Some of the most recent headlines on dietary factors and dementia prevention involve cups of coffee. Yes, coffee.
In fact, the relationship between caffeine and dementia prevention is not new. Over the past few years there have been reports of studies exploring the potential beneficial effect of caffeine on cognitive function, but perhaps the media attention they have received has overstated their impact.
Research into Preventative Dietary Factors May Help Our Understanding of Dementia
The study of dietary prevention for dementia is of real interest for the general public as a way of preventing a disease where effective drug treatment or cures are still lacking. It certainly would also be useful for scientists to investigate the potential biological mechanisms by which caffeine might provide protection. This could add valuable knowledge to a field in need of better understanding so that new forms of drug treatment can be developed.
Is Caffeine Associated with Lower Risk of Dementia?
In the latest study published in the Journals of Gerontology, researchers in the US looked at the self-reported caffeine intake of almost 6500 women aged 65 years and over. They found that those who consumed more caffeine were at lower risk of incidence of dementia.
During the 10-year follow-up, the study, 200 women received a classification of probable dementia and 179 of mild cognitive impairment. Woman in the higher caffeine group, who consumed an average of 261 mg of caffeine (around 3 cups of coffee or 5 cups of tea) compared to the lower caffeine group (average 64 mg of caffeine) were 26% less likely to have either probable dementia or mild cognitive impairment.
The authors concluded that this study was generally consistent with the limited scientific literature that suggests a protective effect between caffeine intake and age-related cognitive impairment.
Limitations in Studies Looking at Caffeine and Dementia
However, we know that many studies of this kind are complex as caffeine consumption in women is also associated with other protective factors such as younger age, higher education and lower body mass index (indicator of weight). This particular study did control for these factors, but did not account for other potentially protective factors.
In addition, coffee the major provider of caffeine in the diet, declines as people age. Perhaps it is an unmeasured health association that causes some individuals to decrease their coffee intake – and it is this that is driving the results. We also know looking at the whole group of studies in this area that the level of caffeine associated with benefit varies considerably, yet we would, with a true benefit, expect a more consistent level across studies.
More studies are required before any public recommendations should be made on caffeine consumption for prevention of dementia. In the meantime, better protective measures against dementia include physical activity and a healthy balanced diet. In terms of hydration, which can be problematic in older people in care home settings, tea and coffee all count as fluid intake and so encouragement to drink is important – and may even be helpful to cognitive function although we are quite a long way from saying this conclusively at this stage.
