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Anti-Cancer Nutrient Synergy in Cranberries

December 12, 2013 by Michael Greger M.D. in News with 23 Comments

Anti-Cancer Nutrient Synergy in Cranberries

In research I profiled in my video Which Fruit Fights Cancer Better?, cranberries were found to suppress the growth of human liver cancer cells in vitro. Other studies have found similar effects against human breast, colon, brain tumor, oral, and ovarian cancer cells. In my 4-min video Cranberries versus Cancer I profile the latest looking at prostate cancer cell growth.

The United States has the highest rate of prostate cancer in the world, so let’s try a native American fruit! Researchers started out with about 50,000 human prostate cancer cells in a petri dish and if you do nothing, within a day you’re closer to 100,000, then 200,000 and then nearly 400,000 within 72 hours. But by adding just a tiny amount of cranberries, that exponential cancer growth can be blocked.

The reason they tested such tiny concentrations is that we only absorb a small fraction of the cranberry phytonutrients we eat into our bloodstream. Still, cranberries are cheap. If drug companies and supplement manufacturers are going to capitalize on this they needed to find cranberry’s active ingredient.

In my video Cranberries versus Cancer I show a graph with some of the various phytonutrients in cranberries. Different fractions were tested against various types of cancer to find the magic bullet. Various fractions of phytonutrients inhibited colon cancer cell proliferation about 15 percent, but nothing compared to the total extract of the whole fruit. There seems to be additive or synergistic anti-proliferative effects resulting from the combination of the various components compared to individual purified phytochemicals. So it’s always better to eat the whole fruit.

How do you do that with cranberries, though? Although five percent of cranberries are sold fresh, the vast majority are consumed as processed products. To get the same amount of anthocyanin phytonutrients in a cup of fresh or frozen cranberries, you’d have to drink 16 cups of cranberry juice cocktail, eat seven cups of dried cranberries, or 26 cans of cranberry sauce!

The problem is that raw cranberries are so tart that folks may opt for the 7 cups of dried. In a taste test survey, consumers said they wouldn’t mind eating dried cranberries every day, but the preference for raw cranberries sloped down toward maybe once a year. The problem is dried cranberries tend to come sweetened. Raw cranberries don’t affect your blood sugar, but sweetened dried cranberries do—even the low sugar varieties.

What about cranberry “juice”? Cranberry cocktail is usually only about a quarter cranberry juice. The ruby red phytonutrients in cranberries and pure cranberry juice are powerful antioxidants, increasing the antioxidant capacity of our bloodstream within hours of consumption. But the high fructose corn syrup acts as a pro-oxidant, even with added vitamin C, canceling out some of the cranberry benefit. So how do you get the upsides without the down? Check out my Pink Juice with Green Foam video, where I offer a recipe for making no added sugar whole fruit cranberry cocktail.

And for another reason to avoid high fructose corn syrup: Mercury in Corn Syrup?

More on nutrient synergy in:

Suppressing cancer growth in a petri dish is nice, but what about within the human body? Check out my videos Strawberries versus Esophageal Cancer and Black Raspberries versus Oral Cancer.

-Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death and More Than an Apple a Day.

Image credit: Muffet / Flickr

Which Common Fruit Fights Cancer Better?

December 10, 2013 by Michael Greger M.D. in News with 11 Comments

Which Common Fruit Fights Cancer Better?

Recently, researchers compared the ability of eleven common fruits to suppress cancer cell growth in vitro. Which do you think was most effective—apples, bananas, cranberries, grapefruits, grapes, lemons, oranges, peaches, pears, pineapples, or strawberries?

There are many ways to compare the healthfulness of different foods. For example, if you were interested in antioxidants you might compare vitamin C content. If you compared vitamin C content between our two most popular fruits, apples and bananas, then bananas would appear twice as healthy (10 mg in a banana compared to only 5mg in an apple). But vitamin C is just one of thousands of different phytonutrients in fruits and vegetables. It turns out the vitamin C in apples accounts for less than 1 percent of an apple’s total antioxidant activity.

In my 5-min video Which Fruit Fights Cancer Better? I show a graph of the total antioxidant content of a red delicious apple. The amount contributed to the vitamin C is so tiny you can hardly see it. Even though there are only about 5mg of vitamin C in a small apple, it has the antioxidant equivalent of 1500 mg of vitamin C! I’ve reviewed before how taking that much vitamin C straight in a supplement may actually have a pro-oxidant effect and cause DNA damage (in my video Preventing Exercise-Induced Oxidative Stress With Watercress), but you can get three times that antioxidant power eating an apple, without the adverse effects.

Of course there’s more than just vitamin C in bananas too. I was surprised to see a study out of Harvard suggesting that bananas were a significant source of anthocyanins, the red/blue/violet phytonutrients found in berries. Maybe I underestimated bananas? They are, after all, technically berries.

Anthocyanins have been found in blue, purple, orange-red, red-purple, and pink-purple wild bananas, but none in domesticated yellow. In the Harvard researchers’ defense, they just took values from the USDA, and it turns out USDA apparently made a mistake. There are no anthocyanins in store-bought bananas, and despite twice the vitamin C, bananas are beat out by apples in terms of overall antioxidant power. But that’s just measuring the ability of these fruits to quench an oxidation reaction in a test tube. It would be nice to measure actual biological activity.

In the red delicious apple study, researchers also measured the ability of apple extracts, from both peeled and unpeeled apples, to suppress the growth of human cancer cells growing in a petri dish compared to control. Wouldn’t it be great to be able to compare that kind of superpower between different fruits? Well, now we can!

In my video Which Fruit Fights Cancer Better? I show a graph of cancer cell proliferation versus increasing concentrations of the 11 most common fruits eaten in the United States. If you drip water on these cancer cells as a control, nothing happens. They start out powering away at 100 percent growth and they keep powering away at 100 percent growth. And pineapples, pears, and oranges don’t do much better.

Peaches start pulling away from the pack. At high peach concentrations, cancer cell proliferation drops about 10 percent, but bananas and grapefruits appear to work four times better, dropping cancer growth rates by about 40 percent. Red grapes, strawberries and apples do even better, cutting cancer cell growth up to half at only half the dose, but the two fruits that won, causing a dramatic drop in cancer proliferation at just tiny doses, were lemons and cranberries. So if you look at the effective dose required to suppress liver cancer cell proliferation, apples are more powerful than bananas, but cranberries win the day. And there was no effective dose listed for orange, pear, and pineapple since they didn’t appear to affect the cancer cell growth at all.

This study reminded me of my #1 Anticancer Vegetable video (along with its “prequel,” Veggies vs. Cancer).

Other videos in which I rank various foods include:

How can you consume cranberries palatably, though? Check out my recipe for Pink Juice with Green Foam and my video Cranberries versus Cancer.

More berried treasure in Strawberries versus Esophageal Cancer and Black Raspberries versus Oral Cancer.

-Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death and More Than an Apple a Day.

Image credit: kanenas.net / Flickr

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