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Is Coffee Good for You by James Hoffmann

Health Benefits and Associations​

Scientific studies, primarily meta-analyses and nutritional epidemiology, have found several positive associations with moderate coffee consumption (around 3 to 4 cups a day):

  • All-Cause Mortality: Drinking coffee has been associated with a reduction in all-cause mortality (e.g., one study showed a 16% reduction for four cups a day)
  • Cardiovascular Disease: There is a strong association between 3 to 4 cups of coffee per day and a reduction in cardiovascular heart disease (e.g., one study showed a 21% reduction).
  • Cognitive Performance: Coffee drinking has been associated with a lower incidence of mental decline and impairment in elderly populations.
  • There is also an association with a lower incidence of diseases like Alzheimer's and Parkinson's.
  • Cancer: Studies have generally found no relationship between drinking coffee and a higher incidence of cancer. Some studies showed a reduced incidence of liver and kidney cancers.
  • Exercise Performance (Caffeine): A dose of 3 to 6 milligrams of caffeine per kilo of body weight is well-established to have a measurable, though relatively minor, impact on improving endurance and peak power output in athletes.

Coffee and the Gut​

Coffee contains beneficial compounds that interact with the gut microbiome:

  • Polyphenols (Antioxidants): These defence chemicals, such as chlorogenic acids, are found in coffee and act as antioxidants.
  • To maximise polyphenols, use fresher coffee (polyphenols dropped 85% after a year in one study) and opt for lighter roasts.
  • Fibre: A typical cup of filter coffee can contain up to two grams of fibre.

Potential Concerns and Caveats​

  • Sleep Interference: Coffee's half-life is about five hours, meaning it can take up to 12 hours to fully clear your system, potentially leading to delayed sleep onset or lower sleep quality. Individuals are either fast or slow caffeine metabolisers, making the effects variable.
  • Brewing Method and Cholesterol: A 2020 Norwegian study found that filtered coffee had an association with lower heart disease, but unfiltered coffee (French press, espresso) did not find the same association.
  • This is speculated to be due to cafestol and kahweol, two oils in coffee that raise serum cholesterol and are mostly removed by paper filters.
  • However, an Italian study looking at espresso (unfiltered) found similar positive associations for 3–4 cups a day.
  • GERD (Reflux): Coffee can be an acidic trigger for gastroesophageal reflux disease (GERD). Hot brewed coffee has been found to be more acidic than cold brew, and to contain more polyphenols/antioxidants.
  • Carcinogens (Acrylamide and Mycotoxins):
    • Acrylamide, a known carcinogen, is found in coffee but at very low levels (lower than french fries). Darker roasts tend to have less acrylamide.
    • Mycotoxins (toxins produced by mold) are found at very low levels in green coffee and are mostly destroyed during the roasting process.