Could larynx inflammation turn malignant? And does milk lead to too much mucus?

Dairy decisions

Dairy decisions

Q. Is there anything in the theory that feeding babies and toddlers a lot of yoghurt is bad for them, because it causes the production of too much mucus? If my 14-month-old son has a persistent runny nose and lies awake at night coughing, could he be helped by reducing his intake of yoghurt, or even all dairy products? I never liked Mrs Thatcher, but when she took away free milk from the very youngest schoolchildren in the Seventies, I seem to remember that the reason given was some theory of this kind.

A. Many people believe that dairy products in the diet cause excess mucus production, but there is no scientific evidence that this is true. In fact, when the subject has been studied objectively, it turns out that it is impossible to prove that there is any relationship between dairy products and mucus production. Of course, products such as full-cream milk and yoghurt can briefly coat the lining of the mouth and throat, giving the sensation that mucus is present. But this milky coating only lasts for a very short time, and when it is gone, there is no evidence that it is replaced by excess mucus. An enterprising team of scientists compared dairy milk with soya milk, in a study designed to see whether milk actually does cause mucus production. The result was that both ordinary milk and soya milk caused similar sensations of mucus in the mouth. Anti-milk fanatics will tell you that cow's milk is a "deadly poison". Like most foods, in moderation it is pretty harmless. If any readers are able to point me in the direction of well-designed scientific studies that show a link between milk and mucus, please get in touch.

Swim to slim

Q. I'm a 5ft 6in tall, 11 stone female, and I would like to lose a couple of stone. I find dieting useless as I always regain the lost weight, so I have decided to exercise instead. Would 30 minutes of swimming four times a week, rising to an hour five times a week over three months, ensure steady weight loss if I also cut out snacking?

A. Swimming for 30 minutes should burn up about 300 calories. If you do this four times a week, you will burn up about 1,200 calories. To lose a pound in weight, you need to burn up about 3,500 calories. So this level of exercise should lead to a weight loss of about one pound every three weeks. If cutting out "snacking" means 50g less of Cadbury's Dairy Milk every day, you will also be reducing your intake of calories by about 260 calories a day, or 1,820 calories a week. The combination of swimming four times a week and less snacking will mean that you lose about a pound a week. If you push your swimming up to one hour five times a week, you will be burning up 3,000 extra calories a week, and your weight will go down at the rate of about three pounds every two weeks. Unfortunately, as you get thinner, the number of calories that you burn up by exercising goes down. When you get down to 10 stone, 30 minutes of swimming will only burn 280 calories. If you stick to your regime for three months, you'll be well on the way to losing two stone.

Can't take the heat?

Q. I was alarmed by your comments about chronic inflammation of the oesophagus. For five years, I have had a recurrent problem with granulomas on the larynx. I have had three operations, and biopsies have shown no malignancy, with "chronic inflammation" being given as the cause of the problem. I have ongoing discomfort, but I have been comforted by the belief that there is little chance of the area becoming cancerous. However, you recently discussed the effect on the oesophagus of drinking hot tea, saying that "it may be that chronic inflammation eventually makes cancer more likely". I find this really worrying. Is it possible to quantify "more likely"? And do your comments apply to chronic inflammation generally, or to the larynx specifically?

A. For centuries, doctors have recognised a link between chronic inflammation and cancer. People who have chronic oesophagitis (inflammation of the oesophagus) are more likely to develop cancer of the oesophagus. And people with an inflammatory bowel disease, such as ulcerative colitis, are more likely to develop bowel cancer. But people who have chronically inflamed lungs (asthmatics, for example) are no more likely to develop lung cancer than anyone else. And people with eczema, which is a chronic inflammation of the skin, do not go on to develop skin cancer. The reason for the apparent link between inflammation and cancer is poorly understood. If you are developing non-cancerous growths on the larynx, I think the chance of these changing into cancer is very small indeed. When a research group studied 150 people with granulomas, they discovered that none of them had any hint of cancer. Another important question, of course, is why you are getting these growths. Sometimes they can be caused by stomach acid seeping up into the throat and larynx, a condition called laryngopharyngeal reflux. This is similar to gastroesophageal reflux, a condition I mentioned last week.

Have your say: readers write

HF of Cheshire believes this is a Proustian reference to asparagus and smelly urine:

Jokes in Proust are few, but is this one? "What delighted me were the asparagus, steeped in ultramarine and pink, whose tips, delicately painted with little strokes of mauve and azure, shade off imperceptibly down to their feet - still soiled though they are from the dirt of their garden-bed - with an iridescence which is not of this earth... all night long following a dinner at which I had eaten them, they played, in farces as crude and poetic as a fairy play by Shakespeare, at changing my chamber pot into a jar of perfume."

Please send your questions and suggestions to A Question of Health, 'The Independent', Independent House, 191 Marsh Wall, London E14 9RS; fax 020-7005 2182; or e-mail Dr Kavalier regrets that he is unable to respond personally to questions