Today’s Superfood: Garlic

Have you ever noticed that every month seems to bring a trendy new diet? And yet obesity rates continue to rise and with it a growing number of health problems. That’s why I wrote my new book How Not to Diet. Check it out at your local public library. Welcome to the Nutrition Facts Podcast. I’m your host Dr. Michael Greger.

Today we continue our series highlighting one special food that contains demonstrable health benefits.  And the star of today’s episode?  The Garlic bulb. As it turns out, there are two superfood classes of vegetables most adept at blocking human cancer cell growth in a petri dish. Let’s play “Which is healthier?”

Imagine you’re standing in line at one of those custom made-to-order salad places, where you get to choose your lettuce, choose your toppings, then choose your dressing. Let’s assume you don’t have a strong family history of any particular cancer, and so, aren’t trying to hone in on avoiding one tumor over any other.

First, let’s choose our lettuce. Boston, endive, radicchio, romaine, or spinach? Which is healthier? Out of the five, spinach is #1 against breast cancer, #1 against brain tumors, #1 against kidney cancer, #1 against lung cancer, and pediatric brain tumors. That’s why we need to feed our kids spinach! #1 against pancreatic cancer, prostate cancer, and stomach cancer.

Now it’s not #1 overall; there are 16 vegetables more powerful at stopping stomach cancer growth than spinach. But out of those five salad greens, spinach wins out across the board, against every cancer type tested.

What if the salad place said they were out of spinach, though? Which comes in second, out of the four left to choose from? For breast cancer, radicchio is #2. Against brain tumors? Radicchio. Kidney cancer? Radicchio. So, overall, out of those choices for greens, radicchio is second healthiest.

Next, we get to choose four toppings. Now, there’s a long line of people behind you, all staring at us to make our choice. We don’t have time to ponder and pick the four absolute best, but we can at least make a guess.

What about shredded beets? Yes or no? Yes. Super yes! Brain tumor? Just beet it. Kidney cancer is a no; close to 50%, but not quite there.

Are we putting cucumber on our salad? As tasty as they may be, no. For most cancers it suppressed tumor cell growth less than 50%.

What about tomatoes? No tomatoes, either.

What about a potato? You can actually choose potatoes for your salad. Yes or no? No potatoes, either.

Wait a second; no iceberg lettuce, carrots, cucumbers, tomatoes, potatoes—that’s all people eat! That’s the problem. Even people eating their vegetables, aren’t really eating their vegetables. The majority of veggies people commonly eat have little effect.

In this study, there was one clear winner. One vegetable that completely 100% stopped cancer growth in seven out of the eight tumor lines. One of the most important findings of the year. Which vegetable was it? Was it bok choy? Broccoli, Brussels sprouts, fiddlehead ferns, garlic, kale, or red cabbage?

#1 against breast cancer? Garlic. #1 against brain tumors? Garlic.#2 against kidney cancer: Garlic. Lung cancer? Garlic. Childhood brain tumors? Garlic. Pancreatic cancer? Garlic. Prostate cancer and stomach cancer? Garlic. So might I suggest a garlicky salad dressing?

But wait. Is it just that garlic is toxic to all cells? Yes, it stops the growth of cancer cells, but maybe it stops the growth of healthy cells, too? That wouldn’t be good. They tested for that. Garlic slams cancer cells, but doesn’t touch normal cells, and the same thing with pretty much all the vegetables. They’re selective; they go after the cancer cells, but leave the normal cells alone. Veggies are amazing.

Now, if you didn’t pick garlic, and instead chose one of those others, you probably weren’t far off. The two best families of vegetables for cancer prevention are the cruciferous vegetables, like broccoli, kale, cabbage, and the allium family vegetables like garlic, onions, and leeks.

So you know all those recipes that start with garlic and onions, and then throw you in some greens? That is the way to eat.

The researchers conclude: “The inclusion of cruciferous and Allium family vegetables in the diet is essential for effective dietary-based chemopreventive or cancer-preventive strategies.”

In our next story, we ask are there any benefits of garlic powder for treating mild-to-moderate lead poisoning?

Dietary strategies for the treatment of lead toxicity are often based on rodent studies. However, for tofu at least, there was a population study of people, showing lower lead levels in men and women who ate more tofu. They controlled for a whole bunch of factors. So, it’s not like tofu lovers were protected just because they smoked less, or ate less meat. But, you can’t control for everything.

Ideally, what we’d have is a randomized, placebo-controlled study. Take a group of people exposed to lead, split them up into two groups; half get the food, half get some kind of identical placebo food, and see what happens. Easy to do with drugs, you can just use look-alike sugar pills as placebos; so, people don’t know which group they’re in.

But how do you make placebo food? One way to do disguised food interventions is to use foods that are so potent they can be stuffed in a pill, like garlic. There had been various studies on the effects of garlic in rats, and as a potential antidote for lead intoxication distributed among different mouse organs. But who eats mouse organs? ” To “explore the possible uses of garlic to clean up lead contents in chickens, which like all of us on planet Earth had been exposed to lead pollution,” in hopes we can “minimize the hazard of lead-polluted chicken meat.”

And, it worked! Feeding garlic to chickens reduces lead levels in the “edible mass” of the chicken by up to 75% or more. Even if you don’t give them lead, raise them on distilled water, they end up with some lead in their meat and giblets; we just live in such a polluted world. But, actively feed them lead for a week, and the levels get really high. But, give them the same amount of lead with a little garlic added, give them some garlicky lead, and much less lead accumulates in their bodies.

Okay, but here’s the crazy part. Same amount of lead, but this time, you wait a week, and then give the garlic. And it worked even better. “The value of garlic in reducing lead concentrations was more pronounced when given” afterwards, after the lead was stopped, after the lead had already built up in the tissues. See, we used to think that “the beneficial effects of garlic against lead toxicity was primarily due to a reaction between lead and sulphur compounds in the garlic” that would glom onto the lead in the intestinal tract, and flush it out of the body. But, what this study showed is that garlic appears to contain compounds that can actually pull lead, not just out of the intestinal contents, but out of the tissues of the body. So, “the results indicate that garlic contains chelating compounds capable of enhancing elimination of lead.” So, “garlic feeding can be exploited to safeguard human consumers by minimizing lead concentrations in meat.”

But if garlic is so effective at pulling lead out of chickens’ bodies, why not exploit garlic feeding more directly, by eating it ourselves? Well, there had never been a study on the ability of garlic to help lead-exposed humans until now.

Actually, I’m embarrassed to say, the study was published back in 2012, but I missed it. That was when I was just setting up NutritionFacts.org, getting it up and running. Now that we have a staff, and a whole research team, hopefully important studies like this won’t slip through the cracks in the future.

But, here we go, a head-to-head comparison of the therapeutic effects of garlic versus a chelation therapy drug called D-penicillamine. A hundred and seventeen workers exposed to lead in the car battery industry were randomly assigned into one of two groups: the drug three times a day, or an eighth of a teaspoon of garlic powder compressed into a tablet, three times a day. That’s about the equivalent of two cloves of fresh garlic a day, for a month. As expected, the chelation drug reduced blood lead levels by about 20%, but, so did the garlic. The garlic worked just as well as the drug and, of course, had fewer side effects. Thus, “garlic seems safer and as effective.” But, saying something is as effective as chelation therapy isn’t saying much. Remember how, for chronic lead poisoning, chelation drugs can lower blood levels, but don’t actually improve neurological function?

This is where it gets amazing.

Significant clinical improvements were seen in the garlic group: less irritability, fewer headaches, improvements in their reflexes and blood pressure after treatment with garlic, but not the drug. So, garlic was safer and more effective. “Therefore, garlic can be recommended for the treatment of mild-to-moderate lead poisoning.”

Finally, today did you know that garlic and flavonoid phytonutrients found in fruits, vegetables, nuts, and grains appear to protect against DNA damage induced by mutagenic chemicals found in cooked meat.

Remember this study, in which garlic won out as the #1 anticancer vegetable? Well, let’s see what it can do. Which kind of garlic would be expected to work the best? Garlic, or elephant garlic, the so-called “garlic for people who don’t like garlic?” And, the answer appears to be garlic-garlic is best.

What about flavonoid phytonutrients,  found in “fruits, vegetables, nuts, and grains?” Are the top 100 sources in the world; do they have a protective effect on the meat mutagen-induced DNA damage? They took white blood cells from healthy individuals and colon cancer patients, and exposed them to increasing doses of two cooked meat carcinogens: IQ (found mostly in fried bacon and baked fish), and PhIP (found mostly in fried bacon, fish, and chicken).

They used the comet assay again, measuring how much DNA was broken off in the tail. And, as the concentration of meat mutagens increases, so does the DNA damage. They then continued to pump in that meat mutagen at the highest level, but started adding some plant phytonutrients, quercetin, found in foods like apples, red onions, and berries, and rutin, found in like citrus, buckwheat, and asparagus. Even as the highest carcinogen dose continues, adding plant phytonutrients starts to bring the damage down. That happened in both healthy individuals (the solid line), and cancer patients (the dashed line).

But, even at a zero concentration of cooked meat chemicals, there was more DNA damage present in the white blood cells circulating in cancer patients. And, they didn’t have, like, blood cancer; they had colon cancer.

Even though the cancer was just in their colon, their whole body was affected by the disease state. Their whole body was under increased oxidative stress, inflicting “significantly higher DNA damage.” Or, maybe the DNA damage came first, and it’s one of the reasons they have cancer in the first place. Either way, cancer patients experience “less reduction of induced DNA damage” suggesting that “higher concentration of flavonoids would be required to achieve the same protective effect.” So, cancer (and other chronic disease) victims need even more fruits and vegetables to reduce the damage done by carcinogens.

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