Losing excess weight could protect your eyesight

A new study has found losing excess weight could reduce damage to your eyesight, writes CLAIRE O'CONNELL

LOSING EXCESS weight is good for your heart and new research suggests it might help protect your eyes too. A study in Waterford has found that when people lose excess fat, levels of an eye-protecting pigment increase in their bloodstream.

Age-related macular degeneration (AMD) is considered the most common cause of registered blindness in the western world, and it involves the loss of protective pigments in an area of the retina called the macula at the back of the eye.

The links between obesity and increased risk of AMD were already known, according to Dr John Nolan, who directs the Macular Pigment Research Group at Waterford Institute of Technology along with Prof Stephen Beatty.

Fat cells are thought to compete with the retina for the macular pigment lutein, and if lutein is stored in fat it is not available to the eye – which could explain why obesity is a risk factor, explains Nolan.

“We wanted to see if we changed body fat how that impacted on the pigment, and the only way to identify that was to perform a gold-standard weight-loss investigation,” he says.

Working with Waterford Regional Hospital and other groups at WIT, they came up with a diet and exercise programme designed to help people lose weight and invited a group of overweight participants to follow it, while another overweight group acted as controls.

Looking at blood samples at intervals over a year, the researchers found that if a person slimmed down their blood lutein levels went up.

“[We found that] weight loss itself is positively correlated with increases in serum lutein levels,” says Nolan, who adds that keeping the weight on did not have the same effect.

“There was a percentage of people who didn’t lose weight and we wouldn’t have expected their levels of serum lutein to change at all – and that’s exactly what we found.”

The study, which controlled for dietary differences and risk factors, backs up the thinking that pigments which protect the eye are stored in fat too, according to Nolan.

“The theory is that if you lose fat these carotenoids [pigments] can go back into circulation into the blood and become available for the eye,” he says. “We want them to go to the retina because they have functional benefits both in terms of visual performance but also primarily protecting against an age-related chronic disease, macular degeneration.”

So did the people who shed kilos on the study also benefit in the eye department?

Not in this case – probably because the weight losses were not large enough over the short study, says Nolan. “The increase in serum was very significant and very positive but it wouldn’t be enough to impact over the time we tested in terms of the retina. They may well have had subtle changes but not to a statistically significant level,” he says.

“If you were to give someone a supplement that contains lutein you would have seen a much bigger change then we achieved with weight loss.”

The weight-loss study was supported by Fighting Blindness and the Health Research Board. AMD awareness week starts next Monday, and free testing to detect the early signs of AMD will be available at participating opticians, eye doctors, public libraries, golf clubs and other locations. See amd.ie