3rd May 2012 - A new study has found that people who eat foods that are rich in omega-3 fatty acids, such as fish, chicken and nuts, may also have lower levels in their blood of the protein beta-amyloid which is associated with Alzheimer's disease and memory problems.
Around 820,000 people in the UK have dementia and more than half have Alzheimer's disease. There is no cure for any type of dementia but this latest study suggests you may be able to reduce the risk of Alzheimer's disease through diet.
Amyloid precursor protein (APP) is found widely throughout the body but in people with Alzheimer's it's thought there is a fault with APP in the brain which leads to the production of a short, sticky, fragment of protein known as beta-amyloid.
The theory is that it's the accumulation beta-amyloid in the brain that triggers the disruption and destruction of nerve cells that causes Alzheimer's disease. It's not possible to study the levels of beta-amyloid in the brain while someone is still alive so this study looked at levels in blood.
In the study 1,219 people from New York older than age 65 and free of dementia were tested for beta-amyloid. The participants provided information about their diet for an average of 1.2 years and researchers looked specifically at 10 nutrients, including saturated fatty acids, omega-3 and omega-6 polyunsaturated fatty acids, mono-unsaturated fatty acid, vitamin E, vitamin C, beta-carotene, vitamin B12, folate and vitamin D.
The study found that the more omega-3 fatty acids a person took in, the lower their blood beta-amyloid levels were. Consuming one gram of omega-3 per day (equal to half a fillet of salmon per week) more than the average omega-3 consumed by people in the study was associated with 20 to 30% lower blood beta-amyloid levels.
The results stayed the same after adjusting for age, education, gender, ethnicity, amount of calories consumed and whether a participant had the APOE gene, a marker for Alzheimer's disease.
Study author, Dr Nikolaos Scarmeas from Columbia University Medical Center in New York and a member of the American Academy of Neurology, said in a press statement: Determining through further research whether omega-3 fatty acids or other nutrients relate to spinal fluid or brain beta-amyloid levels or levels of other Alzheimer's disease related proteins can strengthen our confidence on beneficial effects of parts of our diet in preventing dementia."
Dr Simon Ridley, Head of Research at Alzheimer's Research UK, said in an e-mail: "While this study provides interesting clues that omega-3 fatty acids in diet may be linked to amyloid levels in blood, it doesn't show whether this directly translates to less toxic amyloid in the brain and a lower risk of Alzheimer's disease. So far, research into omega-3 supplements for prevention or treatment of Alzheimer's in people has not shown conclusive benefits.
"Evidence shows that eating a healthy balanced diet can help to reduce the risk of dementia, however the causes of dementia are often complex and likely to result from a combination of lifestyle, environment, age and genetic factors. Much more research is needed to understand all of these risk factors and with 820,000 people in the UK living with dementia, the need for such research has never been greater."
The findings are published in the journal Neurology, the medical journal of the American Academy of Neurology.
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