Many epidemiological studies have shown that diets rich in cruciferous vegetables reduce the risk of developing chronic diseases including some forms of cancer and heart disease. Some studies have shown that cruciferous vegetables may reduce the risk of prostate cancer [i], bladder cancer [ii], breast cancer [iii] and other conditions.
Cohort studies have shown some protection against cardiovascular disease from cruciferous vegetables [iv] as well as prostate cancer [v] [vi] and others. In addition, a number of ‘meta-analyses’ have attempted to combine many of the different studies undertaken by different research groups around the world to give an overview. Meta-analyses have provided evidence that cruciferous vegetables reduce the risk of colon cancer [vii] , prostate cancer [viii] and breast cancer [ix]
The strongest evidence for health-protecting effects of eating certain foods comes from Human Intervention Trials. Professor Mithen has conducted a small-scale human intervention trial to fill in gaps between observational studies [x] in men at risk of developing prostate cancer and showed there were more positive changes in gene expression amongst men who were on the broccoli-rich diet, and these changes may be associated with the reduction in the risk of developing prostate cancer. Additionally he has conducted a much larger study, funded by the Prostate Cancer Foundation looking at the protective effects of broccoli consumption against prostate cancer [xi].
This research using high glucoraphanin broccoli has shown that it ‘re-tunes’ metabolic processes in our cells linked to health outcomes. In further studies, published in 2015, show that a diet rich in high glucoraphanin broccoli reduced blood LDL cholesterol levels. Two independent dietary intervention trials showed that people eating 400g of high glucoraphanin broccoli saw an average reduction of 6% in the LDL cholesterol after 12 weeks [xii].
List of References
[i] Joseph, M. A., K. B. Moysich, J. L. Freudenheim, P. G. Shields, E. D. Bowman, Y. Zhang, J. R. Marshall, and C. B. Ambrosone. “Cruciferous Vegetables, Genetic Polymorphisms in Glutathione S-Transferases M1 and T1, and Prostate Cancer Risk.” Nutr Cancer 50, no. 2 (2004): 206-13. http://dx.doi.org/10.1207/s15327914nc5002_11
[ii] Lin, J., A. Kamat, J. Gu, M. Chen, C. P. Dinney, M. R. Forman, and X. Wu. “Dietary Intake of Vegetables and Fruits and the Modification Effects of Gstm1 and Nat2 Genotypes on Bladder Cancer Risk.” Cancer Epidemiol Biomarkers Prev 18, no. 7 (Jul 2009): 2090-7. http://dx.doi.org/10.1158/1055-9965.EPI-08-1174
[iii] Fowke, J. H., Chung, F. L., Jin, F., Qi, D., Cai, Q., Conaway, C., Cheng, J. R., Shu, X. O., Gao, Y. T. and Zheng, W. (2003) “Urinary Isothiocyanate Levels, Brassica, and Human Breast Cancer ” http://cancerres.aacrjournals.org/content/63/14/3980.full
[iv] Joshipura, K. J., A. Ascherio, J. E. Manson, M. J. Stampfer, E. B. Rimm, F. E. Speizer, C. H. Hennekens, D. Spiegelman, and W. C. Willett. “Fruit and Vegetable Intake in Relation to Risk of Ischemic Stroke.” JAMA 282, no. 13 (Oct 6 1999): 1233-9. http://dx.doi.org/10.1001/jama.282.13.1233
[v] Kirsh, V. A., U. Peters, S. T. Mayne, A. F. Subar, N. Chatterjee, C. C. Johnson, R. B. Hayes, Lung Colorectal Prostate, and Trial Ovarian Cancer Screening. “Prospective Study of Fruit and Vegetable Intake and Risk of Prostate Cancer.” J Natl Cancer Inst 99, no. 15 (Aug 1 2007): 1200-9. http://dx.doi.org/10.1093/jnci/djm065
[vi] Richman, E. L., P. R. Carroll, and J. M. Chan. “Vegetable and Fruit Intake after Diagnosis and Risk of Prostate Cancer Progression.” Int J Cancer 131, no. 1 (Jul 1 2012): 201-10. http://dx.doi.org/10.1002/ijc.26348
[vii] Wu, Q. J., Y. Yang, E. Vogtmann, J. Wang, L. H. Han, H. L. Li, and Y. B. Xiang. “Cruciferous Vegetables Intake and the Risk of Colorectal Cancer: A Meta-Analysis of Observational Studies.” Ann Oncol 24, no. 4 (Apr 2013): 1079-87. http://dx.doi.org/10.1093/annonc/mds601
[viii] Liu, B., Q. Mao, M. Cao, and L. Xie. “Cruciferous Vegetables Intake and Risk of Prostate Cancer: A Meta-Analysis.” Int J Urol 19, no. 2 (Feb 2012): 134-41. http://dx.doi.org/10.1111/j.1442-2042.2011.02906.x
[ix] Liu, X., and K. Lv. “Cruciferous Vegetables Intake Is Inversely Associated with Risk of Breast Cancer: A Meta-Analysis.” Breast 22, no. 3 (Jun 2013): 309-13. http://dx.doi.org/10.1016/j.breast.2012.07.013
[x] Armah, C. N., Traka, M.H., Dainty, J.R., Defernez, M., Astrid Janssens, Leung, W., Doleman, J., Potter, J.F., and Mithen, R.F. A diet rich in high glucoraphanin broccoli interacts with genotype to reduce discordance in plasma metabolite profiles through modulating mitochondrial disfunction, Am J Clin Nutr 2013 98: 712-722 doi: 10.3945/ajcn.113.065235
[xi] Traka MH, Melchini A, Coode-Bate J, Al Kadhi O, Saha S, Defernez M, Troncoso-Rey P, Kibblewhite H, O’Neill CM, Bernuzzi F, Mythen L, Hughes J, Needs PW, Dainty JR, Savva GM, Mills RD, Ball RY, Cooper CS, Mithen RF. Transcriptional changes in prostate of men on active surveillance after a 12-mo glucoraphanin-rich broccoli intervention-results from the Effect of Sulforaphane on prostate CAncer PrEvention (ESCAPE) randomized controlled trial. Am J Clin Nutr. 2019 Apr 1;109(4):1133-1144. doi: 10.1093/ajcn/nqz012.
[xii] Armah, C.N. et al A diet rich in high glucoraphanin broccoli reduces plasma LDL cholesterol: evidence from randomised controlled trials”, Molecular Nutrition and Food Research DOI 10.1002/mnfr.201400863