Coffee: The highs and lows.
Have you had a cup of coffee this morning? I bloody well have. I struggle without a morning cup of coffee, and I love being that douchebag in a café asking for an oatmilk flat white. I went onto decaffeinated coffee during my treatment (decaf, oatmilk, flat white has even more of a douchey ring to it), and then looked into the evidence as to whether caffeine is good or bad in terms of cancer risk and chemotherapy.
Why did I stop drinking caffeine? (Well, technically just reduce my intake as decaffeinated coffee still has caffeine in it - but only about 10% compared to the full fat stuff.) Because I thought my body would be going through enough with the chemotherapy that I didn’t want to throw anything else at it.
So let’s start with cancer risk first…
The IARC (International Agency for Research on Cancer) look at all things cancer related and determine whether certain things, such as caffeine consumption can cause cancer.
In 1991 - they felt that the evidence suggested that coffee “was probably” carcinogenic.
However, they have since revisited this guidance and have downgraded coffee to “unclassifiable” meaning “we don’t know”. This is relating to coffee and ALL types of cancer.
There has been evidence to suggest that it is UNLIKELY to cause certain types of cancer including breast and pancreas.
Several studies have shown that it REDUCES the risk of liver and endometrium (lining of the womb) cancers. It also appears to reduce the risk of prostate cancer in men. See study here about prostate cancer risk.
For many other forms of cancers the scientists are unable to make any specific conclusions, the evidence is not strong enough either way. It also seems to vary depending on if it’s instant or brewed coffee.
The general consensus is that hot drinks, drank at over 65’C can increase your risk of oesophageal (food pipe) and mouth cancers. This is due to burning of the inside of your mouth and throat which increases the risk. See study here.
However coffee does seem to reduce your risk of death from lots of different causes - particularly regarding cardiovascular (heart) and digestive (gut) health. See article here.
There have also been reports of acrylamide which is produced in the roasting process of coffee beans causing cancer. This is not only found in coffee but in foods that contain a lot of starch when they are cooked at high temperatures, for example chips, crisps, crackers, bread etc.
Research looking at humans and the consumption of acrylamide has not shown an increased risk of cancer. There is advice out there to try and limit your intake of foods that contain a lot of it.
Now let’s look at drinking coffee whilst on chemotherapy…
There does appear to be some evidence that it can help INCREASE the toxic effects of some chemotherapy against certain types of cancer. Click here for an interesting article about triple negative breast cancer and cisplatin. See links below for other articles regarding chemotherapy and other forms of cancer.
However it also may DECREASE the effectiveness of some types of chemotherapy. This study suggests that paclitaxel is less effective with caffeine.
In summary…
There is a lot of conflicting evidence out there, more research needs to be done to look into coffee/caffeine and it’s effects, both positive and potentially negative.
If you’re already drinking coffee - I think the key is moderation, a bonus is that it might reduce your risks of certain types of cancer.
If you’re not drinking coffee - I don’t think there’s enough evidence to suggest you should start just for anti cancer benefits.
Here are some really useful websites…
Info on cancer and coffee.
Info on cancer and coffee.
Info on cancer and coffee.
An umbrella review of meta-analyses of observational studies regarding coffee and cancer.
Really interesting study on caffeine and cisplatin (a chemo drug), combining the 2 seems to kill the cancer cells (specifically in triple negative breast cancer) more effectively.
Prostate cancer and coffee.
Interesting study on coffee and colorectal cancer outcomes.
Study on caffeine and chemo for sarcoma.
Info on acrylamide.