Four reasons to eat your salad greens

Spinach, radicchio and watercress may not immediately come to mind as foods for keeping bones strong, but all contain lots of vitamin K. A study at Tufts University in Boston found that low dietary intake of vitamin K in women was associated with low bone mineral density. (The study didn’t find a link in men.) Just one cup (250 mL) of chopped watercress has 100 percent of your daily vitamin K; radicchio, 120 percent; and spinach, 170 percent.

Toss together a salad of spinach, romaine and red leaf lettuce: They all contain loads of the carotenoids vitamin A, lutein and zeaxanthin (keys to seeing better). Vitamin A helps eyes adapt from bright light to darkness. Lutein and zeaxanthin can help filter out high-energy light that may cause eye damage from free radicals.

Recent Swedish research found that inorganic nitrate (abundant in spinach) resulted in muscles using less oxygen. The study, which had healthy participants ride an exercise bike before and after taking a dose of nitrate, found it improved the performance of the mitochondria (which power our cells) in muscles.

A small study done at the University of Southampton, U.K., showed that phen-ethyl isothiocyanate in watercress disrupts the signals from tumours that cause normal tissues to grow new blood vessels to feed cancer cells. Participants, who had all been treated for breast cancer, ate a cereal-bowl-size portion of watercress. The study showed a key protein in the signalling process was affected. Although more research is needed, the study states: ‘Dietary intake of watercress may be sufficient to modulate this potential anti-cancer pathway.’