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alum and alzheimer's disease
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Aluminum and Alzheimer's Disease
Original Airdate: Thursday, February 22, 1996
Reporter: Celina Bell
We like to think of science as being logical and rational, that it progresses in an orderly fashion and that everyone is united in a common pursuit of the truth. Well, as nice as this sounds, it doesn't exactly work that way. Put two scientists to work on the same problem and they're just as likely to run off in opposite directions. Add competition for research money and political and business interests into the mix, and you have a recipe for full- scale gridlock. This scientific stalemate has to do with unlocking the mystery of a disease that's rapidly becoming one of the scourges of our time: Alzheimer's.
In Canada we take our drinking water for granted. Just turn on the tap and out it pours. We drink litres of it a day in our tea, our coffee, and our orange juice. We consume millions of gallons of it in a lifetime. Our drinking water comes to us from the local treatment plant, where it's clarified and purified with chemicals that make it clean and safe to drink. One of those chemicals is aluminum, and some scientists are worried it could be contributing to Alzheimer's Disease.
Allegations of a link between aluminum and Alzheimer's were first made 20 years ago when researchers detected higher amounts of aluminum in the brains of people who died of the disease. They speculated that the aluminum acted as a neurotoxin, gumming up the brain's functioning and contributing to the dementia. When the news first broke people began throwing away their aluminum pots and pans, their deodorants, and worrying about the processed foods they were eating. But experts have never been able to prove a definitive link between the aluminum in these products and Alzheimer's. Now a new series of studies - this time on the aluminum in our drinking water - has stirred up the debate again.
The latest study comes out of Ontario. Researchers autopsied 800 brains, more than a third of them from people who had diagnosed with Alzheimer's Disease. They checked the medical backgrounds of each subject and traced their residential histories, where they've lived and for how long. Then they looked at the records from 55 Ontario municipalities on average amount of residual aluminum in the drinking water supply. What they found was a striking correlation. Communities with high levels of aluminum in the drinking water had higher levels of Alzheimer's Disease.
The aluminum in our water is a chemical called alum. Alum is a cheap and effective way of removing toxic material from our water supply. When it's added to water it attracts and binds itself to organic material, settling it to the bottom of the tank so it can be removed during filtration. But some of it does make it into our tap water - how much varies considerably from place to place. In Toronto, for example, the drinking water comes from Lake Ontario, a fairly large and stable body of water. The amount of alum needed is low, and the levels after treatment are below 100 micrograms per litre. But in the Prairies the source water carries a lot of organic material from the soil and the rivers, and a lot more alum is needed to settle it. In some communities the level of alum in the drinking water is seven times higher than in Toronto.
More important than the amount of alum added at treatment is how much of it comes out of your tap. That's based on how the alum is balanced with other chemicals in the water. It's an intricate process, and in some communities the resources to monitor it properly just aren't available. Roughly 20 per cent of Ontario drinks water in excess of 100 micrograms per litre.
Halfway around the world in Sydney, Australia, another critical study has focused attention on this issue. The city needed a new water plant to service their growing population. The Sydney Water Board, prompted in part by the Ontario study, decided to take a closer look at the aluminum-in-Alzheimer's issue before building its new water-treatment plant. The board hired independent scientist Judie Walton to study whether the alum in drinking water could be absorbed by the body. In Walton's study rats were given the equivalent of one glass of Sydney tap water treated with alum. Two weeks later their brains were examine for the presence of aluminum, and they found it. This is the first study which has shown a direct pathway from the water, across the gastrointestinal tract, into the bloodstream, and then into the brain.
The theory has always been that if you're healthy, the aluminum that you ingest is eliminated by your kidneys. But Walton's study showed otherwise. Based on this and other recent studies, the Sydney Water Board decided to eliminate the use of aluminum in their new water plant, the second-largest in the world. In their announcement they stated: "None of the research is conclusive, but it provides the water board with a basis upon which to make decisions based on prudent avoidance".
In Canada health officials are looking at this new information. They're actually considering new guidelines that would limit the amount of aluminum in our drinking water. If Canada does go ahead and set guidelines, it will be the first country in the world to do so. But not everyone is taking this issue so seriously. There are a lot of scientists out there who think Alzheimer's has little to do with aluminum and much more to do with genetics.
If anybody has played a important role in opposing the aluminum-Alzheimer's link, it's Dr. Henryk Wisniewsky. For the past 20 years Wisniewsky has been one of the most prominent scientists in the field of Alzheimer's research, and he's a vocal critic of the link theory. He's published over 600 academic articles and he's a key organizer of major international conferences on the disease. It's at conferences like these that he challenges the link between aluminum and Alzheimer's, based on the fact that, so far, all the evidence pointing to a link has been inconclusive.
For Wisniewsky and other scientists, the key to Alzheimer's Disease is genetics. They're focusing on something called amyloid. It's a protein that builds up in the brains of Alzheimer's patients. The theory is that too much amyloid causes the degeneration of the brain that marks Alzheimer's victims.
So who's right? Now, when you look at other diseases like heart disease, genetics is seen as an important factor, but not the only one. Things like stress, diet and exercise are also taken into consideration - and the same could apply to Alzheimer's. But genetics is not the only factor, but it could be one of many that contribute to the disease.
But that's exactly where most of the research effort and funding is going, into genetics. Last year the two major governmental agencies in North America that sponsor medical research contributed hundreds of millions of dollars towards the study of Alzheimer's. The National Institute on Aging in the U.S. put $216 million into it, and the Medical Research Council of Canada gave out $850,000 worth of grants for Alzheimer's studies. None of that went to researching the aluminum- Alzheimer's link.
There's no doubt exciting advances are being made in genetics, and because it can yield such clear results, it attracts most of the funding and the attention. But it's very difficult to get those kinds of results when looking at other risk factors. The great debate on the role smoking plays in lung cancer is a case in point. The evidence is still not considered conclusive.
Another player in this debate is the American Aluminum Association, and industry lobby group based in Washington D.C. Twenty years ago it was caught off guard by early research into aluminum and Alzheimer's. The association has been vigilant ever since, challenging the link theory at every opportunity, with the argument that the evidence is inconclusive. There's a lot at stake for the industry, primarily their product image. To protect it, the association has been doing a lot of public relations work, and it set up its own health research program to respond to any allegations of a link. The program funds scientists to do research and regular literature reviews on everything written about the link; as well it funds scientists to organize and attend major international conferences on Alzheimer's where the link is being discussed. And it sponsors its own international conference on aluminum and health.
Among those who receive regular funding from the association is Dr. Wisniewsky. He's been monitoring the debate and conducting literature reviews on aluminum and Alzheimer's for the association for almost 20 years. In 1988 it helped him set up the Center for Trace-Element Studies, of which he's the director.
So where does this debate leave us? Should we be concerned about the aluminum in our drinking water? There is no clear answer. Even the Alzheimer's Society, the organization we rely on for information on this disease, is waiting for conclusive evidence.
In terms of public health policy, Sydney, Australia, took the extreme step of eliminating aluminum from their drinking water. Canada, on the other hand, is considering limiting the amount to a safer level. That action involves setting the recommended amount of aluminum in our drinking water at 100 micrograms per litre, what health officials consider to be safe. In fact, the World Health Organization is keeping a close eye on Canada's decision. In the meantime, there's very little we can do about what comes out of our tap, but you can at least find out - the amount of aluminum in our drinking water is public information - and if the levels are above 100 micrograms per litre and you're worried, you can practice prudent avoidance at home by buying bottled water that doesn't contain alum or by investing in an expensive filtration system.
Alzheimer Canada (National Office)
1320 Yonge Street, Suite 201, Toronto, ON M4T 1X2