Good old prunes may be the answer to constipation.

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Q. I’ve recently learned that cinnamon contains coumarin. I found an article about coumarin being carcinogenic (Food and Chemical Toxicology, April 1999).

I am concerned about this, even though the research is old, because for the past 15 years I’ve been a heavy consumer of cinnamon in my morning oatmeal. How dangerous is cinnamon?

A. Coumarin is a natural component of cassia cinnamon bark and may end up in the powdered cinnamon you find on your spice shelf. The article you cited concluded that the risk of cancer is low, and newer research actually suggests that coumarin may have anti-cancer activity (Current Medicinal Chemistry, Vol. 17, No. 13, 2010).

There are concerns that too much coumarin could harm the liver. Because coumarin levels vary widely from one cinnamon product to another, it is hard to establish a safe amount of the spice on a daily basis. Since you are a heavy cinnamon user, you should ask your doctor to monitor your liver enzymes to make sure you have not exceeded your limit. You can learn more about the pros and cons of cinnamon at

Q. You occasionally get questions about constipation. I’ve seen no reference to the cure I have been using for several years.

I used to need Dulcolax two or three times a month. Then, I remembered hearing about prunes. I started eating two prunes a day along with a small glass of prune juice. Problem solved!

I go once or twice a day now, with absolutely no straining. I’m sure your readers would be eternally grateful to hear about this inexpensive and healthy remedy.

A. Prunes have long held a reputation for overcoming constipation. A review of randomized controlled trials shows that prunes may be even better than psyllium (Metamucil, Konsyl, etc.) for helping to maintain regularity (Alimentary Pharmacology and Therapeutics, October 2014).

Q. My husband was drinking a daily juice comprised mainly of parsley and kale for many months. He got hit with kidney stones. It turns out that parsley, kale and beets are very high in oxalates, which contribute to kidney-stone formation.

A. Juicing is a way to consume concentrated amounts of nutrients with relative ease. As you point out, this could be helpful in some cases, but people juicing foods rich in oxalates such as parsley, beets with greens, collard greens and spinach could easily overdo.

A case report from the Mayo Clinic describes an 81-year-old whose kidney function dropped suddenly after he began juicing all his meals in an attempt to lose weight (American Journal of Medicine, September 2013).

People who want to lower their blood pressure with beet juice should be aware of this risk, especially if they have ever had a kidney stone. You can learn more about beet juice and other nondrug approaches to hypertension control in our Guide to Blood Pressure Treatment. A copy can be downloaded for $2 from our website: