Ok, cite some of them.

(I have problem believing that your conclusion is true, but you should cite at least a subset of your sources.)

Why? You can't search for sources? Do you request bibliography for all claims in a casual conversation?

Dark green leafy vegetables are great sources of nutrition. Salad greens, kale and spinach are rich in vitamins A, C, E and K, and broccoli, bok choy and mustard are also rich in many of the B-vitamins. These vegetables also contain an abundance of carotenoids-antioxidants that protect cells and play roles in blocking the early stages of cancer. They also contain high levels of fiber, iron, magnesium, potassium and calcium. Furthermore, greens have very little carbohydrates, sodium and cholesterol.

The dark greens supply a significant amount of folate, a B vitamin that promotes heart health and helps prevent certain birth defects. Folate is also necessary for DNA duplication and repair which protects against the development of cancer. Several large studies have shown that high intakes of folate may lower the risk of colon polyps by 30 to 40 percent compared to low intakes of this vitamin. Other research suggests that diets low in folate may increase the risk of cancers of the breast, cervix and lung.

If people here are really that "dry"... I might consider not commenting on here anymore and slowly begin to leave. :/

Also, jokes come thru very poorly via typed text.