Coffee, caffeine, and cognition: a defence against dementia?

A recent study from Harvard University suggests that drinking more coffee may be associated with a lower risk of dementia. The study tracked the caffeine intake of over 100,000 participants across 43 years, monitoring who went on to develop dementia. It was discovered that those with the lowest coffee intake were the most likely to develop the condition, while those who drank the most coffee showed noticeably lower rates. Coffee was not the only drink to have this apparent protective effect – higher tea consumption was also associated with a reduced dementia risk.

While previous research has hinted at caffeine’s neuroprotective properties, this is among the first studies to examine its long-term relationship with dementia risk. Previously, caffeine has been shown to lower the levels of amyloid-β in the brains of mice. This protein plays a central role in Alzheimer’s Disease, accumulating into plaques that damage brain cells and contribute to cognitive decline. Caffeine has also been linked to reduced inflammation in the brain, which is thought to underlie many symptoms of dementia, including memory loss and impaired thinking.

“Caffeine has also been linked to reduced inflammation in the brain, which is thought to underlie many symptoms of dementia”

Interestingly, the protective effects observed in the study did not extend to decaffeinated coffee – suggesting that caffeine itself may be the key factor. However, coffee and tea contain numerous other bioactive compounds, including polyphenols, which are known to confer health benefits such as protection against heart disease.

Despite the benefits observed, further studies need to be done. Most participants were healthcare professionals, meaning the results may not generalise to the wider population.The study also did not distinguish between different types of tea – such as black or green – nor did it examine variations in coffee preparation methods, both of which can influence chemical composition.

Nevertheless, the findings add to a growing body of evidence suggesting that moderate caffeine consumption may form part of a healthy lifestyle – welcome news for coffee and tea drinkers alike.

Immunity, infection, and innovation: a universal vaccine

A team of researchers at Stanford University are developing so-called “universal vaccines” – a technology that could reshape how we think about preventing infection. Traditionally, vaccines work by training the immune system to recognise antigens: specific molecules that allow immune cells to rapidly eliminate a familiar pathogen. This means most vaccines are highly specific. In addition, if a virus or bacterium mutates and alters the targeted antigen, vaccine efficacy can decline.

Instead of prompting a highly specific response from the adaptive immune system, this new approach harnesses the body’s innate immune system, which responds more broadly to threats. The vaccine effectively nudges innate immune cells into a heightened state of readiness, priming them to react rapidly to unfamiliar pathogens. An additional compound in the vaccine recruits T cells – part of the adaptive immune system – to communicate with innate immune cells and sustain this activated state.

“The researchers envision a future where people receive a single seasonal nasal vaccine that offers broad protection against a range of respiratory infections”

In experiments, the vaccine was administered intranasally to mice, who subsequently acquired immunity to multiple viral and bacterial respiratory infections, including SARS-CoV-2 (the virus that causes COVID-19) and Staphylococcus aureus. It also appeared to dampen immune responses to allergens such as dust mites, potentially by shifting the immune system from a Th2-dominant profile (associated with allergic responses) toward a Th1 profile, which is more effective at targeting certain pathogens.

The researchers envision a future where people receive a single seasonal nasal vaccine that offers broad protection against a range of respiratory infections – and perhaps even common allergens. However, despite media portrayals of a vaccination ‘revolution’, the technology has not yet been tested in humans. Moreover, the long-term consequences of persistently modulating the immune system remain unknown. Sustained immune activation could carry risks, including excessive inflammation or autoimmunity.