Previous studies have found that eating broccoli can help protect against heart disease and fight cancer growth. Now new research shows that if you want to capitalize on the beneficial phytochemicals and vitamins present in broccoli you should eat it raw or lightly steamed rather than in supplement form.
In the study (subscription required), Oregon State University researchers randomly assigned 24 men and women ages 19 to 50 to consume either a cup of broccoli sprouts each morning or a supplement with the equivalent nutrients for a week. Researchers collected blood and urine samples from each participant prior to the study and throughout the experiment to test individuals' absorption levels of the nutrients in the vegetables and capsules. The researchers found that subjects who consumed the broccoli supplement absorbed significantly less nutrients than those who ate the fresh produce. According to a university release:
The reason, researchers concluded, is that a necessary enzyme called myrosinase is missing from most of the supplement forms of glucosinolates, a valuable phytochemical in cruciferous vegetables [such as broccoli]. Without this enzyme found in the whole food, the study found that the body actually absorbs five times less of one important compound and eight times less of another.
Intensive cooking does pretty much the same thing, [study author Emily Ho, PhD,] said. If broccoli is cooked until it's soft and mushy, its health value plummets. However, it can still be lightly cooked for two or three minutes, or steamed until it's still a little crunchy, and retain adequate levels of the necessary enzyme.
A number of supplements, like those used in this study, only contain an inactive form of the myrosinase enzyme. However, some manufacturers are developing versions that would include the active enzyme. Researchers plan to conduct similar studies in the future using products with the active myrosinase to better understand if those formulas are equally effective consuming fresh broccoli.
Previously: You are what you eat: Study suggests plant-based foods may alter gene expression, Stanford nutrition experts discuss top cancer-preventing foods and Stanford nutritionist offers guidelines for eating healthy on the go
Photo by Isaac Wedin