A glass of cancer prevention: 'Got Milk?'
Milk has just added another benefit when it comes to doing the body good
University of Lund researcher’s find that milk just may do the body good in another way; reducing the growth rate of colon cancer cells over time by delaying the period of the cell cycle before chromosomes become duplicated.
View slideshow: Milk good for health
In this new study researchers report treatment with Lfcin4-14 a milk protein, reduces DNA damage in colon cancer cells exposed to ultraviolet light (UV).
For this new study, researchers exposed colon cancer cells to UV light that caused DNA damage and then grew the cells in the absence or presence of Lfcin4-14.
In order to evaluate DNA damage researchers used a technique called comet assay is a sensitive and rapid technique for quantifying and analyzing DNA damage in individual cells. The Comet Assay can be used to detect DNA damage caused by double strand breaks, single strand breaks, alkali labile sites, oxidative base damage, and DNA cross-linking with DNA or protein and also used to monitor DNA repair by living cells.
After the cells are processed, the cells with DNA damage look similar to that of a comet with a tail and the intensity of the tail compared to the comet head indicates the number of DNA breaks. UV light exposure had produced the number of comets while treatment with Lfcin4-14 reduced the number of comets in UV light-exposed cells.
To understand the mechanism by which Lfcin4-14 reduced DNA damage, investigators evaluated the levels of several proteins involved in cell cycle progression, DNA repair, and cell death and found an increase in flap endonuclease-1, a protein associated with DNA synthesis; a decrease in b-cell lymphoma 2-associated X protein, which is involved with cell death; and a decrease in the level of g-H2AX, indicating more efficient DNA repair.
Professor Stina Oredsson, of the Department of Biology stated in a release "These changes in expression support our hypothesis that Lfcin4-14 treatment resulted in increased DNA repair.”
Dr. Oredsson notes that cancer cells, in general, have defects in the DNA repair mechanisms. Thus, Lfcin4-14 may have a greater effect on normal cells than on cancer cells. Oredsson concludes "Our data suggest that the effects of Lfcin4-14 in prolonging the cell cycle may contribute to the cancer preventive effect of milk. This must be further investigated in different systems.”
This study was published in the Journal of Dairy Science.
A study that appeared in the Journal of the National Cancer Institute, led by Eungyoung Cho Sc.D., assistant professor of medicine, Harvard Medical School along with fellow associates pooled the primary data from 10 cohort studies in five countries that assessed usual dietary intake by using a validated food frequency questionnaire at baseline.
The studies included 534 536 individuals, among whom 4992 incident cases of colorectal cancer were diagnosed between 6 and 16 years of follow-up.
The results had shown that milk intake was related to a reduced risk of colon cancer.
In conclusion researchers had written “Higher consumption of milk and calcium is associated with a lower risk of colorectal cancer.”
Milk also has been found to reduce the risks of breast, uterine and lung cancers.