Here is Dr Briffa's Full blog on the subject:
Perusing on-line newspapers yesterday I came across this. According to the national newspaper the Observer (UK), Professor Chris Hawkey, president of the British Society of Gastroenterology (BSG), is set to debunk more than a dozen ‘fad’ diets when he addresses Gastro 2009 conference for doctors. Locked in his crosshairs, apparently, are the concepts of chewing thoroughly, and the raw, grapefruit, and alkaline diet.
To be honest, when I read that a gastroenterologist was going to pronounce on the suitability of different diets, I felt uncomfortable. For two reasons really. First of all, many dietary approaches that appear to work in practice have not been subjected to systematic study. So, dismissing them on scientific grounds is not, well, very scientific. If Professor Hawkey has a stack of science that shows that such approaches definitely do not work, then I am honestly all ears. But if he hasn’t, then all he is offering is an opinion.
But the other reason I am uncomfortable about Professor Hawkey’s pronouncements is the fact that he is a gastroenterologist. And the fact is, my experience is that many doctors of this specialism appear to believe that diet has little or nothing to do with gastrointestinal disease. I see a steady stream of patients with gastrointestinal symptoms of diagnosed conditions who tell me their gastroenterologist told them, point blank, that their condition is in no way related to what they eat.
Now, many of these individuals are incredulous at this. They argue, quite rightly I think, that what and how they eat is very likely to impact on the health of the gut. Some ask rhetorically “How could what I eat not be affecting my gut?”
Now, not all gastroenterologists dismiss diet as a potential trigger of digestive illness. I, for example, have a friend a colleague who happens to be a gastroenterologist but, nonetheless, embraces diet quite enthusiastically when managing certain gastrointestinal diseases. However, as a general rule, my experience is that gastroenterologists tend not to be particularly open to the nutritional management of the conditions that confront them regularly.
By way of demonstration, let’s have a look at Professor Hawkey’s dismissal of the value of chewing. From the piece linked to above we learn that “The chewing movement emerged in the 19th century with the claim that chewing each mouthful 32 times helped digestion. “Gladstone was apparently very eccentrically in favour of this diet,” said Hawkey of the British prime minister who died in 1898. “The idea is that salivary enzymes start digestion.” However, like many other diets, it was based more on “theory than evidence”, according to Hawkey.”
Let’s have a look at that theory for a moment. As I wrote about here and here, slower eating (and more thorough chewing) appears to lead to people eating less. It does not seem so far fetched, therefore, that advising people to chew thoroughly might help them lose weight.
And even if they do not lose weight, there may be other benefits to be had from proper mastication. Professor Hawkey is right that the action of enzymes in the mouth help kick start the digestive process (amylase and lipase start the digestion of carbohydrate and fat respectively). However, the mechanical effect of chewing is also important. Thorough chewing increases the surface area of food that ends up in the stomach, and this aids digestion. Imagine dropping two ice cubes into water but crushing one first. Which one melts more quickly? The crushed one, right? It’s the same with food in the stomach.
So, one thing that thorough chewing can do is help reduce the risk of symptoms such as heartburn and indigestion. I don’t believe anyone’s ever studied it, but my experience is that it works, and generally leaves individuals feeling far more comfortable after a meal.
Writing this a memory of an event that occurred a few years ago was awoken. A fellow journalist had written about a piece about how to combat indigestion naturally and without drugs. Her advice seemed reasonable to me, and included advice to chew thoroughly. However, she had received a quite irate letter (which she forwarded to me) from a gastroenterologist claiming that her advice was simply bunkum. He also disputed her claim that changing the diet in a specified way might help provide relief from indigestion.
In his letter, the gastroenterologist in question wrote something that it stuck in my memory. He claimed “What one eats has no bearing on the symptoms of indigestion. Whether we eat bananas and cream or old boots and laces, it makes no difference to the stomach.” One does not need to be a gastroenterologist to understand just how jaw-droppingly ill-informed this ‘expert’ opinion is.
Anyway, we can see how Professor Hawkey’s stance on chewing flies in the face of common sense and at least a little science. I am left wondering whether Professor Hawkey’s time might be better spent not debunking supposed myths, but embracing some basic nutritional principles. Starting with advising his patients to chew their food thoroughly.
Best, Ant
