Friday, January 9, 2009

Nutrition for dogs with cancer

Cancer, a disease that most of us are familiar with and nobody really wants to talk about. Just the thought of it makes us shiver, which, in my opinion, is mainly due to the fact of the disease’s reputation. It is very difficult to overcome and, yes, things have gotten better and we can do much about it these days, however, it also remains a fact that it is sort of incurable in many, typically progressed cases. And since we are dealing with pets on this blog, another reality is, these days it becomes more and more common that this dreadful disease also affects our companion animals. As life expectancies of cats and dogs continue to increase, so increase the risks of developing cancer.
Investigations into dietary effects on the survival of pets battling cancer have been made and resulted in interesting studies about certain cancers and how they are affected by nutrition.
Pets with cancer often develop a condition called cancer cachexia. In plain English this means the pet is losing body condition despite adequate calorie intake. Just as we humans, pets undergoing chemotherapy in most cases don’t feel very well and may not eat as well as they should. However, chemotherapy in pets is way different than it is for us humans. To avoid hair loss and vomiting, much lower doses are used. No matter what is causing their illness, keeping ill pets in good body condition helps them recover more quickly.
In this entire equation, diet composition plays a great role. Cancers are most able to use carbohydrates as an energy source, so low carbohydrate diets are best for cancer patients. Diets are made up of protein, fat, moisture, ash, fiber, and carbohydrates. In traditional pet foods, carbohydrates make up the biggest percentage of the diet. If we lower the percentage of carbohydrates, we must add higher percentages of some other category or categories. Since we don’t want to raise the ash or fiber, this leaves protein, fat, and moisture. Most dry pet foods are less than 10% moisture to help prevent mold from developing in the bag. Therefore raising moisture is not an option either. Protein and fat are typically the two nutrients that are present in higher quantities. This helps the patient by restricting carbohydrates that are available to the cancer. Increasing the fat content helps provide more calories to the pet to help prevent cancer cachexia. Fat is also the nutrient that cancer cells are least able to use for energy.
Omega-3 fatty acids are important for keeping many systems of the body in ideal condition. These important substances are known to inhibit the growth of tumors and enhance the body’s ability to fight the cancer by stimulating the immune system. Many pet foods contain ratios of omega-6 fatty acids to omega-3 fatty acids of 5:1 to 10:1. Recommended for cancer patients is a ratio as low as 3:1. Therefore, a supplement of omega-3 fatty acids may be required.
Arginine is an amino acid that is essential for cats and conditionally essential for dogs. This means that cats must obtain arginine from their diets, while dogs require it in their diets only in certain situations. Cancer may just be one of those situations. Arginine enhances the immune system by stimulating T-cells (one of the types of cells that is responsible for attacking foreign invaders). The mechanism behind this is not very well understood. Arginine may also suppress tumor growth, like omega-3 fatty acids.
Vitamins may affect cancer as well, particularly the antioxidant vitamins A, C and E. The Vitamin A family may be responsible for impeding the cancer’s ability to develop new cells. Vitamin C is a water soluble vitamin that has been studied extensively. Despite numerous studies, there is little scientific proof that vitamin C is as effective as many people believe. Vitamin E is the most promising of the three vitamins, with scientific proof that it interferes with cancer and enhances the immune system.Minerals have beneficial and detrimental effects on the cancer patient. Selenium and zinc have the ability to block the development of cancer in rodents. Iron is required by most cancers to grow and multiply. So, restricting iron intake may help slow the process.
It is critical to provide the patient with adequate calories and nutrition to maintain body condition. This may not be possible without other methods of feeding (besides oral). Tubes can be placed into the esophagus, stomach, or directly into the small intestine to provide nutrients directly to the gastrointestinal tract. This is especially true in cases of mouth cancer or facial cancer. Needless to say that working closely with a veterinarian to develop a treatment plan is critical. Focusing on nutrition is just as important as the surgical or medical treatments that are involved.

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