What are Flavonoids and
How Can We Benefit from Them?
Welcome to the 7th issue of Discover The Power of Healing Foods! newsletter. You can read the entire issue on line by clicking here.
In our previous issues we discussed several carotenoid antioxidants and where we can find them. If you've missed those issues catch up here.
In this issue we will discuss:
The one million dollar question is: What makes us sick? What makes us age? Is it always a virus or a bug invading our bodies and attacking our defenses? Sometimes it is. But even when that happens, usually our own defenses should be able to handle the assault. But often we get bombarded from every angle, and our immune system gets overwhelmed and can't cope.
This is where the phytonutrients come in. They are a huge family of chemicals or nutrients found in plants that, apart from protecting the plants themselves from their own enemies, they protects us, too - not from bugs but from forces that wreak havoc in humans: free radicals.
We've discussed before the ongoing battle between free radicals and antioxidants. For those of you who haven't read that newsletter, I'll explain it briefly here.
Every day, your body is under attack by harmful substances known as free radicals. These are oxygen molecules that, due to pollution, sunlight and everyday wear and tear, have each lost an electron. As they attempt to regain their missing electrons, they careen through your body, stealing electrons wherever they can.
The molecular victims of these raids are your cells themselves - and sometimes even your DNA. Unless this chain is stopped, the result is huge numbers of damaged molecules and, over time, irreparable damage and disease.
Take cholesterol, for example (see illustration below). Normal cholesterol is a benign, helpful substance. In fact, we cannot live without cholesterol. But when cholesterol molecules are damaged by free radicals, they begin sticking to the lining of artery walls, causing hardened arteries and heart disease.
Here is another example: When free radicals attack molecules in your body's DNA - the genetic blueprint that tells your cells how to function - that blueprint is damaged. This can spark dangerous cell changes that lead to cancer and other diseases. Even aging, many scientists believe, is caused by free-radical damage.
The phytonutrients in plants, using their antioxidant powers, can quite literally save your life. Essentially, they step between the marauding free radicals and your body cells, offering up their own electrons. When free radicals grab these "free" electrons, they become stable again and do no further damage. Most phytonutrients are potent antioxidants.
In previous newsletters we've discussed a class of antioxidants called carotenoids and the amazing things they do to protect us from free radical damage. Now we'll consider another one: flavonoids.
Like carotenoids, flavonoids are molecules in food that add colour - specifically reds, yellow, blues and shades of brown - to fruits and vegetables. As with carotenoids, these colours often are masked by chlorophyll in plants.
Researchers suspect these flavonoids to be responsible, for example, for what has become known as "the French paradox" - the fact that although French people seem to love all those foods that contribute to heart disease, such as butter, cream and cheese, they die of heart disease 2 1/2 times less often than other people in western countries. Experts suspect that flavonoids present in red wine are responsible for the protection against oxidative damage from LDL cholesterol.
Some flavonoids make the lining of blood vessels more supple, lowering blood pressure and protecting against a build-up of heart-threatening plaque - in one study grape juice and dark chocolate had this effect.
Flavonoids also act like Teflon coating for the millions tiny disks in your blood called platelets. They keep the platelets from clumping together in the bloodstream and forming clots, which helps prevent heart attacks and stroke.
A recent Harvard Medical School lab study has found that one magical flavonoid found in wine and grapes, resveratrol, also lowers blood sugar levels and boosts liver function. In fact, in a group of lucky mice, it increased longevity by 31%. And, in one recent University of Virginia lab study, resveratrol - found in grape skins, raspberries, mulberries and peanuts - literally starved cancer cells by interfering with a protein called nuclear factor-kappa B that helps feed them.
In one Dutch study that examined the eating patterns of 805 men ages 65 to 84, researchers found that those who got the least flavonoids in their diets were 32% more likely to die from heart attack than those who ate the most. It didn't take many flavonoids to get the benefits. The high-flavonoid group had the equivalent of 4 cups of black tea, 1/2 cup apple, and 1/8 cup of onions a day.
When it comes to cancer prevention, flavonoids may help out by influencing cell-signalling pathways - the way cells turn genes on and off in order to perform thousands of everyday maintenance activities.
Flavonoids may help turn on genes that stop cancer cells from dividing or invading healthy tissues, or even may help activate genes that make cancer cells commit suicide, say experts from the Linus Pauling Research Institute at Oregon State University in Corvallis.
In a recent study at the University of California, Los Angeles, those prostate-cancer survivors who drank 8 ounces of pomegranate juice daily increased by nearly four times the period during which their levels of prostate-specific antigens, a cancer bio-marker, stayed stable. The study surprised even the researchers, who say the combination of flavonoids, anti-inflammatory compounds and antioxidants in pomegranate juice may be responsible.
You may be interested to know that Cornell University scientists found that cocoa has twice as many flavonoids as red wine and three times more than a cup of green tea. The results surprised the researchers, who expected green tea to win.
But it's not a good idea to favour one type of flavonoids over another. It's much better to adopt a strategy that gives you the widest variety of flavonoids possible. Dr Chang Y. Lee, PhD, professor of food science and technology at Cornell University suggests the following: "Personally, I would drink hot cocoa in the morning, green tea in the afternoon and a glass of red wine in the evening." I don't know about you, but I quite like the sound of that!
With over 4,000 flavonoid compounds that have been classified so far, you might wonder which ones are the most effective and where you can find them.
Like carotenoids, flavonoids are primarily found in all brightly coloured fruits and vegetables. Even if you don't know what flavonoids are, you are almost certainly already eating them. The question is whether you're eating enough of the right ones to stay healthy.
Flavonoids are found in a huge variety of edible plants, fruits and vegetables, but although they are so common, most of us are likely to be flavonoid depleted, thanks to changing eating habits.
We're eating less than half the amount of fresh fruit we did a century ago, and more processed fruit. The highest concentrations of flavonoids in fruits and vegetables tend to be found in the skin and seeds and industrial processing methods almost invariably discard these parts. Even at home, you might think you're eating plenty of fruit with your apple pie, but the apples are not quite the same as in their original state.
Also different flavonoids work in different tissues of the body. For example, some can enter the brain, whereas others appear to concentrate in the lining of blood vessels. So different flavonoids can be used to target different tissues.
The secret is to get to know some of these powerful antioxidants and see where you can find them.
Just because I have to start somewhere, I'll begin with quercetin here and discuss a few more in the next issues of this newsletter.
Quercetin is consistently the most active of the flavonoids in experimental studies and many medicinal plants owe much of their activity to their high quercetin content. One of the best dietary sources of quercetin is onions.
Quercetin has a versatile anti-disease potential. According to Dr.Terrance Leighton, Ph.D., professor of biochemistry and molecular biology at the University of California at Berkley, quercetin is one of the most potent anticancer agents ever discovered. It inactivates several cancer-causing agents, preventing damage to cell DNA, and inhibits enzymes that spur tumour growth.
At the prestigious Mayo Clinic in the US, research has been conducted into quercetin to help treat and prevent prostate cancer. Their laboratory results showed quercetin blocks the androgen activity in androgen-responsive human prostate cancer cells. By blocking the androgen activity the growth of the prostate cancer cells can be prevented or stopped.
Quercetin is also anti-inflammatory, antibacterial, anti-fungal and anti-viral. It works through the immune system to dampen allergic responses (by inhibiting release of histamine from cells), and thus appears to help combat allergies such as hay fever, asthma and eczema. This power, plus its anti-inflammatory activity may account for onion's reputed therapeutic impact against asthma and allergies. Its anti-viral activity makes it also very useful in combating colds and other infections.
Quercetin is anti-thrombotic, helping block formation of blood clots. As an antioxidant, it absorbs oxygen free radicals and helps keep fat from becoming oxidized. Quercetin is one of the best cardio-protective substances yet discovered.
Quercetin can effectively delay the onset of cataracts in people with diabetes, enhance insulin secretion and protect the pancreatic cells responsible for insulin secretion from free radical damage.
Major Sources of Quercetin:
- Yellow and red onions (not white onions)
- Red grapes (not white grapes)
- Yellow squash
Note: You'll be pleased to know that quercetin is not destroyed by cooking or freezing.
Quercetin is probably the main reason for the formidable therapeutic powers of onions. Some onions are so full of quercetin that the compound accounts for up to 10% of their dry weight.
Read my article on the healing power of onions and to get some ideas on how to include them in your diet.
Quercetin is found mostly on or near the skin of foods, so if you're in the habit of peeling your apples, you might consider a quercetin supplement.
It's much better to take a supplement that contains a combination of flavonoids and carotenoids rather than one single phytonutrient, as they're much more powerful when working together.
I particularly like this supplement, Replete 2. It's a very potent and powerful phyto-antioxidant nutrient formula, containing high levels of flavonoids and carotenoids. Ingredients: Quercetin, broccoli powder, green tea extract, grape seed extract, ginger extract, blueberry extract, bilberry extract, curcumin extract, lycopene, lutein (providing zeaxanthin),beta carotene.
I hope you have enjoyed reading this newsletter. So far we've discussed the many ways flavonoids can protect you from disease and particularly how quercetin can have a huge impact on your health. Next time, I'll discuss another important group of flavonoids, procyanidins, what they are, how they can benefit us and where to find them.
Look out for the next newsletter, you don't want to miss it!
Also, if this newsletter has raised some questions in your mind about antioxidants or you'd like specific information on them, don't hesitate to get in touch with me.
The next issue will be sent out on Wed 15th May 2013.
Until Next Time
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