What is Alzheimer’s disease?
Alzheimer’s disease is a form of dementia that tends to affect people after the age of 60 years. The risk of developing it increases with age.
In Alzheimer’s disease the nerve cells (neurons) in the brain are slowly destroyed, resulting in memory loss and difficulty in completing simple tasks. As the disease progresses personality and emotional changes, often combined with depression, can become evident.
For more on Alzheimer’s disease, please see BUPA’s Alzheimer’s disease factsheet.
How common is Alzheimer’s disease in the UK?
Approximately 425,000 people in the UK have Alzheimer’s disease.
Why did the researchers look at whether vitamin C and vitamin E use reduced the risk of developing Alzheimer’s disease or not?
Alzheimer’s disease is caused by progressive damage to nerve cells in the brain. While it is not know what causes the nerve damage seen in Alzheimer’s disease, there are a number of theories that may explain how it occurs.
One way in which nerve damage can occur is by a process called “oxidative stress”. This is where molecules produced by the body, called free radicals, react with cells.
Certain vitamins, including vitamin C and vitamin E, mop up free radicals in the body and prevent them from damaging the body’s cells. These vitamins are known as antioxidants and are know to combat the effects of ageing on the body.
For more on vitamins, please see BUPA’s Vitamins article.
What were the findings of the research?
The American researchers studied the use of vitamin supplements in elderly (65 years or older) people in Cache County in Utah. Between 1995 to 1997, the researchers asked 4740 people about their use of supplements. These people were followed up in 1998 to 2000 and, of the 3227 survivors, 104 of them had developed Alzheimer’s disease.
By comparing the use of supplements in 1995-1997 to the development of Alzheimer’s disease, the researchers found:
- use of a high-dose supplement of vitamin E and a high-dose supplement of vitamin in combination reduced the risk of developing Alzheimer’s disease
- use of a high-dose supplement of vitamin E in combination with a multivitamin supplement that contained vitamin C also reduced the risk of developing Alzheimer’s disease
- use of a high-dose supplement of vitamin E on its own did not reduce the risk
- use of a high-dose supplement of vitamin C on its own did not reduce the risk
- use of a multivitamin supplement on its own did not reduce the risk
From these results, the researchers argue that it is important that high-dose individual supplements of vitamins C and E are taken in combination for the vitamins to have a positive effect.
What does this research mean?
These results suggest that regularly taking vitamin C and E supplements may reduce the risk of developing Alzheimer’s disease due to the antioxidant effect of these vitamins.
However, there are number of issues that need to be considered before it can be recommended that people take regular vitamin C and E supplements:
- there may be other reasons why people’s risk of developing Alzheimer’s disease was reduced
- the levels of vitamin C and E in these individual supplements was much higher than the recommended daily allowances for these vitamins
- the results are drawn from people reporting their use of supplements at the beginning of the study, with no follow up on their supplements use at the end of the study. Because of this there is no information as to whether or not the people kept on regularly taking the supplements during the time of the study.
What other reasons might explain the reduction in risk of developing Alzheimer’s disease?
It is known that other factors influence the risk of developing Alzheimer’s disease, namely:
- level of education
- general health
The researchers found that those people who took the vitamin E or C supplements were more likely to be female, younger, better educated and in better general health than the other people in the study. Since it is possible that these factors can reduce the risk of developing Alzheimer’s disease anyway, the researchers employed statistical analysis to try to cancel these effects out. After doing this, the researchers still found that taking high-dose vitamin E in combination with vitamin C had a positive effect on reducing risk.
How high were the levels of vitamin C and vitamin E in the supplements?
The recommended daily allowance of vitamin C is 60mg and for vitamin E it is 10mg.
Multivitamins supplements in America normally contain 75-90mg of vitamin C and 15mg of vitamin E.
However, the individual supplements contain high doses of the vitamins: 500-1000mg of vitamin C and up to 680mg of vitamin E.
Is it a good idea to take these vitamins at such high levels?
Vitamin C at high levels is not normally harmful, but doses above 1000mg can cause nausea, stomach cramps and diarrhoea.
Prolonged intake of vitamin E at high levels (above 540mg) can cause abdominal pain, nausea, vomiting and diarrhoea. It can also lead to impaired uptake of other useful vitamins.
The Alzheimer’s Society suggests that we eat five portions of fruit and vegetables a day, along with oily fish and nuts in our general diet, to gain all the vitamins, minerals and essential fatty acids we need. They point out that increasing evidence suggests that there are strong links between a good varied diet, a healthy heart and a healthy brain.
What can we do to reduce our risk of developing dementia?
- don’t smoke
- keep fit by exercising regularly
- keep your blood pressure in check and avoid salty foods
- keep your cholesterol under control and cut out the fat
- live life to the full – enjoy friendships and stimulating hobbies
- drink red wine in moderation
- eat five portions of fruit and vegetables a day
- eat at least one portion of oily fish a week
- wear a helmet when cycling or motorcycling and don’t box.