The molecular basis of lactose intolerance
Abstract:A staggering 4000 million people cannot digest lactose, the sugar in milk, properly. All mammals, apart from white Northern Europeans and few tribes in Africa and Asia, lose most of their lactase, the enzyme that cleaves lactose into galactose and glucose, after weaning. Lactose intolerance causes gut and a range of systemic symptoms, though the threshold to lactose varies considerably between ethnic groups and individuals within a group. The molecular basis of inherited hypolactasia has yet to be identified, though two polymorphisms in the introns of a helicase upstream from the lactase gene correlate closely with hypolactasia, and thus lactose intolerance. The symptoms of lactose intolerance are caused by gases and toxins produced by anaerobic bacteria in the large intestine. Bacterial toxins may play a key role in several other diseases, such as diabetes, rheumatoid arthritis, multiple sclerosis and some cancers. The problem of lactose intolerance has been exacerbated because of the addition of products containing lactose to various foods and drinks without being on the label. Lactose intolerance fits exactly the illness that Charles Darwin suffered from for over 40 years, and yet was never diagnosed. Darwin missed something else – the key to our own evolution – the Rubicon some 300 million years ago that produced lactose and lactase in sufficient amounts to be susceptible to natural selection.
Document Type: Research Article
Publication date: September 1, 2009
SCIENCE PROGRESS has for over 100 years been a highly regarded review publication in science, technology and medicine. Its objective is to excite the readers' interest in areas with which they may not be fully familiar but which could facilitate their interest, or even activity, in a cognate field. Science Progress commissions world authorities to contribute articles on the most interesting, important and meaningful topics - ranging from cosmology to the environment - and ensures that they are presented for the most effective use of those in both academia and industry.
Truly, Science Progress publishes an eclectic mix of articles that no library can afford to be without.
- Editorial Board
- Information for Authors
- Subscribe to this Title
- ingentaconnect is not responsible for the content or availability of external websites