If you’ve been following the news this past week, you probably came across the latest warning issued by the Centers for Disease Control and Prevention. Apparently, there’s a new strain of the norovirus (or Norwalk virus) that has recently been causing digestive havoc in Australia, Japan and Western Europe. And, now, this so-called GII 4 Sydney strain of the norovirus is making a new home in the United States. Given this, you might be wondering if there’s anything in the natural health sector that can help protect you and yours from this highly contagious viral offender.

As is the case with influenza and other easily transmittable viruses, frequent hand washing is the best documented way of reducing the risk of acquiring a norovirus infection. In a previous column, I mentioned that select probiotics may be helpful in limiting “travelers’ diarrhea”, which is sometimes caused by the norovirus. Having said that, to date, only one study has examined the efficacy of a probiotic supplement specifically in relation to norovirus prevention. The results of the trial did not uncover any protective effect, although a significant reduction in duration of norovirus-related fever was reported. As far as other supplements go, one brief mention of the possible utility of psyllium fiber appears in a 1983 issue of the Journal of Hospital Infection. However, the paper in question is based solely on observational data and is, therefore, considered of limited or questionable value.

The remainder of the information in this column ought to be considered experimental/hypothetical in nature. A number of in-vitro or test tube studies have identified several common foods which may antagonize the norovirus and/or inhibit the likelihood that the virus will bind to the digestive tract and cause gastroenteritis (diarrhea and vomiting). The foods in question contain particular phytochemicals, including polyphenols, proanthocyanins and tannic acid. Cranberries, grape seed extract and pomegranate juice are the three most commonly noted foods which show potential in this arena. Currently, what is unknown is whether consuming these fruits or supplementing with fruit extracts will impart any “real world” protection. Nevertheless, if you’re in high-risk environments, such as a cruise ship or a nursing home, you may want to share this preliminary data with your health care team to determine whether it may be appropriate for you.

To learn more about the studies referenced in today’s column, please click on the following links:

Study 1 – Passenger Behaviors Associated With Norovirus Infection On Board … (link)

Study 2 – Effect of the Continuous Intake of Probiotic-Fermented Milk Containing … (link)

Study 3 – Protective Effect of Anticholinergic Drugs and Psyllium in a Nosocomial … (link)

Study 4 – Effects of a Variety of Food Extracts and Juices on the Specific Binding … (link)

Study 5 – Effect of Grape Seed Extract on Human Norovirus GII.4 … (link)

Study 6 – Tannic Acid Inhibited Norovirus Binding to HBGA Receptors, A Study … (link)

Study 7 – Time-Dependent Effects of Pomegranate Juice and Pomegranate … (link)

Study 8 – In Vitro Effects of Pomegranate Juice & Pomegranate Polyphenols on … (link)

Study 9 – Antiviral Effects of Cranberry Juice & Cranberry Proanthocyanidins on … (link)

Study 10 – The Effect of Cranberry Juice and Cranberry Proanthocyanidins on the … (link)

Cranberry Juice (CJ) & Proanthocyanidins (PAC) Antagonize Norovirus

Source: Food Microbiology Volume 27, Issue 4, June 2010 (link)