat healthiest. This is also a much better way to control portions so that your cat doesn't become obese. Many veterinarians tell us that it's our modern over-reliance on the convenience of dry kibble for cats that is causing the recent upsurge in feline diabetes. It's the equivalent of feeding your children a diet composed mainly of French fries and breakfast cereal. They may love it, but it's not healthy.
Even among canned foods, there are differences, however. And price alone is not a factor; many high priced and "prescription" foods are too high in carbs for your cats. And some lower-priced foods are better than you'd think. Canned foods with a lot of gravy or sauce tend to also be heavier in carbs. Ignore the marketing hype. Read the small print on cans, but be aware that those figures may be years old and not reflect what's actually inside that can you're holding. Find a food that gets less than 10% of its calories from carbohydrates.
A cat's natural diet is whole prey. This is about 45-70% dry protein, 15-35% fat, and under 5% dry carbohydrate. If you must feed a commercial cat food, look for one with a makeup as close to these percentages as you can find. There are also places where you can buy frozen whole prey to feed your cats: baby mice ("pinkies"), quail, etc., if you have the stomach for preparing and serving it. Many cats will readily switch over to eating these, even if they've been fed exclusively kibble before.
Watch the fat content in canned food, as well, especially with lower-priced brands. Fat is cheaper than protein, and it makes the food tastier for the cats, so read those labels. Look for diets higher in muscle meat, without vegetable proteins like soy, or grains. Cats cannot survive on a vegan diet. Meat by-products are fine, as these are usually organs a cat would eat naturally on a whole prey diet. You may choose to start making your own cat foods. There are many online guides that can show you how to do this, including some of the sources listed at the end of this article.
Encourage your cat to exercise daily. This is easy, as cats love to play! It can be done by providing plenty of toys and climbing structures, but also by playing with your cat each day using interactive toys. The interaction helps cement the bond between you and your cat, as an added advantage. This will also make your kitty happier emotionally, which leads to better behavior.
Keep track of your cat's weight, water intake, urine output, and appetite. If you notice any changes, especially if all four of them change relatively quickly, visit your veterinarian. Again, diabetic cats should be seeing their vet about every 3-4 months. This is especially important for cats who are over 10 years old.
A diagnosis of diabetes is certainly an inconvenience and an expense, but with proper treatment your cat may recover completely. At the very least, you should be able to enjoy many more years with your kitty!
Sources: "Feline Diabetes", Cornell Feline Health Center; "Diabetes Mellitus in the Cat", Winn Feline Foundation; "Feline Diabetes", The Original Internet Guide to Feline Diabetes; "Feline Diabetes: Symptoms, Treatments, Prevention, and Diet Tips", WebMD; "Feline Diabetes" by Lisa A. Pierson, DVM, CatInfo.org; "Feline Diabetes Mellitus", American Association of Feline Practitioners; "What is feline diabetes?", "Risk factors", "Diagnosis", "Treatment" and "F.A.Q.", My Cat Has Diabetes; "Treating Diabetes Holistically" by Dr. Larry Siegler, Only Natural Pet; "Feline Diabetes: A New Look at an Old Disease" by Dr. Donna Spector, Halo Pets; "Natural Treatment of Feline Diabetes (With Infographic)" by Melody McKinnon, All Natural Pet Care; "Protocol for Success in Managing Feline Diabetes", YourDiabeticCat.com; "Acupuncture Can Help Diabetic Cats & Dogs by Clearing Lactate", Dr. Pollen, "Acupuncture for Dogs and Cats: Diabetes", Bottom Line Personal; "Diabetes Mellitus (Sugar Diabetes)", Long Beach Animal Hospital.