Broccoli was in the spotlight at the American Institute for Cancer Research’s recent annual conference, where global scientists shared their findings on the connection between diet and cancer. Had the researchers been giving out awards, broccoli’s baby sprouts, not just broccoli, would have snatched gold.
How you prepare broccoli, though, is the key to its cancer-fighting ability, said Elizabeth Jeffery, co-chair of one of the conference’s sessions and a professor in the department of food science and human nutrition at the University of Illinois at Urbana-Champaign. Her latest research could dramatically change your culinary habits.
Queen of the crucifers
You know the stinky smell that fills your kitchen when you’re cooking broccoli? That’s because of healthy sulfur-filled compounds, which exist in all crucifers. An enzyme in crucifers — marked by that kick you get when you bite into a raw one — turns sulfurs into two cancer-fighting categories:
More from Zester Daily:
— Indoles, which help break down hormones as well as target a group of genes that promote prostate cancer. (The latter finding was reported by Wayne State University scientist Fazlul Sarkar at the conference.)
— Isothiocyanates (pronounced eye-so-thigh-o-sigh-a-nates), which counteract carcinogens in general and speed up their removal from the body. (Of course, broccoli also has many more healthy compounds.)
Broccoli bears the crown of queen of the crucifers because compared with other crucifers, it contains more of a particularly important isothiocyanate called sulforaphane.
Because heat degrades the enzyme that produces sulforaphane, many food scientists, until now, have recommended we eat crucifers raw or very lightly cooked. In her recent broccoli research, however, Jeffery has developed a more sophisticated approach to maximizing sulforaphane. Her work shows that how you make the broccoli and what you pair it with are vital.
Tips on handling broccoli
To capitalize on sulforaphane, first cook broccoli lightly, Jeffery said. Steam it in a little liquid for 3 to 4 minutes until bright green, using a steamer so that it doesn’t touch the cooking liquid. Or blanch it for 20 to 30 seconds, no more. Those methods are surprisingly better than eating it raw, she said, because when the enzyme acts on broccoli’s sulfur-containing compounds, the compounds can swing either way — and get turned into sulforophanes, which fight cancer, or nitriles, which don’t. “Every molecule of nitriles formed is a sulforaphane not formed,” Jeffery said. And just a little heat will keep nitriles from forming.
To counteract the enzyme reduction caused by heating Jefferey has a second suggestion:
Eat steamed broccoli along with a little raw crucifer — arugula, watercress, a little wasabi or spicy mustard, or perhaps even better, raw red radish. (The stronger the kick, the more enzyme you’re getting.) Red radishes contain sulforaphane and don’t have the inherent ability to produce nitriles. You don’t need much, Jeffery said — just two to three radishes or a ½ teaspoon of mustard or wasabi. And you don’t have to eat them in the same bite as broccoli, just in the same meal.
Here’s the final and most liberating finding for those of us chained to our kitchens: As long as you eat raw crucifers in the same meal, you can go ahead and cook broccoli any way you want, Jeffery said. The enzymes in the raw crucifers will act on compounds in the cooked ones.
Why broccoli sprouts?
While President George H.W. Bush was banning broccoli on Air Force One back in 1990, Johns Hopkins researcher Paul Talalay was busy exploring the crucifer’s newborn sprouts. What, he wondered, was the ideal number of days needed to germinate seeds to get the best sulforaphane content as well as taste?
The answer: three days. He and his son went on to develop a side business selling young broccoli sprouts. (Talalay, now 91, still collaborates on research and goes to his lab almost every day.)
In contrast to mature broccoli, broccoli sprouts have, on average, 20 times the amount of compounds that develop into sulforaphane, said Yanyan Li, a professor of food science at Montclair State University who is studying sulforaphane. Since the 1990s, researchers have been identifying cancer stem cells in many types of cancer, and Li has recently found that sulforaphane targets breast cancer stem cells at relatively low concentrations.
How much is enough?
To obtain that level of sulforaphane, however, you’d need to eat several pounds of broccoli — or, Li suggested, just a heaping cup of raw sprouts, lightly steamed and consumed along with a few raw radishes. Sulforphane is eliminated from the body relatively quickly, she said, so “eating them three times a day would be ideal to maintain the level.”
For the average person, that’s not really feasible, she acknowledges, and scientists at the conference agreed that eating crucifers four to five times a week is a reasonable goal for most — as long as you chew the vegetables well. By breaking the cell walls, you’re releasing those pungent enzymes.
Jeffery’s lab is now comparing the sulforaphane content in common varieties of broccoli, but that research is not yet ready for prime time.
Broccoli Sprout Salad With Synergy
(Recipe courtesy of Holly Botner, the Jittery Cook)
For the dressing:
½ lemon, juiced
2 tablespoons olive oil
1 clove garlic, minced
½ teaspoon salt
freshly ground black pepper to taste
For the broccoli sprout salad:
2 containers broccoli sprouts
4 red radishes, ½ thinly sliced, ½ julienned
1 handful baby arugula
½ carrot, cut into slivers with a peeler
¼ yellow pepper, finely chopped
1 orange, cut into segments as garnish
1. Combine all ingredients for the dressing and mix well.
2. Steam the sprouts until bright green, then cut off their green tops to use in the salad.
3. Arrange salad ingredients on two small plates. Spoon dressing lightly over salad.
Top photo: Broccoli sprout salad. Credit: Holly Botner / jitterycook.com