FoundMyFitness

Research into blueberries does show a modest, consistently positive effect on memory and vascular health, but this concerns cognitive decline, not dementia as a clinical diagnosis. The specific figures of a 34% to 50% lower risk of dementia cannot be found in the available evidence on blueberries. Furthermore, those numbers are closer to what research into depression or other risk factors reports, not to blueberry research.

Multiple controlled studies do indeed show a modest improvement in episodic and verbal memory with daily blueberry consumption over an extended period, specifically in people with mild forgetfulness. The claim is therefore correct in its direction and target group. However, it goes slightly further than the evidence warrants: the direct mechanism of action via anthocyanins has not yet been fully elucidated, and the effects are modest, not spectacular. Moreover, the available human trial research is limited in scale, which does not fully support the certainty with which the claim is made.

Blueberries contain anthocyanins that protect blood vessels, and research shows a modest but consistent positive effect on vascular health with daily consumption. The direction of the claim is therefore correct. However, the claim is more specific than the evidence supports: that one cup a day allows arteries to relax more effectively and improves blood supply to organs cannot be substantiated on the basis of the available studies. The strongest evidence concerns memory in people with mild forgetfulness, not this specific vascular mechanism.

Research does indeed show a striking association between very frequent sauna use (four to seven times a week) and a lower risk of dementia, but the claim presents this as an established fact. The evidence currently comes from a single observational study conducted in Finnish men, which means that a causal relationship has not been demonstrated. Furthermore, the findings have not yet been confirmed in women or other populations, and randomised trials in humans are lacking.

Large observational studies do indeed show that short but vigorous bursts of physical activity spread throughout the day are associated with a substantially lower risk of cancer, cardiovascular disease and premature death. The direction of the claim is therefore correct, but the specific figures of 40% and 48 to 49% cannot be firmly established on the basis of the available research. Moreover, this is observational research, which means it cannot yet be said with certainty that the activity bursts themselves are the cause of the lower mortality.

Research shows that one year of aerobic exercise in older adults reverses 1 to 2 years of age-related brain shrinkage, as demonstrated in a randomised study. The claim is therefore broadly correct. However, the specific figure of 2% hippocampal growth cannot be firmly established on the basis of the available evidence, and the overall support for the claim is considered limited. The direction of the claim is right, but that specific number warrants scepticism.

The link between a sense of purpose and a longer life is well supported: in a large American cohort of people over fifty, those with little sense of purpose were more than twice as likely to die during the study period. However, 'the most important psychological predictor' implies a ranking, which would require directly comparing purpose with factors such as depression, loneliness, and optimism within the same model. That has not been done.

There is a randomized study in which mindfulness training was associated with lower IL-6 levels and changes in brain connectivity. At the same time, other studies found no effect on IL-6, and a study involving brief online meditation found no change in immune markers whatsoever. The specific protocol of five minutes over 28 days is not what has been tested.

This sounds logical and is an appealing idea, but I could find no research to support it. That the brain is more receptive to change during and after physical exertion has been described. That this therefore causes rumination to become more deeply ingrained when you follow gloomy news while exercising is an inference that no one has put to the test.

Two separate things are being conflated here. That aerobic exercise enlarges the hippocampus and improves memory has been demonstrated in humans. Whether adults produce new brain cells every day is, in fact, one of the most hotly debated questions in the field: two leading studies published in the same year reached opposite conclusions about whether this happens in adults at all. 'Every day' is therefore a far more categorical claim than the research supports.

There is evidence that people with stronger social bonds have lower inflammatory markers, and this has been measured on multiple occasions. However, the direction of the relationship cannot be established: people who feel ill and inflamed also tend to withdraw. That social contact itself reduces inflammation is plausible, but not proven.

The association is real and substantial: loneliness and social isolation are linked to a significantly higher risk of premature death. However, the comparison with fifteen cigarettes is merely a rhetorical device that researchers themselves have criticised. The figure comes from a conversion of effect sizes that are not comparable, and there is an analysis that sets out precisely this problem. Take the message seriously, just not the number literally.

This is well supported. A randomised study in older adults found that hippocampal volume increased after a year of aerobic training, and memory improved along with it. The effect is modest and applies primarily to aerobic exercise of a certain duration; a short stroll does not count.