Entries in polyphenols (3)

Thursday
Mar042010

What Oil Do I Use?

One of the questions I hear most frequently in lectures and with my clients is “which oil should I be cooking with?”  This question turns out to be more complicated than you would think.  Years ago, most of the population ate butter. Then, experts reported that vegetable oils were a much healthier alternative, and many people switched to corn or vegetable oils.  This advice did not turn out to be true since weight, heart disease and diabetes have been rapidly increasingly.  The good news is that research on which oils are healthy has become clearer during the last year.  Choosing which oil to buy depends on the purpose – i.e. cooking versus using in salad dressing or baking. 

Olive oil is a monounsaturated fat that is useful in making salad dressing and marinating vegetables and meats.  If you are cooking with olive oil, only use it in recipes where the smoke point is between 200 to less than 400 degrees.  The best olive oil is cold-pressed, extra virgin since it contains both the good monounsaturated fat and powerful antioxidants known as Polyphenols.  This type of olive oil means the olives are processed within 24 hours of picking, which aids in retaining a higher quality product.  It is slightly cloudy due to the small particles of olive flesh in the oil.  Olive oil which is clear still contains the monounsaturated fat but is devoid of the Polyphenols.  “Lite” olive oil is a marketing gimmick that just refers to a milder flavor, rather than less fat and calories.

Coconut oil is a safe oil to cook with at high temperatures since it is saturated and the molecules cannot be damaged.  Organic coconut oil is best since it is free of pesticides.  Avoid high omega-6 oils such as safflower, sunflower, corn, and soybean oil. 

Canola oil, although high in omega-3 fatty acids, has a high sulfur content and can quickly become rancid.  It has been reported that baked goods made with canola oil can quickly develop mold. Due to the high level of rancidity, canola oil must be deodorized, and this process can increase the amount of trans fatty acids in canola oil, which negates the benefits of the omega-3 fatty acids that are present.  In addition, since canola is the result of irradiated seeds from the oilseed rape, 80-85 percent of canola is GMO (genetically modified organism) and best to avoid.

The best oils to buy are cold pressed extra virgin olive oil, organic coconut oil, and to a lesser extent flax seed oil and other nut oils such as walnut, peanut or grapeseed.

Sunday
Feb282010

Quercetin and Resveratrol?

Two buzz words in nutrition and supplement research – quercetin and resveratrol.  What is the lowdown?  Should you take a supplement or just eat the food?

The simple answer is unclear.  Quercetin is a type of antioxidant known as a polyphenol.  Two categories of polyphenols are flavonoids and non-flavonoids.  A flavonoid is a pigment in food that has important health benefits.  Besides antioxidant activity, flavonoids are known for their prevention of heart disease and cancer, since they can lower cholesterol levels and inflammation in the body.

Quercetin is found in the greatest concentration in apple skins, but can also be found in red grapes, green tea and buckwheat.  Several positive studies were done with animals, including one in which quercetin supplemented mice were less likely to get the flu.  Human studies to date have been inconclusive on supplement usage.

Resveratrol is a non-flavonoid polyphenol that is found in grapes and grape skins.  It has strong anti-inflammatory effects in the body which can be helpful in the prevention of atherosclerosis.  Wine drinkers tout they are getting their resveratrol for the day.  However, you would have to consume 180 glasses of wine per day to obtain the amount necessary for health.  Studies are also inconclusive on supplement usage.  More importantly, many supplements tested do not contain the amount of resveratrol that is stated on the bottle.

Bottom line?  Until more research is in, eat apples and grapes, and drink green tea.  You will be receiving the quercetin and resveratrol your body can readily use and absorb and there is nothing to lose except bad health…and maybe the flu.

Tuesday
Sep012009

An Apple a Day to Keep Cancer and Heart Disease at Bay?

We’ve all heard the expression “an apple a day keeps the doctor away” but research is actually starting to show us why this old saying is true.

The key nutrients which prevent disease in produce, including apples,  are known as phytochemicals or phytonutrients.

Phytonutrients are substances which a plant naturally contains to protect it against sunlight, oxidation from air, pollution, and bacteria or viruses.  Once we eat these plants, our immunity increases and we are more resistant to diseases such as cancer and heart disease.   Scientists estimate there are over 100 phytochemicals in one serving of fruits or vegetables and there may be as many as 13,000 different phytonutrients in our food supply.

Polyphenols are the new hot topic in research studies and are a type of phytonutrient.  A group of polyphenols called flavonoids have antioxidant activity and are known for prevention of heart disease and cancer, since they can lower cholesterol levels and inflammation in the body.

Apples contain a polyphenol known as quercetin, which is thought to lower LDL cholesterol and decrease plaque in the arteries.  They also contain pectin, a type of fiber which can lower cholesterol.

A food scientist from Cornell University, Rui Hai Liu, did extensive research on apples and found they contain substances which fight cancer cells and reduce the number and size of tumors in rats.  He also stated that apples contain another compound known as triterpeniods in the peel, which can inhibit or kill cancer cells.

It is important to eat the whole apple, since the key nutrients are in the peel and the interior.  So the old adage of “an apple a day keeps the doctor away” may be more apropos than we moderns ever realized.