Welcome to the Nutrition Facts podcast. I’m your host Dr. Michael Greger. I am thrilled that you have decided to join me today. Because the more I learn about latest nutrition research – the more convinced I am that this information can make a real difference in all of our lives. And I like nothing better – than sharing it with you.
Today we’re talking about splendiferous cruciferous. Say that ten times fast. Cruciferous! Those are those fabulous veggies that belong to the cabbage family: broccoli, brussel sprouts, kale, collards, cauliflower, bok choy.. the list simply goes on. Cruciferous veggies are the original super foods, but you do need to know how to prepare them for maximum benefits.
In our first story, adding myrosinase enzymes in the form of even a pinch of mustard powder to cooked cruciferous (cabbage-family) vegetables like kale, collards or Brussels sprouts can offer anti-cancer sulforaphane levels comparable to raw, removing the necessity to pre-chop for maximum health benefits.
When I used to teach medical students at Tufts, I gave a lecture about this amazing new therapeutic called iloccorB. I’d talk about all the new science, all the things it could do, excellent safety profile and just as they were all scrambling to buy stock in the company and prescribe it to all their patients I did the big reveal, apologizing for my dyslexia, I had got it backwards. All this time I had been talking about broccoli.
Sulforaphane, is thought to be the main active ingredient in broccoli, which may protect our brain, protect our eyesight, protect against free radicals, induce our detoxification enzymes, help prevent cancer, as well as help treat it. For example I’ve talked about sulforaphane targeting breast cancer stem cells.
But then I talked about how the formation of this compound is like a chemical flare reaction, requiring the mixing of a precursor compound with an enzyme in broccoli, which is destroyed by cooking. This may explain why we get dramatic suppression of cancer cell growth from raw broccoli, cauliflower, Brussels sprouts, but hardly anything boiled microwaved or steamed, except for microwaved broccoli —that actually retained some cancer fighting abilities. But who wants to eat raw Brussels sprouts?
I shared a strategy, though, for to how to get the benefits of raw in cooked form. In raw broccoli, when the sulforaphane precursor, called glucoraphanin, mixes with the enzyme, called myrosinase, because you chewed or chopped it, given enough time—sitting in your upper stomach for example, waiting to get digested, sulforaphane is born. Now the precursor is resistant to heat, and so is the final product, but the enzyme is destroyed. And with no enzyme, there’s no sulforaphane production.
That’s why I described the hack and hold technique. If you chop the broccoli, Brussels sprouts, kale, collards, or cauliflower first, and then wait 40 minutes, then you can cook them all you want. The sulforaphane is already made, the enzyme is already done doing its job, so you don’t need it anymore.
When most people make broccoli soup, for example. they’re doing it wrong. Most people cook the broccoli first, then blend it, but now we know it should be done the exact opposite way. Blend it first, wait, and then cook it. What if we’re using frozen broccoli, though? Here’s the amount of sulforaphane in someone’s body after they eat broccoli soup made from fresh broccoli. Hits their bloodstream within minutes.
Commercially produced frozen broccoli lacks the ability to form sulforaphane because vegetables are blanched, flash-cooked, before they’re frozen for the very purpose of deactivating enzymes. This prolongs shelf life in the frozen foods section, but the enzyme is dead by the time you take it out of your freezer, so it doesn’t matter how much you chop it, or how long you wait, no sulforaphane is going to be made. This may be why fresh kale suppresses cancer cell growth up to 10 times more than frozen.
The frozen is still packed with the precursor—remember that’s heat resistant, and they could make lots of sulforaphane out of the frozen broccoli by adding some exogenous enzyme. Where do you get myrosinase enzyme from? They bought theirs from a chemical company, but we can just walk into any grocery store.
This is another cruciferous vegetable, mustard greens. All cruciferous vegetables have this enzyme. Mustard greens, grow out of little mustard seeds, which you can buy ground up in the spice aisle as mustard powder. So if you sprinkled some mustard powder on your cooked frozen broccoli, would it start churning out sulforaphane? We didn’t know, until now.
Boiling broccoli prevents the formation of any significant levels of sulforaphane due to inactivation of the enzyme. However, addition of powdered mustard seeds to the heat processed broccoli significantly increased the formation of sulforaphane. Here’s the amount of sulforaphane in boiled broccoli; this is how much you get if you add a teaspoon of mustard powder. That’s a lot though. How about a just a half teaspoon? About the same amount, suggesting you could use even use less. Domestic cooking leads to enzyme inactivation of myrosinase and hence stops sulforaphane formation, but addition of powdered mustard seeds to cooked cabbage-family vegetables provides a natural source of the enzyme and then it’s like you’re practically just eating it raw. So, if you forget to chop your greens in the morning for the day, or are using frozen, just sprinkle some mustard powder on top at the dinner table and you’re all set. Or some daikon radish, or horseradish, or wasabi—all cruciferous vegetables packed with the enzyme. Here they used just like a quarter teaspoon for seven cups of broccoli, so just a tiny pinch can do it. Or you can add a small amount of fresh greens to your cooked greens. Right—because the fresh greens have that enzyme that can go to work on the precursor in the cooked greens.
One of the first things I used to do in the morning is chop my greens for the day and so when lunch and supper rolls around they’re good to go, as per the hack and hold strategy, but now with the mustard powder plan I don’t have to prechop.
In our next story, simple changes in diet and lifestyle may quadruple a woman’s survival rate from breast cancer.
A half-million Americans are expected to die this year from cancer—equal to five jumbo jets crashing, every day. “The number of Americans who die from cancer each year is more than all those who have died in all US wars combined.” And, this happens every single year.
After a cancer diagnosis, people tend to clean up their diets. About a third to a half of breast cancer patients, for example, make healthy dietary changes following diagnosis—such as increasing fruit and vegetable consumption, and decreasing meat, fat, and sugar intakes. Does this actually help, that late in the game? Well, “the Women’s Healthy Eating and Living [WHEL] Study was undertaken in [a few thousand] breast cancer survivors to determine if a plant-based, low-fat, high-fiber diet could influence breast cancer recurrence rates and survival.”
Previously, they famously reported that simple changes—five or more servings of fruits and veggies a day, and just, like, walking thirty minutes a day, six days a week, was associated with a significant survival advantage—cutting risk nearly in half. Note; I said fruits and veggies and exercise. Here’s the proportion of women with breast cancer surviving nine years in the study, if they had low fruit and vegetable consumption, and low physical activity—or, high in one, and low in the other. But, here’s the survival curve of those high in both.
And, it worked just as well in women with estrogen receptor negative tumors, which normally have twice the mortality—unless, you eat a few fruits and veggies, and take a few strolls. The High should really be in quotes. I mean, you could eat five servings in a single meal, and certainly walk more than, like, two miles a day.
Imagine, for a second, you have been diagnosed with breast cancer. Imagine sitting in that chair, in the doctor’s office, as your doctor gives you the news. But, there’s a new experimental treatment that can cut your chances of dying in the next few years from, like, 16% down to just 4%. To quadruple their survival rate, many women would remortgage their homes to fly to some quack clinic in Mexico, would lose all their hair to chemo, but most, apparently, couldn’t stand the thought of eating broccoli.
And, indeed, that’s what the latest report from the Women’s Healthy Eating and Living Study found. Fruits and vegetables may be good, but cruciferous vegetables may be better. For women on tamoxifen, for example, if one of their five daily servings of fruits and veggies was broccoli or cauliflower, collards, cabbage, or kale, the risk of cancer recurrence may be cut in half.
Cruciferous veggies offer us the best of both worlds—significantly improving our ability to detoxify carcinogens, like diesel fumes, and decreasing inflammation in our airways, all the while improving our respiratory defenses against infections.
Outdoor air pollution may be the ninth leading cause of death and disability in the world, responsible for millions of deaths from lung cancer, emphysema, heart disease, stroke, and respiratory infection. In the U.S., living in a polluted city was associated with a 16, 27, and 28% increase in total, cardiovascular, and lung cancer death, compared to living in a city with cleaner air. Living in a city with polluted air may lead [to] up to a 75% increase in the risk of a heart attack. No one wants to be living in a traffic jam, but it’s better than dying in a traffic jam.
“In addition to causing deaths, air pollution is also the cause of a number of…health problems.” It may not only exacerbate asthma, but increase the risk of developing asthma in the first place. These pollutants may trigger liver disease, even increase the “risk of diabetes.” “Even when atmospheric pollutants are within legally established limits, they can be harmful to health.” So, what can we do about it?
Paper after paper describing all the terrible things air pollution can do to us, but most failed to mention public policy. We’re making “great strides in demonstrating the harmful effects, [but] public authorities are not using these data to” reduce emissions, as they might inconvenience the population, “and, therefore, might not be politically acceptable.”
To treat the cause, we need better “vehicle inspections, efficient public transport,…bus lanes, bicycle lanes, even urban tolls”—to help clean up the air. While we’re waiting for all that, is there anything we can do to protect ourselves?
Well, our body naturally has detoxifying enzymes, not only in our liver, but lining our airways. Studies showing that people born with less effective detox enzymes have an exaggerated allergic response to diesel exhaust, suggesting that these enzymes actively combat the inflammation caused by pollutants in the air. A significant part of the population has these substandard forms of the enzyme, but either way, what can we do to boost the activity of whichever detoxification enzymes we do have?
Well, if you remember, broccoli can dramatically boost the activity of the detox enzymes in our liver. But, what about our lungs? Researchers fed some smokers a large stalk of broccoli every day for ten days to see if it would affect the level of inflammation within their bodies. Why smokers? Because smoking is so inflammatory that you can end up with elevated C-reactive protein levels for “up to 30 years…after quitting,” and that inflammation can start almost immediately after we start smoking. So, it’s critical to never start in the first place.
But, if you do, you can cut your level of that inflammation biomarker CRP nearly in half, after just ten days eating a lot of broccoli. Appears to cut inflammation in nonsmokers as well—maybe explaining, in part, why eating more than two cups of broccoli, cabbage, cauliflower, kale, or other cruciferous veggies a day is associated with 20% reduced risk of dying, compared to eating a third [of] a cup a day, or less.
So, what about air pollution? We know the cruciferous compound is “the most potent known inducer” of our detox enzymes; and so, most of the research has been on its ability to fight cancer. But, for the first time, they tried to see if it could combat “the proinflammatory impact of…pollutants such as diesel exhaust.” They took some human lung lining cells in a petri dish, and yeah, but we don’t inhale broccoli; we don’t snort it; we eat it. Can it still get into our lungs and help? Yes, two days of broccoli-sprout consumption, then you suck some cells out of their nose, and up to 100 times more detox enzyme expression, compared to eating a non-cruciferous vegetable (alfalfa sprouts). Now, all we have to do is squirt some diesel exhaust up their nose, which is what some UCLA researchers did—an amount equal to daily rush-hour exposure on the Los Angeles freeway. Within six hours, the number of inflammatory cells in their nose shot up, and continued to rise. But, in the group that had been getting a “broccoli sprout extract,” the inflammation went down, and stayed down.
Since the dose in these studies is equivalent to the consumption of one or two cups of broccoli, their “study demonstrates the potential preventive and therapeutic potential of broccoli.”
But, if broccoli is so powerful at suppressing this inflammatory immune response, might it interfere with normal immune function? After all, the battle with viruses, like influenza, can happen in the nose. Let’s drip some flu viruses into the nostrils of broccoli-sprout eaters, and find out. And, what you get is the best of both worlds—less inflammation, yet an improved immune response. So, better immune function, yet less inflammation, potentially “reducing the impact of…pollution on allergic disease and asthma”—at least for “an enthusiastic broccoli consumer.”
But, what about cancer, detoxifying air pollutants throughout the rest of our body? We didn’t know, until now. Off to China, where they have some of the worst air pollution in the world. And, by day one, those getting the broccoli sprouts were able to get rid of 60% more benzene from their bodies, a “rapid…highly durable elevation in the detoxification of…a known human carcinogen.” Now, this was using broccoli sprouts, which are highly concentrated—equivalent to about five cups of broccoli a day. So, we don’t know how well more modest doses would work. But, if they do, eating broccoli could provide “a frugal means to attenuate the long-term health risks” of air pollution.
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Thanks for listening to Nutrition Facts. I’m your host, Dr. Michael Greger.