Researchers at the University of Ulster in Northern Ireland have shown that watercress can help to prevent cancer.

In a study published in the February 2007 edition of the American Journal of Clinical Nutrition the researchers found that adult smokers and non-smokers who added 85 grams of watercress to their diets had increased levels of antioxidants in their blood and reduced free radical damage to the DNA in their white blood cells.  

The result of this research should come as no surprise to us as epidemiological and other studies have found that other cruciferous foods such as mustard , wasabi, cabbage, broccoli and Brussels sprouts all contain some of the most powerful anti-cancer compounds.

In this particular study 30 smokers and 30 non smokers were given 85 grams a day of watercress to eat with their normal food for  eight weeks. The effect of eating the watercress was assessed by measuring DNA damage in the white blood cells and the activity of the body's own detoxifying antioxidant enzymes, glutathione peroxidase and superoxide dismutase in red blood cells. Total antioxidant status and the activity of other antioxidants in the blood such as vitamins A, C, E, ß-carotene and lutein was also measured at the beginning and end of the eight week period.

The results of this eight week period of watercress consumption was a 23% reduction in DNA damage, reduced free radical damage and an increase of up to 100% in the levels of the carotenoid antioxidants, ß-carotene and lutein.

Why did the researchers choose watercress for this study?

The reason is that is was sponsored by the Watercress Alliance in the UK to promote the consumption of watercress.

However, as previous studies have shown, the researchers could probably have taken any of the cruciferous vegetables (including yellow mustard) to use in this study and come up with very similar results.

Not only do the brassicas provide antioxidants like ascorbic acid, B carotene, alanine and methionine but they also contain non-antioxidant compounds that have anti-cancer activity.

The Brassicas are vegetables that have a strong tang and are thus far less bland than most other vegetables. The compounds that provide this intense flavor are usually those that contribute to the anti-cancer properties of this important food group.



References:

American Journal of Clinical Nutrition , Vol. 85, No. 2, 504-510, February 2007

Cancer Epidemiol Biomarkers Prev . 2006 Feb;15(2):301-5

Cancer Lett. 2003 Jun 30;196(1):29-34