Diabetes in dogs is increasingly common – but is far from a death sentence.
Article by Mary Straus and CJ Puotinen, published in the Whole Dog Journal, May 2012
Also see these related articles:
Zachary, pictured above, lived a happy and healthy life for four years after being diagnosed with diabetes at age 11.
For years public health officials have reported a diabetes epidemic among America’s children and adults. At the same time, the rate of diabetes in America’s pets has more than tripled since 1970, so that today it affects about 1 in every 160 dogs. But while many human cases are caused and can be treated by diet, canine diabetes is a lifelong condition that requires careful blood sugar monitoring and daily insulin injections.
The medical term for the illness is diabetes mellitus (mellitus is a Latin term that means “honey sweet,” reflecting the elevated sugar levels the condition produces in blood and urine). Diabetes occurs when the pancreas is unable to produce sufficient insulin to metabolize food for energy, or when the body’s cells fail to utilize insulin properly.
The pancreas's inability to produce insulin is known in humans as type 1 (formerly called juvenile or insulin-dependent) diabetes. This is analogous to the type that affects virtually all dogs. Dogs can also develop gestational diabetes during pregnancy.
Type 2 (formerly adult onset) diabetes, which is the result of insulin resistance often linked to diet and obesity, is the most common form of diabetes in humans. Most diabetic cats have type 2 diabetes, but there is no evidence that this form occurs in dogs.
The classic symptoms of diabetes are excessive thirst, increased urination, and weight loss despite normal or increased food consumption. Acute-onset blindness resulting from cataracts can also be a sign.
The diagnosis is easy to confirm with simple tests for glucose (sugar) in the blood and urine.
Other test results linked to diabetes include ketones in the urine, increased liver enzymes, hyperlipidemia (elevated cholesterol and/or triglycerides), an enlarged liver, protein in the urine, elevated white blood cells due to secondary infections, increased urine specific gravity resulting from dehydration, and low blood phosphorus levels.
Canine diabetes may be complicated or uncomplicated. Complicated cases, in which the patient is ill, not eating, or vomiting, require hospital care. Fortunately, most cases are uncomplicated and can be treated at home.
Diabetes is one of the most common endocrine diseases affecting middle-aged and senior dogs, with 70 percent of patients older than seven at the time of diagnosis. Diabetes rarely occurs in dogs younger than one year of age, and it is more common in females and neutered males than in intact males.
Keeshonds, Pulis, Cairn Terriers, Miniature Pinschers, Poodles (Miniature and Toy), Samoyeds, Australian Terriers, Schnauzers, Spitz, Fox Terriers, Bichon Frise, Siberian Huskies, and Pugs may be at higher risk. Because of these breed connections, researchers speculate that the development of diabetes may have a genetic component.
An estimated 50 percent of diabetes cases are likely linked to pancreatic damage caused by autoimmune disorders. These disorders have many possible causes, including genetic predisposition and environmental factors; many holistic vets speculate that they may be linked to overstimulation of the immune system from multiple vaccinations, processed foods, and other environmental insults.
Extensive pancreatic damage resulting from chronic pancreatitis (inflammation of the pancreas) may contribute to diabetes in 30 percent of canine cases. Pancreatic disease can also cause exocrine pancreatic insufficiency, or EPI, resulting in a deficiency of digestive enzymes. When a dog develops both EPI and diabetes, the diabetes typically appears several months before symptoms of EPI. (See “Starving, Not Starved,” WDJ March 2009, for more on EPI.)
An estimated 20 percent of canine patients develop insulin resistance from other conditions, such as Cushing’s disease and acromegaly (too much growth hormone), or from the long-term use of steroid drugs, such as prednisone. (See “Too Much Cortisol,” WDJ November 2011, for information on Cushing’s disease.) In females, insulin resistance may accompany the heat cycle, or gestational diabetes may occur during pregnancy. In these cases, symptoms may disappear when the heat cycle or pregnancy ends, though if the dog continues to go through heat cycles, the diabetes will likely become permanent, so immediate spaying is recommended.. Diabetes may also resolve when steroids are discontinued or Cushing’s disease is treated.
Though many people assume otherwise, there is actually no clear evidence that obesity causes diabetes in dogs. However, obesity can contribute to insulin resistance, making it more difficult to regulate overweight dogs with diabetes. Obesity is also a risk factor for pancreatitis, which can lead to diabetes.
Cataracts are a clouding of the lens of the eye. Diabetic cataracts are a leading cause of blindness in humans, and the same is true for dogs. The majority of canine patients with diabetes develop cataracts within six months of diagnosis, and 80 percent do so within 16 months. The risk of cataract development appears to increase with age regardless of blood sugar levels, so that even well controlled diabetic dogs can develop cataracts.
Surgery has saved the sight of many dogs. Cataracts treated in the early immature stage have the highest success rate and fewest surgical complications.
Hypermature cataracts create inflammation (uveitis), causing pain, eye redness, and pupil constriction. When uveitis is seen prior to surgery, the success rate for pain-free vision six months later is only 50 percent, as opposed to 95 percent for those with no pre-surgical uveitis.
Phacoemulsification to remove the lens is the preferred surgical method for diabetic dogs. After surgery, an artificial lens is installed for optimal post-operative vision. Although cataracts typically affect both eyes, treating just one eye can reduce costs (estimated between $1,500 and $3,000 per eye) and still restore vision.
Other potential ocular complications from diabetes include decreased corneal sensitivity, and keratoconjunctivitis sicca (dry eye).
Kinostat is a new, experimental aldose reductase inhibitor that may prevent the development or progression of diabetic cataracts in newly diagnosed dogs. The company is recruiting eligible dogs for this FDA clinical trial as of 2012. More info on the company's website (Therapeutic Vision) and Facebook page.
Update: A study published in 2015 showed that Ocu-GLO, a supplement marketed to help several vision problems, significantly delayed the progression of cataracts in dogs with diabetes. More info:
- Evidence Update- Ocu-GLO for Prevention of Cataracts in Diabetic Dogs
- An Oral Antioxidant Formulation Delaying and Potentially Reversing Canine Diabetic Cataract: A Placebo-controlled Double-masked Pilot Study
- Ocu-GLO (also available from Amazon)
Concurrent disorders that can make diabetes more difficult to control include hyperadrenocorticism (Cushing’s disease), infections, hypothyroidism, renal insufficiency, liver insufficiency, cardiac insufficiency, chronic inflammation (especially pancreatitis), EPI, severe obesity, hyperlipidemia, and cancer.
Diabetic nephropathy, a kidney problem, occurs in 40 percent of human patients and takes many years to develop. The percentage of canine patients with diabetic nephropathy is unknown (it’s more common in cats), but its earliest sign is hyperalbuminuria (high albumin levels in urine) followed by an increase in the urine protein-to-creatinine (UPC) ratio and hypertension (high blood pressure), which may contribute to kidney damage. Early changes may be reversed if blood sugar levels improve.
Infections – especially urinary tract infections, or UTIs – are common among dogs with diabetes because sugar in urine makes the bladder an ideal incubator for bacteria. In one study, half of the diabetic dogs tested had occult or hidden urinary tract infections that were not detected by urinalysis. The possibility of UTIs in dogs with diabetes is so great that their urine should periodically be cultured to detect infections. A long course of antibiotics (lasting six to eight weeks) can be administered if needed. Follow-up cultures and frequent retesting are recommended.
Dogs with diabetes are also susceptible to infections of the mouth and gums. Diabetic pets should have their teeth checked regularly and cleaned if necessary. Dental tartar seeds the body with bacteria, and when blood sugar levels run high, infections in important organs can take root. The kidneys and heart are particularly vulnerable. Brushing your dog’s teeth daily or at least twice a week helps to prevent and detect early signs of dental disease.
Liver (hepatic) disease is another common problem, resulting from altered fat metabolism caused by diabetes. In one survey of 221 dogs with diabetes, over 70 percent had elevated liver enzymes. Ultrasound tests and biopsies help differentiate between primary hepatic disease and secondary complications of diabetes.
Pancreatitis affects an estimated 40 percent of dogs with diabetes. See “A Pain in the Pancreas,” WDJ November 2008 for information on this disorder.
Hyperadrenocorticism, or Cushing’s disease, is another complication. In one study, 23 percent of dogs with diabetes tested positive for Cushing’s. Most canine patients with both disorders develop Cushing’s disease before the onset of diabetes. About 10 percent of dogs with Cushing’s are also diabetic.
Hypothyroidism (an underactive thyroid) may coincide with diabetes. In the study mentioned above, 9 percent of diabetic canines were hypothyroid. While the glucose intolerance caused by hypothyroidism could lead to the development of diabetes, it’s unlikely to be a major factor because the two don’t often occur together (Update: see Hypothyroidism Associated with Acromegaly and Insulin-resistant Diabetes Mellitus in a Samoyed for a case study of a dog who stopped needing insulin after his hypothyroidism was treated). However, thyroid hormone deficiency can result in insulin resistance, complicating glycemic control. Thyroid hormone replacement should be instituted gradually in dogs with diabetes since their insulin requirements will decrease and, without dosage adjustments, severe hypoglycemia may occur (see Hazards of Hypoglycemia).
It makes sense to test diabetic dogs for hypothyroidism and hyperadrenocorticism, but only after their diabetes is controlled. Otherwise, the diabetes will affect test results.
Hyperlipidemia usually improves as blood sugar levels are controlled. Persistently elevated triglycerides may be linked to Cushing’s disease and can increase the risk of developing acute pancreatitis. Reducing fat in the diet can help to lower triglyceride levels. Elevated cholesterol is often linked to hypothyroidism.
Insulin resistance can be caused by Cushing’s disease, infections, hypothyroidism, pancreatitis, drug therapy (corticosteroids), obesity, acromegaly, estrus (heat cycle), and anti-insulin antibodies. It may also be caused by hypertriglyceridemia (see Diabetes and Insulin Resistance in Miniature Schnauzers). Insulin resistance should be investigated in patients who need doses of 1 unit or more of insulin per pound of body weight.
With proper treatment, dogs with diabetes have survival rates very similar to those of non-diabetic dogs of the same age and gender, though their risk is greatest during the first six months of treatment, when insulin therapy is introduced and glucose levels regulated. Diabetic dogs are more likely to die of kidney disease, infections, or liver/pancreatic disorders than of diabetes itself. But once their condition stabilizes, diabetic dogs can lead happy, healthy lives.
Consider Buster, a 13-year-old Maltese belonging to Mary Butler in Northern California. Buster was diagnosed with diabetes three years ago after suddenly going blind due to cataracts.
"He had lens implants within a month and has had perfect vision ever since," says Butler. "My little guy has been stable ever since his diagnosis. He has lots of energy, his coat is thick and shiny, his stools are formed and regular, and his teeth sparkle. I do brush his teeth three times a week, which I am sure helps."
Vetsulin is back! Most authorities consider Vetsulin, known as Caninsulin outside the USA, to be the initial insulin of choice for treatment of dogs with diabetes mellitus. Manufacturing problems that go back to 2009 led to the FDA having it withdrawn from the U.S. market. These issues have finally been resolved and the FDA has approved the drug for release and it is now available again. Note that the product was not reformulated, but there were label changes involving instructions for use, product description, and shelf life. More info:
Your veterinarian is your best advisor when it comes to medication. There are many different insulin products, and individual responses vary. Finding the right insulin for your dog may require experimentation.
Insulin varies in terms of onset, peak, and duration of action. Most dogs do well with intermediate-acting insulin, such as Humulin N, though some do better with long-acting insulin or mixtures that combine different types. It’s important to use only fresh insulin, switching to a new bottle every 6 to 8 weeks, and to use the correct syringe, which will vary depending on the type of insulin.
Alise Shatoff of San Diego, California, adopted her dog Gryffin five years ago at age four, when he was surrendered after developing diabetes. She feeds a commercial raw diet and says, “We have found that Gryffin does best on Humulin N. This one works really well for dogs on a raw diet. Gryffin has been nice and stable on the Humulin N for four years now.”
Porcine (derived from pigs) and recombinant human insulin most closely resemble insulin produced by dogs, so they usually work best. Although beef insulin was successfully used before the advent of other choices, it is no longer recommended for dogs because it may result in the production of anti-insulin antibodies, leading to poor glucose control.
Diane Di Salvo of Madison, Wisconsin, whose dog, Scout, developed diabetes two years ago, notes that, “Walmart sells Humulin insulin for WAY less than vets and other pharmacies. It is the exact same insulin that Eli Lilly makes for all pharmacies, but it is packaged for Walmart under their ReliOn brand.” (Warning: Walmart switched their insulin, including ReliOn, from Humulin N to Novolin N, around the beginning of 2013, which could cause problems for some dogs. See Changing insulin brands may disrupt diabetics and Humulin Versus Novolin NPH Insulin: Are They Bioequivalent? for more information.)
Insulin is typically administered twice a day, immediately before or after a meal. Feeding just before giving insulin may be safer, to be sure that the dog eats, because without food the insulin’s effect would be dangerous. Assuming your dog is a chow hound, feeding her after administering insulin can be a reward for submitting to the injection.
However, most dogs don’t mind the injections, which are done with very thin needles. Carol Albert of Kensington, Maryland, has a Cardigan Welsh Corgi, Henry, who developed diabetes four years ago. “Henry gets insulin shots twice daily after meals,” says Albert. “He knows he will get a treat after the injection so he comes looking for me after he eats to get his shot.”
It is important to give insulin injections properly. One of the most common reasons for problems in achieving regulation is that the owner doesn't inject the dog correctly. If possible, have your veterinarian observe you giving insulin to your dog. Also see the links to information on giving insulin in Resources below.
When a dog is first diagnosed, frequent monitoring, such as every one to two weeks, may be required until the patient is stable and doing well. After that, monitoring every three to six months (veterinary exam, blood test, urinalysis, and urine culture) is recommended.
A recent study has shown that glargine insulin, commonly used to treat diabetic cats, can be used in dogs to produce a "peakless" insulin. It is released slowly at a relatively constant rate, which helps to maintain steady blood sugar levels.
If your dog is doing well currently, it's not advisable to switch, but if you have a dog who was recently diagnosed, or one who is poorly regulated, this is a new option to try. More info:
Measuring fructosamine (glycated serum protein) is a helpful way to monitor glucose control. If it is not possible to run glucose curves, this test would be the next best option. Blood glucose fluctuations leave a metabolic mark that lasts a week or two, and fructosamine reflects the average blood glucose over that time span. Control is designated excellent, good, fair, poor, or prolonged hypoglycemia. Because fructosamine looks at averages, it will not distinguish excellent control from wide swings of high to low glucose readings, but even with this limitation, fructosamine is worth including in periodic monitoring tests. (Update: beware of using fructosamone levels alone to adjust insulin dosage, as this could lead to hypoglycemia. More info: Top Clinical Endocrinology Research Abstracts, 2014 ACVIM Forum: Diabetes Part 2.)
Ketones are water-soluble compounds produced as by-products when fatty acids are broken down for energy in the liver and kidneys. Dangerously high levels of ketones, called ketoacidosis, can lead to diabetic coma or death. Symptoms include nausea, lack of appetite, and lethargy. Ketoacidosis is often linked to concurrent pancreatitis, urinary tract infection, Cushing’s disease, or other types of infection or inflammation.
Ketostix are used to detect ketones in urine and can be obtained at any pharmacy. Finding ketones occasionally is not a problem, but a positive dipstick three days in a row requires a veterinary visit.
Vintek Nutrition has introduced Dia-Treaties, a new supplement that purports to lower insulin resistance, making it easier to manage blood glucose levels in dogs who are difficult to regulate, and often allowing insulin dosages to be reduced. Clinical observations showed Dia-Treaties® decreased the amount of insulin needed from 15% to 67%. Be sure to monitor your dog's glucose levels when beginning these treats to avoid giving too much insulin.
Dia-Treaties are given as a treat immediately following each insulin injection, and should be kept refrigerated after opening. The treats are expensive, costing $40 (plus shipping) for 56 treats. Suggested dosage per injection is 1 treat for dogs weighing up to 25 pounds (package will last 28 days); 2 treats for dogs 25-50 pounds (package will last 14 days), and 3 treats for dogs over 50 pounds (package will last just over 9 days). Free trial available for a limited time.
In humans and felines with type 2 diabetes, diet is a major component of the illness's cause and treatment. Because the culprits are carbohydrates and obesity, weight loss and a high-protein, low-carb diet are sometimes all the treatment that is needed.
But for dogs with type 1 diabetes, there is no single recommended diet. The most important factor is that the dog likes the food and eats it willingly. Most diabetic dogs can be well managed with an adult maintenance diet. A prescription diet is not required. If the dog has another illness, feed a diet appropriate for that illness.
Try to feed the same amount of the same type of food at the same time each day, ideally in two meals 12 hours apart. Any change in carbohydrates will affect the amount of insulin needed. Some dogs may need a snack between meals to keep glucose levels from falling too low.
Fiber and carbohydrates are controversial topics in diabetes treatment, and recommendations are changing. Only a few nutritional studies have been done on dogs with diabetes. Different dogs respond differently to varying amounts of fiber and carbohydrates, and dietary needs vary depending on whether a dog is underweight or overweight, so there is no “best diet” for this disease.
Diabetic dogs may not need a low-fat diet unless they have concurrent pancreatitis, Cushing’s disease, elevated triglycerides, elevated cholesterol, or lipemia (fatty blood). However, since the majority of diabetic dogs do have one or more of these concurrent diseases, and since pancreatitis can occur at any time (and chronic pancreatitis may cause problems before it is diagnosed), the majority of diabetic dogs will do better on a diet that is moderately low in fat. To be safe, avoid feeding high-fat diets.
The amount of protein in the diet should be normal or increased, especially for overweight dogs and for underweight dogs with muscle wasting or EPI. Protein should be increased when fat is decreased, to avoid feeding too many carbohydrates.
Carbohydrates are responsible for the greatest changes in postprandial (after-eating) blood sugar levels. There is a strong association between the insulin dosage requirement and the carbohydrate content of the meal, regardless of carbohydrate source or type. Keeping the amount of carbohydrates in the diet steady is the best way to keep insulin needs stable.
The glycemic index measures the effects of carbohydrates in food on blood sugar levels. It estimates how much each gram of available carbohydrate (total carbohydrate minus fiber) in a food raises blood glucose level following consumption of the food, relative to consumption of glucose. Glycemic index charts that list hundreds of foods are widely published.
Low-glycemic foods release glucose slowly and steadily, while high-glycemic foods can cause a more rapid rise in blood glucose levels. Low-glycemic foods include most fruits and vegetables, legumes, some whole grains, and fructose. Medium-glycemic foods include whole wheat products, brown rice, sweet potatoes, potatoes, sugar (sucrose), and honey. High-glycemic foods include white rice, white or wheat bread, and glucose. See Carbohydrates 1 = Sugars and Starches for more details on the glycemic index of various foods.
Simple carbohydrates (sugars, such as corn syrup or propylene glycol, which is found in semi-moist foods) should be avoided, as they cause rapid glucose spikes.
Complex carbohydrates (starches) are digested more slowly so that the rise in glucose is spread out and there are no quick spikes. Processing can affect how quickly carbohydrates are digested.
Carbohydrates are digested faster than fats and proteins, and they have the most effect on postprandial glycemic response and insulin needs. Depending on when the insulin effect peaks, it may be important to include a certain amount of carbohydrates in meals so that peak effect of injected insulin will coincide with the rise in glucose and not contribute to hypoglycemia.
Highly digestible diets designed for dogs with sensitive stomachs can contribute to higher blood glucose levels after eating, which is not the best thing for a diabetic dog.
Dietary fiber or roughage is the indigestible portion of plant foods. Fiber slows gastric emptying and the digestion of carbohydrates, which also slows the release of glucose, blunting its postprandial rise (blood sugar increases less after meals). Diabetic dogs do not necessarily need more fiber than healthy dogs, and most do well with moderate amounts of fiber. Dogs with poor glycemic control may benefit from increased fiber, while some diabetic dogs do better with less.
There are two types of fiber, soluble and insoluble. Soluble (also called viscous) fiber ferments in the colon, creating gases. Insoluble fiber is metabolically inert, absorbing water as it moves through the digestive tract. Unlike soluble fiber, insoluble fiber does not produce intestinal gas.
Examples of soluble fiber include fructooligosaccharides (FOS), pectins, guar gum, lactulose, and psyllium. Most soluble fiber, with the exception of psyllium, is also fermentable. Beet pulp provides mixed soluble and insoluble, moderately fermentable fiber.
Prebiotics are fibers that are both soluble and fermentable (see “Praise for Prebiotics,” WDJ April 2012). Prebiotics feed probiotics, the beneficial bacteria that live in the digestive tract and make up an important part of the body’s immune defenses. As it ferments, soluble fiber also produces beneficial short-chain fatty acids (SCFAs).
Too much soluble fiber can cause diarrhea and gas, and can actually speed postprandial glucose absorption. Gas is most likely to develop when the fiber is first introduced or when the dose is suddenly increased. To help prevent this side effect, start with small doses and increase gradually.
Insoluble fiber, such as cellulose and bran, regulates intestinal transit time, speeding it during constipation and slowing it during diarrhea. Insoluble fiber increases stool volume, is generally well tolerated even in high doses, and may help with glucose control.
However, in large quantities, insoluble fiber can decrease the diet’s nutrient value by binding minerals. Other side effects associated with diets high in insoluble fiber include weight loss, a lack of interest in food, poor coat quality, vomiting, voluminous feces, flatulence, diarrhea, and constipation. Increased fiber is not recommended for underweight dogs, dogs who refuse to eat because of the fiber’s taste or texture, or dogs who experience adverse side effects.
It is important to provide ample fluids when adding fiber because they pull water from the body, which can lead to constipation and other problems if fluid intake is insufficient.
Examples of products that contain soluble fiber include Benefiber (wheat dextrin) and Hydrocil (psyllium). Citrucel is an example of a product that contains insoluble fiber (methylcellulose). Fiber One Original cereal can also be used as a source of fiber, with over 28 grams of insoluble dietary fiber per cup of cereal, and no added sugars.
The amount of starch in the diet is not as important as making sure it’s consistent and properly balanced with insulin. Dogs fed diets containing more starch may need more insulin or a different type of insulin than dogs fed a low-carb diet.
Limiting carbohydrates may reduce postprandial hyperglycemia (high blood sugar), but if the dog continues to have wide glucose level swings throughout the day on a low-carb diet, he might do better with more carbohydrates. If dietary protein is reduced for any reason, carbohydrates will usually increase, especially if fat is restricted. Dogs with gestational diabetes may benefit from a diet that is high in protein with restricted carbohydrates and fats, as long as their nutritional needs are met.
If a thin dog fails to gain weight once there is good glycemic control and the food intake is adequate (and not too high in fiber), concurrent EPI may be interfering with digestion. Overweight dogs who fail to lose weight once their diabetes is controlled may be getting too much insulin.
“We know that in both dogs and cats, obesity in general is a problem,” says David Bruyette, DVM, DACVIM, medical director at VCA West Lost Angeles Medical Hospital, “and obese dogs and cats tend to be resistant to the effects of insulin, so we want to have animals at an ideal body weight. If they are too heavy, they can develop insulin resistance, and if they are too thin, they can develop ketoacidosis.”
Next month we’ll review diabetes diets in detail, but for now:
- The most important factor is that your dog likes his food and eats it willingly every time.
- Most diabetic dogs can eat a typical moderate-fiber maintenance diet. They don’t need a high-fiber prescription food.
- It is fine to feed a high-protein diet, but that is not a requirement.
- The diet must be consistent, particularly in terms of the amount of carbohydrates, and should be fed in the same quantities at the same time each day,
- Not every diabetic dog requires a low-fat diet, but because of the disease’s strong links to pancreatitis and other fat disorders, a diet moderately low in fat may be safest, even for dogs who have not been diagnosed with pancreatitis, Cushing’s disease, or hyperlipidemia.
Exercise has a dramatic effect on blood sugar levels. In humans with type 2 diabetes, exercise reduces blood sugar so effectively that patients who walk or jog reduce their need for added insulin.
But for those with type 1 diabetes, including dogs, exercise can be both a blessing and a complication. Exercise can reduce insulin resistance in obese diabetics, but too much exercise can lead to hypoglycemia (see Hazards of Hypoglycemia).
Exercise should be consistent in terms of the type of activity and time of day, avoiding intermittent or unplanned strenuous exercise. One good approach is to exercise the dog for 20 to 30 minutes before the evening meal and its administration of insulin.
Additional exercise can be added to the day’s activities if the insulin dose is adjusted. For example, if a strenuous hike is planned, the morning insulin might be skipped or only half of the usual insulin administered in order to avoid exercise-induced hypoglycemia.
Some supplements may help your diabetic dog while others should be added with caution or not at all. Anything that helps lower blood glucose levels may change insulin needs.
When using human supplements, give the full human dose to large dogs, half that much to medium-sized dogs, and ¼ the adult human dose to small dogs. Tiny dogs require even smaller doses.
L-Carnitine, a conditionally essential amino acid, plays a pivotal role in fatty acid metabolism. It may help control diabetes, improve fat metabolism, maintain lean body mass, and protect muscles from catabolism during weight loss. As little as 50 milligrams per kilogram (2.2 pounds) of dry food may make a difference. Note that beef and lamb are particularly good sources of l-carnitine, with about 20 to 40 mg per ounce (pork has about half as much, mutton has more, while poultry, dairy products, eggs, and organ meats have much less). One veterinary site says, "Recent findings indicate that supplementation with acetyl -L- carnitine may improve abnormal nerve metabolism and impulse conduction in the diabetic. Therefore, daily supplementation of acetyl-l-carnitine (50mg-100mg/kg/day [25-45 mg per pound of body weight daily]) is justified."
Chromium supplements are often recommended for human diabetes patients (especially those with type 2 diabetes), but don’t seem to benefit a dog’s type 1 diabetes. This supplement is recommended only for dogs with a chromium deficiency.
Zinc is an important mineral for diabetic patients, but it’s toxic to dogs if too much is given. Supplementation should be limited to a standard human or canine vitamin-mineral supplement daily.
The omega-3 fatty acids EPA and DHA may help to reduce blood lipid levels (hyperlipidemia) and inflammation as well as regulate the immune system. Human studies show, however, that too much may reduce glycemic control in some patients. EPA and DHA are found in fish, most fish oils, and some algae supplements. An appropriate dose might be 300 mg combined EPA and DHA per 20 to 30 pounds of body weight daily (or per 10 pounds of body weight for hyperlipidemia or kidney disease), preferably split between meals.
Probiotics and cranberry extract can help to prevent urinary tract infections. D-mannose works the same way as cranberry, by preventing bacteria from adhering to the bladder wall, but it is a sugar and some research has found that it may make blood sugar levels harder to control in humans with diabetes.
Digestive enzymes may be helpful for some dogs, particularly those who have had pancreatitis (dogs with EPI need prescription-strength enzymes). See “Digestive Enzymes” for more about enzymes.
Some products affect blood sugar levels and so should be avoided or used with caution. Licorice can elevate blood sugar, while devil’s claw, ginger, and marshmallow can lower it. Amitraz, the active ingredient in Preventic collars, Certifect (new flea and tick control product), and Mitaban (used to treat demodex), can cause elevated blood sugar and should not be used in diabetic dogs.
Glucosamine, on the other hand, should be safe for diabetic dogs. Early research suggested it might raise blood sugar, but more recent and reliable studies refuted those findings. Monitor blood sugar levels after starting to be sure.
Between-meal treats are important, whether they’re training tools, blood sugar stabilizers, afternoon snacks, or rewards for submitting to blood tests and insulin injections.
Avoid treats that are high in carbohydrates or sugar, including all semi-moist commercial foods and treats that use propylene glycol or similar ingredients.
Dehydrated meats make excellent treats, but be sure to avoid those made in China. Chicken jerky treats (also called tenders or strips) manufactured in China have been linked to kidney failure in dogs. Check package labels carefully.
Because dried meat or poultry treats made in the U.S. can be expensive, many pet owners make their own. Simply cut meat or poultry into thin slices for drying in a food dehydrator or baking in a slow oven (250 to 300 degrees F) until they reach your dog’s preferred state of crunchiness.
Other between-meal treats that are safe for diabetic dogs include green beans – raw, cooked, canned, or frozen – or fresh, crunchy snap peas or carrot sticks; sardines or tuna packed in water; small amounts of canned pumpkin (plain, not the pie mix); freeze-dried liver; dried salmon; hard-boiled eggs; cheese (be careful of too much fat); bully sticks; dried beef tendons; chicken feet; and most low-carb treats formulated for dogs or cats.
Caring for a dog with diabetes can be time-consuming, expensive, and stressful. In fact, the initial diagnosis can be overwhelming.
According to Dr. Bruyette, “Several studies have shown that euthanasia is a common cause of death in diabetic dogs and cats mainly as a result of the owners’ concerns, real or perceived, regarding the care of pets with diabetes. It is very important that we emphasize to pet owners that while diabetes is a chronic disease, it can be well controlled with minimal disruption of their lives while maintaining their pet’s quality of life.”
Sheila Laing of Lansing, Michigan, cared for her Lab/Shepherd mix, Zachary (pictured at top), for four years after he was diagnosed with diabetes at age 11. “Zachy was my soul mate and my teacher,” she says. “I am so lucky that I was able to help him lead a healthy normal life in his senior years in spite of the diabetes. People need to know that diabetes doesn't have to be a death sentence. It can be managed!”
Coming next month: Diabetic diets in action; menu planning; and canine diabetes success stories.
Hypoglycemia is a serious risk factor in diabetes management. Recent studies suggest that approximately 10 percent of diabetic dogs experienced hypoglycemic episodes that required hospitalization. One large survey found that the majority of diabetic dogs presented for hypoglycemia were receiving high doses of insulin (0.7 units or more per pound of body weight).
Overdosing, double-dosing, and persistent dosing despite weight loss or reduced food intake are common iatrogenic causes of hypoglycemia. (Iatrogenic diseases are caused by medical treatment.) Strenuous exercise or maldigestion caused by EPI, bacterial overgrowth, inflammatory bowel disease, or other digestive disorders can also lead to hypoglycemia in diabetic dogs.
If you’re ever uncertain about whether insulin was administered, the safest option is to withhold the injection. The consequences of missing a single insulin dose are negligible, while overdosing can be fatal. Never add more if you are unsure, including if some insulin spills while you give the injection.
Changes in body weight may require insulin dosage modifications. Dietary changes, particularly reduced carbohydrates, may require a reduced insulin dosage to prevent hypoglycemia.
Severe hypoglycemia resulting from too much insulin can cause seizures, irreversible brain damage, and death. Warning signs include nervousness, hyperexcitability, anxiety, vocalization, muscle tremors, lack of coordination, wobbliness (the dog may appear drunk), and pupil dilation.
If these signs are seen, the dog should be fed immediately. If the dog can’t or won’t eat, rub Karo syrup, pancake syrup, honey, or even sugar water on her gums before calling your veterinarian. If your dog responds, feed a small, high-protein meal and keep your dog as quiet as possible. If immediate improvement is not seen, transport your dog to the vet after feeding for further care, such as intravenous glucose. Don’t give any more insulin until you have consulted with your vet, as insulin may need to be reduced for a few days, or long term.
When your pet’s condition stabilizes after a hypoglycemic episode, a glucose curve can help to determine why this happened and what a more appropriate insulin dose might be. A glucose curve is a series of blood sugar measurements made after insulin is given. Typically, blood samples are taken every 1-1/2 to 2 hours for 10 hours, or until the effects of the insulin injection can be determined. For ease of understanding, measurements are plotted on a graph whose points usually form a curve. Glucose levels can be monitored at home, improving the accuracy of the data.
Cerebral edema caused by insulin overdose can result in temporary blindness or behavior changes. These signs often resolve over several weeks or months.
If a concurrent illness causes prolonged loss of appetite, the patient should be hospitalized for blood glucose concentration monitoring and treatment with rapid-acting insulin and intravenous fluids supplemented with glucose and potassium.
Update: A study published in 2012 indicates that administering glucagon subcutaneously may be effective in treating hypoglycemia due to too much insulin. Human emergency glucagon kits are available that may be useful for those with diabetic dogs. See Using a Glucagon Emergency Kit for Insulin-Induced Hypoglycemia for more information.
- Revised International Table of Glycemic Index (GI) and Glycemic Load (GL) Values—2008
- University of Sydney Glycemic Index (searchable database)
- Carbohydrates 1 = Sugars and Starches
Fiber content in various foods (keep in mind that portion sizes vary):
- Fiber Content in Foods Includes a breakout of soluble and insoluble fiber
- Carbohydrates 2: Dietary Fibers
- Fiber Content of Foods in Common Portions
- Fiber (also lists soluble and insoluble fiber content of various foods)
- You can also find the amount of soluble and insoluble fiber in at least some foods in the In-Depth Nutrient Analyses provided on the World's Healthiest Foods website. You must first search for the food, then select the entry under "Foods and Spices," then scroll to the bottom of the page and select "In-Depth Nutritional Profile" (below the limited nutrient table, just above References).
Canine Diabetes: Information for owners of Canines with Diabetes Mellitus.
Instructions for giving insulin injections:
VCA West Los Angeles Animal Hospital, 1818 S. Sepulveda Blvd., Los Angeles, CA 90025, (310) 473-2951. David Bruyette, DVM, DACVIM.
Encyclopedia of Canine Clinical Nutrition: Diabetes Mellitus
Linda Fleeman BVSc MACVSc and Jacquie Rand BVSc DVSc Dipl ACVIM, 2008
Dietary treatment of diabetes mellitus in dogs and cats (Sponsored by Nestle Purina)
Kirk’s Current Veterinary Therapy XIV
John D. Bonagura DVM MS Dipl ACVIM, David C. Twedt DVM DipACVIM, 2009.
Kirk’s Current Veterinary Therapy XIII
John D. Bonagura DVM MS Dipl ACVIM, 2000.
Small Animal Clinical Nutrition
4th Edition, Michael S. Hand, Craig D. Thatcher, Rebecca L. Remillard, Philip Roudebush, Lon D. Lewis, 2000.
- The state of diabetes: An industry review of diabetes (Sponsored by Abbott Animal Health)
- Veterinary Practice News: Education is Key in Diabetes Maintenance
A diet lower in digestible carbohydrate results in lower postprandial glucose concentrations compared with a traditional canine diabetes diet and an adult maintenance diet in healthy dogs.
Res Vet Sci. 2012 Aug;93(1):288-95.
Blog posts by Dr. Mark E. Peterson, veterinary endocrinologist:
- What's the Best Diet to Fed Dogs with Diabetes?
- Insights into Veterinary Endocrinology: Diabetes mellitus
- Managing Diabetic Dogs with Exocrine Pancreatic Insufficiency
- Emergency Management of Insulinoma and Other Causes of Hypoglycemia
- A New Insulin for Diabetic Dogs
- What's the Best Insulin for Diabetic Cats and Dogs?
- Insulins available for veterinary use as of 2013 (see box at bottom)
- Insulin and Syringe Facts
- Which insulin should I choose now that my options have dwindled?
- Changing insulin brands may disrupt diabetics
- Managing Dogs with Insulin-Sensitive, Brittle Diabetes
- Glargine Insulin Is Expensive: Is Compounded Insulin an Acceptable Alternative?
- Humulin Versus Novolin NPH Insulin: Are They Bioequivalent?
- Escalating Costs of Insulin Glargine (Lantus): Can We Switch to Another Insulin?
You can contact me if you have any comments, but I regret to say that I can no longer respond to questions about individual dogs. See my Contact page for more information. My name is Mary Straus and you can email me at either or