Monday, 29th May 2023

Debate rages on merits, demerits of regular coffee intake

By Chukwuma Muanya
02 February 2023   |   4:04 am
Regular coffee consumption has been in the news for various reasons- the pleasant and the not so pleasant.


•Inconclusive evidence links drinking coffee, very hot beverages with colorectal cancer
•Regular coffee consumption associated with better kidney function in some people, researchers find
•How caffeine use by expectant mothers linked to lower height of children, delayed growth, by scientists
•Coffee can provide athletes with energy, leads to quicker running time, overall performance
•Drinking coffee regularly after pregnancy may lower risk of type 2 diabetes for women who had condition
•Taking coffee with milk may reduce redness, swelling, pain in humans, studies find

Regular coffee consumption has been in the news for various reasons- the pleasant and the not so pleasant.

In 2016, the media were awash that drinking coffee and very hot beverages could cause cancer. But the World Health Organisation (WHO) in a swift reaction said its Working Group found no conclusive evidence for a carcinogenic effect of drinking coffee.

An international Working Group of 23 scientists convened by the International Agency for Research on Cancer (IARC), the cancer agency of the WHO, had evaluated the carcinogenicity of drinking coffee, maté, and very hot beverages.

Mate or maté, also known as chimarrão or cimarrón, is a traditional South American caffeine-rich infused herbal drink.

A summary of the final evaluations was published in The Lancet Oncology, and the detailed assessments as Volume 116 of the IARC Monographs.

The experts, however, did find that drinking very hot beverages probably causes cancer of the oesophagus in humans. No conclusive evidence was found for drinking mate at temperatures that are not very hot.

The WHO cancer agency was under scrutiny for allegedly causing too many public health scares. Their reports had branded coffee, mobile phones, processed meat and the weed killer glyphosate – among other things – as dangerous products that cause cancer.

Until now, daily consumption of coffee, tea and cocoa have been associated with reduced risk of developing chronic diseases such as cancer, diabetes, gallstones, heart disease, among others.

Indeed, coffee has been hailed as having numerous other health benefits. Last month, it was reported on a study by researchers from Lund University in Sweden, which found coffee could halve breast cancer recurrence for some women, while another study found drinking up to five cups of coffee daily could reduce the risk of clogged arteries and heart attack.

However, some other studies have also linked consuming too much coffee to increased risk of anxiety and depression.

A study published, in 2015, in the journal PLOS ONE has found that drinking two to three cups of coffee a day could reduce the risk of erectile dysfunction by up to 42 per cent.

Erectile dysfunction (ED), or impotence, is the inability to get and sustain an erection that is firm enough for sexual intercourse. It is the most common form of sexual dysfunction in men.

ED can be a devastating condition for men, causing lack of self-confidence, stress and relationship problems. The majority of ED cases are caused by physical problems, including high blood pressure, overweight, obesity, diabetes and high cholesterol, though psychological issues can also trigger it.

Also, there is growing evidence that links increased coffee drinking with better kidney function, although the evidence is still unclear. Observational studies, like one Mendelian Randomisation (MR) study, have either indicated that increased coffee consumption is linked to a lower risk of chronic kidney disease (CKD), albuminuria, or renal failure or there is no association with CKD. It has not yet been determined whether drinking coffee is associated with increased estimated glomerular filtration rate (eGFR) in other high-risk categories for chronic kidney disease.

It is crucial to evaluate these connections in these subgroups because, due to their high levels of inflammation, these people may benefit more from drinking coffee. In addition, there is a lack of research linking coffee consumption with frequent urine albumin-to-creatinine ratio (ACR) measures.

In the present study, researchers investigated whether a person’s regular use of coffee was associated with changes in their eGFR and urinary ACR over time.

The study titled “Association of habitual coffee consumption and kidney function: a prospective analysis in the Rotterdam Study” was published in the journal Clinical Nutrition.

In comparison to non-coffee consumers, men were more likely to be heavy coffee consumers. Furthermore, heavy coffee users were also more likely to smoke, consume more alcohol, and consume the most calories.

Overall, the study findings highlighted that while coffee consumption was not linked with ACR and eGFR in the whole population, it was associated with greater longitudinal eGFR among individuals at a higher risk for CKD, that is, those aged 70 years and older and obese people. The researchers believe that results ought to be confirmed by more prospective cohort studies.

Also, children who were exposed to small amounts of caffeine in utero were shorter on average than those who were not, says a new study published in JAMA Network Open.

“The reductions were apparent even with levels of caffeine consumption below clinically recommended guidelines of less than 200 mg per day,” the authors wrote. “The clinical implication of this height difference is unclear and warrants future investigation.”

The slightly lower sizes were recorded starting at age four and increased through age eight, “translating to a 0.68 to 2.2 cm difference,” the study says.

“To be clear, these are not huge differences in height, but there are these small differences in height among the children of people who consumed caffeine during pregnancy,” lead author Jessica L. Gleason, a perinatal epidemiologist, told CNN.

Pregnant women should consume no more than 200mg of caffeine a day, the American Academy of Obstetricians and Gynaecologists says.

Also, at the international level of sport, even the smallest advantage can take an athlete from being a mere participant to a podium finisher. Consequently, athletes try to achieve that competitive edge with the help of performance enhancing training methods and pre-event performance enhancing aids. Caffeine, a nervous system stimulant, is one such performance enhancing aid, most commonly and popularly used by athletes around the world. In fact, the International Association of Athletics Federations (now called World Athletics, WA) recommends caffeine as an ergogenic (or physical performance-enhancing) aid in a consensus statement of nutritional strategy for athletics. However, owing to the absence of research on caffeine’s effects on sprint performance, the recommendation is reflective of evidence from other anaerobic sports rather than sprint running in athletics, like the 100-m sprint event.

To advance research, a team of researchers from Japan investigated the acute effects of caffeine supplementation on sprint running performance. This study, led by Professor Takeshi Hashimoto from Ritsumeikan University in Japan, was subsequently published in the Medicine & Science in Sports & Exercise journal.

The results revealed that the corrected 100-m sprint time was shortened significantly for athletes who received caffeine, with a decrease of 0.14 seconds compared to the controls. This decrease in the time was largely associated with a decrease in sprint time for the first 60 meters of the sprint.

The researchers also found that the mean sprint velocity for the 0–10 m and 10–20 m splits was significantly higher in the athletes who received caffeine. Moreover, no significant difference was seen in the sprint time for the last 40 meters of the sprint, despite the shortening of the sprint time in the first 60 meters. Together, these observations suggest that the caffeine supplementation provided more explosive acceleration to the sprinters in the early stage of the race.

Also, drinking coffee regularly may keep type 2 diabetes away from women who had diabetes during pregnancy. Replacing artificially sweetened and sugar-sweetened beverages with caffeinated coffee also reduces the risk, by 10 per cent for a cup of artificially sweetened beverage, and 17 per cent for a cup of sugar-sweetened one.

The prevalence of type 2 diabetes is projected to continue rising and one in three Singaporeans currently has a risk of developing diabetes in their lifetime. Several early-life cardiometabolic complications make identifying high-risk populations and application of diabetes preventive strategies paramount.

The team further examined coffee consumption with type 2 diabetes by replacing commonly consumed sugary drinks with coffee. Findings from this study, “Habitual coffee consumption and subsequent risk of type 2 diabetes in individuals with a history of gestational diabetes — a prospective study” was recently published in the American Journal of Clinical Nutrition.

However, concerns should be given when coffee is taken in excessive amounts. It also needs to be emphasised that certain groups should be careful about drinking coffee. Not much is known about the effects of coffee on pregnancies, foetuses and children.

Also, can something as simple as a cup of coffee with milk have an anti-inflammatory effect in humans? Apparently so, according to a new study from the University of Copenhagen. A combination of proteins and antioxidants doubles the anti-inflammatory properties in immune cells. The researchers hope to be able to study the health effects on humans.

A drug or substance that reduces inflammation (redness, swelling, and pain) in the body. Anti-inflammatory agents block certain substances in the body that cause inflammation. They are used to treat many different conditions. Some anti-inflammatory agents are being studied in the prevention and treatment of cancer.

Whenever bacteria, viruses and other foreign substances enter the body, our immune systems react by deploying white blood cells and chemical substances to protect us. This reaction, commonly known as inflammation, also occurs whenever we overload tendons and muscles and is characteristic of diseases like rheumatoid arthritis.

Antioxidants known as polyphenols are found in humans, plants, fruits and vegetables. This group of antioxidants is also used by the food industry to slow the oxidation and deterioration of food quality and thereby avoid off flavors and rancidity. Polyphenols are also known to be healthy for humans, as they help reduce oxidative stress in the body that gives rise to inflammation.

But much remains unknown about polyphenols. Relatively few studies have investigated what happens when polyphenols react with other molecules, such as proteins mixed into foods that we then consume.

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