Many people believe that memory loss is an inevitable part of the ageing process that they’re powerless to prevent, and that their chances of developing dementia is a bit like playing Russian roulette… it essentially all comes down to luck or fate.
But nothing could be further from the truth…
It’s well established that diet and exercise play an important role when it comes to promoting heart health. What many people don’t realise is their importance when it comes to keeping your mind sharp as you age and in the prevention of dementia. I was reminded of this recently when reading a study that found that a regular exercise programme, over the course of a year, led to significant improvements in memory .
But what of diet? I came across an interesting review recently that focused on the role of nutrition in the condition Alzheimer’s disease . This form of dementia is characterized by the build-up in the brain of a protein known as ‘amyloid-beta’.
One of the major points made in the paper is this: cholesterol and fat are really important to the brain. It points out that although the brain is only about 2 per cent of body weight, it contains about a quarter of the total cholesterol in the body.
The authors of the review point out several roles for cholesterol in the brain, including tiny structures called ‘synapses’. Synapses are the areas where one nerve cell can communicate with another. Communication here is via what are known as ‘neurotransmitters’, which are released by one nerve cell and float across the synaptic gap to exert an effect on the nerve adjacent to it.
The authors of the paper summarise the importance of cholesterol in the brain like this: “Cholesterol is required everywhere in the brain as an antioxidant, an electrical insulator (in order to prevent ion leakage), as a structural scaffold for the neural network, and a functional component of all membranes. Cholesterol is also utilized in the wrapping and synaptic delivery of the neurotransmitters. It also plays an important role in the formation and functioning of synapses in the brain.”
The review also points out that the brain actively takes up cholesterol – in the form of supposedly unhealthy ‘LDL’ cholesterol. This in itself suggests that the brain needs cholesterol and that it does something useful. Interestingly, a gene defect that leads to impaired cholesterol uptake by the brain is also associated with an enhanced risk of Alzheimer’s disease.
The authors of this review also point out that the fluid that circulates in and around the brain and spinal column (the cerebrospinal fluid) in individuals with Alzheimer’s disease is low in cholesterol and other fats compared to individuals without the disease. Also, those who run low cholesterol levels tend to be at enhanced risk of dementia.
In short, there’s quite a pile of evidence that strongly suggests that cholesterol is critical to proper brain functioning. In light on this, one might consider what effect cholesterol reduction may have in the long term. The review authors point out that “dietary avoidance of fats and cholesterol along with over-zealous prescription of cholesterol-reducing medications over the same decades in which there has been a parallel rise in AD [Alzheimer’s disease] prevalence.”
Such observations do not prove that lowered cholesterol actually causes Alzheimer’s disease, but as the authors point out, “… it gives weight to underlying research showing a possible link between cholesterol depletion and neuronal failure.”
Low cholesterol may turn out to be bad news for the brain. The problem is, any effects here are likely to be gradual, and the full impact of our cholesterol-phobic policy may not be seen for some time to come.
Here’s to a healthy heart
Dr John Briffa
for The Cholesterol Truth
Bear in mind we are not addressing anyone’s personal situation and you should rely on this for informational purposes only. Please consult with your own physician before acting on any recommendations contained herein.
1. Erickson KI, et al. Exercise training increases size of hippocampus and improves memory. PNAS 31 January 2011 [epub ahead of print]
2. Seneff A, et al. Nutrition and Alzheimer’s disease: The detrimental role of a high carbohydrate diet Eur J Int Med 2011;22:134-140
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