There has been much talk regarding the benefits of Aspirin in preventing the spread of cancer. So what is creating this health storm?
The publication of a collection of three papers (two published in The Lancet and one in The Lancet Oncology) add to the growing evidence base suggesting that daily aspirin can be used to help prevent cancer and, now we understand, may reduce the growth of cancer.
The articles confirmed previous findings of the preventative effect that aspirin may have. The studies that these researchers look at showed a 38% reduced risk of colorectal cancer, matching well to the 42% reduction shown by randomised trials. Similar matches in risk were found for oesophageal, gastric, biliary, and breast cancer.
However the big hoo-ha that has received media coverage in the last week is the confirmation that aspirin may be an effective treatment in preventing the metastasis (or spreading) of some cancers, as well as the mechanism by which it works.
What did they find?
Two of the three published papers in The Lancet report the effect of aspirin (75mg daily) on cancer metastasis (the growth or spreading of cancer). The researchers found that, after an average follow-up time of 6.5 years, those patients in the studies with cancer that took the aspirin reduced their risk of distant metastasis (cancer that has spread away from its original area into other areas of the body) by 36%. It also confirms the mechanism by which metastasis grows by illustrating that platelets play a part in the spread of cancer via the bloodstream to distant tissues, and that such metastasis might be prevented by aspirin. Platelets are components of the blood that, when they become sticky, may clog up and create blood clots, which if near the brain can cause a stroke or, if near the heart, can prevent sufficient oxygen-rich blood reaching the heart, causing a heart attack.
What do I think?
As the mechanism by which aspirin works is by reducing the platelet stickiness then perhaps more natural products that share this action may too have a similar effect on risk of metastasis. Omega-3 oils from fish or flaxseed oil have been shown to reduce the platelet aggregation for example. The Western diet, including vegetarian diets, usually provides a disproportionate amount of omega-6 fatty acids. For example, the typical Western diet often includes an omega-6 to omega-3 fatty acid ratio of 20-30:1 (ideal ratio is 4:1). There is some concern that a diet high in omega-6 fatty acids can lead to long-chain omega-3 fatty acid deficiency and produce a physiological state that is favourable for platelet stickiness and clot formation. Increasing your intake of omega-3 fats (oily fish, nuts, seeds and their oils) may reduce the risk of heart disease and, in light of recent research, perhaps reduce cancer metastasis too.
Garlic comes up trumps at reducing blood stickiness too. Men in China who eat garlic 2.14 grams/day (about one clove) seem to have a 50% lower risk of developing prostate cancer. Whether this benefit is applicable to men in Western countries is not known. Additional preliminary evidence suggests that taking garlic supplements might also decrease the risk of developing prostate cancer. Several population studies suggest that increased dietary intake of raw and cooked garlic can decrease risk of developing colorectal cancer at doses from 3.5 grams per week. Garlic powder and aged garlic preparations have been shown to have antiplatelet properties at 7.2 grams per day. You might want to warn your friends!
I hope that one day scientists may be given the funding and opportunity to explore benefits of the natural wonders around us that may also have the potential to prevent the development and the progression of cancer. If figures published by WHO are to be believed we certainly need all the awareness we can get; cancer rates are estimated to increase by 50% to 15 million new cases in the year 2020. I know what I am having for supper tonight…
Word of warning: Garlic and Omega 3 oils DO WORK and for this reason it is not recommended to take either of these in high doses (more than 2g of garlic or 2g of omega 3) in conjunction with anti-platelet medication such as warfarin or aspirin unless recommended by a medical practitioner.
For more on Omega 3 and the role it plays see 'What makes Omega 3 essential?' and 'Not all fats are created equal'
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Fleischauer AT, Poole C, Arab L. Garlic consumption and cancer prevention: meta-analyses of colorectal and stomach cancers. Am J Clin Nutr 2000;72:1047-52.
Steiner M, Lin RS. Changes in platelet function and susceptibility of lipoproteins to oxidation associated with administration of aged garlic extract. J Cardiovasc Pharmacol 1998;31:904-8.
Steiner M, Li W. Aged garlic extract, a modulator of cardiovascular risk factors: a dose-finding study on the effects of AGE on platelet functions. J Nutr 2001;131:980S-4S.