Berries may reduce cognitive decline – experts respond

New research has found that eating antioxidant-rich berries could delay age-related cognitive decline by up to two and half years.

Blueberries and strawberries, which are high in flavonoids, appear to reduce cognitive decline in older adults according to a new study published this week in Annals of Neurology. The study results suggest that cognitive aging could be delayed by up to 2.5 years in elderly who consume greater amounts of the flavonoid-rich berries.

Flavonoids are compounds found in plants that generally have powerful antioxidant and anti-inflammatory properties. Previous studies of the positive effects of flavonoids, particularly anthocyanidins, are limited to animal models or very small trials in older persons, but have shown greater consumption of foods with these compounds improve cognitive function.

The authors of the new research used data from the US Nurses’ Health Study-a cohort of 121,700 female, registered nurses between the ages of 30 and 55 who completed health and lifestyle questionnaires beginning in 1976.

Researchers observed that women who had higher berry intake delayed cognitive aging by up to 2.5 years. The authors caution that while they did control for other health factors in the modeling, they cannot rule out the possibility that the preserved cognition in those who eat more berries may be also influenced by other lifestyle choices, such as exercising more.

Our colleagues at the UK SMC collected the following expert commentary.

Dr Eric Karran, Director of Research at Alzheimer’s Research UK, said:

“Population studies like this can provide useful clues about the effects of lifestyle and diet on cognition, but we must be sensible when interpreting the results. The study suggests a link between eating berries and slower cognitive decline, but there could be many factors at play.

“It is not possible to say whether the increased consumption of berries resulted in an increased, beneficial level of flavonoid antioxidants in the brain. Further research will be needed to conclude whether antioxidants in berries are beneficial in the brain and we can’t assume that simply eating berries could protect against cognitive aging or dementia.

“Understanding the factors that affect our memory and thinking as we age can help us to understand possible risk factors for dementia. Previous evidence has shown that eating fruit as part of a healthy diet in midlife could help to reduce our risk of dementia and so eating a healthy balanced diet is something we should all be thinking about. With 820,000 people in the UK living with dementia, there is an urgent need to understand more about how to reduce the risk.”

Carol Brayne, Professor of Public Health Medicine, University of Cambridge, said:

“Broccoli, blueberries, Mediterranean diet, Sudoku… is very difficult indeed to be sure that this is not residual confounding as these kinds of dietary patterns are associated with many other positive attributes, which themselves are associated with healthier ageing.

“Blueberries have been of interest for many years and it’s certainly worth further investigation, but for definitive evidence we have to await well designed trials as this is another observational study.”

Derek Hill, CEO of IXICO and Professor of Medical Imaging Sciences, University College London, said:

“Later this year, two major drug trials targeting the proteins in the brain associated with Alzheimer’s Disease will announce their results. Many experts fear these drugs will be added to the long list of potential dementia treatments that fail to demonstrate conclusively that they slow cognitive decline.

“This latest research suggesting that a diet high on berries can slow cognitive decline in the elderly population is therefore especially welcome. It is a large and well-designed study that significantly strengthens the evidence that changes to diet may be able to delay onset of dementia symptoms. This suggests that we can take further steps to tackling the scourge of dementia in society while we await the arrival of effective new medicines.”