How to Eat Better: Simple Science to Supercharge Your Nutrition (Sterling Epicure, 2017), by James Wong, is filled with colorful recipes containing fruits and vegetables. Wong uses research to explain the many health benefits of specific fruits and vegetables. Follow the recipes for a healthier you. Find this excerpt in Vegetables, “Cabbages.”
Just like other leafy greens, the vegetables in the cabbage family (called “crucifers”) are real nutritional superstars, providing calorie for calorie more essential nutrients such as vitamins A, C and folic acid than pretty much any other fruit or vegetable. But why make a section dedicated to them alone? Well, it’s the growing body of research pointing to the potential for a group of chemicals uniquely found in this vegetable family to prevent degenerative diseases that did it. Science may still be piecing the puzzle together, but here’s the latest.
Crucifers Against Cancer?
In order to fight back against attack from insect predators, these plants have evolved the ability to generate pungent, bitter-tasting, sulphur-based compounds called glucosinolates. When chopped, chewed or digested, glucosinolates break down into substances called isothiocyanates, which possess interesting biological effects. While these might be acutely toxic to tiny insects, in our much bigger bodies they paradoxically may have a protective effect according to a growing stack of research. Test-tube and animal studies have shown that glucosinolates and their products can suppress cancer cell development in the colon, lungs, liver, bladder, breast and stomach, and research looking at dietary patterns has frequently (but by no means always) shown that people who eat more of these vegetables tend to have a statistically lower risk of developing certain cancers.
The crazy thing about the products of glucosinolates is that they appear to work in at least three totally different ways. Not only do they demonstrate the ability in some test-tube and animal studies to stop cancer cells from multiplying and even to naturally self-destruct, while ignoring healthy cells, they also appear to be able to neutralize cell-damaging free radicals that are associated with developing cancer in the first place. Other studies have suggested they may go even further, triggering your body’s own natural defenses against carcinogenic substances by stimulating the secretion of enzymes that mop these up before they have a chance to damage cells. This suggests a theoretical trifecta of cell defense, attacking from all sides, if these studies are replicable in humans.
The effects of glucosinolate consumption can be seen pretty quickly, too. In one Italian study, by adding 3 servings of broccoli (that’s a lot of broccoli!) to the daily diets of male smokers, a significant reduction in the inflammation associated with several degenerative diseases was seen in as few as 10 days. In another small trial funded by the US-based National Cancer Institute, adding about 5-1/4 ounces of various cruciferous vegetables to participants’ daily diets was able to reduce levels of oxidative stress (a risk factor for developing certain cancers) by an impressive 22 per cent in just three weeks.
These trials were both very small and extremely short term, and it is important to point out that other human studies have shown mixed results. More evidence is clearly needed before any hard and fast conclusions are drawn, but there does appear to be a growing body of research that suggests that adding a couple of servings of this group of vegetables to your daily diet could be a particularly healthy choice. This section will show you how to get the best from them.
Selecting the Best of the Best
Despite looking almost unrecognizably different, most crops in the cabbage family – including everything from turnips to cauliflower, mustard to red cabbage – are incredibly closely related. In fact, every vegetable on the opposite page technically belongs to just one species, bred to create myriad forms and flavors by thousands of years of farmers selecting for different traits. This is also reflected in their internal chemistry, meaning that when it comes to glucosinolates some varieties can contain almost 20 times more than others ounce for ounce. Thanks to a couple of supergeeks at the University of Queensland, Australia, who pooled the findings of more than 18 studies, we now have a really reliable ranking of the best of the best. So here goes…
With nearly five times the glucosinolates of close relatives such as cauliflower, these guys provide the most glucosinolate bang for buck. Closely followed by collard greens (200mg/3 -1/2 oz), these two vegetables leave the others in the dust.
The humble Savoy might be a runner-up in the glucosinolate stakes with less than half that of Brussels sprouts, but compared to other cabbages it is far richer.
Kale has a similar glucosinolate level to Savoy cabbage, but there is so much more to nutritional value than fixating on a single compound. Containing many times more vitamins A, C and K than any of the other crops on this page, kale is by no means an inferior choice. When it comes to polyphenols, it has more than twice that of Brussels sprouts, too, so enjoy both liberally.
White & red cabbages
White and red cabbage contain about 40 percent fewer glucosinolates than Savoy cabbage. What red cabbage lacks in glucosinolates however, it more than makes up for in polyphenol content, with several trials consistently ranking it as the highest of all cabbages in these potentially heart-healthy compounds, owing to the rich anthocyanin content.
What about white cabbage? Sadly it loses out in both stakes, containing fewer than half the polyphenols of red, which has between two and five times the antioxidant activity of its white cousin. Another reminder that dark green or red leafy vegetables are generally more nutrient dense than their paler cousins.
Well, here’s a surprising one. Broccoli, the cabbage family’s pin-up for health benefits, actually ranks relatively low in terms of total glucosinolates. But it is the type of glucosinolates it contains that has sparked the interest, as it is by far the richest in a specific one called glucoraphanin, which research suggests may be particularly beneficial. It is also one of the highest of all crucifers in heart-healthy polyphenols, alongside kale.
Last, and sadly kind of least, comes the humble cauliflower. Containing just 80 percent fewer glucosinolates than Brussels sprouts and just half the polyphenols of broccoli, this guy isn’t a clear winner in the nutrition stakes.
The Fresher the Better
Broccoli is one of those vegetables you should eat as soon as you can. This is because as soon as it is harvested the florets experience a precipitous decline of nutritional value. A Spanish research team aimed to replicate the conditions that broccoli is typically subjected to from field to fork – storing it at 34 degrees F for a week to mimic industrial transportation and storage, followed by 3 days at 59 degrees F to simulate it sitting on the store shelves – with some brow-raising results. By the time broccoli gets to you it could have lost 80 percent of its glucosinolates. These findings were echoed by others. One study in the journal Food Chemistry found that broccoli could lose up to 70 percent of its vitamin C and betacarotene and 50 percent of its antioxidant activity in just 6 days. Yikes!
Fortunately, there is a simple solution that involves no extra work for you. The same research also showed that keeping the broccoli continuously refrigerated and stored in sealed bags (as opposed to unwrapped in the fridge) could stem these declines almost entirely. So, only buy broccoli in sealed bags from the chiller cabinet, not loose on the shelves, pick bags with the longest possible expiration date, and cook and eat it as soon as you can. Done.
Red Cabbage & Apple Slaw
Swap pallid white cabbage for the brilliant purple kind when you make coleslaw and not only do you get a more vibrant plate of food, but also ten times the vitamin A, twice the iron and double the antioxidants. Slaw doesn’t have to mean a grease-fest either. This deliciously fresh recipe teams up red cabbage with red onions for a double anthocyanin dose for your next cook-off. Halfway between a crisp salad and a tangy condiment, it works just as well with BBQ chicken and corn as it does roast pork and mashed potatoes in winter.
Prep Time 10 Minutes, Plus Infusing
• 7 Ounces Red Cabbage, Finely Shredded
• 1 Carrot, Grated
• 1 Red Chile, Finely Shredded
• 1/2 Red Onion, Finely Shredded
• 1 Green Apple, Finely Shredded
• 1/2 tsp Salt
• Finely Grated Zest and Juice of 1 Lime
• 1 teaspoon Olive Oil
• 1 teaspoon Sugar
Toss all the ingredients together in a large mixing bowl with your hands to ensure everything is evenly mixed. Continue to massage the mixture, squeezing it between your fingers until it starts to slightly soften.
Cover and let infuse in the fridge for 30 minutes.
Text © 2017 James Wong, Photography © 2017 Octopus Publishing Group Ltd.