With any luck, researchers will eventually uncover all of the meaningful factors that contribute to cognitive disturbances later in life. Presently, lifestyle habits and diet provide the most compelling protective measures.
A new pioneering epidemiological study of 2,800 subjects aged 50 and older, published in the American Journal of Clinical Nutrition, for instance, posits that adults with low intake of foods and drinks containing flavonoids, including plants, fruits, and vegetables such as pears, apples, berries, onions, plant-based beverages like tea and wine, and even dark chocolate, are more likely to develop dementia over the course of 20 years, compared to those who consume a higher intake of these items.
“Findings from existing prospective observational studies on the protective associations of flavonoid intake and the risk of Alzheimer’s disease and related dementias (ADRD) are inconsistent largely due to limitations of these studies,” the authors wrote in the new paper. “Given the absence of effective drug treatments to prevent, significantly attenuate, or ameliorate ADRD, extensive efforts are being made to identify modifiable risk factors that can lower the risk of developing ADRD, of which diet could hold significant promise (8, 9). Increasing evidence suggests that the Mediterranean diet, a dietary pattern that emphasizes flavonoid-rich fruits and vegetables, has the potential to reduce the risk of cognitive decline and ADRD.”
Long-term dietary flavonoid intake and risk of Alzheimer disease and related dementias
To assess the preventive potential of long-term flavonoid intake, the researchers analyzed children of the participants enlisted in The Framingham Heart Study that began back in 1948.
Titled, The Offspring Cohort, the pool primarily includes Caucasian participants who have been specifically observed for cardiovascular occurrences over several generations. However, The USDA HNRCA researchers behind the new report suspected that certain elements of The Mediterranean diet might have a role to play in preventing cognitive abnormalities in particular.
At the start of the study, the participants did not have Alzheimer’s disease or ADHD. In light of this, the authors had participants complete valid food frequency questionnaires to determine the extent to which they imbibed the flavonoids indexed above. Flavonoid intakes were updated at each juncture to represent cumulative average intake across a collective five exam cycles.
To ensure that the self-reported information was accurate, the researchers excluded questionnaires from the years leading up to the dementia diagnosis, given dietary behaviors can change as one’s mental health declines.
The paper categorized flavonoids into six types and created four intake levels based on percentiles: less than or equal to the 15th percentile, 15th-30th percentile, 30th-60th percentile, and greater than 60th percentile. They then compared flavonoid intake types and levels with new diagnoses of AD and ADRD.
- Low intake (15th percentile or lower) was equal to no berries (anthocyanins) per month, roughly one-and-a-half apples per month (flavonols), and no tea (flavonoid polymers).
- High intake (60th percentile or higher) was equal to roughly 7.5 cups of blueberries or strawberries (anthocyanins) per month, 8 apples and pears per month (flavonols), and 19 cups of tea per month (flavonoid polymers).
Consistently, participants who routinely received flavonoids, via various capacities, dramatically reduced their cognitive decline outcomes.
“Tea, specifically green tea, and berries are good sources of flavonoids,” said first author Esra Shishtar. “When we look at the study results, we see that the people who may benefit the most from consuming more flavonoids are people at the lowest levels of intake, and it doesn’t take much to improve levels. A cup of tea a day or some berries two or three times a week would be adequate.”
Researchers additionally observed a sort of mutualistic chicken and the egg phenomenon. Meaning, cognitive decline, and poor dietary habits tended to occur around the same time, and each was compounded for it in nearly equal measure.
It really is never too late to adjust, even if the goal post changes. Every year we live past 70, our risk for dementia-related maladies increases exponentially.
“Our study gives us a picture of how diet over time might be related to a person’s cognitive decline, as we were able to look at flavonoid intake over many years prior to participants’ dementia diagnoses,” explained Paul Jacques, senior author and nutritional epidemiologist at the USDA HNRCA in a media release. “With no effective drugs currently available for the treatment of Alzheimer’s disease, preventing disease through a healthy diet is an important consideration.”
CW Headley is a reporter for the Ladders and can be reached at email@example.com