Drinking real coffee, rather than instant, has been shown in multiple studies to reduce the risk of cancer; while caffeine may be a benefit, two polyphenol diterpenes, cafestol and kahweol, and chlorogenic acid, also provide benefits; coffee also has antioxidant and anti-inflammatory benefits, although it can increase blood cholesterol levels.
Coffee and Liver cancer
Drinking coffee reduces the risk of Liver cancer in a ‘dose-dependent manner – the more you drink, the more it reduces risk.
Researchers from the University of Southampton and the University of Edinburgh have found that this applies to both caffeinated coffee and (to a lesser extent) decaffeinated coffee. And the research was no small study – it was a meta-analysis of 26 previous studies involving more than 2 million people in total (1). 5 cups a day halved risk, 3 cups reduced in by 35 per cent and just one cup reduced risk by 20 per cent.
So, it would seem caffeine may play a minor role but other bioactive compounds must be at work.
Coffee polyphenols, Cafestol and Kahweol, have many benefits
Coffee beans contain the polyphenol diterpines, Cafestol and Kahweol, but of which are oils. Cafestol is found in both Robusta and Arabica beans. Kahweol is found in Arabica only.
First, let us explore a potential concern. In Dutch research from 1997 (2) with humans over a 28 day period, both diterpines raised levels of cholesterol, LDL, and triglycerides, although cafestol showed the stronger response. Figures where both were involved rose 0.23, 0.23 and 0.09 mmol/L respectively.
However, the benefits of the diterpines are significant. In a Chinese 2019 review (3), in vitro and in vivo studies show that the two polyphenols have anti-inflammatory, anti-diabetic, and anti-cancer properties as well as protecting bone osteoclasts (so coffee might help protect bones from the effects of drugs such as Letrozole and Denosumab). These two diterpenes have been shown to reduce inflammatory factors, reduce blood supply formation to cancer cells and cause cancer cell death (apoptosis).
This same review also concluded that coffee does seem to protect the liver. This was confirmed in a 2017 review', The Magical bean for liver diseases' by researchers at the University of Missouri (4). They reviewed past research studies showing that coffee drinkers had lower rates if cirrhosis than non-coffee drinkers; and that coffee consumption was associated with decreased levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyltransferase (GGT), and alkaline phosphatase (ALP).
Coffee, Chlorogenic Acid and anti-aging
There is another compound in coffee offering significant health benefits - chlorogenic acid is an ester of caffeic acid and quinic acid. It is in higher levels in organic coffee, and in green beans. In a 2023 study, it appears to improve longevity and have anti-aging benefits. In part, this may be because chlorogenic acid appears to lower blood glucose and insulin (5). Another study (6) showed is was protective of vascular senescence,
In a randomised, double blind, placebo controlled trial, chlorogenic acid was also seen to improve cognitive function (7).
Coffee and cancer
Apart from Liver benefits, what other benefits are there? The same review above (4) reports that real coffee has been associated with improved outcomes in colorectal cancer, esophageal cancer, breast cancer, prostate cancer, pancreatic cancer, ovarian cancer, kidney cancer, hepatitis B virus (HBV), hepatitis C virus (HCV), and non-alcoholic fatty liver disease (NAFLD). Let's look at one of these:
Coffee and Prostate cancer
A study in May 2011 by the Harvard School of Public Health (8) showed that drinking real coffee reduced the risk of an aggressive, lethal form of prostate cancer – and this was true whether it was caffeinated or decaffeinated. So again, its not just the caffeine that's ar work.
Coffee and Kidney disease
in 2022, Johns Hopkins Medicine researchers showed (9) that those who drank any quantity of real coffee every day had a 15% lower risk of acute kidney injury (AKI), and those who drank two to three cups a day had a 22%–23% lower risk. This should allay some of the Internet concerns over coffee and kidney damage.
From the Johns Hopkins Medicine website - “We already know that drinking coffee on a regular basis has been associated with the prevention of chronic and degenerative diseases including type 2 diabetes, cardiovascular disease and liver disease,” says study corresponding author Chirag Parikh, M.D., Ph.D., director of the Division of Nephrology and professor of medicine at the Johns Hopkins University School of Medicine. “We can now add a possible reduction in AKI risk to the growing list of health benefits for caffeine.”
Coffee - overcoming the concerns
Chris Woollams, former Oxford University Biochemist and Founder of CANCERactive said, “Coffee is a complex mix of bioactive natural compounds like flavonoids, phenols and the diterpenes – the latter having strong cancer-correcting epigenetic properties. Core ingredients of real coffee have been shown to have anti-inflammatory, antioxidant, insulin-regulating, longevity and anti-cancer benefits. Only some of the benefit seemed linked to caffeine. We also know that with real coffee consumption, 4-5 cups a day reduces Parkinson’s risk and type-2 diabetes risk. Contrary to popular belief, there may even be benefits against cardiovascular disease.
However, in several studies, but certainly not all, coffee consumption has been shown to increase plasma Homocysteine levels. And this is one reason why all the above benefits have a little cloud of confusion hanging over them. Higher blood levels of homocysteine are associated with higher levels of chronic illness - from cardiovascular disease to cancer; and from dementia to osteoporosis. You could, of course take a fish oil and a B-complex a day to lower levels just to be safe."
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References
8. Coffee Consumption and Prostate Cancer Risk and Progression in the Health Professionals Follow-up Study,” Kathryn M. Wilson, Julie L. Kasperzyk, Jennifer R. Stark, Stacey Kenfield, Rob M. van Dam, Meir J. Stampfer, Edward Giovannucci, Lorelei A. Mucci, Journal of the National Cancer Institute, online May 17, 2011.