This epidemiological study investigated 2,800 people aged 50 and above, and studied the long-term relationship between eating foods containing flavonoids and the risk of Alzheimer's disease (AD), Alzheimer's disease and related dementia (ADRD). Although many studies focus on the relationship between nutrition and dementia in the short term, this study focuses on the correlation for more than 20 years.
Flavonoids are natural substances in plants.
Flavonoids are natural substances found in plants, including fruits and vegetables, such as pears, apples, berries, onions, and plant drinks such as tea and wine. Flavonoids are associated with various health benefits, including reducing inflammation. Dark chocolate is another source of flavonoids.
Dr Paul Jacques, a nutritional epidemiologist and senior author of HNRCA, USDA, said: "Our research provides us with information that diet over time may be related to a person's cognitive decline, because we can study the intake of flavonoids many years before the participants are diagnosed with dementia. 」
Because there is no effective medicine to treat Harmo's disease, it is an important consideration to prevent the disease through a healthy diet. The study included 2,800 people (average baseline age–59.1year, female 52%), and studied the long-term relationship between eating foods rich in flavonoids and the risk of Alzheimer's disease and related dementia.
High intake of flavonoids in long-term diet can reduce the risk of Alzheimer's disease and related dementia in American adults. (Source: HeVoLi)
Experiment and compare with different intake.
In order to measure the long-term intake of flavonoids, the research team used a dietary questionnaire, which was filled out by participants in the Framingham Heart Study about every four years in medical tests. The participants in Framingham Heart Research are mainly Caucasians, who have been studying cardiovascular risk factors for generations.
At the beginning of the study, participants confirmed that there were no AD and ADRD through an effective food frequency questionnaire. The intake of flavonoids will be updated in each test to represent the cumulative average intake in five test periods.
The researchers divided flavonoids into six types and created four intake levels according to percentiles: less than or equal to15%,15-30%, 30-60% and more than 60%.
Examples of the level of research include:
Low intake (15% or less) means no berries (anthocyanins), about one and a half apples (flavonols) and no tea (flavonoid polymers) per month. High intake (60% or more) means about 7.5 cups of blueberries or strawberries (anthocyanins), 8 apples and pears (flavonols) per month and/kloc-0 per month. They found that lower intake of three kinds of flavonoids (15% or lower) was associated with higher risk of dementia compared with the highest intake (more than 60%):
Low intake of flavonols (apples, pears and tea) is associated with a twofold increase in the risk of Alzheimer's disease and related dementia. Low intake of anthocyanins (blueberries, strawberries and red wine) is associated with a fourfold increase in the risk of Alzheimer's disease and related dementia. Low intake of flavonoid polymers (apples, pears and tea) is associated with a twofold increase in the risk of Alzheimer's disease and related dementia. Association between flavonoid intake and all-cause mortality (Source: Nature)
conclusion
Drinking tea (especially green tea) and eating berries are the main sources of flavonoids. Esra Shishtar, the first author of the study, said that when we saw the results of the study, we found that those who benefited the most from eating more flavonoids were those who had the lowest intake themselves, and they did not need to consume too much to bring benefits. A cup of tea a day or berries three times a week is enough.
This study has some limitations, including the use of self-reported food data from the food frequency questionnaire, which are prone to errors in the recall. This finding applies to middle-aged or elderly people of European descent. Factors such as education, smoking, physical activity, body mass index and overall quality of diet may affect the research results, but the researchers considered these factors in statistical analysis. Because of its observational design, this study did not reflect the causal relationship between flavonoid intake and the development of AD and ADRD.