Watercress is most nutrient-dense vegetable, experts

According to health experts, if you want to add leafy greens to your salads or meals, iceberg lettuce is no longer the only option. Many varieties are now available including romaine lettuce, red-leaf lettuce, butter lettuce, beet greens, bok choy, the slightly bitter radicchio and different varieties of arugula.

Sometimes, the choice simply depends on taste and personal preference. However, if you are trying to meet the recommended 2.5 cups of vegetables per day or are reconsidering your salad habits because of the spread of Cyclospora in the United States—a parasite that can cause intestinal diarrhea—you may wonder which vegetables provide the greatest health benefits.

Health experts widely agree that consuming more nutrient-rich fruits and vegetables is associated with a lower risk of chronic diseases. But which leafy green vegetables provide the greatest nutritional benefits?

According to Los Angeles-based nutritionist Jamie Mok, when buying vegetables, it is important to consider nutrient density which refers to the amount of nutrients a food provides relative to the number of calories it contains.

In 2014, the U.S. Centers for Disease Control and Prevention (CDC) published a study aimed at helping people better understand nutrient density. The study identified watercress as the most nutrient-dense vegetable.

It contains approximately 17 different nutrients per calorie, giving it nearly twice the nutrient density of cabbage.

Watercress is rich in vitamins K and C as well as minerals such as calcium, manganese and copper. It also contains abundant phytochemicals which can provide health benefits. Mok says she has been eating watercress since childhood in Chinese soups prepared by her mother.

However, this does not mean that you should eat only watercress and completely avoid other vegetables. Many other vegetables including green cabbage, Napa cabbage and similar leafy vegetables are also highly nutritious. Cabbage and broccoli contain sulfur-containing compounds that have antioxidant properties.