Obesity places heavy weight on bones

In the past few years a growing number of studies have dispelled this theory by showing that very fat adults tend to have thinner bones. Picture: Oupa Mokoena

In the past few years a growing number of studies have dispelled this theory by showing that very fat adults tend to have thinner bones. Picture: Oupa Mokoena

Published Jul 16, 2013

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London - Being very overweight could put you at risk of brittle bones, research shows.

Until recently scientists had thought that carrying a few extra pounds helped protect bones and prevent fractures.

But a study revealed that adults with excess fat in their blood and organs are more at risk from osteoporosis which causes bones to become progressively weaker and prone to fractures.

The researchers think that instead of protecting bones, the extra fat triggers the formation of cells called osteoclasts which gradually wear them down. They also suspect that if large amounts of fat are stored within the bone it inhibits the production of new bone tissue.

Experts had assumed that being overweight or obese protected bones as fat cells release the hormone oestrogen. This is known to encourage bones to absorb the mineral calcium from the diet, which makes them stronger.

But in the past few years a growing number of studies have dispelled this theory by showing that very fat adults tend to have thinner bones.

This latest study by academics at Harvard University has suggested a cause by claiming that high levels of fat in the bones gradually wears them down.

Miriam Bredella, associate professor at Harvard Medical School in Boston who led the study, said: “Obesity was once thought to be protective against bone loss. We have found that this is not true. Bone marrow fat makes bones weak. If you have a spine that’s filled with fat, it’s not going to be as strong.”

Her study – published in the journal Radiology – looked at the bones and fat deposits of 106 obese men and women. The researchers used a type of scan called proton magnetic resonance spectroscopy to measure fat in the bone marrow, muscles and liver.

They found that adults with the most fat in their liver and muscles also had the highest levels of fat in their bone marrow, which increases the risk of osteoporosis.

More than three million people in Britain suffer from the disease for which there is no cure.

Children as young as eight are showing signs of high blood pressure due to obesity, according to a study.

Campaigners say these children are putting themselves at high risk of strokes, heart attacks and liver disease in adulthood and should watch their weight and salt intake. Harvard academics looked at blood pressure readings, weights and diets of 8 300 children aged eight to 17 surveyed between 1999 and 2008. They compared their average results with those of a group of 3 200 similar-aged children who were studied from 1988 to 1994.

Girls in the most recent group were 53 percent more likely to have higher than normal blood pressure. Some 12.6 percent had higher than normal readings compared to 8.2 percent of those surveyed earlier.

The proportion of boys with higher blood pressure rose from 15.8 percent to 19.2 percent, an increase of 21 percent.

British experts suspect the US results would be similar over here as so many children are now obese.

Doireann Maddock, senior cardiac nurse at the British Heart Foundation, said: “It’s a real concern to see raised levels at such a young age. Unhealthy habits formed in childhood can be hard to shake off.” - Daily Mail

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