Full text of
an article from New Scientist, April 15,
1989, pg. 30. (2nd of two by Lesser)
Reproduced with permission from New
Scientist.
"HUMAN" INSULIN LOSES ITS
CLEAN APPEAL
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.