YOUR HEALTH Dr James Le Fanu: 28 September

Insulin-dependent diabetics may be suffering severe problems caused by modern treatment regimes – they deserve to be heard

Medicine is, for the most part, a sane and scientific enterprise but can be surprisingly intolerant of even the most well-intentioned criticism, illustrated by the plight of patients with diabetes who find that modern regimes of treatment can cause, paradoxically, severe problems.

Ever since the discovery of the life-saving potential of insulin back in 1921, diabetics have successfully controlled the level of sugar in their blood by regularly injecting themselves with extracts of the hormone derived from pigs and cows. This is cheap, plentiful and highly effective. Then, in the early 1980s, scientists deployed the revolutionary techniques of genetic engineering to produce human insulin – inserting the gene into bacterium that then produced the hormone in prodigious quantities. In practical terms the chemistry of this human insulin is virtually identical to the animal variety, but it seemed obvious that the human form must be 'better' and doctors accordingly advised their patients to switch.

This worked well for most, though some found their diabetes suddenly went haywire as the level of sugar in the blood oscillated wildly. Family doctor Matthew Kiln discovered he could no longer anticipate the potentially serious situation where his blood sugar fell too low – known as a 'hypo' that must be promptly corrected. His personality changed too as he became more irritable and argumentative, with unfortunate consequences for his personal and professional life. Subsequent surveys revealed that about one in four diabetics were experiencing similar difficulties – though most were able (with some difficulty) to persuade their doctors to prescribe them the animal-based forms to good effect.

But this situation is rather different for those newly diagnosed with diabetes who may not be aware of this problem with human insulin. Another doctor, Ann Robinson, was diagnosed with the condition in her early 40s. Her human insulin injections, as intended, kept the levels of the sugar in her blood within the normal range but she felt terrible. 'I did not feel like me with an illness. I felt like someone else,' she recalls. 'I became a zombie. I could not concentrate for more than a few minutes and whenever I took the least exercise my blood sugar went through the floor.'

As the months went by her perplexed consultant changed Dr Robinson's regime of injections at least five times, but to no avail. She felt that there was no alternative but to take early retirement on medical grounds. Then, one evening, while idly flipping through a medical journal, she chanced upon an article by Dr Kiln that rang a peal of bells with her. She rushed round to her doctor, persuaded him to switch her from human to pig insulin and within a couple of days, her life changed.

'I woke feeling hungry for the first time in two years,' she says, as her body's metabolism started to work as it should. Her intellect emerged from the twilight and she found she could concentrate once more, her joints loosened up and her personality returned. 'I was me again,' she says.

She wonders, naturally, how many others there are like her: children, for example, whose behavioural and learning problems are blamed on their reaction to being diagnosed with diabetes – but who might become their sunny selves again simply by switching to pig insulin. But how are they (or their parents) to know?

And there's the rub. Dr Kiln helped to set up the Insulin Dependent Diabetes Trust to promote research and publicise this important issue – but, astonishingly, it has been an uphill struggle. It is scarcely revolutionary to propose that some with diabetes might fare better with animal-based insulin. Surprisingly, for many and complex reasons, neither the diabetes specialists nor the drug companies have really been prepared to give them a sympathetic hearing.

Contact the IDDT at PO Box 294, Northampton NN1 4XS: 01604- 622837, www.iddt.org

drjames@lady.co.uk