Chewing more can provide a wide range of health benefits, from improving digestion and helping people consume fewer calories to alleviating stress and anxiety and improving cognition by solidifying memory skills and boosting attention span.
For once chewing a shallot 722 times before swallowing it, Horace Fletcher was dubbed “The Great Masticator”. The American self-taught nutritionist believed food should be chewed “until it is completely liquefied” and it “practically swallows itself”.
An important first step
At the most basic level, chewing breaks food down into small particles and moistens them with saliva so that they can be easily swallowed. “It’s the first phase of digestion,” says Andries van der Bilt, a pioneer in the field of oral physiology and chewing, who worked as a researcher at the University Medical Center Utrecht in the Netherlands for over three decades.
Not only does chewing increase saliva production and the amount of digestive enzymes like amylase that help break down food, it also triggers the gut and pancreas to secrete juices that will help process food further, too. “If you don’t chew, the gut is not prepared to handle food,” says Trulsson.
The act of breaking food particles into smaller pieces also increases their surface area, which means digestive juices can act on them more efficiently, says orofacial neuroscientist Abhishek Kumar, who works with Trulsson at the Karolinska Institutet. This is important for gut health. Bigger particles tend to linger in the gut longer, giving microorganisms more time to ferment them. This causes “feelings of bloatedness, fullness, constipation, and other symptoms”, Kumar says.
Improving absorption and feelings of fullness
The act of chewing helps release nutrients in food, allowing our bodies to absorb them more effectively. In a 2009 study, for instance, 13 healthy adults were asked to chew a small handful of almonds 10, 25, or 40 times. When researchers collected samples of participants’ poo, they discovered that the more people chewed, the less fat they excreted, suggesting that the absorption of energy from the nuts was up to a third higher. (In the early 1900s, in fact, Fletcher believed chewing more helps produce poo of superior quality – “quite dry” and smelling of a “hot biscuit”.)
What’s more, chewing 40 times left participants feeling fuller for longer. it takes around 20 minutes for the body to adjust its production of hunger-related hormones and send signals to the brain that you’re full – and chewing buys you more time.
A boost for brain health
Nutrition and digestion aside, researchers are increasingly uncovering that chewing plays an important role in other aspects of our wellbeing – especially brain health – as we get older. “There is growing interest in the ‘bite–brain axis,’ which proposes that mastication is directly linked to brain health,” says Kumar. Tooth loss, for instance, has also been linked with a higher risk of Alzheimer’s disease and dementia.
Memory is affected, too. In a survey involving more than 28,500 people older than 50 across 14 European countries, participants with good chewing ability or those without dentures performed better on a battery of cognitive tests. They demonstrated significantly better word recall, verbal fluency, and numeracy skills than those with chewing problems.
Heightening alertness
In some instances, chewing has also been found to improve concentration in the general population. One meta-analysis, comprising 21 studies, detected a weak but statistically significant improvement in attention levels of gum-chewing participants compared to non-chewers during some cognitively demanding tasks. (This research was funded by gum manufacturer Mars Wrigley, suggesting a potential conflict of interest.)
In an unrelated study of 80 participants, chewing improved alertness levels by 10% during a series of cognitive tasks. Gum-chewers also performed better on an intelligence test. Scientists “don’t really know exactly how it works,” but the link between chewing and heightened attention is fairly strong, says Trulsson.
Lowering stress
Outside the lab, chewing is a good stress-reliever too. When a group of Turkish researchers studied 100 nursing students preparing for mid-term exams, they found that students who chewed gum for at least 30 minutes daily experienced lower levels of stress, anxiety and depression. This was regardless of whether they began chewing gum 15 days or two days before their exams.
For two separate groups of women undergoing elective gynaecological surgery in Korea, chewing on gum helped alleviate their pre-operative anxiety.
Chewing seems to be a natural reflex in stressful times, says Jianshe Chen, an oral processing researcher at Singapore’s Agency for Science, Technology and Research. “When some people are stressed, they start to chew unconsciously.” Teeth grinding or bruxism, which uses the same jaw muscles as chewing and affects roughly one in 10 adults, is commonly triggered by stress and anxiety.
Credit: webmd
