The past decade has brought a significant increase in attention to the role that food and nutrients might play in fighting cancer. Media response to incremental news has sent consumers scurrying to eat more blueberries, cherries, tomatoes, broccoli, carrots, cranberries, and leafy green vegetables, and to drink green tea and red wine in hopes of warding off disease.
But whether these foods actually can help prevent cancer, or whether they are best utilized at the molecular level or in combination with other treatments once tumors have been discovered, are questions researchers are still exploring. Support for such research is on the rise, but results are coming in fits and starts as promising foods or nutrients become the latest favorites, stimulate controversy, or fade in the stretch.
Among the most promising studies are investigations into pomegranate juice that researchers at the Jonsson Comprehensive Cancer Center at the University of California, Los Angeles (UCLA) are conducting.
Allan Pantuck, MD, MS, director of Translational Research at the UCLA Kidney Cancer Program, is the principal investigator in a study in which it was found that drinking an 8-ounce glass of pomegranate juice each day increases by nearly 4-fold the period during which prostate specific antigen (PSA) levels remained stable in men being treated for prostate cancer.
Pomegranate juice is known to inhibit inflammation—which is thought to play a role in many cancers—and contains high levels of antioxidants, which are believed to protect the body from free-radical damage. Specifically, it contains polyphenols, natural antioxidant compounds found in green tea, as well as isoflavones commonly found in soy, and ellagic acid, which is believed to play a role in cancer cell death.
The findings might prove particularly helpful amid the uncertainty that persists over the precise implications of rising PSA levels. Currently, there is no standard treatment for men who have recurrent prostate cancer detected by an increase in PSA level only, according to the National Cancer Institute (NCI).1
Allan Pantuck, MD, MS, is investigating the influence of pomegranate juice on PSA levels in a phase III trial.
“In a phase II trial we conducted, daily consumption of pomegranate juice resulted in a significant lengthening of PSA doubling time and disease stabilization,” said Pantuck.
In that phase II Simon 2-stage clinical trial, men with rising PSA levels after surgery or radiotherapy were treated. Eligible patients had a detectable PSA >0.2 and <5 ng/mL and Gleason score of v7. Patients were treated with 8 ounces of pomegranate juice daily (Wonderful brand, 570 mg total polyphenol gallic acid equivalents) until disease progression. Clinical endpoints included safety and effect on serum PSA, serum-induced proliferation, and apoptosis of human prostate cancer (LNCaP) cells, serum lipid peroxidation, and serum nitric oxide levels.2
Researchers are now conducting a phase III, double-blinded, placebo-controlled study that is one of the most advanced of the current food and nutrient clinical trials, Pantuck said.
Drinking a glass of pomegranate juice or taking a pill each day “would be ideal” as a treatment with minimal side effects, he said.
Pantuck is sufficiently impressed by the results that he has added pomegranate juice to his own diet several times a week as part of his personal practice of eating a rainbow of foods. “I try to eat what I call a colorful diet,” he said, in keeping with the belief that the substances that give color to a food are an indicator of the antioxidants contained within.
Pomegranate also is being investigated as a possible treatment for breast cancer, heart disease, and other health issues, he said.
Marilene Beth Wang, MD, is studying the interaction of curcumin and cisplatin.
Out of the Kitchen Cabinet
Elsewhere at UCLA, Marilene Beth Wang, MD, is lead author of a study of curcumin, the major component in the spice turmeric. Curcumin has been found to enhance chemotherapy’s ability to suppress head and neck cancer cell growth when combined with the drug cisplatin.
Turmeric is among the many spices and foods that have been used throughout history by healers; it is widely used in South Asian and Middle Eastern cooking, and is credited with having anti-inflammatory effects. In India, women use it as an antiaging agent rubbed into their skin and as a poultice to promote wound healing.