26 January 1996

BST experiment under attack by leading American scientist

By Shelley Wright

A LEADING US scientist has accused the US government of subjecting its population to an experiment, with the milk boosting hormone BST, which poses serious potential health risks.

Samuel Epstein, professor of environmental and occupational medicine at the University of Illinois, told a New York conference there was increasing evidence milk and dairy products from cows treated with BST could cause breast and gastrointestinal cancer.

He said various studies had shown that levels of insulin-like growth factor 1 (IGF-1) were substantially increased in the milk of BST-treated cows. The levels were further increased, by up to 70%, when milk was pasteurised.

IGF-1 is absorbed from the gut with marked growth-promoting effects, even in short-term studies on rats. And Prof Epstein concluded that absorption was likely to be even higher in infants.

The US Food and Drugs Administration licensed BST in 1993. But Prof Epstein accused it of using "highly speculative and misleading calculations". The FDA and pharmaceutical industry had both made "simplistic quantitative comparisons" to trivialise the risk of higher levels of IGF-1 and their calculations were not meaningful, he said.

"FDAs flawed analysis of their cited data is compounded by a misleading presentation of the data." Drug companies had used incomparable doses for test and control animals, allowing them to manipulate the data, he alleged.

Prof Epstein said more research was needed because critical information on a wide range of potentially adverse health effects of IGF-1 was still unavailable.

Recent UK research by David Challacombe at Musgrove Park Hospital, Taunton, has confirmed that the addition of IGF-1 to human small bowel tissue samples makes cells divide more quickly than normal.

Dr Challacombe said all tumours began by unusually rapid cell division. "I have avoided the concept of a direct link between IGF-1 and cancer but on the other hand the effects are there for a link to take place." He said more funding was needed to continue the work on IGF-1 and obtain some answers on its effect in humans.

Although BST is banned in Europe until 2000, the US wants the ban to be lifted.