How to Design a Misleading Study to Show Diet Doesn’t Work

How to Design a Misleading Study to Show Diet Doesn't Work.jpeg

A study out of the University of North Carolina found no association between dietary fiber intake and diverticulosis. They compared those who ate the highest amount of fiber, 25 grams, to those who ate the smallest amount, which was three times lower at only 8 grams. Finding no difference in disease rates, researchers concluded that a low-fiber diet was not associated with diverticulosis.

The university sent out a press release entitled: "Diets high in fiber won't protect against diverticulosis." The media picked it up and ran headlines such as "High-fiber diet may not protect against diverticulosis, study finds." It went all over the paleo blogs and even medical journals, publishing such statements as an "important and provocative paper...calls into question" the fiber theory of the development of diverticulosis. Other editorials, though, caught the study's critical flaw. To understand this, let's turn to another dietary deficiency disease: scurvy.

Medical experiments on prisoners at Iowa State Penitentiary showed that clinical signs of scurvy start appearing after just 29 days without vitamin C. Experiments on pacifists during World War II showed that it takes about 10 mg of vitamin C a day to prevent scurvy. Imagine going back a few centuries when they were still trying to figure scurvy out. Dr. James Linde had this radical theory that citrus fruits could cure scurvy. What if an experiment was designed to test this crazy theory, in which sailors were given the juice of either one wedge of lemon or three wedges of lemon each day? If a month later on the high seas there was no difference in scurvy rates, one might see headlines from printing presses touting that a low-vitamin C diet is not associated with scurvy.

Well, a wedge of lemon only yields about 2 mg of vitamin C, and it takes 10 mg to prevent scurvy. They would have been comparing one vitamin C-deficient dose to another vitamin C-deficient dose. No wonder there would be no difference in scurvy rates. We evolved eating so many plants that we likely averaged around 600 mg of vitamin C a day. That's what our bodies are biologically used to getting.

What about fiber? How much fiber are we used to getting? More than 100 grams a day! The highest fiber intake group in the North Carolina study was only eating 25 grams, which is less than the minimum recommended daily allowance of about 32 grams. The subjects didn't even make the minimum! The study compared one fiber-deficient diet to another fiber-deficient diet--no wonder there was no difference in diverticulosis rates.

The African populations with essentially no diverticulosis ate diets consisting in part of very large platefuls of leafy vegetables--similar, perhaps, to what we were eating a few million years ago. They were eating plant-based diets containing 70 to 90 grams of fiber a day. Most vegetarians don't even eat that many whole plant foods, although some do. At least vegetarians tend to hit the minimum mark, and they have less diverticulosis to show for it. A study of 47,000 people confirmed that "[c]onsuming a vegetarian diet and a high intake of dietary fiber were both associated with a lower risk of admission to hospital or death from diverticular disease." They had enough people to tease it out. As you'll see in my video Does Fiber Really Prevent Diverticulosis?, compared to people eating a single serving of meat a day or more, those who ate less than half a serving appeared to have a 16% lower risk and pescatarians (eating no meat except fish) had a risk down around 23%. Both of these results weren't in and of themselves statistically significant, but eating vegetarian was. Vegetarians had 35% lower risk, and those eating strictly plant-based appeared to be at 78% lower risk.

As with all lifestyle interventions, it only works if you do it. High-fiber diets only work if they're actually high in fiber.

There's more great information in my video Diverticulosis: When Our Most Common Gut Disorder Hardly Existed.

This reminds me of an ancient video I did: Flawed Study Interpretation.

People commonly ask Do Vegetarians Get Enough Protein?, but maybe they should be more concerned where everyone else is getting their fiber. Ninety-seven percent of Americans don't even reach the recommended daily minimum.

In health,

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:

Image Credit: Yoshihide Nomura / Flickr. This image has been modified.

Original Link

How to Design a Misleading Study to Show Diet Doesn’t Work

How to Design a Misleading Study to Show Diet Doesn't Work.jpeg

A study out of the University of North Carolina found no association between dietary fiber intake and diverticulosis. They compared those who ate the highest amount of fiber, 25 grams, to those who ate the smallest amount, which was three times lower at only 8 grams. Finding no difference in disease rates, researchers concluded that a low-fiber diet was not associated with diverticulosis.

The university sent out a press release entitled: "Diets high in fiber won't protect against diverticulosis." The media picked it up and ran headlines such as "High-fiber diet may not protect against diverticulosis, study finds." It went all over the paleo blogs and even medical journals, publishing such statements as an "important and provocative paper...calls into question" the fiber theory of the development of diverticulosis. Other editorials, though, caught the study's critical flaw. To understand this, let's turn to another dietary deficiency disease: scurvy.

Medical experiments on prisoners at Iowa State Penitentiary showed that clinical signs of scurvy start appearing after just 29 days without vitamin C. Experiments on pacifists during World War II showed that it takes about 10 mg of vitamin C a day to prevent scurvy. Imagine going back a few centuries when they were still trying to figure scurvy out. Dr. James Linde had this radical theory that citrus fruits could cure scurvy. What if an experiment was designed to test this crazy theory, in which sailors were given the juice of either one wedge of lemon or three wedges of lemon each day? If a month later on the high seas there was no difference in scurvy rates, one might see headlines from printing presses touting that a low-vitamin C diet is not associated with scurvy.

Well, a wedge of lemon only yields about 2 mg of vitamin C, and it takes 10 mg to prevent scurvy. They would have been comparing one vitamin C-deficient dose to another vitamin C-deficient dose. No wonder there would be no difference in scurvy rates. We evolved eating so many plants that we likely averaged around 600 mg of vitamin C a day. That's what our bodies are biologically used to getting.

What about fiber? How much fiber are we used to getting? More than 100 grams a day! The highest fiber intake group in the North Carolina study was only eating 25 grams, which is less than the minimum recommended daily allowance of about 32 grams. The subjects didn't even make the minimum! The study compared one fiber-deficient diet to another fiber-deficient diet--no wonder there was no difference in diverticulosis rates.

The African populations with essentially no diverticulosis ate diets consisting in part of very large platefuls of leafy vegetables--similar, perhaps, to what we were eating a few million years ago. They were eating plant-based diets containing 70 to 90 grams of fiber a day. Most vegetarians don't even eat that many whole plant foods, although some do. At least vegetarians tend to hit the minimum mark, and they have less diverticulosis to show for it. A study of 47,000 people confirmed that "[c]onsuming a vegetarian diet and a high intake of dietary fiber were both associated with a lower risk of admission to hospital or death from diverticular disease." They had enough people to tease it out. As you'll see in my video Does Fiber Really Prevent Diverticulosis?, compared to people eating a single serving of meat a day or more, those who ate less than half a serving appeared to have a 16% lower risk and pescatarians (eating no meat except fish) had a risk down around 23%. Both of these results weren't in and of themselves statistically significant, but eating vegetarian was. Vegetarians had 35% lower risk, and those eating strictly plant-based appeared to be at 78% lower risk.

As with all lifestyle interventions, it only works if you do it. High-fiber diets only work if they're actually high in fiber.

There's more great information in my video Diverticulosis: When Our Most Common Gut Disorder Hardly Existed.

This reminds me of an ancient video I did: Flawed Study Interpretation.

People commonly ask Do Vegetarians Get Enough Protein?, but maybe they should be more concerned where everyone else is getting their fiber. Ninety-seven percent of Americans don't even reach the recommended daily minimum.

In health,

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:

Image Credit: Yoshihide Nomura / Flickr. This image has been modified.

Original Link

How to Design a Misleading Study to Show Diet Doesn’t Work

How to Design a Misleading Study to Show Diet Doesn't Work.jpeg

A study out of the University of North Carolina found no association between dietary fiber intake and diverticulosis. They compared those who ate the highest amount of fiber, 25 grams, to those who ate the smallest amount, which was three times lower at only 8 grams. Finding no difference in disease rates, researchers concluded that a low-fiber diet was not associated with diverticulosis.

The university sent out a press release entitled: "Diets high in fiber won't protect against diverticulosis." The media picked it up and ran headlines such as "High-fiber diet may not protect against diverticulosis, study finds." It went all over the paleo blogs and even medical journals, publishing such statements as an "important and provocative paper...calls into question" the fiber theory of the development of diverticulosis. Other editorials, though, caught the study's critical flaw. To understand this, let's turn to another dietary deficiency disease: scurvy.

Medical experiments on prisoners at Iowa State Penitentiary showed that clinical signs of scurvy start appearing after just 29 days without vitamin C. Experiments on pacifists during World War II showed that it takes about 10 mg of vitamin C a day to prevent scurvy. Imagine going back a few centuries when they were still trying to figure scurvy out. Dr. James Linde had this radical theory that citrus fruits could cure scurvy. What if an experiment was designed to test this crazy theory, in which sailors were given the juice of either one wedge of lemon or three wedges of lemon each day? If a month later on the high seas there was no difference in scurvy rates, one might see headlines from printing presses touting that a low-vitamin C diet is not associated with scurvy.

Well, a wedge of lemon only yields about 2 mg of vitamin C, and it takes 10 mg to prevent scurvy. They would have been comparing one vitamin C-deficient dose to another vitamin C-deficient dose. No wonder there would be no difference in scurvy rates. We evolved eating so many plants that we likely averaged around 600 mg of vitamin C a day. That's what our bodies are biologically used to getting.

What about fiber? How much fiber are we used to getting? More than 100 grams a day! The highest fiber intake group in the North Carolina study was only eating 25 grams, which is less than the minimum recommended daily allowance of about 32 grams. The subjects didn't even make the minimum! The study compared one fiber-deficient diet to another fiber-deficient diet--no wonder there was no difference in diverticulosis rates.

The African populations with essentially no diverticulosis ate diets consisting in part of very large platefuls of leafy vegetables--similar, perhaps, to what we were eating a few million years ago. They were eating plant-based diets containing 70 to 90 grams of fiber a day. Most vegetarians don't even eat that many whole plant foods, although some do. At least vegetarians tend to hit the minimum mark, and they have less diverticulosis to show for it. A study of 47,000 people confirmed that "[c]onsuming a vegetarian diet and a high intake of dietary fiber were both associated with a lower risk of admission to hospital or death from diverticular disease." They had enough people to tease it out. As you'll see in my video Does Fiber Really Prevent Diverticulosis?, compared to people eating a single serving of meat a day or more, those who ate less than half a serving appeared to have a 16% lower risk and pescatarians (eating no meat except fish) had a risk down around 23%. Both of these results weren't in and of themselves statistically significant, but eating vegetarian was. Vegetarians had 35% lower risk, and those eating strictly plant-based appeared to be at 78% lower risk.

As with all lifestyle interventions, it only works if you do it. High-fiber diets only work if they're actually high in fiber.

There's more great information in my video Diverticulosis: When Our Most Common Gut Disorder Hardly Existed.

This reminds me of an ancient video I did: Flawed Study Interpretation.

People commonly ask Do Vegetarians Get Enough Protein?, but maybe they should be more concerned where everyone else is getting their fiber. Ninety-seven percent of Americans don't even reach the recommended daily minimum.

In health,

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:

Image Credit: Yoshihide Nomura / Flickr. This image has been modified.

Original Link

No More Than a Quart a Day of Hibiscus Tea

NF-May17 How Much Hibiscus Tea is Too Much?.jpeg

Over the counter antacids are probably the most important source for human aluminum exposure in terms of dose. For example, Maalox, taken as directed, can exceed the daily safety limit more than 100-fold, and nowhere on the label does it say to not take it with acidic beverages such as fruit juice. Washing an antacid down with orange juice can increase aluminum absorption 8-fold, and citric acid-the acid found naturally concentrated in lemon and limes--is even worse.

Just as sour fruits can enhance the absorption of iron (a good thing), the same mechanism they may enhance the absorption of aluminum (a bad thing). This raises the question of what happens when one adds lemon juice to tea? Previously, I concluded that the amount of aluminum in tea is not a problem for most people because it's not very absorbable (See Is There Too Much Aluminum in Tea?). What if we add lemon? Researchers publishing in the journal Food and Chemical Toxicology found no difference between tea with lemon, tea without lemon, or no tea at all in terms of the amount of aluminum in the bloodstream, suggesting that tea drinking does not significantly contribute to aluminum getting inside the body.

The researchers used black tea, green tea, white tea, oolong tea, but what about the "red zinger" herbal tea, hibiscus? The reason hibiscus tea is called "sour tea" is because it has natural acids in it like citric acid. Might these acids boost the absorption of any hibiscus's aluminum? While a greater percentage of aluminum gets from the hibiscus into the tea water than from the other teas, there's less aluminum overall.

The real question is whether the aluminum then gets from the tea water into our bodies. We don't have that data, so to be on the safe side we should assume the worst: that hibiscus tea aluminum, unlike green and black tea aluminum, is completely absorbable. In that case, based on this data and the World Health Organization weekly safety limit, we may not want to drink more than 15 cups of hibiscus tea a day, (based on someone who's about 150 pounds). If you have a 75 pound 10-year-old, a half-gallon a day may theoretically be too much. Recent, more extensive testing highlighted in my video, How Much Hibiscus Tea is Too Much?, suggests that levels may reach level twice as high. Therefore, to be safe, no more than about two quarts a day for adults, or one quart a day for kids or pregnant women. Hibiscus tea should be completely avoided by infants under six months--who should only be getting breast milk--as well as kids with kidney failure, who can't efficiently excrete it.

There is also a concern about the impressive manganese level in hibiscus tea. Manganese is an essential trace mineral, a vital component of some of our most important antioxidant enzymes, but we probably only need about two to five milligrams a day. Four cups of hibiscus tea can have as much as 17 milligrams, with an average of about ten. Is that a problem?

One study from the University of Wisconsin found that women given 15 milligrams of manganese a day for four months, saw, if anything, an improvement in their anti-inflammatory, anti-oxidant enzyme activity. Another study using 20 milligrams a day similarly showed no adverse short-term effects, and importantly showed that the retention of dietary manganese is regulated. Our bodies aren't stupid; if we take in too much manganese, we decrease the absorption and increases the excretion. Even though tea drinkers may get ten times the manganese load (10 or 20 milligrams a day) the levels in their blood are essentially identical. There is little evidence that dietary manganese poses a risk.

These studies were conducted with regular tea, though, so we don't know about the absorption from hibiscus. To err on the side of caution we should probably not routinely exceed the reference dose of ten milligrams per day, or about a quart a day for adults and a half-quart for a 75 pound child.

I've actually changed my consumption. Given the benefits of the stuff, I was using it as a substitute for drinking water, drinking around two quarts a day. I was also blending the hibiscus petals in, not throwing them away, effectively doubling the aluminum content, and increasing manganese concentrations by about 30%. So given this data I've cut back to no more than a quart of filtered hibiscus tea a day.

Lemon can actually boost the antioxidant content of green and white tea. See Green Tea vs. White. For a comparison of their cancer-fighting effects in vitro, Antimutagenic Activity of Green Versus White Tea.

Before that I covered another potential downside of sour tea consumption in Protecting Teeth From Hibiscus Tea, and before that a reason we should all consider drinking it in: Hibiscus Tea vs. Plant-Based Diets for Hypertension.

For more on the iron absorption effect, see my video Risks Associated with Iron Supplements.

In health,
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, More Than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: mararie / Flickr

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Which Nut Suppresses Cancer Cell Growth the Most?

NF-Dec22 Which Nut Fights Cancer Better?.jpg

People who eat nuts in their adolescence may have a better chance of fighting off breast cancer later in life, according to data from the Harvard Nurse's Study. A follow-up study involving the daughters of the nurses corroborated the findings. Those eating more peanut butter, nuts, beans, lentils, soybeans, or corn were found to have just a fraction of the risk for fibrocystic breast disease, which places one at higher risk of cancer. The protective effects were found to be strongest for those most at risk, such as those with a family history of breast cancer.

Another study out of the British Journal of Cancer found that even two handfuls of nuts a week may protect against pancreatic cancer, one of our most fatal malignancies.

Nuts are described as "nutritionally precious," which may explain some of the mechanisms by which nut components induce cancer cell death and inhibit cancer growth and spread in vitro. But which nuts work the best? In my video #1 Anticancer Vegetable, we learned that two classes of vegetables--the broccoli family vegetables and the garlic family vegetables--most effectively suppressed breast cancer cell growth. In Which Fruit Fights Cancer Better?, cranberries and lemons took the title.

What about nuts? In terms of antioxidant content, walnuts and pecans steal the show. Twenty-five walnuts have the antioxidant equivalent of eight grams of vitamin C (the vitamin C found in a hundred oranges).

But how do they do against cancer? In the video, Which Nut Fights Cancer Better?, you can see a graph of human cancer cell proliferation versus increasing concentrations of the ten most common nuts eaten in the United States. If you drip water on these cancer cells as a control, nothing happens. Hazelnuts, pistachios and Brazil nuts don't do much better. Pine nuts, cashews and macadamias start pulling away from the pack. Almonds appear twice as protective, halving cancer cell growth at only half the dose as pine nuts, cashews, and macadamias. Walnuts, pecans, and peanuts come out as the clear winners, causing a dramatic drop in cancer proliferation at just tiny doses.

More nuttiness:

-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, More Than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: Mariya Chorna / Flickr

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Citrus to Reduce Muscle Fatigue

 

 

 

 

 

 

 

 

Citrus to Reduce Muscle Fatigue

The lactic acid that makes yogurt tangy is the same lactic acid that builds up in our muscles when we exercise strenuously. Instead of bacteria fermenting the sugar in milk to make energy for themselves, our muscles ferment sugar in our diet to produce energy to contract. If, like when we’re sprinting, lactic acid builds up in our muscles faster than it can be removed we can end up with a burning sensation in our muscles, forcing us to stop.

Now if we train, we can increase the number of blood vessels in our muscles and clear out the lactate faster. For example, when researchers took some overweight sedentary women and started them on an aerobic training program of running and walking, at the end of three months, their lactate levels during exercise dropped 17%. But those on the same program who drank two cups of orange juice a day dropped their levels 27%. They did the same exercise program, but the citrus group experienced a significant decrease in blood lactate concentration, indicating an improvement in physical performance with less muscle fatigue.

I don’t recommend drinking juice, though, because we’re losing all that wonderful fiber that slows the rate of fruit sugar absorption into our system. In my video, Reducing Muscle Fatigue with Citrus, we can see the blood sugar spike one might expect after drinking Coca-Cola. Compare that to the spike we see with orange juice? No difference. However, if we eat the same quantity of sugar in the form of orange slices we experience a significantly smaller spike in blood sugar.

So the whole fruit is nearly always better than fruit juice. Now this is not to say OJ isn’t better than coke. OJ has those citrus phytonutrients like hesperidin, which may be why the women’s triglycerides didn’t go up even though they were drinking two cups of fruit juice every day. Hesperidin may actually help lower our digestion of fats, but once we get up to three cups a day, we really can start bumping our triglycerides.

The burning sensation during strenuous exercise may be related to the build-up of lactic acid in our muscles, but that’s different than the delayed onset muscle soreness that occurs in the days following a bout of extreme physical activity. That’s thought to be due to inflammation caused by muscle cell damage, little micro-tears in the muscle. If it’s an inflammatory reaction then might anti-inflammatory phytonutrients help? Find out in my video Reducing Muscle Soreness with Berries.

For more about what citrus phytonutrients can do can be found in my video, Keeping Your Hands Warm with Citrus.

-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: Rennett Stowe / Flickr

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How Citrus Might Help Keep Your Hands Warm

 

 

 

 

 

 

 

 

How Citrus Might Help Keep Your Hands Warm

In 1936, Albert Szent-Györgyi, who won the Nobel Prize for discovering vitamin C, described a vitamin “P,” which we now know encompasses a class of thousands of phytonutrients called flavonoids. Some, like quercitin, are widespread in plant-based foods. We can tell something is widespread in the plant kingdom when one can even find it in iceberg lettuce!

Others, however, are only found in specific plant families. For example, hesperidin is found primarily in citrus fruits. This may be one of the reasons that, out of all the different types of fruit that have been looked at, citrus may cut our risk of stroke the most.

The citrus phytonutrient hesperidin increases blood flow. Using a machine called a Doppler fluximeter (sounds like something from Back to the Future) one can measure blood flow through the skin using a laser beam. When researchers give people the amount of hesperidin found in two cups of orange juice, blood flow goes up. It works even better when they gave them the orange juice itself, so there’s other beneficial stuff besides just the hesperidin in citrus.

For example, if we measure the changes in genetic expression, orange juice consumption induces changes in the expression of 3000 of our genes, whereas hesperidin alone only modulated the expression of about 2000. Still, the fact that nearly 2000 stretches of our DNA expressed differently because we consumed just one of the thousands of phytonutrients in plants is pretty mind-blowing.

These changes in blood flow are not just in theory. Researchers took volunteers with cold sensitivity (cold hands and feet), put them in an air-conditioned room and measured the temperature of their fingertips after drinking a placebo drink (like orange Kool-Aid) versus drinks with two doses of actual citrus phytonutrients. In the Kool-Aid group, their fingers got colder and colder, dropping nearly nine degrees Fahrenheit. The fingers of those consuming low or high doses of citrus didn’t get nearly as cold because their blood flow remained steady. In my video, Keeping Your Hands Warm with Citrus, we can see the laser test of the subject's blood flow. When we’re exposed to cold temperatures our body starts to clamp off peripheral blood flow to keep our core warm, but if we eat a bunch of oranges before we go skiing our risk of frostbite may go down since we’re keeping up our blood flow to our fingers and toes.

They even took these poor women and plunged their hands into some chilly water, and their finger temperature rebounded faster towards normal in the citrus group, demonstrating that citrus phytonutrients not only keep our extremities warmer but may also warm us back up faster.

But don't forget, don't brush your teeth immediately after consuming citrus. We have to make sure to rinse our mouth with water and wait 30 minutes before brushing to protect our tooth enamel (see Plant-Based Diets: Dental Health).

Because different families of fruits and vegetables can have entirely different phytonutrient profiles, variety is important. See, for example:

Eating oranges is always better than drinking orange juice, as seen in my video Reducing Muscle Fatigue with Citrus. 

-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: macjryan / Flickr

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Which Common Fruit Fights Cancer Better?

 

 

 

 

 

 

 

 

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 Are Vitamin C Pills Good For You?), 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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