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

Is Okra Good for Diabetes?

According to a handful of recent studies, okra may reduce symptoms of diabetes - a group of diseases that includes type 1 diabetes, type 2 diabetes, and gestational diabetes.

 

Diabetes claimed the lives of 75,578 Americans in 2013, according to the United States Centers for Disease Control and Prevention (CDC). In 2014,8.5 percent of adults worldwide had the condition, the World Health Organization (WHO) report. By 2030, diabetes may be the seventh leading cause of death.

A number of factors increase a person's risk of developing diabetes, including a family history of the disease. Lifestyle factors also play a role, so doctors routinely recommend diet changes and increased exercise to reduce blood sugar levels.

Okra may help reduce blood sugar levels in some people with diabetes. Research into the effects of this seedy vegetable is still in the early stages, but the results are promising.

Okra thrives in temperate climates, producing large hibiscus-like flowers that eventually give rise to green seed pods. It is a member of the mallow family, which includes a number of other popular plants, including hibiscus, cocoa, and cotton.

Scientifically known as Abelmoschus esculentus, okra may have been grown as long ago as 2000 BCE in Egypt.

Okra's flavor is mild, and the entire seed pod can be eaten. This vegetable-like fruit also has a long history in traditional medicine.

Kew Royal Botanic Gardens report that in Eastern traditional medicine, okra leaves and fruit were used as pain relievers, moisturizers, and to treat urinary disorders. In Congolese medicine, okra is used to encourage a safe delivery during childbirth.

Can okra help with symptoms of diabetes?

Diabetes can often be well-managed with increasing a hormone called insulin and other medical therapies. However, some people with diabetes wish to avoid regular insulin injections. Others experience blood sugar dips and other unpleasant side effects, and diabetes medications do not work for everyone.

The possibility that a readily available seed pod could help control diabetes is an exciting one. But there is no evidence yet that okra can cure diabetes. So far, the research on okra has only looked at its effects on animals. Human bodies are similar to animals, but not all research on animals has worked out in humans.

Increased absorption of sugar by muscles

A 2005 study published in Planta Medica investigated the effects of okra on rats with diabetes. A substance called myricetin is present in okra and some other foods, including red wine and tea.

Researchers isolated myricetin from okra, then administered it to the rat. The treatment increased absorption of sugar in the rats' muscles, lowering their blood sugar.

A 2012 Food Science and Human Wellness review points to a number of other laboratory and animal studies that have linked myricetin to lower blood sugar. The study argues that myricetin may also reduce other risk factors for diabetes.

Reduction in blood sugar spikes after eating

A 2011 study published in ISRN Pharmaceutics found a link between okra and decreased blood sugar spikes after eating.

Researchers fed rats liquid sugar as well as purified okra through a feeding tube. Rats who consumed the okra experienced a reduction in blood sugar spikes after feeding. The study's authors think this is because the okra blocked the absorption of sugar in the intestines.

The study also explored possible interactions between okra and metformin, a drug that can reduce blood sugar in type 2 diabetes. Okra appeared to also block absorption of metformin. This suggests that okra could reduce the effectiveness of metformin, and should therefore not be eaten at the same time as the drug.

Lower blood sugar levels

A 2011 study published in the Journal of Pharmacy and Bioallied Sciences points to a link between eating okra and lower blood sugar. The researchers allowed the blood sugar of rats with diabetes to stay level for 14 days. They then gave the rats powdered okra peel extracts and seeds dosages of up to 2,000 milligrams per kilogram of body weight.

There were no poisonous effects linked with these relatively high doses of okra. The rats that ate okra had reduced blood sugar levels after up to 28 days of eating okra. The study ended on day 28, so it is unclear if the effects on blood sugar levels would have lasted longer.

Considerations for using okra

Few studies have linked okra to negative side effects, but some negative side effects are possible:

• Okra may make the drug metformin less effective.
• Okra is high in substances known as oxalates. Oxalates may increase the risk of kidney stones in people vulnerable to kidney stones.
• Okra can contain bacteria, pesticides, and other dangerous substances if it is not thoroughly washed. People should never consume rotten okra, frozen okra that is past its expiration date, or okra that has not been thoroughly washed.
• People with an okra allergy should not consume okra. Those with an allergy to other plants in the mallow family, such as hibiscus or cotton, may also be allergic to okra.
• Even if okra proves to be ineffective in fighting diabetes, it remains a safe snack for people with diabetes. A single serving of 100 grams contains just 30 calories, but offers a number of nutritional benefits:
  • Okra contains no saturated fats or cholesterol
  • Okra is rich in fiber, containing 9 percent of the recommended daily value (RDV)
  • Okra contains 8 percent of the RDV of calcium, 43 percent of the RDV of manganese, 10 percent of the RDV of iron and copper, and 44 percent of the RDV of vitamin K
  Okra is rich in protective substances known as antioxidants, including myricetin. According to the National Center for Complementary and Integrative Health, antioxidants may reduce oxidative stress, a process that damages cells in the body. Oxidative stress plays a role in the development of diabetes, as well as diseases such as:
  • Parkinson's disease
  • Alzheimer's disease
  • Cataracts
  • Macular degeneration
  • Heart and blood vessel disease
  • Cancer
  In addition to its antioxidant benefits, okra may also reduce tiredness. A 2015 study published in Nutrients found that substances found in okra seeds known as polyphenols and flavonoids could reduce fatigue.

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