Experts have strongly condemned "irresponsible" and "deeply cynical" claims that a new food supplement can slow the progress of Alzheimer's.
A study of 13 patients found that a combination of fish oil and eye-protective nutrients led to "significant" improvements in memory, sight and mood.
Trial patients who took the Memory Health supplement "displayed overwhelmingly positive responses", according to a press release accompanying the product's launch.
Progression of the disease was delayed and the supplement helped "maintain cognitive abilities and quality of life", it was claimed.
A month's supply of 30 of the capsules costs £27.50 and is available online from www.memoryhealth.com.
But leading experts strongly criticised the research behind the product, calling the "breakthrough" claims irresponsible and warning that the findings were "highly unlikely to be true".
Thirteen patients with mild to advanced Alzheimer's disease were given the supplement for 18 months and their progress assessed.
Each Memory Health capsule contains a combination of macular carotenoids and fish oil containing omega-3 fatty acids.
Macular carotenoids such as lutein and zeaxanthin are plant-derived pigment compounds that are thought to protect the retina from damage.
The new approach to tackling Alzheimer's was pioneered by Dr Alan Howard, inventor of the low-calorie rapid weight loss plan the Cambridge Diet.
Dr Howard, who chairs The Howard Foundation charity that promotes nutrition research and was one of the study authors, said: "This represents one of the most important medical advancements of the century.
"Alzheimer's disease is the largest public health crisis the UK has ever faced, and drug companies have so far fallen at every hurdle in finding a solution.
"This study gives us that breakthrough, in a unique natural compound of nutrients."
Colleague Professor John Nolan, founder of The Nutrition Research Centre Ireland (NRCI) in Waterford, where the study took place, said: "I believe this is a valuable discovery that will challenge perceptions worldwide about the role of nutrition in brain function."
However, independent experts reviewing the results published in the Journal of Alzheimer's Disease were not impressed.
Naveed Sattar, Professor of Metabolic Medicine at the University of Glasgow, said: "Whilst any research in Alzheimer's disease is to be welcomed, this is too small a trial and lacks a placebo control so that its findings are highly unlikely to true.
"In fact I would place no reliance on these results, especially since we know little effect of fish oils or carotenoid supplements on other outcomes in proper trials."
Professor Robert Howard, head of Old Age Psychiatry at University College London, said: "This report is sadly not much more than low-grade anecdotal evidence. Certainly, it falls seriously short of the standards of a high-quality clinical trial in terms of scale and conduct.
"The accompanying claims made by Dr Howard seem irresponsible and completely unsupported by any reasonable reading of his data.
"Sadly, people with dementia and their carers will grasp at any straw and I would worry about the impact of media reports around what seem either naive or deeply cynical attempts to exploit this."
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."
Memory Health is licensed on a not-for-profit basis by the Howard Foundation with £1.50 from every purchase supporting research into Alzheimer's disease.