Could a daily dose of fish oil help with Alzheimer's disease?

Could a daily dose of fish oil help with Alzheimer's disease? Eating oily fish, fruit and vegetables can prevent brain shrinkage in old age linked to Alzheimer’s disease, a study has found. U.S. researchers discovered that elderly people with high levels of certain vitamins and omega 3 oils in their blood did better in memory tests than those with a less healthy diet.
Brain scans confirmed those with the highest levels of vitamin D and omega 3, found in fish such as mackerel, and vitamins B, C and E, found mainly in fruit and vegetables, also had a significantly larger brain volume.
Conversely people whose blood had higher levels of trans fats – found in cakes and fried foods, as well as red meat – had the worst scores and less brain tissue.
This is thought to be the first study to investigate nutrient levels through blood tests rather than looking at food diaries or questionnaires.
The scientists, from Oregon Health & Science University, say this gives a more accurate picture because it does not rely on memory or honesty, and because in old age some people’s blood absorbs more of the nutrients they eat than others.
Study author Dr Gene Bowman said: ‘These results need to be confirmed, but obviously it is very exciting to think that people could potentially stop their brains from shrinking and keep them sharp by adjusting their diet.’
As the research was carried out on healthy patients, rather than those with the degenerative disease, it suggests the effect of fish oils could be preventative, rather than a cure for age-related memory loss.
Dr Bowman said nutrient levels in the blood accounted for 37 per cent of the variations seen in brain volume. In memory tests, it accounted for a ‘significant’ 17 per cent -  other factors being age, years of education and blood pressure.
The authors noted that very few studies have assessed the risk of effect of trans fats on Alzheimer’s, and the fact that they ‘may aggravate cognitive decline’.
They studied blood samples from 104 healthy older people with an average age of 87, and few known risk factors for Alzheimer’s, who also undertook cognitive tests.
Brain scans were then carried out on 42 of the participants which found those with nutrient-rich diets had larger brains as well as higher test scores, according to the study published today in the journal Neurology.
Dr Simon Ridley, head of research at Alzheimer’s Research UK, welcomed the study, although noted that it was a small sample of people and the researchers did not investigate whether these people went on to develop Alzheimer’s.
He said:  ‘One strength of this research is that it looked at nutrients in people’s blood, rather than relying on answers to a questionnaire.
‘Although there is no sure-fire way of preventing Alzheimer’s yet, we know that risk factors for heart disease and stroke can also increase the risk of dementia.
‘The best advice at the moment is to eat a balanced diet with plenty of fruit and vegetables, and keep healthy by not smoking, taking regular exercise and keeping blood pressure and cholesterol in check.
‘There is a clear need for conclusive evidence about the effect of diet on our risk of Alzheimer’s, which can only come from large-scale, long-term studies.
‘Currently 820,000 people are affected by dementia in the UK and with a rapidly ageing population, those numbers are expected to soar.
'We urgently need to find ways to prevent dementia if we are to head off a future crisis, and that means it’s vital to invest in research.’
A major £7million study last year from the same U.S. university found taking fish oil supplements did not slow mental or physical decline in patients who already had the degenerative brain disease.
However previous studies have linked them with reduced risk of developing Alzheimer’s.