Reducing Cancer Risk
Cancer is a group of diseases with complicated risk factors. Approximately 20% to 40% of certain cancers are related to unhealthy diet, physical inactivity and excess body weight.1 The actual contributions of these factors is unknown.
1. Canadian Cancer Society/National Cancer Institute of Canada. Canadian Cancer Statistics 2005. (available at www.cancer.ca) [accessed April 2007].
Conjugated linoleic acid (CLA) is a normal product of metabolism by bacteria in the gut of ruminants like cattle, sheep and goats. A natural trans fat, it has attracted attention because it affects a variety of biological processes, including tumour suppression.1,2
CLA isomers appear to modulate cancer, body composition, body weight, immune function and glucose metabolism in experimental models.3,4
While CLA appears to have anticancer effects in animal and cell culture models, a preventative role for CLA in human cancer is still being determined.5
Encouraging Canadians to eat red meat and dairy products – the two main sources of CLA – as part of a healthy, balanced diet is a prudent approach to ensuring that CLA intakes are maintained.
CLA Content of Beef and Dairy Products a
| Food |
mg CLA/serving |
| Cooked Beef (100 g serving) |
| Rib roast |
78 |
| Ground beef b |
36 |
| Sirloin tip roast |
29 |
| Ground beef, extra lean |
12 |
| Milk (250mL serving) |
| Whole milk |
26 |
| 2% milk |
26 |
| 1% milk |
10 |
| Other Dairy Foods |
| Cheddar cheese (50g serving) |
72 |
| Butter (15g serving) |
64 |
| Yogurt (175g serving) |
43 |
a Values represent the average of four brands of the same product or four samples of the same product from different locations. All products were obtained locally during the Canadian spring and summer months.
b Type of ground beef not specified. Adapted with permission from Ma DWL, Wierzbicki AA, Field CJ and Clandinin MT. Conjugated linoleic acid in Canadian dairy and beef products. J Agric Food Chem 1999; 47:1956-1960. Copyright (1999) American Chemical Society. |
Good to Know
Beef also contains selenium and Vitamin D, nutrients reported to be preventive with respect to cancer.6,7
1. Kemp MQ, et al. J Nutr, 2003; 133: 3670-77.
2. Hubbard NE, et al. Cancer Lett, 2003; 190: 13-19.
3. Whigham LD, et al. Pharmacol Res. 2000; 42:503-510
4. Pariza MW, et al. Prog Lipid Res, 2001; 40:283-298.
5. Belury MA. J Nutr, 2002; 132:2995-2998.
6. Kellen E, et al. Int J Urol 2006 Sep;13(9):1180-4.
7. Brown KM, et al. Public Health Nutr 2001 Apr;4(2B):593-9.
Colorectal Cancer
In Canada, colorectal cancer is the second leading cause of death from cancer in both males and females.1 There are several modifiable risk factors such as smoking, obesity, physical inactivity, heavy alcohol consumption and unhealthy diet.
Evidence linking red meat to colorectal cancer is inconsistent. Some epidemiological studies have suggested that high consumption of red meat is a risk factor for colorectal cancer; however, the relationships in these studies have been weak.2,3
Furthermore, some studies, including clinical trials, have not found an association between red meat consumption and colorectal cancer risk.4,5
In all research linking a dietary factor and a chronic disease, there must be a proposed mechanism that would lead to the development of disease. The results of research linking colorectal cancer to mutagenic compounds (e.g. nitrosamines, heterocyclic amines and polycyclic aromatic hydrocarbons) that may be formed from the processing and preparation (e.g. charring) of red meat are inconsistent.6,7,8,9
The best approach to decrease colon cancer risk is to enjoy a healthy balanced diet that includes lots of vegetables, fruits and whole grains, stay physically active, don’t smoke and reduce alcohol consumption.10,11
Want to know more?
For more information on colorectal cancer research, download Meat and Colorectal Cancer This resource includes a reproducible fact sheet for your clients.
For more information on nutrition and cancer, visit the Canadian Cancer Society.
1. Canadian Cancer Society/National Cancer Institute of Canada. Canadian Cancer Statistics 2006. (available at www.cancer.ca) [accessed April 2007].
2. Truswell AS. Eur J Clin Nutr, 2002; 56(Suppl 1):S19-S24.
3. Norat T, et al. J Natl Cancer Inst, 2005; 97:906-16.
4. Mathew A et al. Eur J Cancer Prev, 2004; 13:159-64.
5. Beresford SAA, et al. JAMA, 2006; 295:643-54.
6. Le Marchand L et al. Mutation Res, 2002; 506-507:205-214.
7 Cross AJ et al. Cancer Res, 2003; 63:2358-60.
8. Kabat GC et al. Br J Cancer, June 5 2007; advance online publication, doi:10.1038/sj.bjc.6603837. http://www.bjcancer.com (accessed June 2007).
9. Cross AJ and Sinha R. Environ Molecular Mutagenesis, 2004; 44:44-45.
10. Canadian Cancer Society. Available at www.cancer.ca
11. Byers T, et al. CA Cancer J Clin, 2002; 52:92-119.