Regular coffee and tea consumption linked to fewer memory complaints

Adults who regularly drank caffeinated coffee or tea were less likely to say they had problems with memory and thinking in a large U.S. study. They also showed a lower risk of dementia, although the gains on formal cognition tests were modest.

The findings point to different parts of brain health. Self-reported changes reflect what people notice in daily life, while standardized tests measure performance on specific tasks and a dementia diagnosis reflects a more serious decline.

Researchers from Mass General Brigham, Harvard and the Broad Institute published the results in JAMA. Their analysis drew on 131,821 participants in the Nurses’ Health Study and the Health Professionals Follow-up Study, with follow-up records extending for as long as 43 years.

Participants were asked at intervals about their food and beverage habits. The researchers examined regular coffee, decaffeinated coffee and tea separately, then compared each one with several measures of brain health.

By the end of the study period, 11,033 participants had developed dementia. After accounting for other factors, those in the highest caffeinated coffee intake group had an 18% lower relative rate of dementia than those in the lowest group.

About 7.8% of people in the higher caffeinated coffee group reported worsening memory or thinking, compared with 9.5% in the lowest group. The team also found slightly better results on some formal cognitive measures, but the differences were small.

Other diet-and-brain studies have looked at whether the MIND diet may help slow cognitive aging.

Tea showed a similar overall pattern. The strongest associations appeared at roughly one to two cups of tea or two to three cups of caffeinated coffee a day, while decaffeinated coffee did not show a clear link to lower dementia risk or better test scores.

The formal cognitive tests were available only in the nurses’ study. On one 41-point telephone test, the average gap between the highest and lowest caffeinated coffee groups was just 0.11 points.

The researchers also examined whether inherited Alzheimer’s risk altered the pattern. They found no clear evidence that the associations varied by genetic risk, leaving open a question they can study across groups with different backgrounds.

People who drink different beverages often differ in diet, smoking, exercise and overall health. Although the researchers adjusted for many such factors, their data cannot account for every difference or rule out the possibility that early health changes affected what participants drank.

The study’s long follow-up and multiple outcome measures make it possible to compare whether the pattern holds across more than one endpoint. The next step would be to test whether changing beverage intake in an experiment affects memory or thinking, and whether any effect would be large enough for people to notice in everyday life.

If you are interested in this topic, please read articles about Coffee Could Boost Healthy Aging in Women Study Finds, and A Healthy Lifestyle Could Slow Down Memory Decline Study Finds.

For more information, please see articles about The Complicated Relationship Between Coffee and Diabetes, and How Tea and Coffee Influence Your Risk of High Blood Pressure.

Source: Mass General Brigham and Harvard T.H. Chan School of Public Health.