
A recent meta-analysis, in October 2023, found that higher flavonoid intake was associated with a 17% lower risk of cognitive impairment and dementia. Mild cognitive impairment is the mild decline in memory and functioning that can often be seen several years before any dementia diagnosis.
This meta analysis looked at 13 observational studies (cohort and cross sectional) , and a further systematic review looked at a total of 27 studies. It looked at the general population aged 47-81.
Notably the flavonoids Anthocyanins and Flavones were found to confer the greatest reduction in risk (27 and 23% respectively). But in which foods do we find these and how can we include them in our diet?
Anthocyanins are most commonly quoted as found in blueberries. But it is important to remember that blackcurrants, Açai berries and pomegranates (fresh, rather than juice) are also particularly concentrated sources.
Flavones are particularly concentrated in chamomile, a great reason to get drinking the chamomile tea! In addition there are a number of herbs containing high levels: Oregano, Mint, Parsley, Rosemary and Shiso top the list, so even a small sprinkle of these to dishes can make an impact. Shiso is an aromatic leaf, related to the mint and basil family. Traditionally used in Japanese dishes, it can be easily grown in the summer months in the UK from seed and sprinkled into salads. It is also known as perilla leaf in English.
This study also showed a dose response relationship; the higher the intake of flavanoids the better- up to 250mg/day, which is quite difficult to achieve!
The drawbacks of this analysis include the common problem with many nutritional studies- that the flavonoid intake was estimated by dietary questionnaires, and some of the studies included did not adjust for confounders. In addition the studies that looked at cognitive impairment and dementia were not separated.
Dietary (Poly)phenols and Cognitive Decline: A Systematic Review and Meta-Analysis of Observational Studies
Justyna Godos et al. Mol Nutr Food Res. 2024 Jan.
Andrew Fisher
May 2024
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