can anorexic bones ever catch up?

by Jenny Bryan

Just when they thought they had conquered their eating disorders, some young women are finding that their recovery came too late for their skeleton, and they are succumbing to fractures as a result of osteoporosis – or thin bones. Research underway at St George's Hospital, London, is investigating how best to help women with anorexia increase their bone mass in order to protect them from osteoporosis in later life.

image to accompany feature
© Getty

'We've known for some years that anorexia causes problems in the skeleton, mainly thinning of the bones, but we're not sure whether those who recover from their anorexia can end up with normal bone density,' explains Dr Jim Bolton, lecturer in psychiatry at St George's Hospital.

He is following the progress of a group of women aged 15-46 years to see if their bones can make up for lost time before they reach the menopause, and he is testing whether hormone replacement therapy (HRT) can protect those with the lowest weight.

why anorexic bones break

Bone is not a static tissue and its cells multiply, grow and die, just like other parts of the body. For this to happen, a regular supply of nutrients is needed, especially during the second and third decades of life when bones reach their peak mass and strength.

After the menopause, when oestrogen levels fall, women's bones tend to become thinner because the whole process of bone build-up and breakdown speeds up, and bone breaks down faster than it is built up. Taking HRT to replace the missing oestrogen helps to prevent excessive bone break-down.

In anorexia, the process is slightly different, explains Dr Bolton. Recent American research has shown that bone formation is significantly reduced in young women with anorexia because they have low levels of an important growth factor called insulin-like grown factor (IGF-1).

'In anorexia, there is less energy going into the system so the whole process of bone turnover slows down, especially bone formation. For most of these women, HRT may not be the answer because it slows down bone formation as well as destruction,' he says.

The only group who have achieved a small benefit from taking HRT or the contraceptive pill in the past have been the thinnest women, who are not managing to put on weight. This is why Dr Bolton is also testing HRT in this group of women with anorexia.

alternatives to HRT

In the St George's study, women taking HRT are using a brand that does not cause withdrawal bleeding. This is because young women with anorexia tend to be unwilling to use HRT or the contraceptive pill because they may gain weight or feel bloated. Such treatments also raise issues of fertility and growing up which some women do not want to address.

Studies are investigating the possibility of using bisphosphonate drugs to help reduce the risk of broken bones in women with anorexia and osteoporosis. This group of drugs is not hormone-based like HRT but prevents fractures in post-menopausal women with osteoporosis by reducing bone breakdown. However, the fact that they do not boost bone formation may limit their effectiveness in anorexia.

putting on weight

At present, the only way for women with eating disorders to protect themselves from osteoporosis is to try to maintain a reasonable weight during as many as possible of their teen years and twenties, when their bones reach their peak strength. If they delay their recovery beyond that time, it may be too late to build the bones they need to carry them into middle and old age.

help and info

Channel 4 is not responsible for the content of third party sites.

Read more about anorexia nervosa in our feature dieting without end.

organisations

National Osteoporosis Society
Manor Farm
Skinners Hill
Camerton
Bath BA2 0PJ
General Enquiries: 0845 130 3076/01761 471 771 (Mon-Thur 9am-4.30pm, Fri 9am-4pm)
Osteoporosis Helpline: 0845 450 0230 (Mon-Fri 9am-5pm)
E-mail: nurses@nos.org.uk
Support Groups: 01761 473 122
E-mail: groups@nos.org.uk
Website: www.nos.org.uk
Dedicated to improving the diagnosis, prevention and treatment of osteoporosis. Provides support to people with osteoporosis, their families and carers through a range of information booklets, a national telephone helpline and a network of regional support groups.

beat (formerly Eating Disorders Association)
103 Prince of Wales Road
Norwich NR1 1DW
Adult Helpline: 0845 634 1414 (Mon-Fri 10.30am-8.30pm and Sat 1-4.30pm)
E-mail: help@b-eat.co.uk
Youthline: 0845 634 7650 (Mon-Fri 4.30-8.30pm and Sat 1-4.30pm)
E-mail: fyp@b-eat.co.uk
Website: www.b-eat.co.uk
Campaigning organisation that provides information, advice and publications on all aspects of eating disorders. Operates a UK-wide telephone helpline and a youthline for information, help and support if you're aged 18 years and under. There is also a webzine, message board and chat room on the website.

websites

Foundation for Osteoporosis Research and Education (FORE)
www.fore.org
A US-based non-profit resource centre dedicated to preventing osteoporosis through research and education of the public and medical community to increase awareness of risk, detection, prevention and treatment.

The Jean Hailes Foundation
www.bonehealthforlife.org.au/sr_eating_disorders.asp
Australian site explaining the relationship between eating disorders and osteoporosis and providing information on maintaining bone health.

Osteoporosis
www.netdoctor.co.uk/diseases/facts/osteoporosis.htm
Well presented information page from Netdoctor on bone structure, bone disease and the diagnosis of osteoporosis.

reading

	Anorexia Nervosa by Janet Treasure (Psychology Press, 1997) This book attempts to answer some of the questions that are asked by sufferers, their families and friends. Get this book
	Osteoporosis: your questions answered by John Fordham (Churchill Livingstone, 2003) This book, written in a Q&A format by a renowned osteoporosis specialist, will provide the information needed by GPs and other practitioners to be able to understand and treat patients with osteoporosis. Get this book

	Understanding, Preventing and Overcoming Osteoporosis by Jane Plant and Gill Tidey (Virgin Books, 2004) An extensive study into the ways in which nutrition can be used to help conquer this disease. Get this book

	'The Effects of Anorexia Nervosa on Bone Metabolism in Female Adolescents' by LA Sokya and others in the Journal of Clinical Endocrinology & Metabolism vol 84, pg 4489-4496 Abstract available at: www.ncbi.nlm.nih.gov/ ..

	'Osteoporosis in Anorexia Nervosa' by JGF Bolton and S Patel in Journal of Psychosomatic Research, vol 50, pages 177-178 Link to full article at www.ncbi.nlm.nih.gov/ ..