Study: Antioxidant flavonol linked to lower risk of Alzheimer's dementia

In continuation of my update on kaempferol, myricetin and  quercetin

 

                                                                 kaempferol

                                                                       

                                                                      myricetin

                                                 

                                                                          Quercetin

        

People who eat or drink more foods with the antioxidant flavonol, which is found in nearly all fruits and vegetables as well as tea, may be less likely to develop Alzheimer's dementia years later, according to a study published in the January 29, 2020, online issue of Neurology, the medical journal of the American Academy of Neurology.

"More research is needed to confirm these results, but these are promising findings," said study author Thomas M. Holland, MD, of Rush University in Chicago. "Eating more fruits and vegetables and drinking more tea could be a fairly inexpensive and easy way for people to help stave off Alzheimer's dementia. With the elderly population increasing worldwide, any decrease in the number of people with this devastating disease, or even delaying it for a few years, could have an enormous benefit on public health."

Flavonols are a type of flavonoid, a group of phytochemicals found in plant pigments known for its beneficial effects on health.

The study involved 921 people with an average age of 81 who did not have Alzheimer's dementia. The people filled out a questionnaire each year on how often they ate certain foods. They were also asked about other factors, such as their level of education, how much time they spent doing physical activities and how much time they spent doing mentally engaging activities such as reading and playing games.

The people were tested yearly to see if they had developed Alzheimer's dementia. They were followed for an average of six years. The researchers used various tests to determine that 220 people developed Alzheimer's dementia during the study.

The people were divided into five groups based on how much flavonol they had in their diet. The average amount of flavonol intake in US adults is about 16 to 20 milligrams per day. In the study, the lowest group had intake of about 5.3 mg per day and the highest group consumed an average of 15.3 mg per day.

The study found that people in the highest group were 48 percent less likely to later develop Alzheimer's dementia than the people in the lowest group after adjusting for genetic predisposition and demographic and lifestyle factors. Of the 186 people in the highest group, 28 people, or 15 percent, developed Alzheimer's dementia, compared to 54 people, or 30 percent, of the 182 people in the lowest group.

The results were the same after researchers adjusted for other factors that could affect the risk of Alzheimer's dementia, such as, diabetes, previous heart attack, stroke and high blood pressure.

The study also broke the flavonols down into four types: isorhamnetin, kaempferol, myricetin and quercetin. The top food contributors for each category were: pears, olive oil, wine and tomato sauce for isorhamnetin; kale, beans, tea, spinach and broccoli for kaempferol; tea, wine, kale, oranges and tomatoes for myricetin; and tomatoes, kale, apples and tea for quercetin.

People who had high intake of isorhamnetin were 38 percent less likely to develop Alzheimer's. Those with high intake of kaempferol were 51 percent less likely to develop dementia. And those with high intake of myricetin were also 38 percent less likely to develop dementia. Quercetin was not tied to a lower risk of Alzheimer's dementia.

Holland noted that the study shows an association between dietary flavonols and Alzheimer's risk but does not prove that flavonols directly cause a reduction in disease risk.

Other limitations of the study are that the food frequency questionnaire, although valid, was self-reported, so people may not accurately remember what they eat, and the majority of participants were white people, so the results may not reflect the general population.

https://en.wikipedia.org/wiki/Myricetin

https://en.wikipedia.org/wiki/Quercetin

https://medicalxpress.com/news/2019-07-high-hemoglobin-linked-dementia.html

Plant flavonols significantly reduce Alzheimer’s risk

A new study published in the journal Neurology in January 2020 concludes that increasing the intake of plant flavonols steeply reduces the risk of Alzheimer’s dementia (AD) by up to a half. In other words, AD could be prevented in many people simply by regularly eating and drinking more foods containing these compounds such as tea, oranges, and broccoli.

Alzheimer’s disease

AD is a progressive brain disorder in which the individual loses cognitive skills, including memory and thinking skills, and the ability to perform simple tasks. It is by far the leading cause of such disorders and affects over 5 million Americans.

One study was carried out on over 900 people, who were part of a community-wide ongoing larger research project called the Rush Memory and Aging (MAP) Project. These participants were assessed yearly for their neurologic health and dietary patterns, for an average of 6 years, but some for as long as 12 years. The average age was 81 years, and 3 out of 4 were female.

The findings

In the first study, 220/921 participants developed AD during the study. The risk of AD fell with a greater intake of flavonols. This finding held good even after the researchers adjusted for other health-associated factors – because those with the highest total flavonol intake were also the best educated, most active and took part in more cognitive activities. They also accounted for genetic factors like the presence of the APOE4 gene, and for cardiovascular risk factors that could influence the risk of AD, such as diabetes mellitus, history of heart attack, or stroke, or hypertension.

When classified into five groups based on decreasing flavonol intake, the participants in the first group (highest intake) consumed over 15 mg of flavonols a day. Compared to those in the lowest fifth (about 5 mg a day), these individuals showed an approximately 50% reduction in AD risk.

In concrete terms, 28 of 186 patients in the highest-intake group developed AD, vs. 54 of 182 in the lowest-intake group.

With respect to individual flavonols, kaempferol intake was linked to a reduction of almost 50%, and both myricetin and isorhamnetin by 40% each. A fourth flavonol, called quercetin, had no noticeable effect on AD risk.

Participants with the highest flavonol intake drank about one cup of black tea a day. Kale, and about a glass of red wine each day, could also supply flavonols.

Sources of flavonols

Kaempferol is richly present in green leafy vegetables, including spinach, broccoli, beans, tea and kale – and also in tea. Isorhamnetin-rich foods include olive oil, red wine, pears and tomato sauce. Myricetin is found in tea, kale, oranges, tomatoes and red wine.

Researcher Thomas Holland says, “More research is needed to confirm these results, but these are promising findings. Eating more fruits and vegetables and drinking more tea could be a fairly inexpensive and easy way for people to help stave off Alzheimer's dementia.”

Implications

Many scientists disagree with the emphasis on flavonols. Though these were thought to have antioxidant activity in the body, this theory was discredited many decades earlier. Antioxidant activity ceases when they are ingested and subjected to the activity of enzymes in the digestive tract.

They point out that flavonols are found in many plants, fruits and vegetables, which have been associated with good health for centuries. Nutritionists say that the AD-delaying effects of such foods are likely due to other plant chemicals which are relatively more abundant. On the other hand, taking flavonol pills or tea extracts is unlikely to produce the same healthful effect, and overdoses could be counterproductive.

This is not to say that eating more flavonol-rich foods or drinking a cup of black tea in the morning would hurt, since any foods containing these chemicals would also contain many more healthful compounds including vitamins, minerals and plant fiber. Holland makes a valid point with his conclusion: “'With the elderly population increasing worldwide, any decrease in the number of people with this devastating disease, or even delaying it for a few years, could have an enormous benefit on public health.”

https://n.neurology.org/content/early/2020/01/29/WNL.0000000000008981

Plant flavonols significantly reduce Alzheimer’s risk

Researchers identify potential sources of medicines derived from plants against diabetes

A group of researchers from the university's School of Science, led by Dr Solomon Habtemariam, believe they have identified potential sources of medicines derived from plants which may have fewer adverse side-effects for diabetes sufferers.

The scientists are investigating the properties of two plants found in south-east Asia which they think could have properties that are not only anti-diabetic, but also lipid- or fat-lowering, and so can help tackle obesity. The researchers at Greenwich aim to isolate and identify certain extracts from the plants Cassia auriculata and Cassia alata, which could have 'active ingredients' for treating diabetes. They discovered that one of the compounds isolated from the plant, kaempferol 3-O-rutinoside, (structure below)  has proved to be more than eight times more potent than the standard anti-diabetic drug, acarbose.  

The team also found the plants have anti-oxidant properties, which is beneficial when treating diabetes.

"Our other most interesting finding is that many of the active ingredients from the Cassia auriculata plant work through a process called 'synergism' - in other words, they work together to produce an effect greater than the sum of their individual effects," Dr Habtemariam says. "Overall, this suggests that the crude plant extract has lots of potential to be used clinically for treating diabetes and associated diseases."

The researchers adds that the research  is ongoing and requires further study and validation, in my opinion it is interesting...

Ref : http://www2.gre.ac.uk/about/news/articles/2012/a2410-drugs-for-diabetes-scientists-test-the-power-of-plants

Researchers identify potential sources of medicines derived from plants against diabetes

Animal studies examine role of raspberry products in weight management and motor function

 

The latest issue of the Journal of Berry Research includes two new animal studies that investigate the effects of raspberry consumption in helping to support healthy weight and motor function (strength, balance and coordination). Future studies are needed to support the results found in these studies.

One-cup of frozen red raspberries has only 80 calories, is an excellent source of vitamin C, and provides nine grams of fiber (more fiber than any other berry). Like most berries, raspberries are a low-glycemic index food. Raspberries contain phytochemicals, such as ellagic acid, quercetin, gallic acid, cyanidins, pelargonidins, catechins, kaempferol and salicylic acid.

Animal and cellular studies examining how phytochemicals may work at the molecular level suggest that certain phytochemicals may help slow age-related declines. Age is the number one risk factor for many chronic diseases. Likewise, obesity is a major risk factor for chronic disease. These latest animal studies examine two important areas of health where raspberry products may play a role in weight management and also support motor function.

OBESITY

An animal study conducted by researchers at Oregon State University found that when added to a high-fat, high-sucrose diet, raspberry products and raspberry phytochemicals were found to significantly decrease weight gain associated with a high-fat, high calorie diet. Raspberry juice and raspberry puree concentrates were provided at 10% of total energy (the equivalent of 200 calories in a 2,000 calorie diet), and a combination of ellagic acid and raspberry ketone were provided at 0.2% weight/weight.

In the study, 76 male mice were divided into the following diets: a low-fat control group (10% calories from fat), a high-fat control group (45% calories from fat) and seven "high-fat treatment" groups that included a high-fat diet plus either raspberry juice concentrate, raspberry puree concentrate, raspberry fruit powder, raspberry seed extract, raspberry ketone and a combination of equal parts of ellagic acid and raspberry ketone.

"The addition of raspberry juice concentrate, raspberry puree concentrate and the combination of ellagic acid plus raspberry ketones to the high fat diet significantly reduced weight gain observed in the high-fat fed mice," said Dr. Neil Shay, Principal Investigator. "In the case of the high-fat and raspberry juice concentrate diet, weight gain was reduced to a level that was statistically equivalent to the weight gain of the low-fat fed mice, despite the fact that all high-fat fed groups consumed the same amount of calories and more energy than the low-fat control group throughout the study."

The researchers concluded that the intake of a reasonable level of some raspberry food products may influence some of the metabolic consequences of consuming a high-fat, high-calorie diet in the development of obesity in male mice.

"We hope that the findings from this study can help guide the design of future clinical trials," said Dr. Shay.

MOTOR FUNCTION

Researchers from the Human Nutrition Research Center on Aging at Tufts University evaluated the effectiveness of a red raspberry-supplemented diet on age-sensitive measures of learning, memory and motor performance in older rats.

In this 10-week study, red raspberry supplementation was found to significantly improve motor skills. Specifically, compared to rats fed a standard well-balanced diet, rats fed a diet supplemented with freeze-dried raspberry extract performed better on tests which measured psychomotor coordination and balance, as well as tests that measure muscle tone, strength, and stamina.

"These results may have important implications for healthy aging," said lead researcher Barbara Shukitt-Hale, PhD. "While further research in humans is necessary, animal model studies are helpful in identifying deficits associated with normal aging."