Tea, red wine among foods tied to lower risk for dementia

Key takeaways:

• Greater adherence to flavonoid-rich foods reduced the risk for dementia.
• This risk reduction was greater in some people, like those with higher genetic risk or hypertension.

Adults who more frequently consumed several flavonoid-rich foods, like berries and tea, had a significantly lower risk for dementia, according to an analysis published in JAMA Network Open.

Certain individuals, like those with depressive symptoms or hypertension, benefited even more from higher adherence to a flavonoid-rich diet, the researchers found.

Flavonoids and flavonoid-rich foods have been previously tied to reduced risk for several diseases and health outcomes, including type 2 diabetes and mortality in those with colorectal cancer.

Meanwhile, as dementia cases and dementia-related mortality continue to rise, finding interventions for the disorder is “a major public health priority,” Amy Jennings, PhD, from Queen’s University Belfast in Ireland, and colleagues wrote.

“As the major food sources of flavonoids are similar in different regions, developing a composite score of flavonoid-rich foods may provide an opportunity to deliver a clear public health message on the range of foods with the potential to lower dementia risk,” they explained.

In the study, the researchers examined the effects of higher flavonoid consumption on dementia, as well as its interactions with factors like depression, high genetic risk and hypertension, within a cohort of 121,986 participants aged 40 to 70 years from the U.K. Biobank.

Researchers determined flavodiet scores, which reflected participants’ adherence to flavonoid servings, and flavonoid subclass intake based on 24-hour dietary assessments.

At a mean follow-up period of 9.4 years, 882 cases of dementia occurred.

Jennings and colleagues found that consuming an additional six servings of flavonoid-rich foods daily — the difference between the highest flavodiet score vs. the lowest — conferred a lower risk for dementia among:

• all participants (adjusted HR = 0.72; 95% CI, 0.57-0.89);
• participants at high genetic risk (aHR = 0.57; 95% CI, 0.42-0.78);
• participants with depressive symptoms (aHR = 0.52; 95% CI, 0.33-0.81); and
• participants with hypertension (aHR = 0.7; 95% CI, 0.52-0.94).

Among flavonoid subclasses, anthocyanins (aHR = 0.78; 95% CI, 0.62-0.97), flavan-3-ols (aHR = 0.72; 95% CI, 0.58-0.89), flavonols (aHR = 0.73; 95% CI, 0.59-0.91) and flavones (aHR = 0.71; 95% CI, 0.56-0.9) all reduced the risk for dementia.

Participants who consumed at least two of three ideal intakes — five servings of tea, one serving of red wine and 0.5 servings of berries — had a lower dementia risk compared with participants who did not achieve any of the intakes (aHR = 0.62; 95% CI, 0.46- 0.84).

Regarding the dementia risk reduction found in those with depression, “depression activates many of the mechanistic pathways known to be targeted by flavonoids, including increased proinflammatory cytokines, reduced cerebral blood flow, and modified vascular risk factors,” Jennings and colleagues noted.

Researchers identified multiple study limitations. The findings may not be generally applicable to a wider population because the U.K. Biobank cohort is healthier, consumes higher amounts of tea and has lower rates of smoking and obesity vs. the general population

Additionally, participants self-reported dietary data, while the researchers could not look at associations between those who consume flavonoid and those that do not.

Still, based on the findings, “modest changes to the diet could increase flavonoid levels to that required to lower dementia risk,” they wrote.