I am sure, we have all heard it hundreds of times: THERE ARE IMPORTANT LINKS BETWEEN OUR DIET AND CERTAIN CANCERS. The evidence for this statement seems fairly compelling. Yet it also is complex and often confusing.
A recent review, for instance, suggested that fruits (particularly citrus) and vegetable consumption may be beneficial in the primary prevention of pancreatic cancer, the consumption of whole grains has been shown to reduce the risk and fortification of whole grains with folate may confer further protection. Red meat, cooked at high temperatures, should be avoided, and replaced with poultry or fish. Total fat should be reduced. The use of curcumin and other flavonoids should be encouraged in the diet. Another equally recent review, however, indicated that there is no conclusive evidence as an independent risk factor for isolated nutrients versus adoption of dietary patterns for cancer risk. Cancer colon risk derived from meat intake is influenced by both total intake and its frequency. The interaction of phenolic compounds on metabolic and signalling pathways seems to exert an inhibitory effect on cell proliferation and tumor metastasis and induces apoptosis in various types of cancer cells, including colon, lung, prostate, hepatocellular or breast cancer. A third recent review concluded that cruciferous vegetable intake protects against cancer of the colon, while a forth review suggested that the Mediterranean dietary pattern and diets composed largely of vegetables, fruit, fish, and soy are associated with a decreased risk of breast cancer. There was no evidence of an association between traditional dietary patterns and risk of breast cancer.
Not least based on these mixed messages from the scientific literature, an entire industry has developed selling uncounted alternative cancer-diets and dietary supplements to desperate patients and consumers. They promise much more than just cancer prevention, in fact, leave little doubt about the notion that cancer might be curable by diet. Here are just a few quotes from the thousands of websites promoting alternative cancer diets:
- The Ketogenic Diet is believed capable of starving cancer cells to death, and thus capable of restricting tumour development.
- a more alkaline body makes it difficult for tumors to grow.
- Budwig diet: This diet was developed by Dr. Johanna Budwig who was nominated for the noble Prize sixth times. The diet is intended as a preventative as well as an alternative cancer treatment.
- the Gerson Therapy naturally reactivates your body’s magnificent ability to heal itself – with no damaging side effects. This a powerful, natural treatment boosts the body’s own immune system to heal cancer, arthritis, heart disease, allergies, and many other degenerative diseases. Dr. Max Gerson developed the Gerson Therapy in the 1930s, initially as a treatment for his own debilitating migraines, and eventually as a treatment for degenerative diseases such as skin tuberculosis, diabetes and, most famously, cancer.
- the concept of macrobiotics is much more than an alternative diet for cancer, or any other illness, but rather the ancient Chinese belief that all life, indeed the whole universe, is a balance of two opposing forces Yin and Yang.
Confused? Yes, I do worry how many cancer patients listen to these claims and pin their hopes on one of these diets. But what exactly does the evidence tell us about them?
A German team of researchers evaluated the following alternative cancer-diets: raw vegetables and fruits, alkaline diet, macrobiotics, Gerson’s regime, Budwig’s and low carbohydrate or ketogenic diet. Their extensive searches of the published literature failed to find clinical evidence supporting any of the diets. Furthermore, case reports and pre-clinical data pointed to the potential harm of some of these diets. The authors concluded that considering the lack of evidence of benefits from cancer diets and potential harm by malnutrition, oncologists should engage more in counselling cancer patients on such diets.
In other words, alternative cancer diets – and I mean not just the ones mentioned above, but all of them – are not supported by good evidence for efficacy as a treatment or prevention of any type of cancer. In addition, they might also cause harm.
What follows is obvious: cancer patients should take sound nutritional advice and adopt a healthy general life-style. But they should run a mile as soon as anyone suggests an alternative dietary cure for their disease.