flying coffee
Moderate coffee consumption is linked to reduced depression risk and lower levels of Parkinson's and dementia, new research finds.

Not only that, but the review of more than 200 studies found that drinking 3 to 4 cups of coffee a day is linked to many other benefits.

These include lower levels of heart disease, reduced risk of some cancers, diabetes and liver disease.

The study's authors write:
"Coffee consumption was consistently associated with a lower risk of Parkinson's disease, even after adjustment for smoking, and across all categories of exposure.

Decaffeinated coffee was associated with a lower risk of Parkinson's disease, which did not reach significance.

Consumption had a consistent association with lower risk of depression and cognitive disorders, especially for Alzheimer's disease."
Coffee was also associated with a lower risk of several cancers:
  • prostate cancer,
  • endometrial cancer,
  • skin cancer,
  • and liver cancer,
Risk of type 2 diabetes, gallstones and gout was lower in those drinking coffee as well.

Coffee's apparent effect was particularly strong for liver conditions, such as cirrhosis.

The evidence for drinking decaffeinated coffee was not as strong.

So, if you don't drink coffee already, should you start?

Writing in a linked commentary, Professor Eliseo Guallar, an expert in public health, gives the answer:
"Should doctors recommend drinking coffee to prevent disease?

Should people start drinking coffee for health reasons?

The answer to both questions is "no." "
But if you do already drink coffee, then how much should you drink?

Professor Guallar explained:
"...the lowest risk of disease is associated with drinking three to five cups of coffee a day.

Higher intake may reduce or reverse the potential benefit, and there is substantial uncertainty, both in individual studies and in meta-analyses, about the effects of higher levels of intake.

Conclusions on the safety of coffee should thus be restricted to moderate intake, generally considered as ≤400 mg of caffeine a day (about four or five coffee drinks)."
The research was an 'umbrella review' which is a kind of review of the reviews.

It aggregates data from lots of different studies including many participants.

However, the way the studies were designed, it cannot tell us that drinking coffee causes these health benefits.

It just tells us there is a link to be explained.

The study was published in The British Medical Journal (Poole et al., 2017).