Macular degeneration is the primary cause of blindness in Australia today. And evidence is mounting that the likely cause of the disease is consumption of vegetable oils. But once again Australia’s Dietitians Association is on the side of the processed food industry instead of the consumer (or in this case, the patient).
Our eyes are exquisitely complex pieces of machinery which work much like a camera. Light from the outside world hits the the retina at the back of our eye. The macula is the centre of the retina. It is responsible for our detailed vision. If our macula is damaged, we can no longer see fine detail, drive, read or recognise faces.
Macular degeneration begins in a layer of cells underneath the retina called the Retinal Pigment Epithelium (RPE). The RPE is responsible for transporting oxygen and other nutrients up to the retina and moving waste products down to the blood vessels underneath. It also contains a specialised immune system which reacts to some of the more dangerous waste products produced by the macula.
When the RPE wasted disposal system fails, junk from the retina builds up underneath the RPE. These junk deposits, known as drusen, appear as yellow spots on the retina and are visible in a normal eye examination. As the disease progresses, vision loss happens because the RPE cells die (‘dry’ macula degeneration) or because the RPE cells fail to prevent blood vessels from growing into the retina (‘wet’ macula degeneration) from below the RPE.
The macula contains a high concentration of some of our most specialised hardware, the rod and cone cells that allow us to see in fine detail and in colour. These cells are unusual in that they use polyunsaturated fats in their membranes rather than the saturated and monounsaturated fats used by most of the remainder of our cells.
If you’ve ever wondered what an essential fat (like omega-3 DHA) is essential for, there’s a big part of your answer. The omega-3 DHA fats make up the outer segments of the light sensitive cells in the retina and are the most frequently replaced cell membranes in our body.
When these molecules are exposed to light they oxidise rapidly (this is thought to be an important part of how our light sensing cells work). Normally oxidation is a very bad thing because of the waste products it produces (broken bits of fat molecules and free radicals).
But our body didn’t fall off the back of the potato truck yesterday. The special immune system built into the RPE does a magnificent job of getting rid of all the junk, so the oxidation is not normally a problem. That is unless we use the wrong kind of polyunsaturated fats.
Researchers have consistently found that people with macular degeneration have abnormally low levels of Omega-3 fatty acids in their retina. This has inspired many studies which look at the dietary fat breakdown of the participants.
As expected a lot of those trials have shown that when people are eating a diet high in fish (the principal dietary source of the correct omega-3’s) they tend to have less macular degeneration. But closer analysis of the figures has unearthed a very worrying exception. They are only better off if they are also NOT eating omega-6 fats. Indeed, people eating a diet high in omega-6 fats are twice as likely to have macular degeneration as those eating a diet low in those fats (regardless of how much omega-3 they are consuming).
We have known for at least two decades that our body isn’t that picky when it comes to omega-3 and omega-6 fats. If we need an omega-3 polyunsaturated fat and the only one handy is omega-6 then our body just goes ahead and uses that. And there’s no reason to suspect that our body isn’t doing exactly the same thing in our eyes.
A number of researchers have speculated that what is going on in macular degeneration is that when we eat too much omega-6 fat, our body is simply using that instead of the preferred omega-3. When the omega-6’s are oxidised, their waste products are different to those produced by the omega-3’s. This waste is not recognised by the RPE, not cleaned up by its immune function and accumulates as the drusen which lead to macular degeneration.
The only place we are likely to encounter significant quantities of omega-6 fats in our everyday life is in, well, everything. Over the last two decades, the Australian Heart Foundation and the Dietitians Association of Australia (DAA) have been busily ensuring that the dominant health message in this country is that we should be eating those fats (rather than ‘unhealthy’ saturated fats).
The omega-6 fats occur in large quantities in ‘vegetable oils’ made from seeds (canola, cottonseed, soybean, sunflower, safflower, rice-bran and grape-seed). And it is exactly those oils which now form the basis of every margarine, every fried food, every ‘ovenfry’ food, most biscuits, most breads, and most ‘heart-healthy’ products on sale in Australia today.
Faced with this research, the DAA’s response is exactly the same as their response to research that sugar is an extremely dangerous addition to our diet – denial. Worse than that, their official position appears to be a rerun of a press-release provided by the Australian Oilseed Federation (the folks representing those with money to make out of seed oils).
Macular Degeneration is a debilitating disease which now affects a significant proportion of our population. The average Australia is four times more likely to suffer from macular degeneration than they are to suffer from Dementia. One in seven Australians over the age of 50 (a little over a million people) has macular degeneration and this number is likely to increase by at least 70 per cent by 2030.
There is now significant evidence of the role of seed oils in the development of the disease. But once again, the folks charged with looking out for our health are squarely on the side of their corporate sponsors.
Luckily there is something you can do without their assistance. Don’t eat seed oils.
Image courtesy of dream designs at FreeDigitalPhotos.net