Macular degeneration affects 1.5 million people in the UK and is the biggest cause of sight loss. There are many forms of macular disease however the largest percentage are those affected by age-related macular degeneration. This accounts for around 600,000 people in the UK and affects mainly over-50’s. If left untreated or if diagnosed too late the results can be devastating that can result in blindness. Macular degeneration is something that runs in my own family and so I found myself doing some research to understand it more and to see if there was anything I could do to lower my own risks of developing this horrible disease. I thought I’d share a summary of my findings with you.
What is the macular?
The macula is part of the retina at the back of the eye. It is only about 5mm across but is responsible for all of our central vision, most of our colour vision and the fine detail of what we see.
The macula has a very high concentration of photoreceptor cells that detect light and send signals to the brain, which interprets them as images. The rest of the retina processes our peripheral (side) vision. Macular disease causes loss of central vision.
Is there anything we can do to help prevent this?
Diet was always considered to be particularly important because certain nutrients protect the body against substances called “oxidants”. Many of the vitamins and minerals found in a healthy diet are called antioxidants.
Most research has focused on vitamins A, C and E. These are thought to maintain healthy cells and tissues in the eye. They are found in many fruits and vegetables, such as oranges, tomatoes and in green leafy vegetables. They can also be found in nuts, seeds, dairy products and other food types.
More recently, interest has grown in another antioxidant, lutein, and a similar substance, zeaxanthin. Both of these are yellow plant pigments, which give certain fruit and vegetables their colour, for example the yellow and orange in peppers, sweetcorn and saffron. Surprisingly perhaps, green leafy vegetables such as kale, spinach and broccoli also have high levels of lutein (you can actually see the lutein as the vegetables age and turn yellow).
The human body cannot make lutein or zeaxanthin; they have to be eaten. Several studies suggest that consuming at least 10mg of lutein per day has the most beneficial effects on macular pigment levels.
What about exercise?
A new study published this year from the University of Virginia School of Medicine has found that exercise reduced the harmful overgrowth of blood vessels in the eyes of lab mice by up to 45%. This tangle of blood vessels is a key contributor to macular degeneration and several other eye diseases.
The study represents the first experimental evidence showing that exercise can reduce the severity of macular degeneration.
“There has long been a question about whether maintaining a healthy lifestyle can delay or prevent the development of macular degeneration. The way that question has historically been answered has been by taking surveys of people, asking them what they are eating and how much exercise they are performing,” said researcher Bradley Gelfand, PhD, of UVA’s Center for Advanced Vision Science. “That is basically the most sophisticated study that has been done. The problem with that is that people are notoriously bad self-reporters … and that can lead to conclusions that may or not be true. This [study] offers hard evidence from the lab for very first time.”
Enticingly, the research found that the bar for receiving the benefits from exercise was relatively low — more exercise didn’t mean more benefit. “Mice are kind of like people in that they will do a spectrum of exercise. As long as they had a wheel and ran on it, there was a benefit,” Gelfand said. “The benefit that they obtained is saturated at low levels of exercise.”
An initial test comparing mice that voluntarily exercised versus those that did not found that exercise reduced the blood vessel overgrowth by 45%. A second test, to confirm the findings, found a reduction of 32%.
The scientists aren’t certain exactly how exercise is preventing the blood vessel overgrowth. There could be a variety of factors at play, they say, including increased blood flow to the eyes.
Gelfand, of UVA’s Department of Ophthalmology and Department of Biomedical Engineering, noted that the onset of vision loss is often associated with a decrease in exercise. “It is fairly well known that as people’s eyes and vision deteriorate, their tendency to engage in physical activity also goes down,” he said. “It can be a challenging thing to study in older people. … How much of that is one causing the other?”
The researchers already have submitted grant proposals in hopes of obtaining funding to pursue their findings further.
“The next step is to look at how and why this happens, and to see if we can develop a pill or method that will give you the benefits of exercise without having to exercise,” Gelfand said. “We’re talking about a fairly elderly population [of people with macular degeneration], many of whom may not be capable of conducting the type of exercise regimen that may be required to see some kind of benefit.” (He urged people to consult their doctors before beginning any aggressive exercise program.)
Gelfand, a self-described couch potato, disclosed a secret motivation for the research: “One reason I wanted to do this study was sort of selfish. I was hoping to find some reason not to exercise,” he joked. “It turned out exercise really is good for you.”
Oh well Mr Gelfand, keep looking…!