Cruciferous vegetables are high in indole-3-carbinol (I3C) and antioxidants including beta-carotene and sulforaphane. Indole-3-carbinol once ingested gets converted to diindolylmethane (DIM). I3C and DIM modulate estrogen metabolism so that estrogen is broken down into non-cancer causing metabolites. More specifically they increase the ratio of 2/16 hydroxyestrone. A high ratio is protective against estrogen sensitive cancers (breast, endometrial, and cervical), and possibly prostate cancer (estrogen levels increase in men with age).
These and related compounds in cruciferous vegetables induce cell apoptosis (cell death) and inhibit tumor blood vessel formation making cancer less likely to develop and spread.
They are also antioxidants which also protect against cancer. Antioxidants protect against DNA damage that lead to cancer development.
I3C and DIM can be obtained as supplements. 400 mg a day of I3C a day appears to provide maximal cancer prevention with higher doses showing no additional benefit.
More Benefits of Cruciferous Vegetables
Cruciferous vegetables have anti-inflammatory properties and antiviral/antibacterial effects. They are high in fiber and vitamins C and E – two other antioxidants. These veggies are also high in vitamin K, an underappreciated vitamin when it comes to bone and cardiovascular health. Vitamin K helps to keep calcium in the bone and out of blood vessels. Patients who take coumadin (blood thinner that inactivates vitamin K) are more likely to develop brittle bones (osteoporosis).
Types of Cruciferous Vegetables
Now that we know cruciferous vegetables are healthy, what are some examples. First, cruciferous vegetables get their name because of their cross-shaped flower petals.
Cruciferous vegetables include arugula, Bok choy, broccoli, brussels sprouts, cabbage, cauliflower, chard, collard greens, horseradish, kale, mustard greens, radishes, rutabaga, turnips, watercress, and wasabi.
Is There Any Down Side to Eating Cruciferous Vegetables?
Raw cruciferous vegetables can block thyroid hormone production. People with hypothyroidism should avoid eating them raw, and eating excessive amounts. It is also best not to overheat these vegetables. One study showed that just minutes of microwaving deactivated many of the healthy compounds found in cruciferous vegetables. Steaming is considered the best method for cooking.
See related articles.