As the number of E. coli O157:H7 outbreaks continues to grow, it may be time for people to consider a natural preventative measure—cranberry juice. Over the years, a number of studies have looked at the health benefits of cranberries, particularly in the prevention of urinary tract infections. Researchers have found that cranberry juice may be able to prevent E. coli infections.

How much cranberry juice cocktail should one consume?

According to a study published in 2002 (Howell), 8 ounces of cranberry juice cocktail every morning and evening may help prevent an E. coli infection. The research conducted jointly between Rutgers, The State University of New Jersey and the University of Michigan, looked at the affect of cranberry juice cocktail on E. coli adhesion in the urinary tract. Researchers took urine samples of healthy men and women, some of whom had consumed 8 ounces of cranberry juice cocktail. The urine was allowed to interact with urinary tract cells that had been exposed to E. coli. The urine of the people who had consumed the cranberry juice prevented 79% of the bacteria from sticking to the urinary tract cells. The study also found that cranberry juice cocktail’s beneficial effect may start within two hours and can last for up to 10 hours in the urine. If this is correct (more studies are needed) an 8 ounce serving in the morning and evening may be adequate provide anti-adhesion protection.

What does cranberry juice do to E. coli bacteria?

Research at Worcester Polytechnic Institute (Liu) found that a group of tannins (called proanthocyanidins) found primarily in cranberries affect E. coli in three devastating ways, all of which prevent the bacteria from adhering to cells in the body, a necessary first step in all infections:

• They change the shape of the bacteria from rods to spheres.
• They alter their cell membranes.
  
• They make it difficult for bacteria to make contact with cells, or from latching on to them should they get close enough.
  

For most of these effects, the impact on bacteria was stronger the higher the concentration of either cranberry juice or the tannins, suggesting that whole cranberry products and juice that has not been highly diluted may have the greatest health effects.

"We are beginning to get a picture of cranberry juice and, in particular, the tannins found in cranberries as, potentially potent antibacterial agents," Camesano says. "These results are surprising and intriguing, particularly given the increasing concern about the growing resistance of certain disease-causing bacteria to antibiotics."

Disclaimer: Cranberry juice cocktail is a food, not a drug, nor should it be used in place of a drug. Anyone who suspects an infection should always consult a physician. Cranberry juice cocktail should not be used as a treatment for infection, but may be an effective part of a prevention routine.

References:
1. Amy B. Howell and Betsey Foxman, Cranberry Juice and Adhesion of Antibiotic-Resistant Uropathogens, Journal of the American Medical Association, 2002, 287, 3082-3083.
2. Liu, Y., Black, M.A., Caron, L., and T.A. Camesano. Role of cranberry juice on molecular-scale surface characteristics and adhesion of Escherichia coli, Biotechnology and Bioengineering. 2006, 93, 297-305.
3. Worcester Polytechnic Institute Press Release

Labels: cranberries, cranberry juice cocktail, E. coli, E. coli prevention