Post by Tim Wescott on Jun 11, 2004 15:25:29 GMT -5
Flavonoids: Heart Friendly Nutrients
In search for hidden nutrients in food, researchers have discovered there's more to nutrients than minerals and vitamins. Among these "other nutrients" is the largest group - flavonoids. They have a number of key antioxidant, anti-inflammatory, antihistaminic, and antiviral prperties as well as lowering the "bad" LDL cholesterol.
Like their better known chemical cousins, the carotenes, flavonoids are plantpigments, creating a rainbow of colors. In addition, many flavonoids andcarotenes function as antioxidants and protect plants from damaging freeradicals. The big difference is that flavonoids are water soluble, whereascarotenes are oil soluble.
First isolated in the 1930s by Albert Szent-Gyorgyi, the Nobel Laureate whodiscovered Vitamin C, flavonoids are broken down into categories, thoughthe issue of how to divide them is not universally agreed upon. One systembreaks flavonoids into isoflavones, anthocyanidins, flavans, flavonols, flavones,and flavanones. Some of the best-known flavonoids, such as genistein in soy,and quercetin in onions, can be considered subcategories of categories. Althoughthey are all structurally related, their functions are different. Flavonoidsalso include hesperidin, rutin, citrus flavonoids, and a variety of othersupplements. Dr. Szent-Gyorgyi found that flavonoids strengthened capillarywalls in ways vitamin C could not. Some function as anti-inflammatory, antihistaminic,and antiviral agents. Quercetin has been reported to block the “sorbitolpathway” that is linked to many problems associated with diabetes. Rutinand several other flavonoids may also protect blood vessels.
A number of MD+ supplements, including MVM, AntiOx and Renew, contain flavonoids for their protective and metabolic effects.
Heart-friendly
Flavonoids come into researchers' focus from studies of the 'French paradox'.The French diet is known to be high in fat and cholesterol yet the Frenchhave a much lower risk of coronary heart disease than those from other Westerncountries like the US. The researchers have zeroed in on one particular Frenchtrait - wine drinking as a contributing factor for this.
At least eight medical studies have found that a glass or two of wine dailyprotects against heart disease. But some studies have reported that red wineis better than white wine, suggesting that some of the benefits might beunrelated to the alcohol.
To explore this, a team of Israeli researchers led by Alexendra Lavy, Ph.D.,compared the effects of red and white wine on 20 healthy men. Half of thesubjects were given 400 milliliters (roughly two glasses) of either red orwhite wine daily for two weeks. Both of the wines contained 11 percent alcohol.
Lavy and her colleagues examined how the wines affected blood fats. The mostdramatic effect was the increase in high-density lipoproteins (HDLs), theso-called 'good' cholesterol, among men drinking red wine. Their HDL levelsrose 26 percent and their apolipoprotein A-1 levels, closely related to HDL,increased 12 percent, according to Lavy's report in Annals of Nutrition andMetabolism (Sept./Oct. 1994). The white-wine drinkers had no change in HDL.
On the negative side, red-wine drinkers had a 26 percent increase in triglyceridelevels, a type of blood fat associated with risk of heart disease. Furthermore,Lavy found no decrease in blood clotting among either the red- or white-winedrinkers.
If it's not the alcohol, then it must be the grapes, more specifically thecolor of the grapes. John D. Folts, Ph.D., director of the coronary thrombosislaboratory at the University of Wisconsin, Madison, recently fed dogs redwine, white wine, or unsweetened 'purple' grape juice and then measured theirblood-clotting factors and blood flow. Red grapes are particularly high intwo flavonoids, quercetin and rutin, which are absent in white grapes.
Folts found that blood clotting decreased and blood flow increased in thedogs given red wine and purple grape juice, but not in the animals fed whitewine. 'It is therefore possible to speculate that the cardioprotective effectsof red wine consumption observed in the French and other populations maybe attributed in part to the ethanol content of the wine and in part to theantioxidant and platelet inhibitory properties of other naturally occurringcompounds in the wine. Consumption of flavonoid-containing foods and beveragesmay retard atherogenesis and prevent thrombosis on a daily basis,'
Another dietary factor likely influences the French paradox. In additionto their wine consumption, the French eat a high-flavonoid diet. In an analysisof the eating habits of people in 40 nations, William E. Connor, M.D., anexpert in blood fats at Oregon Health Sciences University, failed to finda strong relationship between wine consumption and heart disease risk. Instead,Connor determined that the French eat large quantities of vegetables, richin vitamins, carotenes, and flavonoids, according to his article in Circulation
Other Benefits
As antioxidants, some flavonoids, such as quercetin, protect LDL cholesterolfrom oxidative damage. Others, such as the anthocyanidins from bilberry,purple cabbage, and grapes, may help protect the lens of the eye from cataracts.Animal research suggests that naringenin, found in grapefruit, may have anticanceractivity. Soy isoflavones are also currently being studied to see if theyhelp fight cancer.
In a small, preliminary trial, rutoside (500 mg twice daily), a derivativeof the flavonoid, rutin, combined with vitamin C (500 mg twice daily) producedmarked improvement in three women with progressive pigmented purpura (PPP),a mild skin condition.3 Although not a serious medical condition, cosmeticconcerns lead persons with PPP to seek treatment with a variety of drugs.The vitamin C/rutoside combination represents a promising, non-toxic alternativeto these drug treatments, but larger, controlled trials are needed to confirmthese preliminary results.
Flavonoids in Tea: free radical killers
Common green and black tea leaves which are about 25-30 percent flavonoids,including quercetin and gallic esters provide significant protection fromheart disease.
For five years, Dutch researchers Michaël Hertog, M.Sc., and Edith Feskens,Ph.D., followed the dietary and lifestyle habits of 805 men ages 65-84 inthe town of Zutphen. After accounting for the men's physical activity, smokinghabits, and intake of vitamins C and E, and beta-carotene, the researchersfound that men eating a lot of flavonoids-in tea, onions, and apples-werefar less likely to suffer heart disease or heart attacks than men eatingfew flavonoids.
The researchers attributed the result to the free radical fighting abilitiesof the flavonoids. 'There is evidence that free-radical oxidation of LDLplays an important part in atherogenesis,' Hertog and Feskins wrote in Lancet,a medical journal. 'Flavonoids are scavengers of free radicals...It is possiblethat quercetin and other flavonoids reduce the rate of formation of oxidisedLDL and thus inhibit the growth of atherosclerotic plaques.'
The benefits of tea flavonoids were confirmed earlier this year by researchersat the Saitama Cancer Research Center, Japan. K. Imai, PhD, and K. Nakachi,PhD, studied 1,371 men enrolled in a 40-year study of eating habits and health.They reported that elderly men who drank 10 or more cups of green tea dailyhad lower blood levels of cholesterol and triglycerides than men who drankless of the tea.
Flavonoids in Soy
Soybeans are also important source of flavonoids. In a recent analysis of730 people and 38 medical studies, James W. Anderson, M.D., found that flavonoid-containingsoy protein can dramatically lower blood levels of cholesterol. Anderson,an endocrinologist and nutritionist at the University of Kentucky, Lexington,found that daily consumption of 47 grams of soy protein-one-tenth of a pound-significantlydecreased total cholesterol, the 'bad' low-density lipoprotein (LDL) formof cholesterol, and triglycerides.
Although the amounts of soy protein consumed varied in the 38 studies, Andersonestimated that 25 grams daily would probably reduce blood cholesterol levelsby an average of 8.9 percent and 50 grams by 17.4 percent.
According to Anderson, it would be very easy for people to increase theirsoy consumption. An 8-ounce glass of soy milk contains 4 to 10 grams of soyprotein, 4 ounces of tofu contain 8 to 13 grams of soy protein, and a soyhamburger or hotdog contains about 18 grams of soy protein. Drinking twoglasses of soy milk (instead of regular milk) and eating one soy burger dailywould provide approximately 30 grams of soy protein.
In search for hidden nutrients in food, researchers have discovered there's more to nutrients than minerals and vitamins. Among these "other nutrients" is the largest group - flavonoids. They have a number of key antioxidant, anti-inflammatory, antihistaminic, and antiviral prperties as well as lowering the "bad" LDL cholesterol.
Like their better known chemical cousins, the carotenes, flavonoids are plantpigments, creating a rainbow of colors. In addition, many flavonoids andcarotenes function as antioxidants and protect plants from damaging freeradicals. The big difference is that flavonoids are water soluble, whereascarotenes are oil soluble.
First isolated in the 1930s by Albert Szent-Gyorgyi, the Nobel Laureate whodiscovered Vitamin C, flavonoids are broken down into categories, thoughthe issue of how to divide them is not universally agreed upon. One systembreaks flavonoids into isoflavones, anthocyanidins, flavans, flavonols, flavones,and flavanones. Some of the best-known flavonoids, such as genistein in soy,and quercetin in onions, can be considered subcategories of categories. Althoughthey are all structurally related, their functions are different. Flavonoidsalso include hesperidin, rutin, citrus flavonoids, and a variety of othersupplements. Dr. Szent-Gyorgyi found that flavonoids strengthened capillarywalls in ways vitamin C could not. Some function as anti-inflammatory, antihistaminic,and antiviral agents. Quercetin has been reported to block the “sorbitolpathway” that is linked to many problems associated with diabetes. Rutinand several other flavonoids may also protect blood vessels.
A number of MD+ supplements, including MVM, AntiOx and Renew, contain flavonoids for their protective and metabolic effects.
Heart-friendly
Flavonoids come into researchers' focus from studies of the 'French paradox'.The French diet is known to be high in fat and cholesterol yet the Frenchhave a much lower risk of coronary heart disease than those from other Westerncountries like the US. The researchers have zeroed in on one particular Frenchtrait - wine drinking as a contributing factor for this.
At least eight medical studies have found that a glass or two of wine dailyprotects against heart disease. But some studies have reported that red wineis better than white wine, suggesting that some of the benefits might beunrelated to the alcohol.
To explore this, a team of Israeli researchers led by Alexendra Lavy, Ph.D.,compared the effects of red and white wine on 20 healthy men. Half of thesubjects were given 400 milliliters (roughly two glasses) of either red orwhite wine daily for two weeks. Both of the wines contained 11 percent alcohol.
Lavy and her colleagues examined how the wines affected blood fats. The mostdramatic effect was the increase in high-density lipoproteins (HDLs), theso-called 'good' cholesterol, among men drinking red wine. Their HDL levelsrose 26 percent and their apolipoprotein A-1 levels, closely related to HDL,increased 12 percent, according to Lavy's report in Annals of Nutrition andMetabolism (Sept./Oct. 1994). The white-wine drinkers had no change in HDL.
On the negative side, red-wine drinkers had a 26 percent increase in triglyceridelevels, a type of blood fat associated with risk of heart disease. Furthermore,Lavy found no decrease in blood clotting among either the red- or white-winedrinkers.
If it's not the alcohol, then it must be the grapes, more specifically thecolor of the grapes. John D. Folts, Ph.D., director of the coronary thrombosislaboratory at the University of Wisconsin, Madison, recently fed dogs redwine, white wine, or unsweetened 'purple' grape juice and then measured theirblood-clotting factors and blood flow. Red grapes are particularly high intwo flavonoids, quercetin and rutin, which are absent in white grapes.
Folts found that blood clotting decreased and blood flow increased in thedogs given red wine and purple grape juice, but not in the animals fed whitewine. 'It is therefore possible to speculate that the cardioprotective effectsof red wine consumption observed in the French and other populations maybe attributed in part to the ethanol content of the wine and in part to theantioxidant and platelet inhibitory properties of other naturally occurringcompounds in the wine. Consumption of flavonoid-containing foods and beveragesmay retard atherogenesis and prevent thrombosis on a daily basis,'
Another dietary factor likely influences the French paradox. In additionto their wine consumption, the French eat a high-flavonoid diet. In an analysisof the eating habits of people in 40 nations, William E. Connor, M.D., anexpert in blood fats at Oregon Health Sciences University, failed to finda strong relationship between wine consumption and heart disease risk. Instead,Connor determined that the French eat large quantities of vegetables, richin vitamins, carotenes, and flavonoids, according to his article in Circulation
Other Benefits
As antioxidants, some flavonoids, such as quercetin, protect LDL cholesterolfrom oxidative damage. Others, such as the anthocyanidins from bilberry,purple cabbage, and grapes, may help protect the lens of the eye from cataracts.Animal research suggests that naringenin, found in grapefruit, may have anticanceractivity. Soy isoflavones are also currently being studied to see if theyhelp fight cancer.
In a small, preliminary trial, rutoside (500 mg twice daily), a derivativeof the flavonoid, rutin, combined with vitamin C (500 mg twice daily) producedmarked improvement in three women with progressive pigmented purpura (PPP),a mild skin condition.3 Although not a serious medical condition, cosmeticconcerns lead persons with PPP to seek treatment with a variety of drugs.The vitamin C/rutoside combination represents a promising, non-toxic alternativeto these drug treatments, but larger, controlled trials are needed to confirmthese preliminary results.
Flavonoids in Tea: free radical killers
Common green and black tea leaves which are about 25-30 percent flavonoids,including quercetin and gallic esters provide significant protection fromheart disease.
For five years, Dutch researchers Michaël Hertog, M.Sc., and Edith Feskens,Ph.D., followed the dietary and lifestyle habits of 805 men ages 65-84 inthe town of Zutphen. After accounting for the men's physical activity, smokinghabits, and intake of vitamins C and E, and beta-carotene, the researchersfound that men eating a lot of flavonoids-in tea, onions, and apples-werefar less likely to suffer heart disease or heart attacks than men eatingfew flavonoids.
The researchers attributed the result to the free radical fighting abilitiesof the flavonoids. 'There is evidence that free-radical oxidation of LDLplays an important part in atherogenesis,' Hertog and Feskins wrote in Lancet,a medical journal. 'Flavonoids are scavengers of free radicals...It is possiblethat quercetin and other flavonoids reduce the rate of formation of oxidisedLDL and thus inhibit the growth of atherosclerotic plaques.'
The benefits of tea flavonoids were confirmed earlier this year by researchersat the Saitama Cancer Research Center, Japan. K. Imai, PhD, and K. Nakachi,PhD, studied 1,371 men enrolled in a 40-year study of eating habits and health.They reported that elderly men who drank 10 or more cups of green tea dailyhad lower blood levels of cholesterol and triglycerides than men who drankless of the tea.
Flavonoids in Soy
Soybeans are also important source of flavonoids. In a recent analysis of730 people and 38 medical studies, James W. Anderson, M.D., found that flavonoid-containingsoy protein can dramatically lower blood levels of cholesterol. Anderson,an endocrinologist and nutritionist at the University of Kentucky, Lexington,found that daily consumption of 47 grams of soy protein-one-tenth of a pound-significantlydecreased total cholesterol, the 'bad' low-density lipoprotein (LDL) formof cholesterol, and triglycerides.
Although the amounts of soy protein consumed varied in the 38 studies, Andersonestimated that 25 grams daily would probably reduce blood cholesterol levelsby an average of 8.9 percent and 50 grams by 17.4 percent.
According to Anderson, it would be very easy for people to increase theirsoy consumption. An 8-ounce glass of soy milk contains 4 to 10 grams of soyprotein, 4 ounces of tofu contain 8 to 13 grams of soy protein, and a soyhamburger or hotdog contains about 18 grams of soy protein. Drinking twoglasses of soy milk (instead of regular milk) and eating one soy burger dailywould provide approximately 30 grams of soy protein.