Dieting by teenage girls desperate to reach 'size zero' could be putting their
bones at risk, say British researchers.
They found bone strength is linked to fat levels - meaning the pressure to be
thin may increase the chances of fractures.
A long-term child development study shows fat mass is more important to bone
development in girls than boys.
'Size zero' pressure leads to weak bones in girls
Warning: 'Size zero' pressure leads to weak bones in girls
It has long been known that being anorexic leads to prematurely thin bones, but
the latest study suggests a reason for decreased bone strength.
A team from Bristol University looked at more than 4,000 young people aged 15,
scanning their bones to calculate their shape and density, as well as how much
body fat they had.
Those with higher levels of fat tended to have thicker bones, with the
connection being 'particularly marked' in girls.
An increase in fat mass of 11lb (5kg) in girls was associated with an 8 per cent
increase in the thickness of the lower leg bone.
As girls tend to have higher levels of fat than boys, even when they are normal
weight, the findings suggest fat plays an important role in female bone
development.
Bone mass continues to increase slowly into the mid-20s but after the age of 35,
bone loss increases as part of the natural ageing process.
Building strong bones in youth is particularly important for women as they are
three times more likely to develop bone thinning, or osteoporosis, and suffer up
to three times more hip fractures than men in later life.
Professor Jon Tobias, leader of the research, said 'There is a good deal of
pressure on teenage girls to be thin, but they need to be aware that this could
endanger their developing skeleton and put them at increased risk of
osteoporosis.
'Many people think that exercise is the key to losing weight and building strong
bones at the same time - but this may only be true up to a point.
'If you do a good deal of low impact exercise, such as walking, you will
certainly lose fat but you may not be able to put enough stress on the bones to
build them significantly.
'To offset the detrimental effect of fat loss on your bones, it may be important
to include high impact exercise as well, such as running or jumping.'
Top doctors warned last year that 'size zero' supermodels were not only
jeopardising their own fertility and health, but setting a bad example to young
girls.
The latest findings came from a study called Children Of The 90s, which enrolled
14,000 mothers during pregnancy between 1991 and 1992.
It has since followed the youngsters and their parents in looking at various
aspects of health and bevahiour.
Other research also shows that young girls fail to eat sufficient calcium or
vitamin D to build optimal bone strength - up to 20 per cent less than
recommended.
Exercise levels among teenage girls are also consistently lower than advised for
maximising bone growth.
