Garlic and flavonoid phytonutrients found in fruits, vegetables, greens, and grains appear to protect against DNA damage induced by mutagenic chemicals found in cooked meat.
What about garlic? Remember this study in which it won out as #1 anticancer vegetable? Well, let's see what it can do. This is what's called a comet assay, currently the standard technique for the evaluation of DNA damage. What you're seeing is the DNA of a single cell, the normal breast cell, as visualized under a fluorescence microscope. It's in an electric field trying to pull the negatively charged DNA to the right, but the DNA is all supercoiled together. But you add a carcinogen like PhIP that literally breaks up our DNA, you can see the chopped up pieces breaking away and flowing out into kind of a comet tail. But what if you add the same amount of carcinogen but also add some garlic phytonutrients? You get some damage, some DNA breakage, but now as much as before. 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. What about flavonoid phytonutrients, found in fruits, vegetable, leaves, and grains? 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 cooked meat carcinogens, IQ—found mostly in fried bacon and baked fish and PhIP, found mostly in fried fish, bacon, and chicken [animal pics] and then continued to pump in that meat mutagen at the highest level but started adding some plant phytonutrients, quercitin, found in foods like apples, red onions, and berries (raspberries), and Rutin, found in citrus, buckwheat, and asparagus. They used the comet assay again, measuring how much DNA was broken off into the tail. And as you can see, as the concentration of meat mutagens increases so does the DNA damage, but then even when the highest dose continues, adding plant phytonutrients starts to bring the damage down. That happened in both healthy individuals, and cancer patients. But I want you to notice something else. 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 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 reasons they have cancer. Either way, they experiences less reduction of induced DNA damage, ''"suggesting that higher concentration of flavonoids will be required to achieve a protective effect. So cancer patients need even more fruits and vegetables to reduce the damage done by carcinogens.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring watch the above video. This is just an approximation of the audio contributed by Jonathan Hodgson.
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The prior garlic video I mentioned is #1 Anticancer Vegetable (one of the most popular videos on the site!). Make sure to also watch its "prequel" Veggies vs. Cancer. Other foods that may protect DNA include kiwifruit (Kiwifruit and DNA Repair), cruciferous vegetables (DNA Protection from Broccoli), green tea (see my last video Cancer, Interrupted: Green Tea), and plants in general (Repairing DNA Damage).
Should garlic be raw or cooked? See How can I preserve the anti-cancer effects of cooked garlic?
Which foods have the most flavonoids? See my cheat sheet to the USDA nutrient database.
Which foods have the most antioxidants? See my video series starting with Antioxidant Content of 3,139 Foods.
What other dietary changes should we consider after a cancer diagnosis? See:
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