Professor John Nolan said the trial, involving 25 Alzheimer’s patients, was “a stepping stone”. His acknowledgement of the study’s limitations states “the number of subjects in each trial for this report was small and therefore our findings must only be viewed as preliminary”.
“The findings presented here will need to be confirmed by a larger powered sample, and with appropriately definite outcome measures and study design,” he wrote in the June edition of the Journal of Alzheimer’s Disease.
However when the research was published yesterday, the man who pioneered it, academic Dr Alan Howard, inventor of the Cambridge Diet, described it as “one of the most important medical advancements of the century”.
His claims attracted considerable criticism, including from Naveed Sattar, professor of metabolic medicine at the University of Glasgow, who said “this is too small a trial and lacks a placebo control so that its findings are highly unlikely to be true”.
Dr David Reynolds, chief scientific officer at the charity Alzheimer’s Research UK, said: “The experimental design of this study makes it hard to draw meaningful conclusions about the effect of these supplements on the symptoms of Alzheimer’s... claims about the significance of these findings should be met with caution.
Prof Nolan said while the research team “greatly appreciate the review and commentary of our scientific peers”, it is “important to note that the findings from this exploratory clinical trial have been informed by two decades of research”.
“Specifically, we have shown in a very large population based study [4,453 participants] that the specific nutrients examined in this trial [carotenoids] are highly correlated with cognitive performance in a group of older adults.”
Prof Nolan said the data in the latest study was supported by biologically plausible scientific rational and that high-performance liquid chromatography (HPLC) analysis of the blood samples of the patients had borne out their findings.
This is an exact science and the statistical implications are clear, and valid,” he said.
The trial involved 25 patients, split into two groups of 12 and 13. Twelve patients with AD were given a nutritional supplement containing antioxidants found in green leafy vegetables (carotenoids), while 13 were given a formula that also contained fish oil.
Prof Nolan said carers of Alzheimer’s patients who took part “did identify improvements in patients taking the carotenoid and fish oil combination compared to carotenoids alone,” including to memory, sight and mood.
Carotenoids, found in many fruits and vegetables, are thought to confer health benefits due to their role as antioxidants. Fish oil, containing omega 3, also has recognised health benefits.
The study, entitled ‘Nutritional Intervention to Prevent Alzheimer’s Disease’, was conducted by the Nutrition Research Centre Ireland in collaboration with University Hospital Waterford (UHW).