Last Updated: 03/15/04 06:40 PM  

Full text of an article from New Scientist, April 15, 1989, pg. 30. (2nd of two by Lesser) Reproduced with permission from New Scientist.


By Frank Lesser

Preparations of "Human" insulin may put some insulin-dependent diabetics at life-threatening risk by depriving them of the warning symptoms of hypoglycemia, a low level of sugar in the blood. The rush amongst doctors over the past seven years to switch patients to the artificially produced human insulins, available in Britain since 1982, is the result mainly of promotional pressure from manufacturers, not a reflection of medical need, according to some researchers.

These criticisms appeared in last month’s update on the topic in the Drug & Therapeutics Bulletin, published by the Consumers’ Association. For the past three years, researchers in the treatment of diabetes have been debating, so far, inconclusively, whether or not the human insulins are more liable than others to cause "hypoglycemic unawareness." This condition is characterized by a masking of the signs of low blood sugar, so that someone with diabetes is not aware that their body is entering a dangerous state.

Contributions to the debate include, for example, a report published in Balance, the journal of the British Diabetic Association (1988, 106, p.66). Of 158 patients who were transferred to human insulin from beef or pork insulin, 14% thought it better, 33% noticed no change, while the remaining 53% felt that control of blood sugar was worse and the warning of hypoglycemia less clear.

A second study showed that, of 189 diabetics who switched, to human insulin over a period of two years, only 6% noticed a diminution of warnings while 3% thought they had better warning (Diabetic Medicine, vol. 5, p. 26).

Human insulins are produced either by modifying porcine insulin using enzymes, or biosynthetically in the bacterium Escherichia Coli, by using recombinant-DNA techniques. The producers of human insulins claim they are "identical to the body’s own insulin and therefore the logical choice." They say that they are "outstandingly pure and less immunogenic" – less likely to cause an immune reaction in the body – than alternative animal products.

Robert Tattersall, a consultant in diabetes at the University of Nottingham’s medical school, argued in the Drug & Therapeutics Bulletin that highly purified pork insulin is only slightly immunogenic. Furthermore, the human insulins have similar defects because they contain additives and because they break down partially.