Q: I have started taking cranberry capsules in the hope that they will work as well against urinary-tract infections as cranberry juice. What do you think?
A: A recent study tested cranberry extract pills against placebo among women in nursing homes (JAMA, Nov. 8, 2016). Unfortunately, in this randomized clinical trial, the cranberry pills were no more effective than placebo.
Some readers report that a dietary supplement containing D-mannose helps protect against urinary-tract infections. A pilot study published in the European Review of Medical and Pharmacological Sciences (July 2016) found that D-mannose helped both in the prevention and treatment of urinary-tract infections.
When that wore off, I started taking Dannon Activia yogurt. The ad says if you take it daily for two weeks and it doesn’t work, they will refund your money. They didn’t have to: It works for me just great.
Not only that, my husband has had a problem with constipation for as long as I’ve known him. He started taking it, and it has helped him, too.
A: Scientists are learning more about the balance of bacteria in the digestive tract. Adjusting this balance with probiotics found in live-culture yogurt can help ward off the unfriendly organisms such as Giardia that can cause diarrhea (Journal of Clinical Medicine online, Nov. 16, 2016). There also is some evidence that probiotics can be helpful in managing constipation (Current Oncology Reports, December 2015).
The Activia refund has expired, but live-culture yogurt still may be worth a try. You will find other strategies for dealing with both diarrhea and constipation in our Guide to Digestive Disorders and Constipation. Anyone who would like a copy, please send $4 in check or money order with a long (No. 10), stamped (68 cents), self-addressed envelope to: Graedons’ People’s Pharmacy, No. GG-33, P.O. Box 52027, Durham, NC 27717-2027. They also can be downloaded for $4 from our website: www.peoplespharmacy.com.
Q: I have been taking L-lysine for years, and I can’t remember my last cold sore. I had shingles one time many years ago and took L-lysine daily. It took one day for the pain to end and about two days for the rash to disappear.
I explain the efficacy of lysine this way: Herpes viruses cause both cold sores and shingles. They require the amino acid arginine to replicate itself. Somehow, the viruses recognize lysine as if it were arginine. The lysine prevents viral replication.
A: Your explanation is plausible, supported by research on the herpes simplex virus 1 (Journal of Virology, June 2009). Sadly, there have been very few well-controlled trials involving L-lysine for cold sores. That has led to the conclusion that there is inadequate data to support the use of L-lysine to prevent or treat herpes infections (Cochrane Database of Systematic Reviews, Aug. 7, 2015). Despite the lack of clinical research, many readers have found L-lysine as helpful as you have.
In their column, Joe and Teresa Graedon answer letters from readers. Write to them in care of this newspaper or email them via www.PeoplesPharmacy.com. Their newest book is “Top Screwups Doctors Make and How to Avoid Them.”