Three or four cups of coffee a day does you more good than harm

by Robin Poole / 29 November, 2017

Help us find and write the stories Kiwis need to read

Who can resist a decent flat white? Now, what about if it's also good for you? Photo / Getty Images

Drinking moderate amounts of coffee – about three or four cups a day – is more likely to benefit our health than harm it, our latest research shows. This is important to know because around the world over two billion cups of coffee are consumed every day.

Earlier studies have suggested beneficial links between coffee drinking and liver disease. Our research group has an interest in liver conditions. As such, we had previously conducted two meta-analyses, one looking for links between coffee drinking and cirrhosis and another at coffee drinking and cancer of the liver. We found that there was a lower risk of both conditions in people who drank more coffee.

Most of the evidence, however, is from observational studies, which can only find probable associations but can’t prove cause and effect. To overcome these limitations, we plan to conduct a randomised controlled trial in patients with non-alcoholic fatty liver disease to see if coffee works as a treatment to reduce the risk of the disease progressing.

But before we can start giving coffee to patients, we needed to know whether coffee drinking had any recognised harms, so we decided to conduct an umbrella review to capture as much important information about coffee drinking and health as we could. Umbrella reviews combine previous meta-analyses and give a high-level summary of research findings.

Many benefits

Overall, our umbrella analysis showed that drinking coffee is more often linked with benefits than harms. For some conditions, the largest benefit appeared to be associated with drinking three to four cups of coffee each day. This included lower risk of death from any causes, or getting heart disease. Drinking coffee beyond these amounts was not associated with harm, but the benefits were less pronounced.

Drinking coffee was also associated with a lower risk of developing type 2 diabetes, metabolic syndrome, gallstones, renal stones and gout. We also found that it was associated with a lower risk of getting some types of cancer, Parkinson’s disease, depression and Alzheimer’s disease. But liver diseases stood out as having the greatest benefit compared with other conditions.

Reassuringly, harms were not apparent apart from during pregnancy when coffee drinking was linked to low birth weight, premature birth (in the first six months of pregnancy) and miscarriage. This is not new knowledge, and there are guidelines for limiting caffeine intake in pregnancy. We also found a small increase in risk of fracture in women, but there is some discrepancy in the evidence and further investigation is needed.

Coffee drinking during pregnancy is linked with low birth weight. OndroM/Shutterstock

Careful how you consume it

Findings of our umbrella review should be interpreted with caution. Evidence in the review came mainly from observational research, so we can’t extrapolate our findings to suggest people start drinking coffee or increasing their intake in attempts to become healthier. What we can say is that people who already enjoy moderate amounts of coffee as part of their diet are most probably getting health benefits from it, rather than harm.

Our research is about coffee. It’s not about sugar, syrups, biscuits, cakes and pastries. Standard health messages still apply to those types of food. In other words, if you already drink coffee, enjoy it, but try to make it as healthy as possible.

Robin Poole, Specialist Registrar in Public Health, University of Southampton

The Conversation

This article was originally published on The Conversation. Read the original article.

Latest

Killer robots: The question of how to control lethal autonomous weapons
93876 2018-07-20 08:23:45Z Tech

Killer robots: The question of how to control leth…

by Peter Griffin

The computer scientist who has become a leading voice on the threat posed by killer robots describes himself as an “accidental activist”.

Read more
The man who's making sure performing artists are seen in the regions
93813 2018-07-20 00:00:00Z Theatre

The man who's making sure performing artists are s…

by Elisabeth Easther

For 35 years, Steve Thomas has been at the helm of Arts On Tour, taking musical and theatrical acts from Kaitaia to Stewart Island.

Read more
The Eco Economy: Millennials, money and saving sustainably
93645 2018-07-20 00:00:00Z Economy

The Eco Economy: Millennials, money and saving sus…

by Sharon Stephenson

Millenials are leading the rise of the eco economy.

Read more
Cuba Libre is a new Caribbean-influenced restaurant-bar in Ponsonby
93862 2018-07-19 15:05:51Z Auckland Eats

Cuba Libre is a new Caribbean-influenced restauran…

by Kate Richards

Rum, cigars and Cuban sandwiches are on the menu at new Ponsonby restaurant, Cuba Libre.

Read more
Our plastic recycling efforts will go nowhere without the right information
93822 2018-07-19 00:00:00Z Environment

Our plastic recycling efforts will go nowhere with…

by The Listener

If turns out that some plastics marketed as eco-friendly degrade only to a certain point and often outlive their human recyclers.

Read more
NZ International Film Festival: 50 years of bringing world cinema to our shores
93745 2018-07-19 00:00:00Z Movies

NZ International Film Festival: 50 years of bringi…

by David Larsen

The NZ International Film Festival is 50 years old this year – find out how they choose the line-up from long-standing director Bill Gosden.

Read more
Mary Shelley – movie review
93770 2018-07-19 00:00:00Z Movies

Mary Shelley – movie review

by James Robins

A biopic about writer of Frankenstein turns into lacklustre period piece.

Read more
We need to know more about what’s behind NZ's dire youth-suicide rate
93676 2018-07-19 00:00:00Z Psychology

We need to know more about what’s behind NZ's dire…

by Marc Wilson

New Zealand's youth-suicide rates are the highest in the OECD and the burden falls heavily on Māori and Pasifika peoples.

Read more