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Nutrition and the Canine Cancer Patient

By Cynthia McFadden
RRCUS Health & Genetics Committee

*NOTE:  This article is intended for informational purposes only, and makes no claim to the effectiveness of any specific disease treatment. Readers are encouraged to discuss their animal’s individual health concerns with a qualified, licensed veterinary practitioner.

 “Your dog has cancer.” The words are guaranteed to make even the most stalwart owner break out in a cold sweat. Suddenly, a bewildering array of decisions must be made, bringing up uncomfortable emotions and painfully reminding us that our canine companions share our lives for such a short time.

What kind of cancer is it? What is the best treatment? How long can we expect him or her to live? What quality of life will he or she have? Can we cure it?

Increasingly, along with decisions on the costs and benefits associated with such conventional treatments as radiation and chemotherapy, owners are learning of options related to their dog’s nutrition and the effects of food choices on cancer. This article explores the growing area of nutrition in managing and treating the canine cancer patient.

For the most part, nutrition occupies a very minor role in the veterinary curriculum.  Often taught by representatives from major dog food companies, with subsidies to students in the form of free food, nutrition classes focus on basic metabolic requirements.  Specialized commercial diets (sometimes produced by the same companies used to teach classes) are suggested to treat specific disease processes with the aim of relieving symptoms, but may not necessarily correct the underlying imbalances that result in disease. In general, drugs are used to treat diseases, and nutrition is but a minor consideration when designing a treatment protocol.

Veterinarians interested in obtaining further information on therapeutic nutrition are largely left to fend for themselves, often seeking advice from “alternative” or “holistic” practitioners who have found success using various herbs and nutritional supplements to treat clients’ pets. This alternate approach focuses on balancing an animal’s internal and external environments, and treats disease symptoms as metabolic and energy disruptions that can often be brought back into alignment through use of diet and other modalities. Nutritional supplements are often used with other therapeutic options to boost the animal’s immune system and fight disease naturally from within. As more and more research demonstrates the benefits of diet consideration when managing and treating disease, opportunities for education are slowly increasing.

From the beginning, in addition to needing oxygen and water, an animal depends on approximately 40 essential nutrients plus additional factors that come from the diet to sustain life, says Dr. Roger V. Kendall, PhD, in his chapter “Basic and Preventive Nutrition for the Cat, Dog, and Horse”1 (see references). The basic diet must contain adequate amounts of energy, protein, essential fatty acids, vitamins, minerals and accessory food factors (such as enzymes, bioflavinoids and choline) to maintain normal biologic and metabolic functions. Dr. Kendall suggests that the diet be based on high-quality ingredients that are readily assimilated, as unprocessed as possible, and free of artificial preservatives, flavors and coloring agents. Processing lowers the nutritional quality of the various components, and chemical additives such as the preservatives BHA, BHT, and ethoxyquin are controversial for their potentially deleterious effects on animal health.

The National Research Council (NRC) has published guidelines containing recommended daily nutrient requirements, which represent average amounts of nutrients that should be consumed by animals to maintain growth and prevent deficiencies over time. These recommendations, however, do not address individual differences in nutrient needs that may result from physiology, genetics (including breed), stress, age and environmental factors, among others. Cancer places a metabolic burden on an animal that will vary greatly with type, grade, location and the animal’s inherent condition, in addition to the individual differences listed above for nutrient requirements. Cancer can change the way the body utilizes certain nutrients, leading to disruptions in vital metabolic systems. With this in mind, it becomes apparent that for cancer patients, an individualized approach to nutrition is more appropriate than a diet based on NRC guidelines alone. 

In addition to a basic high-quality diet, dietary supplements can provide valuable benefits for all animals, whether healthy or suffering from disease. Studies show that nutritional supplementation can increase life span, reduce degenerative conditions, increase the efficiency of cellular regeneration, improve immune function and enzymatic activity, enhance waste and toxin elimination, and decrease the effects of damaging free radicals1.  Common supplements indicated for specific conditions include the use of glucosamine for joint repair, essential fatty acids for allergic skin conditions, bioflavinoids as antioxidant and anti-inflammatory agents, and probiotics as digestive aids. Supplements used to prevent or treat cancer include vitamin C, pycnogenol (and related bioflavinoids and proanthocyanidins), coenzyme Q10, omega-3 fatty acids, vitamin E, vitamin A (and its precursor, beta-carotene), curcumin, the amino acids glutamine and arginine, the enzyme L-Asparaginase, and garlic2,3.  In some cases, suggestive preliminary research on product efficacy needs to be supported by further studies to confirm earlier results. Doses vary considerably, and owners are encouraged to consult their vet for individual recommendations.

The use of dietary supplements together with an appropriate basic diet forms the backbone for the nutritional approach to disease treatment and management, and is often most successful when a combination of products is used together to enhance and boost metabolic pathways.

 “I look for a synergistic balance of components when coming up with a treatment plan,” says Dr. Donna Starita, DVM, a traditionally trained vet and member of the American Holistic Veterinary Medical Association. Dr. Starita owns a thriving holistic practice outside Portland, Ore., that specializes in nutritional therapy. “No one product is going to be good for all – a balance is needed. And while a raw diet is best for *most* animals, what’s best for all, especially cancer patients, is an approach that emphasizes a healthy preventative diet, detoxification and minimizing stress. We want to help the animal heal from the inside out.”

Dr. Starita recommends a raw diet based on meat, bone, vegetables, limited fruits, minimal grains and vitamin/mineral supplements, similar to the BARF (Bones and Raw Food, or Biologically Appropriate Raw Foods) diet proposed by Australian veterinarian Dr. Ian Billinghurst. When carbohydrates are indicated, they should be limited to less than 10 percent of the diet and consist of complex, starchy carbs high in fiber such as potato, pumpkin and sweet potato.

Recognizing that many owners may be reluctant to embrace the responsibility and time associated with a raw diet, Dr. Starita offers suggestions for other basic diet options, including raw frozen commercial diets and home-cooked stews, followed in preference by commercial canned food made with high-quality, human-grade ingredients, and holistic blend natural kibble. She does not consider commercial supermarket-brand kibble diets to be appropriate for dogs, especially those with special needs. Quality canned food is preferable to kibble, as canned food contains few or no preservatives due to its airtight packaging, and usually boasts a higher level of meat protein and fewer grains than comparable kibble formulas.

To the chosen basic diet various supplements are added, picked for a particular animal’s disease, energy level, and nutritional needs.  The process is not static, and formulas are varied and adjusted as the patient’s condition changes. 

Cancer becomes more likely as a dog ages, so preventative nutrition in the elderly animal focuses on those processes that tend to break down with age. Overall, Dr. Starita recommends increased antioxidants, milk thistle for liver functioning, and vitamin C, along with increased probiotics and digestive enzymes to aid with nutrient absorption and assimilation. She notes that most calcium found in bag foods is not readily utilizable by the body, so recommends calcium supplements for geriatric dogs in general, and cancer patients in particular.

To this list, Dr. Kendall adds B complex vitamins, vitamin E, coenzyme Q10, fish oil, primrose oil, dimethylglycine and zinc.

When examining speed of relief, Dr. Kendall notes that nutritional therapy often does not produce the dramatic decrease in symptoms that drugs can show, but that the use of nutrients and supplements can bring more stable and long-lasting results over the long term. In some cases, symptoms seem to get worse before they get better. This is usually due to a detoxification process, where the animal purges its body of years of accumulated waste products and pollutants before reestablishing normal metabolic pathways. The time needed to effect an improvement in symptoms may work against owners dealing with some kinds of cancer, however, especially those that hit hard and progress rapidly, like osteosarcoma.

Dr. Starita agrees. “Sometimes there is just not much time for a purely alternative approach, but nutritional support can always be used, even if the owners decide to pursue options like surgery and radiation treatments.” In fact, nutritional therapy is often used in conjunction with conventional cancer treatments such as surgery, radiation, and chemotherapy.

Dr. Mary Alissa Crist, DVM, of Veterans Memorial Drive Animal Hospital in Houston, Texas, has seen significant differences in patients that have undergone a detoxification regimen before undergoing chemotherapy and/or radiation treatments, compared to those animals sent for chemotherapy or radiation alone.

“The dogs that have gone through detox and nutritional support programs have fewer fluctuations in their white blood counts, less lethargy, and in general far fewer side effects from the chemotherapy than dogs that aren’t being nutritionally treated,” she says. “The dogs I’ve seen do much better with chemotherapy and radiation if they’re detoxed before they start.”  

With slower-progressing cancers, there is more time for nutritional therapy to have an effect. Dr. Starita states that she has had very good luck using a strictly nutritional approach with mast cell cancers and hystiocytomas, sometimes attaining complete resolution of tumors and symptoms. In other cases, use of diet and supplements has resulted in management of the cancer in a modified chronic state, where symptoms are minimized and the dog maintains a good quality of life without resorting to surgery.

In many of these cases, the animal eventually dies years later of causes unrelated to the cancer. Outcomes vary depending on the vitality and energy state of the animal when brought in, type and stage of cancer, and the agenda of the owner (including owner compliance with suggested therapies).

As mentioned earlier, cancer can change the way the body metabolizes nutrients, and this can have very drastic effects on the quality of life and outcome for an animal battling cancer. The term cancer cachexia refers to a complex syndrome of symptoms that includes involuntary weight loss, even with adequate nutritional intake. Studies show that humans with cancer cachexia experience a decreased quality of life, decreased response to treatment, and decreased survival times when compared to patients with similar diseases but who don’t demonstrate the biochemical changes associated with the syndrome.

Not all cancer patients become cachexic, but those who do face poorer prognoses than those who can avoid it. Nutritional therapy in some cases can help abate or eliminate cancer cachexia by facilitating weight gain, improving response to and tolerance of radiation, surgery, and chemotherapy, improving immune responsiveness, and increasing immunoglobulin levels and the phagocytic ability of white blood cells3.

Research by Dr. Gregory Ogilvie D.V.M. and associates at Colorado State University has identified three stages of cachexia in veterinary cancer patients. The first stage is often a preclinical “silent” phase, where the patient shows no clinical signs of the syndrome, but biochemical alterations are already present in bloodwork. These changes often include hyperlactatemia (increased levels of lactate in the blood), hyperinsulinemia (increased levels of insulin in the blood), and altered amino acid profiles.

The second stage is manifested by weight loss, anorexia and lethargy. The animal appears to be “aging” rapidly, and is more likely to show side effects from surgery, chemotherapy and radiation.

The third stage is an accentuated form of the second stage, where the animal demonstrates marked debilitation, weakness, loss of fat deposits, loss of muscle mass, and appears to be literally wasting away. The third stage is generally terminal. As the early metabolic changes associated with cachexia occur before the animal shows clinical signs of the syndrome, it is important to begin nutritional therapy early.

Cachexia results from alterations in the metabolic pathways associated with certain nutrients. The most drastic alterations affects carbohydrate metabolism. This is due to the fact that many tumors preferentially metabolize glucose for energy by inefficient anaerobic pathways, which forms lactate as an end product (resulting in elevated lactate levels in the blood). The energy cycle associated with the conversion of lactate back into glucose uses more energy than it produces, resulting in a net energy loss for the host. Moreover, these changes do not improve if the patient enters remission.

Studies by Dr. Ogilvie have shown that dogs with lymphoma fed a diet high in simple carbohydrates had significantly worse outcomes than dogs with lymphoma fed a high fat diet. Note that these results apply to diets high in simple carbohydrates, and do not mention complex carbohydrates specifically. Dogs treated for lymphoma who were infused with a lactated Ringer’s solution also fared worse than a comparable control group, as the increased lactate levels associated with the Ringer’s solution placed a metabolic burden on the host. This finding could be important for critically ill patients who require intensive fluid therapy, and Dr. Ogilvie recommends that glucose- or lactate- containing fluids be avoided in these cases unless specifically indicated. Diets high in simple carbohydrates should be avoided when considering nutritional options for dogs with cancer.

Cancer also induces changes in protein metabolism, and alters nitrogen balances by changing amino acid profiles. Amino acids form the building blocks of proteins. Many tumors will use amino acids as energy sources (via a process called gluconeogenesis) at the expense of the host, leaving the host with protein loss that exceeds production. As both the host and tumor are competing for the same amino acids, it becomes important to provide sufficient, high-quality protein in the diet so that the malignant process does not remove protein from the host. As well, supplementation with specific amino acids such as arginine and glutamine can improve immune function and reduce gastrointestinal toxicity.

Most weight loss associated with cachexia is due to loss of fat stores, so it’s no surprise that fat (lipid) metabolism is altered in cachexic patients. Disruptions in circulating lipid levels result from increased breakdown of fats for energy by the host and decreased lipid storage and production. Many malignant cells cannot utilize lipids for energy, while the host is able to readily utilize fats, so feeding a patient a diet relatively high in fats makes sense. Dr. Ogilvie’s research shows that specific kinds of fats (n-3 or omega-3 fatty acids) can reduce many metabolic alterations associated with cancer, as well as provide anti-cancer properties and reduce the side effects associated with radiation therapy.  N-3 fatty acids are found in fish oil and linseed/flaxseed oil, as well as leafy green vegetables such as spinach. Antioxidants are also indicated when using n-3 fatty acids.

An optimal diet for a cancer patient won’t work if the patient is reluctant to eat it. Anorexia is a common problem with cancer patients, especially those undergoing chemotherapy or radiation. To complicate matters, dogs can develop a learned food aversion if pressured to eat while feeling poorly, making adequate nutrient intake even more problematic.

Most veterinarians agree that a fast lasting a couple of days is not a big concern, but anything longer than this should be brought to the attention of the vet, and steps taken to encourage eating. These include presentation of highly palatable, aromatic food that is warmed to just below body temperature, blending of food into a gruel, use of baby food (temporarily), or hand-feeding. Short-term use of appetite stimulants can also encourage a reluctant animal to eat. An animal showing interest in food should be encouraged to eat, while dogs exhibiting less interest may benefit by having food presented at cooler temperatures, so that the smell of food does not provoke a learned negative association.  For more extreme cases of anorexia, a feeding tube may be indicated.

Dogs should be fed amounts of food comparable to those of healthy, disease-free animals.  Research indicates that canine cancer patients in general, and even those recovering from surgery, do not require increased caloric intake when compared to healthy animals.

Technology is available today to help dog owners support wellness in healthy animals and improve health for those that need it, including canine cancer patients. The Nutritional Blood Test (NBT) is a tool used by veterinarians to look for deficiencies in nutrient levels beyond what is typically measured in a routine blood test, and is based on the philosophy that changes in the blood occur before symptoms appear.

Originally developed by Dr. Robert Goldstein VMD, the analysis examines 34 blood chemicals and places values into categories of normal, outside normal, or optimal. Optimal values are derived from a narrower set of parameters within the normal reference range, and suggest a range at which organs and metabolic processes are functioning at peak efficiency. Lab results are then sent to Animal Nutrition Technologies (ANT), a referral-only service that examines all values outside the optimal range and suggests a custom formulation of nutritional supplements to bring the patient back into balance for all parameters. ANT, in consultation with the referring veterinarian, then combines a specialized blend of vitamins, minerals, enzymes, herbs, nutrients, homeopathic remedies, and other medicinals into a powder that is added to the pet’s food.

The NBT is not meant to diagnose any particular disease, and is designed to be used as an adjunct to other methods of treatment. This technology is being embraced by both conventional and holistic veterinarians as an aid in maintaining wellness, managing cancer and other chronic diseases, and as a valuable support for canine athletes asked to routinely perform stressful activities.

Dr. Mary Alissa Crist is a strong advocate, and offers testing under the name Neutraceutical Analysis. “We don’t expect Olympic athletes to perform at high levels without a strong nutritional base, and we shouldn’t expect it of our dogs, either,” she says. “Animals in stressful working environments and those asked to perform should be able to benefit from this kind of testing.  It’s not just for sick dogs.”

Dr. Dan Kirby, DVM, owns Alamo Heights Pet Clinic in San Antonio, Texas and is the regional coordinator for the Nutritional Blood Test. He is the proud owner of a healthy 15-year old golden retriever and highly recommends the program for health maintenance as well as therapeutic purposes. When asked about how the optimal ranges were established, given that different breeds and individuals have differing needs, he replied with sound advice.

“That’s when it’s important for the veterinarian to use his brain.  I know that what I consider to be an optimal T4 level will be different for a greyhound, or a Ridgeback, or a Doberman. ANT works with the referring vet to come up with a set of supplements that best meets the animal’s needs, and that includes looking at the patient’s history, environment and other stresses they’re exposed to.”

Costs for the testing are approximately $185 for the consultation and analysis. If the owner decides to purchase the recommended supplements, a three-month supply generally costs about $120, but will vary depending on the number and type of supplements. A three-month follow-up exam is suggested, and at that time supplements may be reordered, modified, or discontinued, depending on the patient’s response.

Dr. Kirby encourages veterinarians or owners interested in learning more about the NBT to contact him at alamoheightspetclinic.com, or to call (210) 821-5544. He is also happy to field questions during his weekly call-in radio show, Dr. Dan Kirby on Your Pet’s Health, airing Sunday afternoons from 3-4 PM Central on KLUP 930 AM. The radio show is also available online, at www.KLUP.com. Phone numbers for the radio show are (210) 308-8867 (locally), or (866) 308-8867 (toll free).

In summary, nutritional requirements for canine cancer patients can vary tremendously, and an individual approach is best when formulating dietary recommendations, whether as adjunct to conventional cancer treatments, or as a primary therapeutic tool. The backbone of a nutritional regimen includes a sound basic diet that includes moderate levels of high-quality proteins and fatty acids, minimal carbohydrates, and sufficient vitamins and minerals, along with nutritional supplements appropriate for the type of cancer and patient condition. While a raw or minimally processed diet is preferred, raw frozen commercial diets, home-made stews, human-grade canned food, or super-premium holistic blend kibble are all suitable alternatives.

Nutritional therapies may take longer to work than drugs, but should result in longer-lasting and more stable results over time, based on the philosophy that a balanced body and healthy immune system is better able to heal itself. Some cases of slow-growing cancers can be managed nutritionally as a chronic illness over many years, where the animal maintains a good quality of life without surgery. Alternative therapies are less effective with aggressive cancers. A detoxification program can improve an animal’s response to conventional cancer treatments and reduce side effects associated with radiation and chemotherapy.

Cancer cachexia is a complex syndrome that results from alterations in the way the body metabolizes nutrients. Nutritional therapies can help reduce or eliminate the complications of cachexia, which include lethargy, wasting and anorexia. The Nutritional Blood Test is a tool veterinarians can use to balance an animal’s nutritional needs, and can be used to support wellness as well as combat illness.

Dr. Kirby sums it up this way:  “It’s not about using one way or modality. It’s about doing what’s best for the animal and using common sense.  Do no harm.”

References

1Kendall, Roger V. 1998. Basic and Preventative Nutrition for the Cat, Dog, and Horse.  In Complementary and Alternative Veterinary Medicine, Principles and Practice, Allen B. Schoen and Susan G. Wynn, eds.  Mosby, Inc.  St. Louis, MO pp. 23-52

2Kendall, Roger V.  1998. Therapeutic Nutrition for the Cat, Dog, and Horse.  In Complementary and Alternative Veterinary Medicine, Principles and Practice, Allen B. Schoen and Susan G. Wynn, eds.  Mosby, Inc.  St. Louis, MO pp. 53-72

3Ogilvie, Gregory K.  1998. Nutritional Approaches to Cancer Therapy.  In Complementary and Alternative Veterinary Medicine, Principles and Practice, Allen B. Schoen and Susan G. Wynn, eds.  Mosby, Inc.  St. Louis, MO pp. 93-111

Resources (books, websites)

There is a tremendous amount of resource material available on the Internet. A Google search on “canine cancer nutrition” will yield approximately 200,000 hits. Some of the available information is based on science, some is not. Some sites are commercial, some are not. Readers are encouraged to explore the available information with an open mind and talk with their veterinarians for specific recommendations.

There are many good books available on alternative health care, natural feeding, and raw and home-cooked diets. Some of these include “Natural Dog Care” by Celeste Yarnall, “Four Paws, Five Directions” by Cheryl Schwartz, “Natural Nutrition for Dogs and Cats” by Kymythy Schultze, “Holistic Guide for a Healthy Dog” by Wendy Volhard and Kerry Brown, “The Holistic Dog Book: Canine Care for the 21st Century” by our own Denise Flaim, and of course Complementary and Alternative Veterinary Medicine, Principles and Practice (listed above in references).

The American Holistic Veterinary Medical Association has a great website (www.ahvma.org) that includes a veterinary referral service, bookstore and seminar tapes on a variety of health topics available for purchase. Most of the books listed above also contain extensive resource lists.

Other interesting websites are

Cynthia McFadden is a member of the RRCUS Health and Genetics committee and has been involved with Ridgebacks since 1992. A licensed radiologic technologist for 18 years, she also finished a master’s degree in Wildlife and Fisheries Science (animal behavior emphasis) in December 2003, and is beginning preliminary studies toward a Ph.D. in animal behavior at Texas A&M University. Her first Ridgeback, Am/Can Ch. K-Tai Dakota Justice, FCh, JC, CGC, has lived with mast cell cancer since 2000 and malignant melanoma since 2003, and remains healthy at nearly 13 years of age on nutritional support.


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