Dr John Briffa: Chewing it over

One memory I have from childhood is of Mrs Pearl - a formidable playground patroller and dinner lady at the junior school I attended in suburban Essex. She had a very clearly defined view of how children should behave, right down to their eating habits. One of Mrs Pearl's preoccupations was to remind us of the importance of proper chewing, and anyone caught speed-eating would always incur her wrath.

Latterly, my interest in nutrition has led me to give the subject of mastication proper consideration. And I have found that, while the act of chewing may seem relatively superfluous, it actually plays a critical role in digestion. Chewing helps to ensure that we extract maximum nutritional value from the food we eat. It turns out that Mrs Pearl's views on the importance of chewing have real bite after all.

When the pace of life is fast and we're trying to cram as much as possible into the day, eating can be something we tend to do on the hoof. Many of us find ourselves stuffing a sandwich or cereal bar into our mouths, satisfied that we've at least managed to get something down us. However, the gut is essentially a long tube that runs through the middle of the body, and this means that the food contained within it is not really in the body at all. It's only once food makes its way through the gut wall into the body proper that it can liberate its nutritional goodies into the system.

Before we can absorb our food, it needs to be broken down (digested) first. Chewing is important because it plays a starring role in the digestive process. During chewing, glands found under the tongue and inside the cheeks and lower jaw secrete saliva into the mouth. Saliva helps moisten and shape the food for easy swallowing. It also contains an enzyme known as amylase which starts the digestion of starchy foods such as bread, potatoes, pasta and rice. During chewing, the tongue also secretes an enzyme called lipase which participates in the digestion of fat.

Once food is swallowed, it is further digested through the secretion of a variety of compounds including acid in the stomach, bile from the gallbladder and enzymes in the small intestine. Chewing, and the sensation of food in the mouth, are believed to help stimulate the secretion of these food-dissolving substances.

(Eating bitter foods such as salad leaves helps stimulate digestive secretions particularly effectively, making them an ideal choice as a starter. Chicory is especially good in this respect, and is renowned in herbal medicine for its ability to boost digestion.)

However, for acid, enzymes and bile to do their work, they need to be able to penetrate the food we eat. One final function of chewing is to grind food up, which gives the digestive secretions a fighting chance of getting in there to complete the process. What is more, the smaller the food particles we swallow, the quicker and more efficient digestion tends to be. Inadequate mastication can stall the digestive process, and cause food to go down the pan with some of its goodness intact.

So, the message is clear: a very simple and effective way of boosting the nutritional value of our diet is to comply with Mrs Pearl's demands, and make sure we chew our food thoroughly before swallowing.

Dear John

For many years I have suffered from dry eyes - recently diagnosed as sicca syndrome. Is there a way of treating this through diet?
L Sullivan, Bury St Edmunds

The surface of the eye is kept moist by tears secreted by what are known as the lacrimal glands. Sicca syndrome is a condition characterised by dry eyes caused by insufficient tear production, and is quite often associated with dryness in the mouth, too.

Sicca syndrome often seems to respond to treatment with healthy fats known as essential fatty acids (EFAs). There is some evidence that sicca syndrome might be related to a deficiency of what are known as omega-6 fats. These are found most abundantly in foods such as margarine and vegetable oil. However, the processing of these foods can damage the fats they contain, which may reduce their health-giving potential. I recommend that you try supplementing with hemp-seed oil, as this is a good natural source of omega-6 fats. In practice, I have found this is often an effective remedy for conditions such as sicca syndrome and dry skin. You can obtain hemp-seed oil by mail order from Advanced Herbals on 02920 219 853.

Take 1 tablespoon (15 ml) per day - though bear in mind benefit may not be seen for some weeks or months.

Two other nutrients which have been used with some success in the treatment of dry eyes are vitamins C and B6.

I recommend that you take 500mg of vitamin C and 25mg of B6, twice a day.

· If you have any issues you would like Dr Briffa to address in this column, please email him on john.briffa@observer.co.uk. Please note that Dr Briffa cannot enter into any correspondence.

Thanks to guardian.co.uk who have provided this article. View the original here.