Low cholesterol and Alzheimer's disease
Alzheimer's disease makes up 55% of dementia cases in the UK, according to the Alzheimer's Society and over 800,000 people in the UK currently suffer from Alzheimer's.
It is argued by some that the recent growth in numbers of people succumbing to Alzheimer's disease may be because it is a disease of the elderly and people are living longer. But that theory doesn't stand up to scrutiny as Alzheimer's is increasingly seen in younger people. It is also seen in people with other conditions known to be caused by an incorrect 'healthy' diet such as diabetes; and the number of people with Alzheimer's has more than doubled since 1980.
The low cholesterol we are all supposed to strive for is a likely cause of this increase in Alzheimer's disease. Work in the 1950s found that as we get older, the level of cholesterol in our brains declines.[1] Later studies suggested that this decline to 'healthy' low cholesterol levels may be the cause of brain disorders such as Alzheimer's.
In 1991, a paper discussing the relief of Alzheimer's Disease, asked that 'strategies for increasing the delivery of cholesterol to the brain should be identified' and recommended increasing fat intake.[2]
The Framingham Study added weight to this proposition when it examined the relationship between total cholesterol and cognitive performance.[3] Participants were 789 men and 1105 women who were free of dementia and stroke and who received biennial cholesterol checks over a 16- to 18-year surveillance period. Memory and cognitive tests were administered four to six years after the surveillance period and consisted of measures of learning, memory, attention, concentration, abstract reasoning, concept formation, and organizational abilities.
The researchers found a significant linear association between the level of blood cholesterol and measures of verbal fluency, attention, concentration, abstract reasoning, and a composite score measuring multiple cognitive domains. Participants with 'desirable' cholesterol levels of less than 5.2 mmol/L (200 mg/dL) performed significantly less well than participants with cholesterol levels higher than 6.25 mmol/L (240 mg/dL). Dr. Penelope K. Elias from Boston University said that:
'It is not entirely surprising that lower cholesterol levels were associated with moderately lower levels of cognitive function, given [that] cholesterol is important in brain function.'
And Henry Lorin in his book, Alzheimer's Solved, shows that low cholesterol level is the main cause of Alzheimer's disease.[4]
In November 2007, another study looked at the effects of taking statins on cognitive function and dementia. What the study found was that the:
"Initial use of statins resulted in less cognitive decline in individuals, but continued use of a statin resulted in more cognitive decline. "(emphasis added)
At first sight, this looks confusing. But this new study actually confirms the role of low cholesterol in Alzheimer's disease and in cognitive decline generally. And this is why:
Having a high cholesterol is associated with having good cognitive function but, as people with higher cholesterol are often put on statins, it isalso associated with being on a statin. Hence, just after the beginning of statin therapy, people with high cholesterol recently put on statins will still show a relatively good cognitive function.
If they continue with the statins, however, the detrimental effects of lower cholesterol on brain function will progressively show up.
This is exactly the pattern this study shows. And this is why those who started taking statins, then stopped, were in a better state than those who continued to take them.
In view of all this evidence, why on earth is the government so keen to get everyone on cholesterol-lowering drugs?
References
1. Max Burger. Altern und Krankheit als Problem der Biomorphose. 3rd Ed, Georg Thieme, Leipzig, 1957.
2. Corrigan FM, et al. Dietary supplementation with zinc sulphate, sodium selenite and fatty acids in early dementia of Alzheimer's Type II: Effects on lipids. J Nutr Med 1991; 2: 265-71.
3. Elias PK, et al. Serum Cholesterol and Cognitive Performance in the Framingham Heart Study. Psychosom Med 2005; 67:24-30.
4. Lorin, Henry. Alzheimer's Solved. BookSurge Publishing, 2006.
5. Szwast SJ, Hendrie HC, Lane KA, et al. Association of statin use with cognitive decline in elderly African Americans. Neurology 2007; 69: 1873-1880
Last updated: December 9, 2011
