Older people who eat a diet high in carbohydrates are four times more likely to develop mild cognitive impairment - a precursor to Alzheimer’s disease.
New research from the prestigious Mayo Clinic in America has found the risk is also higher with a diet high in sugar.
On the other hand, proteins and fats appear to offer some protection – people who consumed plenty of them are less likely to suffer cognitive decline.
Not everyone with mild cognitive impairment (MCI) develops Alzheimer's disease, but many do, said lead author Rosebud Roberts, a professor in the department of epidemiology at the Mayo Clinic.
High-carb diets may play a role in the development of beta amyloid plaques, proteins found in the brains of people with Alzheimer's
MCI is defined as memory loss apparent to the individual and those around them, but with an absence of other dementia symptoms such as changes in personality and mood.
There are currently 800,000 people with dementia in the UK and 60,000 deaths a year are directly attributable to it, according to the Alzheimer’s Society. It’s estimated around six per cent of us will develop MCI.
Previous research suggested that 10-15 per cent of people with MCI went on to develop dementia every year the research results were followed up.
In community studies and clinical trials the rates are about half this level, but still represent a significantly increased level of risk.
That's why it's so important to identify people with MCI, as they may be in the very early stages of the disease and more likely to benefit from early treatment in the future.
The Mayo Clinic research tracked 1,230 people ages 70 to 89 and asked them to provide information on what they ate the previous year.
However proteins and fats appear to offer some protection - those who consumed plenty of them were less likely to suffer cognitive decline
Among that group, only the 940 people who showed no signs of cognitive impairment were asked to return for follow-ups every 15 months.
By the study's fourth year, 200 of the 940 were beginning to show mild cognitive impairment - problems with memory, language, thinking and judgment.
Compared with the 20 per cent of people with the lowest carbohydrate consumption, the 20 per with the highest had a 3.68 times greater risk of MCI, the study found.
‘If we can stop people from developing MCI, we hope we can stop people from developing dementia. Once you hit the dementia stage, it's irreversible,’ Professor Roberts told USA Today.
‘A high-carbohydrate intake could be bad for you because carbohydrates impact your glucose and insulin metabolism.
'Sugar fuels the brain, so moderate intake is good. However, high levels of sugar may actually prevent the brain from using the sugar - similar to what we see with type 2 diabetes.’
She added that high glucose levels might affect the brain's blood vessels and play a role in the development of beta amyloid plaques, proteins toxic to brain health that are found in the brains of people with Alzheimer's. It’s thought these plaques are a leading cause of the disease.
People whose diets were highest in ‘good’ fats, such as those found in nuts and healthy oils were 42 per cent less likely to get cognitive impairment. Those with a high intake of protein (such as meat and fish) had a reduced risk of 21 per cent.
Read more: http://www.dailymail.co.uk/health/article-2220173/People-eat-high-carbohydrate-diets-times-likely-develop-mild-cognitive-impairment--precursor-Alzheimer-s-disease.html#ixzz29kxVNNsp
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