Coffee has been the subject of conflicting studies but recent research places it in the healthy bracket. Picture: SOMSAK SUDTHANGTUM/123RF
Coffee has been the subject of conflicting studies but recent research places it in the healthy bracket. Picture: SOMSAK SUDTHANGTUM/123RF

Who would have thought that coffee has so much in common with eggs? Both have undergone dramatic reputation rehabilitation in recent years.

From being demonised for decades as bad for hearts, both are back in the healthy fold. And for both, scientists say that it’s a case of more is better. The latest research applies that thinking even more to coffee for arterial and heart health.

A new UK study shows that drinking even as much as 25 cups of coffee a day may not stiffen arteries after all, as some research has suggested. Because arteries carry blood containing oxygen and nutrients from the heart to the rest of the body, stiffening arteries increase the heart’s workload. This can increase your chance of having a heart attack or stroke, the researchers say.

Other research builds on growing evidence of coffee’s benefits as a weight-loss aid. A new UK study suggests coffee as a secret to beating obesity and type 2 diabetes. Both conditions are epidemic in SA, as they are in other countries.

In the latest research on coffee and hearts, Queen Mary University of London scientists looked at 8,000 people in the UK. The average highest intake was five cups a day but the study included participants who drank up to 25 cups a day.

Data showed that drinking even that much coffee a day was not associated with artery stiffening.

The researchers corrected for contributing factors to associations between drinking coffee and artery stiffness measures. Those factors included age, gender, ethnicity, smoking status, height, weight, how much alcohol participants drank, what they ate and high blood pressure (hypertension).

Previous studies linking coffee intake with stiffening arteries were “inconsistent”, the researchers said, and could be limited by lower participant numbers.

The study was presented at the recent British Cardiovascular Society Conference in Manchester and part-funded by the British Heart Foundation (BHF).

Study data analyst was Dr Kenneth Fung, an honorary specialist cardiology registrar at Queen Mary University of London. Despite coffee’s huge popularity globally, differing reports could “put people off” enjoying it, Fung said in a BHF release.

The study was associational, and thus, did not prove any causal link, he said. The researchers want to study coffee drinkers more closely in future to be able to advise safe intake limits.

BHF associate medical director Prof Metin Avkiran said that understanding coffee’s impact on the heart and circulatory system has “been brewing” among researchers and the media for some time.

Conflicting studies about coffee make it difficult for people to “filter what they should and shouldn’t believe”, Avkiran said. The new research “rules out one of the potential detrimental effects of coffee on our arteries”. This will hopefully put some media reports “in perspective”, he said.

Heart and Stroke Foundation SA CEO Prof Pamela Naidoo was less sanguine about the impact of large coffee intake on hearts.

Consuming three to five cups of coffee per day has shown a reduction in cardiovascular diseases risk. 
Pamela Naidoo

Via e-mail, Naidoo described drinking up to 25 cups of coffee as “addictive, excessive and bound to cause palpitations”.

A high coffee intake can have other harmful effects, she said. These include anxiety, insomnia and digestive upset — due to caffeine’s laxative effect – also, fatigue, increased blood pressure and heart rate.

“Some studies have consistently associated coffee consumption with a lower risk of mortality from all causes of cardiovascular disease, coronary heart disease and stroke,” Naidoo said. 

“Consuming three to five cups of coffee per day has shown a reduction in cardiovascular diseases risk. Consuming larger amounts has not shown a pronounced or significant beneficial effect.”

The UK study “is not conclusive and depends on individual risk factors”, she said.

In the coffee-and-obesity study, University of Nottingham researchers said that drinking coffee daily can stimulate “brown fat”, also known as brown adipose tissue (BAT). (Adipose tissue is the medical profession’s euphemism for excess body fat.)

The researchers have described BAT as the body’s “own fat-fighting defences”, hence their conclusion that coffee could be key to tackling obesity.

BAT is one of two types of fat found in humans and other mammals, they said. Scientists initially attributed BAT to babies and hibernating mammals only but have since discovered that adults also have BAT. It is also located mostly in the neck region.

BAT’s main function is to generate body heat by burning calories, often in response to cold, the researchers said. That is compared to “white fat” that results from storing excess calories. People with a lower body mass index (BMI) have a higher amount of BAT, they said.

Study co-author Prof Michael Symonds, from Nottingham University School of Medicine, said that increasing BAT’s activity improves blood sugar control, as well as blood lipid (fat) levels. The extra calories burnt “helps with weight loss”, Symonds said.

Until now, no-one has found an acceptable way to stimulate BAT’s activity in humans, he said. That makes his team’s study “pioneering” as it is one of the first carried out in humans to find components that could have a direct effect on BAT functions.

It is also the first in humans to show that “something like a cup of coffee can have [that direct effect]”, Symonds said. The study’s potential implications are, therefore, “pretty big” because obesity and diabetes are major public health concerns, he said.

The research was published in Scientific Reports in June.

Naidoo also weighed in on the Nottingham University study: “Coffee has been used as a weight management strategy as caffeine increases metabolic rate, energy expenditure and lipid [fat] oxidation. However, on its own, coffee cannot induce long-term weight loss and should be taken in moderation as part of a healthy balanced diet and exercise regime,” she said.

Coffee Fun Facts

  • Coffee is the world’s second most-traded commodity —– the first is oil;
  • It is the world’s most popular drink, with about 2-billion cups consumed every day;
  • Legend has it that an Ethiopian goat herder first discovered coffee. He noticed that his goats were more energetic after grazing berries from a specific tree;
  • Coffee is actually a fruit, a “cherry” packed with antioxidants and generally makes people feel happier;
  • Mecca banned coffee in 1511 because it was believed to stimulate radical thinking and idleness.
  • It takes about 168l of water to grow and process the coffee beans to make one cup of coffee;
  • The word “coffee” has been in the English language since 1582. We can thank the Dutch (koffie), the Turkish (kahveh) and the Arabic language (qahwa) for it;
  • “Covfefe” came into the English language in 2017. It is a “Donald-Trumpism” — one of many tweeted spelling errors that has nothing whatsoever to do with coffee.

Source: The Internet