Cauliflower belongs to the group of vegetables called cruciferous or brassica vegetables which includes broccoli, Brussels sprouts, cabbage, kale, rutabaga and turnips, among others. Cauliflower doesn't rank among America's favorite vegetables; Americans consumed just 2 lbs. per year, on average, in 2003, according to VegOnline. Like almost any food, cauliflower consumed in excess can have side effects, some potentially serious and some merely annoying -- and odorous.
Iodine Absorption and Cauliflower
Cruciferous vegetables like cauliflower can interfere with iodine absorption if you eat too much of them. Since iodine plays an essential role in thyroid functioning -- it's why salt has added iodine -- low iodine levels can lead to hypothyroidism. Cruciferous vegetables contain cyanogenic glucosides, sugar-like molecules that block iodine absorption when you digest them. When you have low iodine levels, the thyroid enlarges so it can trap more iodine, a condition known as a goiter. Hypothyroidism, characterized by decreased metabolism, cold sensitivity, dry hair and skin, difficulty thinking and weight gain may occur if you eat a diet consisting almost entirely of cruciferous vegetables.
Cauliflower has another potential side effect if you eat too much of it -- gas. While not as serious for your health as thyroid problems, intestinal gas can cause social embarrassment. The bloating and abdominal discomfort that accompany gas can also make you miserable. Cruciferous vegetables contain complex carbohydrates that don't break down easily for digestion. Intestinal bacteria digest them in the intestine, producing carbon and hydrogen dioxide gas. You need an enzyme called alpha galactosidase to break it down. Some people don't produce enough of this enzyme, which you can buy in the form of over-the-counter anti-gas pills, although evidence that it actually works is limited, according to NYU Langone Medical Center.
If you take the blood thinning medication coumadin, too much cauliflower may interfere with the effectiveness of the medication. Cauliflower contains large amounts of vitamin K, around 96 micrograms per one-half cup. Vitamin K helps your blood blot. Coumadin decreases your blood's ability to clot. Eating large amounts of any food with high vitamin K levels makes coumadin less effective. If you already eat a lot of cauliflower, tell your doctor this before starting on coumadin. Suddenly decreasing your intake of vitamin K could also change the way coumadin works in your body. Keeping your vitamin K intake stable is essential when you take coumadin, St. Luke's Family Practice stresses.
It's always better to eat a rounded diet than to concentrate on a single food. Cauliflower, a generally healthy vegetable high in vitamin C and vitamin K, low in calories and high in fiber, has hidden risks for some people. One cup of cauliflower per week will provide the health benefits without the risks, VegOnline suggests.