Researchers find that a “high dose” of strawberries can help beat esophageal cancer.
Eating More Fruit May Protect You From Cancer
Fruits and vegetables have been gaining increasing attention among cancer researchers for their cancer-preventative and cancer-fighting abilities (Donaldson, 2004; Ornish, 2005). Numerous studies have now honed in on berries, in particular, for their especially high level of antioxidants and phytonutrients that have been shown to prevent cancer formation, interfere with cancer cell replication, and in some cases help reverse the progression of and heal cancer.
Studies Suggest Strawberries Can Help Fight Cancer
In the last couple decades there has been a growing body of research suggesting that strawberries can be effective at both preventing the development of cancer and halting its progression. Before any study examined the anti-cancer effect of strawberries on human subjects, there was first a body of evidence that showed strawberries could help beat cancer both outside the body and in animal subjects. Here are a few studies that helped paved the path for strawberry research in human cancer patients:
Berries Prevent and Slow Cancer Growth in Rats
A 2006 study mixed freeze-dried strawberry, black raspberry, and blackberry powders into the diets of rats before, during, and after treatment with an esophageal carcinogen. After 25 weeks, all three berries were found to inhibit the number of esophageal tumors. Rats who were fed the berry powders actually metabolized less of the carcinogen, leading to reduced DNA damage and less presence of tumors. The black raspberry and strawberry powders were all tested separately on rats who were treated with the carcinogen but had not been fed berries prior to or during this period. The berry powder diet inhibited tumor growth by 31-64% demonstrating that the berries helped to inhibit both tumor formation and tumor progression in rats (Stoner, 2006).
Strawberries Cause Cancer Cell Death Ex Vivo and Inhibit Tumor Growth in Mice: Another study examined the anticancer activity of strawberry fruit extract on leukemia and breast cancer cells lines ex vivo (outside of the body) and the cancer therapeutic potential of strawberries in mice. The study found the strawberry extract was toxic in both lines of cancer cells and that the effect increased with both concentration and time. When the strawberry extract was given to mice with breast cancer, it effectively blocked cancer growth in a time-dependent manner and helped extend the lifespan of the mouse subjects (Somasagara, 2012).
Eating Strawberries Protects Hamsters from Oral Cancer: In another animal study researchers tested the cancer-fighting ability of berries by painting a carcinogen inside the cheek pouches of hamsters three times a week for six weeks. Some Hamsters were fed a strawberry-enriched diet prior to, during, and after the carcinogen treatment while others only received berries afterwards. After twelve weeks researchers evaluated the total number of precancerous lesions and oral tumors in the hamsters. They found a significant difference between hamsters who ate strawberries and those who did not. Molecular analysis revealed those who ate the strawberries had modified genes related to tumor development. The researchers concluded that strawberries can inhibit oral tumor formation in hamsters (and possibly in other animals and humans too)(Casto, 2013).
Strawberry Extract Beats Invasive Breast Cancer in Mice: A study using mice infected with a highly invasive form of breast cancer fed the mice a polyphenol-rich strawberry extract (PRSE) and found that cancer cell growth was inhibited in mice who were fed strawberry extract. The number of viable cancer cells decreased as the dose of strawberry extract increased in a dose-dependent relationship (Amatori, 2016).
Can Strawberries Help Beat Esophageal Cancer?
Esophageal cancer, the cancer affecting the tube that connects your mouth and stomach, is bad news for anyone. Once diagnosed, only 13% of people will survive for at least five more years and most will die in the first year (Greger, 2013). This particular cancer takes a predictable developmental path from a normal esophagus, to precancerous lesions, to localized cancer growth, to the spread of the cancer cells, to eventual death. Because esophageal cancer proceeds in an observable step-wise fashion, it is an ideal testing ground for the potential of berries to reverse cancer progression.
80% Of Patients Improve on a Daily Pound of Strawberries
The promising research on the power of strawberries to fight cancer ex vivo and in animal subjects helped provide justification for testing strawberries in human subjects. In one remarkable study, Chinese researchers gave patients with precancerous lesions in their esophagus 1 to 2 ounces of freeze dried strawberries every day for six months (the equivalent of 1 pound of fresh strawberries). Strawberries were chosen for the study because they are the most common berry grown in China and are widely grown and available throughout the world. Interestingly, the Chinese study used California-grown strawberries that were hand harvested into plastic trays and transported to a facility where they were sorted, washed, and frozen within 24 hours of harvest. Berries were then dehydrated, ground into powder, and packaged for shipment while frozen to Ohio State University and then to Beijing China where the were kept frozen until used for this experiment.
Seventy-five patients who had precancerous lesions in their esophagus agreed to eat either 30 g or 60 g of freeze-dried strawberries a day for six months. The strawberries were ground into powder, mixed with water, and drunk. After half a year on their strawberry-enriched diet, researchers assessed the changes in esophageal lesions in a blind fashion. Remarkably, the disease was reversed in 80% of patients who ate the daily dose of strawberries. Unlike with traditional chemotherapy treatment, no toxic or serious side effects were experienced from drinking strawberries. For most patients, their precancerous lesions regressed or disappeared completely. Half of the strawberry-eaters walked away from the study disease-free (Chen, 2012; Suh, 2012).
These studies suggest that eating (or drinking) strawberries can inhibit cancerous oral lesions and can modify expression of genes related to oral cancer growth and development. As if you needed another reason to eat more of the sweet red berries that are readily available in the warm-weather months, nutrition science delivers again with more evidence in support of the healing power of plants. You may already love strawberries for their juicy sweet deliciousness, but now you can thank your berries for protecting your body’s cells and your oral health too.
REFERENCES: 1. Amatori, S., Mazzoni, L., Alvarez-Suarez, J. et al. "Polyphenol-rich strawberry extract (PRSE) shows in vitro and in vivo biological activity against invasive breast cancer cells." Sci Rep 6, 30917 (2016). https://doi.org/10.1038/srep30917 2. Casto, Bruce C et al. “Chemoprevention of oral cancer by lyophilized strawberries.” Anticancer research vol. 33,11 (2013): 4757-66. 3. Chen, Tong et al. “Randomized phase II trial of lyophilized strawberries in patients with dysplastic precancerous lesions of the esophagus.” Cancer prevention research (Philadelphia, Pa.)vol. 5,1 (2012): 41-50. doi:10.1158/1940-6207.CAPR-11-0469 4. Donaldson, Michael S. “Nutrition and cancer: a review of the evidence for an anti-cancer diet.” Nutrition journal vol. 3 19. 20 Oct. 2004, doi:10.1186/1475-2891-3-19 5. Greger, Michael. "Strawberries Can Reverse Precancerous Progression." NutritionFacts.org. December 17, 2013, https://nutritionfacts.org/2013/12/17/strawberries-can-reverse-precancerous-progression/. 6. Ornish, Dean. "Intensive Lifestyle Changes May Affect the Progression of Prostate Cancer." The Journal of Urology, Vol. 174, 1065–1070, September 2005. DOI: 10.1097/01.ju.0000169487.49018.73 7. Somasagara RR, Hegde M, Chiruvella KK, Musini A, Choudhary B, Raghavan SC (2012) "Extracts of Strawberry Fruits Induce Intrinsic Pathway of Apoptosis in Breast Cancer Cells and Inhibits Tumor Progression in Mice." PLoS ONE 7(10): e47021. https://doi.org/10.1371/journal.pone.0047021 8. Stoner, Gary D et al. “Protection against esophageal cancer in rodents with lyophilized berries: potential mechanisms.” Nutrition and cancer vol. 54,1 (2006): 33-46. doi:10.1207/s15327914nc5401_5 9. Suh, Nanjoo and John M. Pezzuto, "Strawberry Fields Forever?" Cancer Prev Res January 1 2012 (5) (1) 30-33; DOI: 10.1158/1940-6207.CAPR-11-0534