This piece was written as a contribution to Chef Lilly Allison Steirer’s weekly newsletter “In Season”
I think of kale as an amazing vegetable, primarily because of its hardiness in my garden. Kale is one of the very first vegetables in my garden ready for eating in mid-to-late April; it weathers the heat of the summer and stays hardy all the way through late November when we till everything up for the winter. Frankly, if we didn’t so get many feet of snow each year I think it could go year-round. Given the wide variety of temperatures and weather here in Colorado I think of this as nothing short of remarkable.
One of the interesting aspects of the vegetables in the cabbage (also called crucifer) family is their affect on the endocrine, or hormone, system. All of the members of this family including kale contain some amount of indole-3-carbinol, a chemical that has been getting a lot of press lately. Indole-3-carbinol helps the body to metabolize our most potent estrogens into a less active form, which can be quite useful therapeutically for those who would benefit from reduced estrogen levels. This can include problems with uterine fibroids, menopausal symptoms due to high estrogen and low progesterone, fibrocystic breast disease, and prevention of breast cancer. Although this chemical can be found in an isolated form in a nutritional supplement, eating whole foods from the crucifer family will give you the added benefit of fiber, B vitamins, minerals, and chlorophyll.
On the flip side, cruciferous vegetables also can inhibit absorption of iodine which will decrease production of thyroid hormone. This can be of some use to those with hyperthyroidism, but people with low thyroid should be wary of consuming these too frequently. That said, many sources note that heat destroys the component of kale that inhibits the absorption of iodine so if you prefer your kale cooked, this should not be too big of a problem.