Scientists have created an “anti-Alzheimer's milkshake” that boosts memory, according to the Daily Mail. The newspaper says that the “once-a-day miracle drink” could be available within two years. This news is based on early-stage research that gave a daily nutrient drink to 225 people with early Alzheimer’s disease over a 12-week period. Although this was a well conducted study, its findings have been exaggerated by the news. The shake improved verbal recall, just one aspect of Alzheimer’s disease from a spectrum of potential problems. Improvements in one aspect of the disease may not have a large effect on the overall function of the person. The safety and effectiveness of this shake will need to be confirmed in further studies. This single, initial study does not provide sufficient evidence to confirm that the drink either reverses or prevents Alzheimer’s disease. Where did the story come from? This research was conducted by Dr Philip Scheltens and colleagues from VU University Medical Center in Amsterdam and other research centres in The Netherlands, USA, Germany and the UK. The study was funded by Danone Research through its Centre for Specialised Nutrition, which also provided the study products. Danone Research assisted in designing and planning the study, collected the data, and assisted an independent statistician in data analysis. The study is reported to have been submitted to the journal Alzheimer's & Dementia, but at the time of writing, the article was not available on the journal’s website. This appraisal is based on a copy of the draft manuscript of the study made available on the website of one of the authors. What kind of research was this? This was a randomised controlled trial designed to investigate how a multinutrient milkshake affected the cognitive function of people with mild Alzheimer’s disease (AD). The researchers noted that people with AD are often deficient in specific nutrients, and that these deficiencies could increase a person’s likelihood of developing AD. The drink, Souvenaid, has been specifically formulated to contain the nutrients that people with AD often lack, and is believed to improve transmission of impulses along nerve cells. A randomised controlled trial (RCT) is the best way of investigating the effectiveness and safety of a new treatment. Among other things, RCTs need to involve a reasonable sample size, have predefined outcomes and a sufficient duration of follow-up. What did the research involve? The researchers enrolled 225 people that fulfilled diagnostic criteria for mild AD but had not previously received any treatment for AD or for other psychological disorders. The trial was carried out in multiple centres in the UK, The Netherlands, Germany, Belgium and the US. Participants were randomised to drink either Souvenaid or a placebo drink daily, for 12 weeks. The placebo lacked the key ingredients but was identical in terms of other ingredients, looking and tasting similar to Souvenaid. Neither patients nor researchers knew which drink each participant had been randomised to receive. The amount of product taken daily was self-recorded by every participant, with non-compliance considered to be drinking less than 70% of the recommended dose overall or taking the drink on less than 75% of study days. The main outcomes assessed at study end were two tests of cognitive function: the delayed verbal recall task of the revised Wechsler Memory Scale, and the 13-item ADAS cognitive test. Blood tests were used to assess safety of the product at 6, 12 and 24 weeks. This is a well designed trial that used careful statistical analyses to measure the safety and efficacy of the product and to detect differences between the two groups. In certain parts of their analyses the researchers chose to include data on all individuals regardless of whether they completed or were compliant with the study. Results from 13 participants from one centre were excluded from the analyses of how effective the shake was because the centre did not comply with study guidelines. What were the basic results? There were no differences between the pre-treatment characteristics of the two groups. At 12 weeks, the treatment group showed improved verbal recall compared to the placebo group. However, there were no differences between the two groups in any other cognitive function outcomes measured, including clinicians’ observational assessments of any change or improvement in conducting activities of daily living. Compliance was said to be 95%, and the product was reported to be tolerated well. How did the researchers interpret the results? The researchers conclude that supplementation with a nutrient shake improved verbal recall in people with mild Alzheimer’s disease. They say that their ‘proof of concept’ study justifies further clinical trials of the drink. Conclusion Although this was a well designed randomised controlled trial, it was quite preliminary and has only shown improvement of verbal recall, a single aspect in people affected by mild Alzheimer’s disease. In Alzheimer’s disease a whole spectrum of memory and cognitive functions are impaired, including recognition of people and things, the ability to plan, conversing and understanding, and the ability to carry out normal activities of daily life. It is unclear whether a change in one aspect of the disease would make a difference to the person’s overall function. Even for this one measure, it was unclear from the research what the size of this improvement on the verbal recall scale was, and hence it is unclear whether it would make a notable clinical difference to memory. As such, the Daily Mail’s claim that the drink is a “once-a-day miracle” seems to be stretching the implications of this research too far. It is also unclear what has informed the newspaper’s estimate that the drink could be available in two years. The researchers have planned and conducted this study well, but there are some limitations that must also be considered: Further research will need to investigate how the drink affects people already taking drugs for their AD, or in people with moderate and severe disease. It is certainly too early to say that the nutrient shake could be of any benefit in the prevention of AD when taken by healthy people, as this has not yet been studied. AD is a diagnosis of exclusion, meaning that it is only considered when people fulfil specific diagnostic criteria and no other cause for their symptoms is identified. In any case, AD can only be definitely diagnosed at autopsy, so it is not known for certain that all of these participants had AD. The participants themselves recorded how much of the carton of drink they had consumed each day. This would be likely to involve some inaccuracy and variability, even in people with no cognitive impairment. As all participants had mild AD, inaccuracy seems more likely. As Danone Research funded the study and provided the drink, the organisation is likely to have a vested interest in the study’s findings. The double-blind nature of the study reduces the chance that the results can be influenced by researchers’ and participants’ beliefs about the effects of the product. This study has not yet been fully published, and reporting may change in the final published version. Until that time results should be interpreted with this caution.