Coffee is a beverage enjoyed by millions of people and it is a valuable economic commodity. Coffee is prepared from roasted coffee beans, which are the seeds of the berries from the Coffea plant. Coffee has a stimulating effect because of its caffeine content.
The general consensus is that moderate coffee drinking does no harm. In addition, there are some studies that suggest coffee does people some good; however, there are also some studies that suggest coffee can have negative health effects. Let’s look at the evidence.
There are some general concerns about hot drinks voiced by the World Health Organization. This is connected with cancer and applies to all very hot drinks.
There is, however, no direct link between coffee and an increased risk of cancer. In 2016, the International Agency for Research on Cancer (IARC) reviewed some 1000 human and animal studies and concluded that there was no evidence that coffee has a substantial effect on the risk of developing cancers of the pancreas, bladder, prostate or breast. With other cancers, such as bowel, oesophageal, lung and stomach cancer, there was no conclusive evidence either way.
A website called ‘Health Ambition’ raises concerns about bloating and ulcer risks, but no links to peer reviewed papers are provided. More science-based was a general concern was voiced a year or so ago about coffee drinking. The study produced statistics like “men under 55 who drank at least 28 cups of coffee per week were 56 percent more likely to have died during the study than men who drank less.” However, this was born more out of correlation than causation.
However, research published since then has come to a different conclusion. Here a paper published in the New England Journal of Medicine found that coffee drinkers “who drank at least two or three cups a day were about 10 percent or 15 percent less likely to die for any reason during the 13 years of the study.”
A further risk is an association with a high consumption of unfiltered coffee (boiled or espresso) and mild elevations in cholesterol levels. Here researchers from Baylor College of Medicine found that cafestol, a compound found in coffee, elevates cholesterol by hijacking a receptor in an intestinal pathway critical to its regulation. However, the association is connected with a relatively high daily intake.
Other risks refer to disruption to the body clock (circadian rhythms) and over consumption, but these do not relate to the drink itself, more to careful use.
So, with the few studies that suggest coffee causes harm, there is competing literature that suggests this is not the case.
In favor of coffee comes a new study, from Ulster University and published in the journal Comprehensive Reviews in Food Science and Food Safety (“A Comprehensive Overview of the Risks and Benefits of Coffee Consumption”), suggests benefits of moderate coffee drinking outweigh the risks.
Scientists reviewed 1,277 studies from 1970 to-date on coffee’s effect on human health. This meta-analysis discovered that there was no evidence of coffee causing harm in relation to:
Mortality
Cardiovascular disease
Cancer
Metabolic health
Neurological disorders
Gastrointestinal conditions
And there was moderate evidence that there might be some beneficial health effects.
Further in terms of benefits, there are some clinical studies which suggest that moderate coffee consumption is mildly beneficial in healthy adults. Here coffee could help to inhibit cognitive decline during aging. Moreover, coffee drinking may lower the risk of some forms of cancer.
A further finding indicates that drinking coffee on a regular basis lowers the risk of developing cirrhosis of the liver. These findings were published in the journal Alimentary Pharmacology and Therapeutics (“Systematic review with meta-analysis: coffee consumption and the risk of cirrhosis.”) This is perhaps because coffee contains anti-oxidative and anti-inflammatory agents. In addition, there could be lower incidences of primary sclerosing cholangitis (PSC) associated with higher coffee consumption.
Furthermore, the European Science Foundation has discovered that regular coffee consumption is associated with a lower incidence of diabetes; and a Swedish study has reported that breast cancer rates are lower with frequent coffee drinking.
The consensus of the literature suggests coffee does not do any serious harm, and it may do some good – provided coffee is drunk in moderation. This is based on the current balance of medical and scientific literature. In relation to this, American Heart Assoc (@American_Heart) tweeted this week: “Moderate coffee consumption linked to a reduced risk of coronary heart disease & stroke.” This prompted coffee writer Sandra Balzo (@SandraBalzo) to message: “Not that I need a reason to drink #coffee, but there are 17 health benefits!”
This article is part of Digital Journal’s regular Essential Science columns. Each week we explore a topical and important scientific issue. Last week we considered a new study that indicated supplementing the diet of people with metabolic syndrome with resistant starch helps to improve the condition. This happens by altering gut bacteria. The week before we traced how West Nile virus is leading to memory loss due to a change with the immune system.
