Some people are sensitive to caffeine, but there never was any evidence that (in moderation) it “exhausts the adrenal glands” ... a common claim.
Nor are claims that coffee raises levels of the stress hormone cortisol backed by consistent evidence, with some studies finding that it lowers cortisol levels.
Coffee is rich in the polyphenol-type “antioxidants” that make berries, tea, cocoa, onions, and colorful fruits and vegetables so healthy.
In fact, coffee is the richest sources of polyphenols in the average American’s diet, and ranks very high among sources of chlorogenic acids, which are some of the most beneficial polyphenols known.
Coffee's documented benefits
A growing body of evidence shows that coffee – and caffeine – offer very real health benefits, including lower risk of premature death, and reduced risk of cardiovascular disease (Ding M et al. 2013; Je Y et al. 2013).
For example, see “Coffee May Curb Breast Cancer”, “Coffee and Tea Aid Livers and Prostate”, “Coffee Linked to Extreme Longevity”, “Caffeine May Curb Diabetes”, and “Caffeine May Boost Brain Power and Deflect Dementia”.
Caffeine may induce antioxidant effects in the body, and it’s already been proven beneficial to brain function, memory, and concentration, and improve symptoms in Alzheimer's patients (León-Carmona JR et al. 2011; Nehlig A 2013).
In fact, the results of a clinical study published this month show, for the first time, that caffeine enhances human memory substantially for at least 24 hours after it's consumed (Borota D et al. 2014).
Harvard studies found that men and women who drank one to four cups of caffeinated coffee daily were 58 percent less likely to develop Parkinson's disease (Ascherio A et al. 2001; Palacios N et al. 2012).
Likewise, they found that drinking two to five cups of coffee daily cut the risk of diabetes sharply (Campos H et al. 2007; van Dam RM 2008; Wedick NM et al. 2011).
Liver cancer: A rising risk
Liver cancer is the sixth most common type, and the third leading cause of cancer death, worldwide.
A type called hepatocellular carcinoma or HCC accounts for more than 90 percent of cases, and is linked to hepatitis B and C infections, alcohol, tobacco, obesity, and diabetes.
Rates of HCC continue to rise in the United States, especially among white men aged 45 to 54 years of age … which may be explained by hepatitis C infections acquired during the 1960s and 1970s (El-Serag HB et al. 2004).
Now, research from Italy suggests that coffee may reduce the risk of HCC, very substantially.
Coffee may curb the most common liver cancer
According to an evidence review from Italy, drinking coffee daily may reduce the risk of hepatocellular carcinoma (HCC), by about 40 percent (Bravi F et al. 2013).
Further, some evidence indicates that drinking three cups of coffee per day reduces liver cancer risk by more than 50 percent.
“Our research confirms past claims that coffee is good for your health, and particularly the liver,” said co-author Carlo La Vecchia, MD, from Italy’s University of Milan.
As he noted, “The favorable effect of coffee on liver cancer might be mediated by coffee’s proven prevention of diabetes, a known risk factor for the disease, or for its beneficial effects on cirrhosis and liver enzymes.” (AGA 2013)
The Italian team performed a meta-analysis (review) of articles published from 1996 through September 2012. They found 16 high-quality epidemiological studies, covering 3,153 cases of HCC.
The results possess considerable credibility, thanks to consistent results across studies, time periods and populations.
However, epidemiological studies cannot prove whether an association between a food or nutrient and reduced disease risk is causal.
The researchers said that the apparent link could in part be due to the fact that patients with liver diseases often reduce their coffee intake.
“It remains unclear whether coffee drinking has an additional role in liver cancer prevention,” added Dr. La Vecchia. “But, in any case, such a role would be limited as compared to what is achievable through the current measures.” (AGA 2013)
Primary liver cancers are largely avoidable through hepatitis B vaccinations, control of hepatitis C transmission, and cutting back on booze.
These three measures could, in principle, prevent more than 90 percent of liver cancers worldwide.
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