We’ve often heard that certain foods might have the power to reduce our risk of disease. There’s Epigallocatechin gallate (EGCG), a major polyphenol found in green tea, that may help prevent tumor growth, or DHA, one of the major omega-3 fatty acids found in fish and nuts, that could protect neurons and perhaps lower the chances of developing a neurodegenerative disease. Now, even more evidence suggests that cruciferous vegetables may be able to slow the cell growth of one of the most prolific cancers – breast cancer. It’s the second leading cause of cancer death in women, and it’s fascinating to think that simply eating cruciferous vegetables – chock full of sulforaphane – might help slow its growth. Although future studies are needed to substantiate these claims, one of the first clinical studies to investigate the effects of this compound on cancerous breast tissue has found that it may potentially slow the growth of cancer cells.
Broccoli and other cruciferous vegetables, such as cauliflower, Brussels sprouts and cabbage, are known to contain sulforaphane, a compound that previous research has linked to cancer prevention. This new study, conducted by scientists at Oregon State University and the Oregon Health & Science University, was published in Cancer Prevention Research and outlines the possible benefits of sulforaphane in slowing the growth of cancer along with other well-established approaches including radiation, surgery, and chemotherapy.
Professor in the OSU College of Public Health and Human Sciences and co-author of the study, Emily Ho, explained: “Our original goal was to determine if sulforaphane supplements would be well tolerated and might alter some of the epigenetic mechanisms involved in cancer.”
“We were surprised to see a decrease in markers of cell growth, which means these compounds may help slow cancer cell growth. This is very encouraging. Dietary approaches have traditionally been thought to be limited to cancer prevention, but this demonstrated it could help slow the growth of existing tumors.”
Ho is also the endowed director of the Moore Family Center of Whole Grain Food, Nutrition and Preventative Health and a principal investigator at OSU’s Linus Pauling Institute. She said, once additional studies are conducted to illuminate more evidence on the effect of sulforaphane and other dietary compounds on cancer growth, they might be administered in conjunction with traditional cancer therapies to prevent cancer, stop its recurrence, or treat it entirely.
This study included 54 women who had abnormal mammograms and were scheduled for a breast biopsy. In the 2-8 week clinical trial, which was randomized, double-blind, and placebo-controlled, women ingested either a supplement that contained sulforaphane equal to one cup of broccoli sprouts or a placebo. Then, the researchers evaluated the chemopreventive effect of sulforaphane on selective biomarkers from blood and breast tissues.
Several studies have previously found that women who eat a lot of cruciferous veggies, such as cabbage, cauliflower, broccoli, or kale, have a lower risk of breast cancer. Sulforaphane, found in large quantities in these types of foods, has been shown to modulate the risk of breast cancer at various stages of carcinogenesis via different mechanisms.
In this study, sulforaphane was demonstrated to inhibit histone deacetylases, or HDACs, which impacts an epigenetic mechanism known as histone deacetylation. The researchers found that sulforaphane reduced HDAC activity along with cancer cell growth. Specifically, they reported that HDAC3 levels were significantly decreased as well as PBMC (peripheral blood mononuclear cell) HDAC activity.
Histone modifications known as histone deacetylation and histone acetylation impact gene expression by removing an acetyl group from histones and adding an acetyl group to histones, respectively. HDAC activity leads to a transcriptionally silenced and condensed chromatin structure known as heterochromatin which reduces gene expression. Typically, tumor suppressor genes are silenced in cancer, but inhibiting HDACs bolsters tumor suppressor gene expression, thereby prohibiting abnormal tumor growth.
Although this research indicates that sulforaphane may be able to impact HDACs and decrease breast cancer growth in early stages, the scientists note, “future studies employing larger sample sizes should evaluate alternative dosing and duration regimens to inform dietary [sulforaphane] strategies in breast cancer chemoprevention.”
Source: Atwell, L.L., Zhang, Z., Mori, M., Farris, P.E., Vetto, J.T., Naik, A.M., Oh, K.Y., Thuillier, P., Ho, E., and Jackilen Shannon (2015). Sulforaphane Bioavailability and Chemopreventive Activity in Women Scheduled for Breast Biopsy. Cancer Prevention Research, 8:1184.
Reference: Oregon State University. Nutrient slowed cancer cell growth in early-stage breast cancer. Oregon State University News & Research Communications. 10 Feb 2016. Web.