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  1. 1. IS4 October 2003 Information sheet Aluminium and Alzheimer’s disease Introduction Alzheimer's disease is the Introduction...................1 commonest form of Causes............................1 dementia. It causes Scientific evidence..........2 progressive loss of all mental Sources of aluminium.....4 powers - the powers to Controlling intake...........4 think, to remember and to 1. Food...........................4 reason. Alzheimer’s disease 2. Packaging....................5 affects about 35,000 people 3. Pots and pans..............7 in Scotland. The disease 4. Medicines.....................7 kills brain cells and leaves 5. Water..........................8 behind a tell-tale scattering 6. Air..............................8 of dead cells with tangled Summary........................9 fibres (neurofibrillary tangles) and the accumulation of clumps of a Causes protein called ‘A beta’. These clumps are known as No-one really understands plaques. Its not yet clear if the cause (or causes) of the plaques cause the cells Alzheimer's disease. Genetic to die, if they are part of a inheritance may play a part defence mechanism or and it does seem that a rare possibly both at different early onset form of the times. disease is inherited in a few families. Page 1
  2. 2. Aluminium and Alzheimer’s disease Scientists have also loss of memory in the suggested that animals. environmental factors such 2. It has been claimed as virus infections, toxins, that, in Alzheimer's disease, head injuries and metabolic the aluminium content in the disorders may be involved. nerve cells with tangles is No-one really knows for higher than in adjacent, sure. undamaged nerve-cells. Similar findings have been Some people think that one claimed for tangle-bearing of the clues to the mystery cells present in a rare may lie in aluminium. There disease similar to is circumstantial evidence Alzheimer's disease (the so- linking aluminium with called ‘Guam’ disease). Alzheimer's disease. But it is However, recent studies impossible to say so far using a new and very whether aluminium may be a powerful kind of analytical cause of Alzheimer's disease, microscope (nuclear although it is looking less microscopy) have shown that and less likely. the high levels of aluminium in tangles are actually Scientific evidence caused by the way the cells were prepared when they The evidence has were being examined. accumulated over a period of decades and comes from 3. Studies in Newcastle several sources: appeared to show that there is a deposit of aluminium combined with silicon at the 1. Aluminium is one of the centre of the senile plaque. few substances known to However, other research has cause tangles when injected suggested that this is not the into animals. Although these case. tangles are not identical to those which occur in man, they appear to contain some 4. Aluminium was similarities. These identified as the cause of experiments also cause a ‘dialysis dementia’. Patients Page 2
  3. 3. Aluminium and Alzheimer’s disease undergoing dialysis for ‘free radicals’, which are kidney disease developed probably responsible for cell severe memory loss and death in all degenerative other symptoms including diseases. There is some convulsions. By removing evidence that aluminium, aluminium from the dialysis which is not a highly reactive fluid this condition was metal like iron or copper, prevented. Patients with may interfere with this ‘dialysis dementia’ do not, process, possibly allowing however, seem to develop more free iron to circulate the plaques and tangles seen and so generate more free in Alzheimer's disease. radicals which in turn generate yet more free 5. Studies on the uptake of radicals in a chain reaction. aluminium have indicated that it enters the brain 6. A recent survey bound to a protein called suggests that rates of transferrin. Transferrin is a Alzheimer's disease are protein that binds and higher in areas with the transports iron around the highest level of aluminium in body. The greatest uptake of the water supply. The aluminium in the brain disease was approximately occurs in areas rich in one and a half times more transferrin receptors and frequent in districts with these coincide with the higher levels of aluminium in regions which are vulnerable the water, compared with in Alzheimer's disease. those in which it was low or absent. This is a relatively Iron, together with copper, small increased risk and the binds to proteins such as A researchers agree that this beta. Iron and copper are research is inconclusive, highly reactive ‘transition raising more questions than metals’ which are involved in answers. ‘oxidation-reduction reactions’. These reactions Taking all the research lead to the production of findings together, the Scots highly toxic chemicals called law verdict of ‘not proven’ Page 3
  4. 4. Aluminium and Alzheimer’s disease seems like the best verdict, fatigue. There have been although ‘not guilty’ is reports of persistent illness beginning to look more since the incident including likely. However there is little instances of memory loss. doubt that aluminium is Reports have failed to agree neurotoxic (poisonous to on whether these health brain cells) and excessive complaints could have been intake should be avoided. caused by the water contamination. Sources of aluminium Controlling intake Aluminium is all around you - visible in pots and pans, Is it possible to control invisible in food, water and aluminium intake from the air. It is the most abundant six main sources - food, metal in the earth's crust. packaging, medicines, pots and pans, water and air? An average person has a daily intake of 7mg of 1. Food aluminium. By far the Most foods contain some greatest intake comes from aluminium. Tea and some food. But most is not herbs and spices contain retained and passes straight particularly high levels. through the gut and is Scientists think you probably excreted. absorb very little of the aluminium you take in from At Camelford in Cornwall, 20 food. Aluminium often binds tons of aluminium sulphate strongly with other was accidentally discharged substances in food such as into the water supply in fluoride and phosphate, 1988. Some people were which may make it less exposed to very high absorbable. Tannin in tea concentrations of aluminium combines with aluminium so in the water. There were that little is absorbed. short-term toxic effects including diarrhoea, Studies have found that vomiting, headaches and beverages (tea, coffee and Page 4
  5. 5. Aluminium and Alzheimer’s disease soft drinks) and cereals double your daily aluminium (cakes, puddings, biscuits, intake from food. There are breakfast cereals, bread, plans to tighten the flour, oatmeal and rice) are regulations to allow additive our main sources of E173 to be used only on the aluminium from food. small silvered cake decorations. Some aluminium is naturally present in food but some, in Aluminium concentrations the form of aluminium salts, are 10 to 20 times greater in is added for various most cow's milk formulas purposes. Aluminium-based (and 100 times greater in additives are widely used in soya-based formulas) than in bleaching, in preserving and breast milk. But this is pickling processes, and in generally not thought to powdered foods such as pose a risk, except in instant coffee, dried milk, premature babies or infants artificial ‘creamers’ and table with kidney disease, who salt. Bread, cake, biscuits may absorb and retain more and baking powders may be aluminium. high in aluminium if they contain aluminium food 2. Packaging additives. Your food may come into contact with aluminium from Four aluminium additives packaging, foil trays, foil have E-numbers: E173, lined cartons and aluminium E541, E554 and E556. cans. Or you may cook or Others are shown by name store food in foil. in additive listings on foods. Additive E173 is powdered The amount of aluminium aluminium. Its only added to most foods by permitted use is for coating freezing, storing and cooking a range of sweets from small it in foil or disposable cake decorations to sugared aluminium trays is negligible. almonds. Eating just a handful of the bigger Most foil-lined cartons or 'silvered' sweets could aluminium cans have a layer Page 5
  6. 6. Aluminium and Alzheimer’s disease of lacquer, plastic or cardboard covering the metal and the food or drink picks up very little aluminium. Page 6
  7. 7. Aluminium and Alzheimer’s disease 3. Pots and pans It is best not to clean The aluminium added to uncoated aluminium pans most foods by cooking in with cleaning soda or bleach. uncoated aluminium pans is These strip away the surface less than 0.1mg per 100 of pans, leaving newly gram serving. But the acid in exposed metal, which is some foods can increase the more likely to dissolve into amount of aluminium in food food. Acidic food stored in picks up from uncoated uncoated aluminium aluminium pans. cookware can also accumulate aluminium. Rhubarb cooked in an uncoated aluminium pan or Recent reports suggesting pressure cooker can, for that fluoride in water example, pick up 4mg of increases the aluminium aluminium per 100g serving. dissolved from cooking Adding sugar can halve the utensils have been amount of aluminium disproved. dissolved. If you want to reduce your aluminium 4. Medicines intake from cookware, you Many antacids used for could avoid cooking acidic treating indigestion and foods (most fruits, including ulcers contain large amounts tomatoes) in uncoated of aluminium compounds. aluminium pans. But little of the aluminium is normally absorbed. Cooking food in coated/non- stick or hard-anodised The recommended daily dose aluminium pans adds of some antacids may virtually no aluminium. contain 1,000mg to 2,000mg Coated or non-stick pans are of aluminium. Studies of easy to distinguish from people using antacids have uncoated pans. Hard- shown however that those anodised aluminium pans are exposed to high levels of steely grey or black. aluminium over long periods are no more prone to Alzheimer's disease than Page 7
  8. 8. Aluminium and Alzheimer’s disease other people. Antacids make addition, aluminium sulphate the stomach more alkaline, is widely used in the filtering and this prevents the of public water supplies. The absorption of most of the European standard is not aluminium. Aluminium based on any estimate of absorption is higher if possible health risk, but on antacids are taken with aesthetic considerations of orange juice instead of water colour. Most people's water. water in the UK has less aluminium that 0.2mg in a Some deodorants also litre. contain aluminium but there is no evidence that Aluminium salts are added to aluminium salts in water supplies in virtually all deodorants pass through areas of Scotland. There are skin. alternative ways of treating the water but they are more 5. Water expensive and less effective. Your intake of aluminium You have the right, as a from water is very small. But consumer, to be provided some scientists think the with an analysis of your aluminium in water is in a supply. We believe that no form that's easier for your water authority should body to absorb. exceed the European limits. Even if your water was at Some water filters will the maximum recommended remove aluminium from the European standard for water though not all are aluminium content (0.2mg in effective. a litre), your intake from two litres a day would be only 6. Air 0.4mg - less than one-tenth There isn't much you can do of the average daily about aluminium in the air. aluminium intake from food. Your intake from the air is in any case negligible. Some Aluminium in naturally inhaled aluminium enters present in some water. In Page 8
  9. 9. Aluminium and Alzheimer’s disease your lungs, but hardly any moment there is no known enters the rest of your body. test which will identify those at risk from Alzheimer's All in all, there isn't a very disease and it is not known great deal that you can do to whether limited aluminium reduce your aluminium would prevent the disorder intake. And until we know or slow down its progression. more about the how It is extremely difficult to aluminium might affect the control exposure to brain we can't even be sure bioavailable forms of about any risks or benefits. aluminium. The evidence linking aluminium in water Summary supplies with Alzheimer's disease is inconclusive. None of the evidence so far has proved that aluminium Although foods and contributes the degenerative medicines rich in aluminium changes which cause additives can be avoided, it Alzheimer's disease. must be emphasised that we However, there is more do not know if they evidence linking aluminium constitute a risk. with this disorder than there is for any other Any precise link between environmental factor. The Alzheimer's disease and disease may involve an aluminium will remain a interaction between genetic mystery for the meantime. and environmental factors. The majority of older people do not get Alzheimer's disease despite the widespread presence of aluminium in the environment. The risk from increased exposure to aluminium must be small in general terms. At the Page 9
  10. 10. Aluminium and Alzheimer’s disease This publication was This information sheet was produced with the support of revised in 2003 with the kind the Community Fund. assistance of Dr Nikki MacLeod, University of Edinburgh. It was first written in 1991, based on material prepared by Professor J. A. Edwardson for the Alzheimer's Disease Society and in the consumer magazine Which?, June 1990. Alzheimer Scotland 22 Drumsheugh Gardens, Edinburgh EH3 7RN Telephone: 0131 243 1453 Fax: 0131 243 1450 Email: Alzheimer Scotland - Action on Dementia is a company limited by guarantee and is recognised as a charity by the Inland Revenue. Registered in Scotland No. 149069. Scottish Charity No. SC022315. Find us on the internet at Page 10