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New Study to Investigate Shift Work-Cancer Link

Through a new study, researchers at the Cancer Institute of New Jersey (CINJ) hope to learn whether shift work predisposes employees to cancer by altering the body’s response to hormones, and if so, whether a dietary supplement can help.

Helmut Zarbl, Ph.D., associate director for Public Health Science at CINJ and professor of toxicology at UMDNJ-Robert Wood Johnson Medical School in the area of cancer prevention and circadian rhythms, will lead the study. Circadian rhythms are best described as one’s “body clock,” which controls sleep, hunger, hormones, and activity among other things in all living cells.

According to Zarbl, epidemiological studies consistently have shown that women and men, who serve the community by working at night, have a significantly elevated risk of breast cancer and possibly prostate cancer. In fact, shift work that alters circadian rhythm is now classified as a probable carcinogen by the International Agency for Research Cancer.

Dietary MSC

Zarbl and his team recently found that chemical carcinogens also disrupt circadian rhythm, leading to what he considers an imbalance in a protein that prevents cancer by regulating the cell’s response to hormones. More importantly, they found that a naturally occurring compound, methylselenocysteine (MSC), found in many foods, prevents cancer in rats by restoring circadian rhythm and the cell’s response to estrogens. MSC contains the trace mineral selenium, which a number of epidemiological studies have shown can reduce the incidence of several types of cancer.

During the course of the 3-year grant period, the team will determine if shift work also disrupts the cell’s response to estrogens, and if this effect can be reversed by dietary MSC. The team will address these questions in two groups of participants. The first group, comprised of primarily hospital workers, will be asked to donate blood while working the day shift, and again after working at least 1 week on the night shift. This group will determine the effect of shift work on various biomarkers related to circadian rhythm and estrogen response.

In the second phase of the study, 100 volunteers who engage in traditional “shift work” professions, such as firefighters, police, airline and factory personnel, will be recruited through the New Jersey Family Medicine Research Network. For 30 days, this group will take an over-the-counter MSC supplement. Blood taken from these study participants will be used to determine if the MSC supplement can reverse the harmful effects of shift work on circadian rhythms and estrogen response. If so, the results will form the basis for a prospective study to determine if MSC supplements can prevent breast and prostate cancer in those who serve the community by working at night.

Far-Reaching Implications

CINJ recently received a $600,000 grant from The V Foundation for Cancer Research to support the study.

“The V Foundation has long been committed to unlocking the mysteries of cancer through the funding of novel research,” Zarbl said. “Through their generous support of this translational study, we have an opportunity to determine whether a supplementation of the diet with the amount of MSC found in a single Brazil nut can prevent two of the most common forms of cancer. The implications from such findings could be far reaching.”

“We’re very excited about this project,” added Nick Valvano, CEO of The V Foundation for Cancer Research. “Through this important research, we’re working toward a future where we can help people by preventing breast and prostate cancers.”

TAGS: Archive Health
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