“Rabbit food” is the familiar derogatory term commonly used by devoted steak & potatoes guys to dismiss the thought that they’d ever waste time eating lettuce leaves tossed with sunflower seeds and grated carrots. So just imagine how they might react to the offering of a watercress salad.
What rabbits, hamsters, and your average carnivores don’t know is that watercress delivers plenty of calcium, as well as good amounts of vitamin C, folic acid, potassium, beta-carotene, and iron.
In addition, watercress is one of the best sources of phenylethyl isothiocyanate (PEITC). This compound doesn’t quite have the household-word status of those other nutrients, but it just might turn out to be the most valuable component of watercress.
Block that enzyme!
The PEITC in watercress and other cruciferous vegetables is believed to inhibit the activation of an enzyme that’s necessary for cancer to thrive. Researchers at the Northern Ireland Centre for Food and Health (University of Ulster) recently put watercress to the test with an intervention study.
- Sixty healthy adults with an average age of 33 were recruited
- Half of the subjects were cigarette smokers
- Subjects were given 85 grams of raw watercress to include in their regular diets each day
- Blood samples were taken before and after the eight-week trial period
- Researchers measured several biomarkers related to cancer risk, including DNA damage to lymphocytes, activity of detoxifying enzymes, antioxidant levels, and lipid levels
- DNA damage to white blood cells dropped by more than 20 percent
- On average, levels of lutein (an antioxidant) increased by 100 percent
- On average, levels of beta-carotene (an antioxidant) increased by one third
- On average, levels of triglycerides dropped by 10 percent
- These changes were most pronounced among smokers, whose antioxidant levels were much lower than non-smokers at the outset of the study
Professor Ian Rowland – leader of the study – told the BBC: “Blood cell DNA damage is an indicator of whole body cancer risk, and the results support the theory that consumption of watercress is linked to an overall reduced risk of cancer at various sites in the body.”
Watercress and then some
In the opening of the University of Ulster study, the authors state that cruciferous vegetable consumption has been associated with a reduced risk of several types of cancers.
Last year, for instance, a study conducted at Rutgers University examined the effect of cruciferous vegetables and curry on prostate cancer in mice. Researchers found that the combination of PEITC and curcumin (a known cancer fighting component of curry) significantly reduced prostate tumor growth.
Fortunately, when you go shopping for cruciferous vegetables, there’s a long list to choose from. In addition to watercress, these vegetables are cruciferous:
- Brussels sprouts
- Collard greens
- Bok choy
And a side note for anyone who wants to include more calcium in their diet: Arugula contains nearly 100 grams of calcium per cup and watercress contains more than 120 grams per cup.
“Watercress Supplementation in Diet Reduces Lymphocyte DNA Damage and Alters Blood Antioxidant Status in Healthy Adults” American Journal of Clinical Nutrition, Vol. 85, No. 2, February 2007, ajcn.org
“Watercress May Cut Cancer Risk” BBC News, 2/15/07, news.bbc.co.uk