Tilly's Diabetes Homepage

6 Important Factors

1. A Low-Carb Diet

Cats are carnivores. Their metabolism is optimized for a meat-based diet: they primarily require protein and fat as energy sources. Therefore, feeding cats carbohydrates (contained in dry cat food in large amounts) may potentially have a negative effect on their health. Diabetic cats in particular should eat as few carbohydrates as possible, since carbohydrates rapidly raise blood sugar levels.

The typical prey of a cat - a mouse or a small bird - is composed of 3-5% carbohydrates. Most brands of dry food range from 35% to almost 50% carbohydrates. Low quality canned foods have 20% carbohydrates, while many of the better ones have under 10% (or even <5%). You can get a good overview of these figures from Janet & Binky’s tables, which illustrate the general differences between canned and dry food, even though not all of the brands mentioned are necessarily available in Europe.

Diabetic cats, until they are well regulated on insulin, also require more water. When cats eat dry food, they need to compensate for the lack of moisture by drinking more. It has been observed that even healthy cats do not do this sufficiently, because they have a low thirst drive. A sufficient intake of water is even more important in diabetic cats. Canned food makes it easier to keep your cat well hydrated.

Therefore, I fed Tilly canned food only. The ingredient information which manufacturers are required to provide in Germany is extremely minimal - it is next to impossible to reliably determine the carbohydrate content of cat food. Therefore, my rule of thumb is that the food may only ever contain the following ingredients:

• meat
• meat by-products
• fish
• fish by-products
• minerals

In particular, the food should not contain any wheat, soy, rice, corn (maize) or plant byproducts because these ingredients can sharply increase blood sugar levels and may also cause allergic reactions in some cats. Yeast can be an allergen. Sugar, coloring and preservatives are unsuitable. And gravies often contain caramel for colouring and for this reason, I avoided all foods with gravy or jelly.

You should be cautious when you switch your cat to a proper canned food diet, as the amount of insulin necessary to maintain proper blood glucose control is nearly always significantly reduced. You should always carefully monitor blood sugar values in the first 3 days when changing the feeding regimen and adjust the dose accordingly. It has been known for years that cats who don't eat dry food require less insulin. Careful selection of canned food can also have a very beneficial influence on remission rates, as a this study demonstrates.

I have been periodically feeding Tilly ultra-low-carb raw food since August 2005. I make it with fresh meat and Natascha Wille's Raw Diet Premix (formerly called InstinctsTC) powder. I also invested in a good meat grinder and made Dr. Lisa Pierson's recipe. If a cat is very badly regulated and/or has complications, it may have trouble with raw and might do better on canned. But generally, raw food diets are an excellent choice for diabetic cats.

Good Links:
• "The carnivore connection to nutrition in cats", DL Zoran, JAVMA, 221(11), 1559-1567, 2002
• "In support of bones and raw food diets", L Stogdale and G Diehl, Can Vet J, 44(10), 783, 2003
• "Canine and Feline Diabetes Mellitus: Nature or Nurture?", JS Rand et al., J Nutr , 134, 2072S-2080S, 2004
• "Insulin sensitivity, fat distribution and adipocytokine response to different diets in lean, and obese cats before and after weight loss", M Hoenig et al., Am J Physiol Regul Integr Comp Physiol, 292(1), R227-34, 2006
• "Comparison of a low carbohydrate-low fiber diet and a moderate carbohydrate-high fiber diet in the management of feline diabetes mellitus", N Bennett et al., J Feline Med Surg, 8(2), 73-84, 2006
• "Feline diabetes mellitus: low carbohydrates versus high fiber?", CA Kirk, Vet Clin North Am Small Anim Pract, 36(6), 1297-306, 2006
• "Feline diabetes and diet: The high carbohydrate culprit", LA Pierson, DVM
• "Feline diabetes and obesity: The preventable epidemics", E Hodgkins, DVM
• "Dietary recommendations for cats with DM", D Greco, DVM
• "Making Cat Food: Homemade and Raw Cat Food Diets", in collaboration with Mallory Crusta from Wilderness Cat
• "Pet Food & Nutrition: A Necessary Review For Veterinarians", ME Smart, DVM et al.

2. The Right Insulin - Lantus®

Recent research shows that newly diagnosed diabetic cats can frequently go into remission with Lantus. This insulin is manufactured by Sanofi-Aventis and also called insulin glargine.

In a head-to-head comparison between Lantus, PZI and Caninsulin®/Vetsulin® (also called porcine lente insulin) in newly diagnosed diabetic cats

• 8 of 8 cats treated with Lantus went into remission (100%)
• 3 of 8 cats treated with PZI went into remission (38%) and
• 2 of 8 cats treated with Caninsulin/Vetsulin went into remission (25%).

The authors came to the conclusion that remissions occur more frequently with Lantus in newly diagnosed cats than with the other two insulins.

These results are similar to those in an older study on Caninsulin/Vetsulin: 25 newly diagnosed diabetic cats were studied, only two went into remission. The nadir was at 4.1 +/- 0.3 hours. The maximum duration was less than 12 hours. An ideal blood glucose curve, as described by the manufacturer Intervet is here. It is worthwhile to look at this curve properly, because then one begins to understand why the remission rate with Caninsulin/Vetsulin is relatively low: remissions are not only helped by nadirs in the range of those of a healthy cat, but also by values that are mostly under the renal threshold of 200-220 mg/dl (more regarding this topic below).

More recent work has also shown that already treated diabetic cats which have not gone into remission with Caninsulin/Vetsulin and a low carb diet can achieve remission upon switching to Lantus. Significantly higher remission rates are achieved in cats switched to Lantus within 6 months of diagnosis (84%), compared to those cats switched later (35%).

Occasionally, the argument is made that bovine PZI is more suitable for cats than human(-type) Lantus as bovine PZI's amino acid sequence is most similar to a cat's own. There are several problems with this argument. Describing Lantus as a human insulin is incorrect: it is an insulin analogue and its amino acid sequence is different from any insulin occurring in nature. Human diabetics have significantly benefited from insulin analogues, which have improved pharmacokinetic and pharmacodynamic properties when compared to human insulin. Some analogues are more rapid acting than human insulin, while some are longer-acting (like the basal insulin Lantus). It therefore seems illogical to conclude that cats will benefit from an insulin because it is most similar to their own, when there is a published comparison study demonstrating the opposite, and human diabetics are clearly benefiting from not using human insulin. I also know of no example of an allergic reaction to insulin analogues in cats.

Cost: 3 x 3 ml Lantus cartridges (100 IU/ml) cost about 50 Euros (0.056 Euros/IU). Lantus may therefore be cheaper than Caninsulin/Vetsulin (40 IU/ml) where current prices are 5-7 Euros for 2.5 ml (0.05-0.07 Euro/IU). This is non-intuitive, but the reason is that Lantus is much more concentrated than Caninsulin/Vetsulin.

A few tips for handling Lantus. One should not mix or dilute Lantus with other insulins or liquids, otherwise its special pH-based mechanism is destroyed. Using the 3 ml cartridges that belong in the pens is easiest, so you can more frequently use a new cartridge and you mostly have an unused cartridge as backup. Lantus was much nicer to use than any other insulin I tried with Tilly: it is in solution and does not require mixing. I stored Lantus in the fridge. Opened Lantus can be used for up to 6 months when stored in the fridge, stored at room temperature for 1 month. If you notice "snowflakes" in your bottle at any time, throw it out.

I used the syringes manufactured by Becton Dickinson (BD) that are U100 syringes, have a small total volume (3/10 cc = 0.3 ml), have the half-unit scale printed on the barrel (very important), are fine gauge (30, but I think 31 is still okay) and have a short needle (8mm or 5/16"). These allow dosing adjustments of 0.25 IU or less, with a little practice.

At this point I want to mention Levemir®, also called insulin detemir. It, like Lantus, is a basal insulin analogue, with similar duration. It seems as effective as Lantus in cats.

Good Links:
• "Insulin glargine and a high protein-low carbohydrate diet are associated with high remission rates in newly diagnosed diabetic cats", R Marshall, JS Rand, ACVIM, #63, 24, 2004
• "Understanding feline diabetes mellitus: pathogenesis and management", J Rand, R Marshall, Waltham Focus, 15(3), 2005
• "Treatment of newly diagnosed diabetic cats with glargine insulin improves glycaemic control and results in higher probability of remission than protamine zinc and lente insulins", GJ Martin, JS Rand, JM Morton, J Feline Med Surg, 11(8), 683-91, 2009
• "Intensive blood glucose control is safe and effective in diabetic cats using home monitoring and treatment with glargine.", K Roomp, JS Rand J Feline Med Surg, 11(8), 668-82, 2009
• "Evaluation of detemir in diabetic cats managed with a protocol for intensive blood glucose control.", K Roomp, JS Rand J Feline Med Surg, 14(8), 566-72, 2012

3. Hometesting and a Strategy for Success

Without hometesting, it can be very difficult to achieve remission in a cat. Not only can the dangers of hypoglycemiabe minimized by hometesting, but a cat can more easily achieve regulation.

Here is a now outdated protocol for Lantus from 2004 by Dr. Ellen Behrend, which I initially used with Tilly. I started with 0.25 IU/kg BID (twice daily). I had to reduce the dose very quickly and stopped giving insulin when I measured <50 with a drop of Lantus, even though the two weeks described in the protocol had not yet passed.

However, I am now of the opinion, that one should try to achieve tighter control of blood glucose values than the above protocol allows for. This rational behind this strategy is very well described by Dr. Elizabeth Hodgkins. The text refers to PZI, but in my opinion Lantus can be used in a similar, but not identical, way:

"For those cats that do not become euglycemic with diet alone, the objective of PZI insulin therapy is to bring the cat into a normal range of blood glucose (80-130) and keep it there! I cannot emphasize this enough. Because continual hyperglycemia perpetuates the pancreatic suppression/ toxicity that has caused the diabetes in the first place, cure can only happen if the highly effective PZI tool is used to titrate the diabetic cat into the normal range for glucose in this species. In fact, the 80-130 range is a bit high for the cat at rest without excitement. Most cats operate when relaxed between 50-80! As long as you make increases in your insulin dose to achieve these lower BG numbers gradually, you will not cause seizures in your patients. In dozens of cats that I have put through this protocol, I have never caused a single one to seizure, despite taking many below 100 mg/dl. You must give up the fear you have been taught about taking a diabetic cat into the normal BG range, or your patients will always be diabetic."

The first goal with a long or ultra-long acting insulin should be to have the cat's nadir in the normal blood glucose range of a healthy cat. The second goal should be to keep the blood glucose levels under the renal threshold (200-220 mg/dl) for as long as possible every day. The first goal is the more important of the two. The second goal stems from the fact that the renal threshold is the blood glucose level above which the kidneys begin to extract glucose from the blood and excrete it into the urine. Blood glucose levels above the renal threshold are unhealthy for the cat and eventually lead to organ damage. The insulin doses should overlap: the dose that I gave my cat 12 hours ago (i.e. in the morning) should still be working when I give my cat its insulin now (i.e. in the evening). This keeps the overall curve as flat as possible, minimizing high pre-shots. A protocol for tight regulation with Lantus or Levemir, which I helped develop, has been shown to work very well.

It is best to inject the sides of the body and not in the scruff of the neck, where the circulation is relatively poor. Initially, I did not take rotating the injection site seriously. Promptly, Tilly had hard lumps under her skin. Then I started to keep a careful record of the position of each injection site, maximizing the time between two injections at the same spot. Within two weeks all the lumps had disappeared.

Good glucometers have the following features: they require tiny amounts of blood and they have relatively cheap test strips. Also, they measure whole blood, because models which test plasma serum measure higher values, which is something that I don't like when I am aiming for a low nadir. Two models are: Bayer's Ascensia Contour® (0.6 µL of blood per test) and Abbott/Ypsomed's Freestyle Freedom® (0.3 µL). The glucometer I initially used with Tilly was Roche's Accu-Check Sensor® which was poor choice unfortunately, as it uses 4 µl.

A well controlled cat receiving Lantus, which has its blood glucose values tested regularly and is behaving normally has a very small chance of developing clinical hypoglycemia i.e. with symptoms. Nevertheless, it is good to be prepared to act quickly and to always get professional advice should such an event occur. When hypoglycemia occurs without symptoms, the blood sugar can generally be raised with dry cat food. If mild symptoms occur, glucose which has been dissolved in water, should be given - I always had a large syringe (without a needle) on standby. If severe symptoms occur and the cat is unconscious, or having seizures which make it impossible to safely give glucose, a glucagon emergency kit, available at pharmacies, can be a lifesaver. Tilly was never in a situation where she needed glucagon; in fact, she never had clinical hypoglycemia.

Good Links:
• Hypoglycemia - Always be prepared
• "The Somogyi effect is rare in diabetic cats managed using glargine and a protocol aimed at tight glycemic control", K Roomp, JS Rand, ACVIM, #298, 104-105, 2008
• "Intensive blood glucose control is safe and effective in diabetic cats using home monitoring and treatment with glargine.", K Roomp, JS Rand J Feline Med Surg, 11(8), 668-82, 2009
• "Protocol for success in managing, even curing, feline diabetes", E Hodgkins, DVM
• Research connecting organ damage with slightly levels blood sugar levels in humans and mice

4. Dangerous Ketones

Testing for ketones regularly in a diabetic cat is important. Particularly if the cat has been newly diagnosed, or you are changing the insulin and therefore reducing the amount of insulin you are giving. Sometimes infections reduce the effectiveness of the insulin and ketones can develop. Ketones in the blood and then urine are the first sign, that the cat's is suffering from a lack of insulin and cannot use glucose as an energy source properly anymore. The body starts looking for a new energy source: body fat, the by-product of breaking down body fat is ketones.

If you should detect ketones, contact your vet immediately. Treatment depends on the cause and can encompass a higher insulin dose, an insulin with longer duration, giving 2 injections per day instead of 1, feeding cats without appetite, treating infections or a combination of the above.

A cat with ketones that is left untreated will develop into ketoacidosis and this is FATAL IN MOST CASES! Ketoacidosis is a medical emergency that can only be treated in a veterinary clinic. Ketoacidosis is caused by a high number of ketones in the blood, which change the blood's pH and chemistry. Symptoms of ketoacidosis are, among others, vomiting, dehydration, apathy, weakness, refusal to eat and in the last stages coma and death. It is possible that the breath of the cat will smell "sweet."

The crisis treatment of ketoacidosis involves normalizing the blood chemistry via electrolyte infusions and a number of other treatments. The body has to stop using fat as an energy source and switch back to glucose: this achieved by giving glucose infusions and small, frequent doses of quick-working insulin.

Tilly, like all other cats, developed ketones after too long with too little insulin. How quickly the situation develops from just ketones to ketoacidosis depends on the cat and is extremely difficult to predict. I recommend testing for ketones once a week. But in situations where the cat is ill or not regulated and getting low insulin doses, daily. I used the Ketostix® or Keto-Diastix® from Bayer. The urine must be fresh, because ketones are volatile. Tilly uses woodchip-based kitty litter: you can actually press the test strips directly into the wet litter.

Since 2003, the American Diabetes Association recommends testing for blood ketones in human diabetics. The reasons: the test result is more exact, sensitive and quicker (urine ketones will always lag behind blood ketone levels). In humans, measuring ketones in the blood allows them to be detected two to four hours earlier than with urine testing and allows small changes in ketone levels to be monitored rapidly to determine the effectiveness of therapy. Therefore, in cats that have a tendency to develop ketones, testing blood is preferable to urine. The device is the Precision Xtra® from Abbott. It and the test strips are expensive.

Good Links:
• Ketoacidosis
• "Understanding diabetic ketoacidosis", T Schermerhorn, WSAVA, 2005

5. Weighing

Weighing Tilly regularly gave me a very good idea of how she was doing, i.e. the improvement in her health. And my vet was adamant about this. When Tilly was diagnosed she had lost a lot of weight. I could easily follow the positive impact of insulin treatment by watching her increasing weight. Once a month is plenty, with a scale that can measure 100g differences. You can weighed yourself, then weighed yourself holding the cat, and finally calculated the difference. And even better are baby scales: these measure 10g differences.

6. Taurine

Taurine is a beta-amino acid and is particularly important for cats. Cats are not able to synthesize this amino acid in sufficient quantities and are therefore required to take it up in their food. In healthy cats, a diet deficient in taurine leads to a number of serious clinical problems including retinal degeneration, dilated cardiomyopathy, platelet aggregation, reproductive failure and growth retardation, dysfunction of the central nervous system and impaired immune functioning. Prolonged deficiency over a period of several months or even years is required before clinical symptoms appear in most healthy cats. Supplementing a diabetic cat's diet with taurine would seem to be beneficial, for reasons described in the articles referenced below.

Here the most important points:

• Taurine has been found to affect blood sugar and insulin levels favorably in humans and other animal models.
• Supporting kidney function with taurine: kidney cells do not require insulin to take up glucose. The high plasma glucose levels caused by diabetes result in high intracellular levels of glucose. Via a chain of events this leads to a decrease in the taurine quantity in kidney cells. Organic osmolytes - such as taurine - play an important role in the regulation of cell volume.
• The clinical state of diabetes is often accompanied by elevated blood levels of cholesterol, triglycerides, and free fatty acids. Taurine is important for the formation of bile acids. The formation of bile acids represents the most important route for the elimination of cholesterol. Too little bile acid can entail increased cholesterol values. In studies of diabetic rats, taurine also lowered plasma triglyceride values. As many diabetic cats have elevated cholesterol and triglyceride values, taurine may help to lower them. Additionally, according to the lipotoxicity hypothesis, chronic exposure to high concentrations of lipids contribute to deteriorating beta-cell function in diabetic patients.
• Taurine has been shown to reverse neurological damage in diabetic rats.

A typical quantity of taurine that many people give their diabetic cats is 500 mg per day. No scientific studies were found to support this dosage in cats and the guidelines used by the pet food industry vary widely.

Good Links:
• "The role of taurine in diabetes and the development of diabetic complications", S Hansen, Diabetes Metab Res Rev, 17, 330-346, 2001
• "Chronic oxidative stress as a central mechanism for glucose toxicity in pancreatic islet beta cells in diabetes", RP Robertson, J Biol Chem, 279(41), 42351-4, 2004
• "Taurine supplementation and diabetes mellitus", F Franconi, A Loizzo, G Ghirlanda, G Seghieri, Curr Opin Clin Nutr Metab Care, 9(1), 32-6, 2006
• "Taurine reverses neurological and neurovascular deficits in Zucker diabetic fatty rats", F Li et al., Neurobiol Dis, 22(3), 669-76, 2006

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