Discover the Wonders of Watercress

Watercress is a member of the cruciferous vegetable family. Like other cruciferous vegetables such as broccoli and kale, when chewed or chopped, watercress releases a variety of phytochemicals that are thought to ward off cancer.

While all cruciferous vegetables are good sources of these cancer-fighting plant compounds, watercress is uniquely abundant in one in particular, phenylethyl isothiocyanate (PEITC). Evidence is mounting to suggest PEITC may provide strong protection against cancer by interfering with tumour development.

When breast tumours outgrow their blood supply, they send a message via a protein called hypoxia inducible factor (HIF) that signals surrounding healthy tissue to feed them the nutrients they need. This process is thought to be a critical step in the transformation of a dormant tumour into a cancerous one.

Researchers from the University of Southampton found that when breast cancer survivors ate a cereal-sized bowl (80 g) of watercress, HIF’s ability to deliver its message was significantly reduced. The high levels of PEITC found in watercress are credited for this potentially tumour-inhibiting effect.

Although evidence is still preliminary, PEITC is also showing promise in warding off cancer in other areas of the body including the prostate, lung, and colon.

In one laboratory study, researchers from New York Medical College found PEITC was able to inhibit rapid cell division, slow tumour development, and cause death in human prostate cancer cells.

Researchers from Georgetown University Medical Center also found PEITC to work in a similar fashion to protect mice from developing both benign and cancerous tumours in the lungs after being exposed to tobacco carcinogens.

And in another study, funded by the National Institutes of Health, this cancer-fighting plant compound was shown to make changes at a cellular level to reduce chronic inflammation in the colon, effectively reducing symptoms associated with ulcerative colitis—considered a major risk factor in the development of colon cancer.

PEITC isn’t watercress’s only disease-fighting compound. Rich in dietary antioxidants such as vitamins A and C, watercress may also help to ward off chronic disease by protecting cells from damaging free radicals.

A study published in the American Journal of Clinical Nutrition found that when eaten regularly, watercress may significantly reduce free-radical damage to immune-boosting white blood cells. During the study 60 healthy men and women ate an 85 g bag of fresh watercress daily. After eight weeks the researchers found that DNA damage to the participants’ white blood cells had been reduced on average by 23.9 percent.

In addition to protecting the participants from free-radical damage, the daily dose of watercress was found by the researchers to have reduced artery-clogging blood triglyceride levels by 10 percent and significantly increased levels of other antioxidant compounds such as lutein and beta carotene.

High blood levels of lutein in combination with zeaxanthin have been linked to a lower risk of age-related macular degeneration. Containing over 1,900 mcg of lutein and zeaxanthin in a one cup (48 g) serving, raw watercress is an excellent source of these two eye-healthy carotenoids.

The nutritional merits of watercress don’t stop there. Watercress is also a good source of bone-strengthening vitamin K, calcium, and folic acid.

Just one cup (48 g) of raw watercress provides 106 percent of the recommended daily value of vitamin K, needed by bones to properly process calcium. Diets high in vitamin K have been linked to greater bone density and a reduced risk of bone fractures in postmenopausal women.

Folic acid, although better known for its role in promoting a healthy pregnancy, also helps to keep homocysteine levels under control. Homocysteine is an amino acid that in high amounts is associated with an increased risk of bone fractures. In one study researchers found that participants who had high amounts of homocysteine in their blood were nearly two times more likely to break a bone, regardless of bone density.

The high folic acid content of watercress not only strengthens the bones, but also may protect the heart. Preliminary research has associated elevated levels of homocysteine with blood vessel damage and an increased risk of heart disease and stroke.

From promoting strong bones to warding off cancer, watercress is certainly one healthy leafy green to eat often.

Although best known for its place at English afternoon tea, watercress makes a tasty addition to a wide array of dishes. Available year round, it is easy to take advantage of all the health-protecting properties watercress has to offer by including it as part of your regular diet.