Nutritional Intervention During Cancer Treatment

4. Nutritional Intervention During Cancer Treatment

In recent years there has been a significant increase in the use of antioxidants in pet foods, which has hypothetically been associated with less free radical damage in cells throughout the body. This antioxidant supplementation has been associated with amelioration of a variety of different disease processes (Figure 9).

Figure 9. Antioxidants and cancer prevention. Massive antioxidant supplementation may be contra-indicated during chemotherapy or radiation therapy, as antioxidant supplementation may facilitate the survival of cancer cells.  

Though these approaches to cancer prevention may be beneficial in theory, once the veterinary patient has been diagnosed with cancer and is undergoing chemotherapy or radiation therapy, use of various antioxidants may actually be contraindicated. If antioxidants are used to prevent free radical damage, and a chemical or radiation treatment has been initiated, the higher levels of cytosolic or membrane bound antioxidant may actually provide a survival advantage to cancer cells. Therefore, it has been recommended by many veterinary oncologists that pets not be given these antioxidant supplements during such treatment. This hypothesis is very controversial, and has yet to be proven. Since the veterinary patient is usually already ingesting sufficient amounts of the essential antioxidants, supplementation may not be necessary (Virtamo et al., 2003; Prasad, 2004).

On the other hand, many other ingredients and nutrients such as fish oil and arginine, are unlikely to be detrimental. Indeed, supplementation with fish oil has been associated with better radiation therapy recovery and less inflammation to surrounding tissue. Studies in animal models have also suggested that the increase in long chain polyunsaturated fatty acids in cell membranes resulting from fish oil supplementation may actually provide more highly reactive fatty acids for lipid peroxidation during radiation therapy, thus promoting cell death in the neoplastic tissue (Colas et al., 2004).

Conclusion

Clinical veterinary studies have shown that a number of metabolic anomalies produced in human and rodent cancer models are also found in dogs. The nutritional approach to cancer used in human medicine could therefore be adapted to veterinary medicine to influence the progression of the cancer.