Plant Polyphenols for Bladder Cancer and Health

A recent animal study showing that plant polyphenols may lower the risk of cancer cell development adds to the existing research on resveratrol and quercetin. Polyphenols are plant-derived chemicals thought to have antioxidant, anti-inflammatory, antibacterial and skin rejuvenating capabilities.

Resveratrol is found in over 70 plant species including nuts, grapes, pine trees, certain vines and red wine. Some experts believe resveratrol may be a factor in the French paradox that coronary heart disease mortality in France is lower than other similar industrialized countries due to the frequent consumption of red wine.

Resveratrol has been shown in animal and laboratory studies to exhibit antioxidant, anticancer, antiproliferative, antifungal, antiviral and antibacterial effects. However, data in humans is lacking.

At this time, there are no high-quality human trials available supporting the efficacy of resveratrol for any indication. However, there are several observational studies that correlate the consumption of wine with a decrease in cancer and/or cardiovascular disease risk. There are multiple possible contributing factors to these conditions, and studies of resveratrol are difficult to design and implement. Too much alcohol intake can actually be dangerous. Further research is needed before a firm recommendation can be made.

Quercetin is a major flavonol, one of the almost 4,000 flavonoids (antioxidants) that occur in foods of plant origin, such as red wine, onions, green tea, apples, berries and brassica vegetables (cabbage, broccoli, cauliflower and turnips). It is also found in Gingko biloba, St. John's wort and American elder. It mainly occurs in plants as glycosides, such as rutin (quercetin rutinoside) in tea.

Quercetin and rutin are used in many countries as vasoprotectants (for blood vessel health) and are ingredients of numerous multivitamin preparations and herbal remedies. They occur mainly as glycosides or molecules in which a sugar part is bound to some other part. It is uncertain to what extent dietary flavonoid glycosides are absorbed from the gut. Flavonoids, dietary components in vegetables, fruits and beverages, may protect against coronary heart disease, stroke and cancer. However, the ability of the body to absorb these compounds is questionable.

Quercetin and other flavonols have a wide variety of biological effects, but the scientific evidence for use in prevention or treatment of disease is weak. Quercetin has been considered as a therapy for cardiovascular diseases, high cholesterol, cancers, diabetic cataracts, inflammation, ischemic injury, chronic prostatitis, chronic venous insufficiency, gastrointestinal ulceration, hepatitis, allergies, asthma, viral infections and hay fever.

Review of the literature shows several studies on the association with risk reduction for coronary heart disease and stroke, cancers and a few studies on other medical conditions. However, there is not strong evidence to support for any of these associations.

For more information on polyphenols, please visit Natural Standard's Foods, Herbs & Supplements database.

Comments

[Pete]

I've been reading a lot about resveratrol and other polyphenols lately. Even though most studies have been done in animals, not humans, the early results are promising.

[Chase]

I've been saying from the very beginning that your diet has immediate and direct effects on your overall health. I hope studies such as this will inspire people to realize that the cures for most of our maladies exist in their natural forms all around us.

[Stella]

I think the use of plant polyphenols offers important advantages, and they appear to have a good safety profile and are low cost. However, drinking a bottle of red wine each day for cancer benefits doesn't exactly sound healthy or safe. Someone out there needs to convert this into a pill.

[Justin A.]

Is resveratrol the only active component in red wine that makes it have antioxidant and anticancer activity? I often hear people say that red wine once a day is good for you, and I never knew exactly what contributed to this beneficial effect.

[Stacy]

Weak evidence is enough evidence for me. You won't have to tell me twice to keep nuts and red wine in my diet!

[Mike]

What is the connection between resveratrol and quercetin? They don't really explain this here.

[Jake]

It's interesting that more and more research is coming out on the benefits of foods that have been used since ancient times. It just proves that we should eat as our ancestors did, and forgo all the processed, packaged "modern" foods of today!

[Rihanna]

To answer Mike's question, I think the connection between resveratrol and quercetin is that they are both found in wine and they are both polyphenols.

[Missy]

Are there any ongoing clinical trials that are using polyphenols in people who have cancer, or is it too early to start studies in people?

[Kellyanne]

Why are polyphenols only in red wine, not white? Is it because it's the skin of grapes that contains polyphenols?

[Kevin]

Isn't there evidence that alcohol consumption increases a person's chance of developing cancer? If so, doesn't that contradict the potential benefit of polyphenols in red wine?

[Linds254]

In response to Kevin, I think consuming a lot of alcohol regularly is what could lead to health problems, such as the risk of cancer. From the studies I have seen on red wine, if it is consumed moderately, then it doesn’t seem to cause an issue, but then I guess you can never be sure whether drinking red wine could directly lead to anything without further study.

[Laurie]

I agree with Linds254. I think to much of anything can be a bad thing. If someone wants to get extra polyphenols in his/her diet, I hope he/she doesn't plan to just drink lots of red wine. You should eat grapes, nuts, and other foods that contain polyphenols. A glass or two of red wine every now and then is probably not going to be bad for you. I just wouldn't consume it all the time.

[Ed]

Are polyphenols available in supplement form? If so, are they safe?

[Lambert]

Even though there may be observational studies that correlate the consumption of wine with a decrease in cancer and/or cardiovascular disease risk, getting the beneficial effect from quercetin and resveratrol may outweigh the harmful effects of drinking alcohol. Since these ingredients can be obtained from other sources that are not harmful, such as nuts or grapes, it is better to gain the beneficial effects without harming yourself (which could potentially occur from drinking alcohol if not taken in moderate amount). However, it is unrealistic for people to stop drinking in socially acceptable environment that we live in. So in such a case, if there was a choice to drink wine versus beer, it would be beneficial to drink wine.

[Marge]

Have polyphenols been studied for other types of cancer besides bladder cancer?

[Brittany]

Does anyone know whether cooking foods that contain flavonols does anything to the nutritional content? I heard somewhere that the best way to eat healthy is to consume raw fruits and vegetables.

[Gina D.]

It's fascinating that resveratrol can possibly be helpful in so many ways. The idea that it may be help prevent coronary heart disease, various viruses, cancers and bacteria, as well as the fact that it is found in many common foods, such as nuts, grapes and even red wine, make me want to eat and drink these things as a possible precaution. This plus the quercetin might be a great way to supplement any diet.

[Ray]

This article leaves me at a loss. I am dying to know what would happen if studies of this nature were done on humans, if that is even a possibility. It really does sound plausible. I know a lot of people who would be grateful for this kind of information. I’m also curious if people are more likely to use these plant polyphenols if they come from a natural food, such as grapes, or if they are in a supplement form (if possible). It seems like it's often difficult to plan a fully balanced meal for many people, and supplements are often the best alternative to doing so.

[Sandy]

I’m not sure that I understand how quercetin has been considered a therapy for various diseases, such as cancer or cardiovascular disease, if the scientific evidence for their use in prevention and treatment is weak. I’m not sure that this would make me feel very good about trying to get it into my diet. I’d rather try something that has been proved to work. There definitely needs to be more studies on this so that it can be considered a more valid way to help prevent such diseases.

[Helena R.]

Both cancer and cardiovascular disease are mentioned quite a few times in this article. Is there any correlation between the two, or are there other treatments and supplements that may help both conditions? It would be interesting to know the links, if any. Also, this article further validates the idea that a diet that consists of natural foods is one of the most important preventative factors for health-related issues.

[JP]

I am going to have to disagree with Lambert. Although wine may be a good choice in terms of polyphenols, a light beer actually has fewer calories than a glass of wine. Weight is a big issue these days in terms of American health. I think that if you are at a healthy weight, than sure, go for the glass of wine. However, if you are overweight or obese: a) watch the alcohol consumption because you don't need the empty calories and b) if you must drink, don't binge and go for a light beer over wine or a mixed drink.

[D]

In response to Marge, there have been other studies with resveratrol other than bladder cancer. There have been studies with breast cancer (to increase effect of vitamin D), prostate cancer and pancreatic cancer. It is good to see dietary supplements for the treatment of cancer because people don’t want to go through more chemotherapy than they have to. These are ways that can hopefully decrease the chance of relapsing or developing metastatic cancer.

[Jacob]

Colon cancer has also been effectively reduced using polyphenols in multiple studies. Disease in the colon is also dramatically reduced and prevented in the presence of polyphenols. This is really good for dietary supplements.
How many different kinds of polyphenols are there?