Onions and Phytos

Since this posting is the first of many on selected phytochemicals (dubbed phytos – those plant chemicals that are not considered nutrients but impart significant health benefits), I thought it wise to begin with a food that can be added to many other foods – ONIONS.  People often respond in a more positive way if you tell them what they CAN eat rather than what they cannot eat.

What is in Onions That is Beneficial?

Any kind of onion contains some level of a phyto called quercetin.  Actually, nine such compounds have been isolated from the outer scales of onion (1).  Nine?  I think that is significant!  Shallots and 10 varieties of onion (Western Yellow, Northern Red, New York Bold, Western White, Peruvian Sweet, Empire Sweet, Mexico, Texas 1015, Imperial Valley Sweet, and Vidalia) were evaluated for the content of this beneficial food component.  Shallots and Western Yellow onions contained the highest amounts.  All varieties contained some level of quercetin, and all exhibited antioxidant properties (2).    

How Can Onions Affect Cancer Risk?

Cancer is promoted, in part, by inflammation and the presence of growth factors.  Quercetin in onions has decreased both inflammation and growth in colon cancer cells (3).  It has also been effective in decreasing the growth of human liver cancer cells (2) and human leukemia cells (4).  Rats fed a diet including onion had reduced colorectal cancer cell growth (5).

 

Why should we even think about these cancers?  Cancer is a terrible disease and devastates families every day.  Starting at the age of 50 and earlier if there is a family history of colon cancer, doctors now recommend that people have colorectal exams because of the incidence of colon and rectal cancers.  The survival rate from these types of cancers is quite good if caught early.  A diet rich in fiber and phytochemicals, including quercetin, can help us to keep our colons healthy and minimize the need for colonoscopies in the future.  Let’s all have healthy colons and not give them a reason to probe further!

 

If you have ever known anyone with liver cancer, you know how horrible it is.  Liver failure affects the whole body because very important functions occur there, such as the processing of nutrients.  Last but not least, the type of cancer that many children have is leukemia (but adults may have it, also).  Wouldn’t it be wonderful to not have that threat for our precious children! 

  

The point is, we should think about prevention of diseases, such as cancer, instead of waiting for them to strike and devastate our lives.  Many cancers including colon, rectal, liver, and leukemia, can be prevented by changing the way we eat.

How Can Onions Affect the Risk of Heart Disease?

As you are probably aware, high levels of LDL cholesterol (the bad cholesterol) in the blood are associated with plaque in the arteries, leading to heart disease.  Quercetin in onions can keep LDLs from contributing to plaque because of its antioxidant properties (6).  In a study of Japanese women, onion quercetin was associated with lower total and LDL cholesterol.  The low incidence of heart disease was contributed to the high onion and soy intake of this population (7).

Another risk factor for heart disease is high blood pressure.  Plaque and high blood pressure tend to make each other worse.  Quercetin has shown to decrease the incidence of high blood pressure in rats (8).  Reducing effects on LDL and decreasing blood pressure are a couple of different methods by which this onion component may decrease the risk of heart disease.

 

Why should we care about reducing the risk of heart disease?  Heart disease is the #1 killer in the United States and in many industrialized countries.  It strikes someone in most families in the U.S.  Again, much could be prevented with a healthy lifestyle. 

  

What Else?

 

 Because of its effects on inflammation, quercetin in onions may have potential for arthritis treatment (9).  Several members in my family have been affected by arthritis.  I really like this information!

How to Incorporate Onions into Your Meals

Onions can be added to almost any meal.  Some people enjoy eating raw onions on their sandwiches or with meals.  Here in Texas, raw onions are commonly served with barbequed meats.  Personally, I prefer the green onion variety for eating in the raw state. 

 

If you do not like eating raw onions, keep in mind that onions have a milder flavor after they are cooked.  It only takes a small amount of oil or margarine to stir-fry onions.  You may also cook them in a very small amount of water.  However, the flavor will be more magnified if cooked in a small amount of oil.  Keep in mind that heat treatments such as normal cooking may have an impact on the structure of quercetin, which may change the bioavailability (how well your body uses it) and the activity of it (10).  Raw onions will probably have the forms of quercetin that are more active and have more benefits than cooked onions, but cooked onions will still have some active forms.

 

Using onions in foods will add flavor, thus lessening the need for using the amount of salt you would normally add for flavor.  Using less salt is part of a healthy lifestyle and is beneficial for most people who have high blood pressure, congestive heart failure, edema, or other type of fluid imbalance.

 

I do not presume to present unusual ideas or recipes to you that you could not think of yourself.  I simply encourage you to incorporate onions heartily into your daily diet and enjoy the benefits of quercetin!

Simple recipe:

1 pound of fresh green beans (may use 2-14 oz. cans)

½ cup sliced onions

 1 tablespoon canola oil

1 teaspoon black pepper

dash of salt