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

Best Foods for Acid Reflux

Best Foods for Acid Reflux.jpeg

Gastroesophageal reflux disease (GERD) is one of the most common disorders of the digestive tract. The two most typical symptoms are heartburn and regurgitation of stomach contents into the back of the throat, but GERD is not just burning pain and a sour taste in your mouth. It causes millions of doctor visits and hospitalizations every year in the United States. The most feared complication is cancer.

You start out with a normal esophagus. If the acid keeps creeping up, your esophagus can get inflamed and result in esophagitis. Esophagitis can transform into Barrett's esophagus, a precancerous condition which can then turn into adenocarcinoma (a type of cancer). To prevent all that, we need to prevent the acid reflux in the first place.

In the last three decades, the incidence of this cancer in the US has increased six-fold, an increase greater than that of melanoma, breast, or prostate cancer. This is because acid reflux is on the rise. In the United States, we're up to about 1 in 4 people suffering at least weekly heartburn and/or acid regurgitation, compared to around 5% in Asia. This suggests that dietary factors may play a role.

In general, high fat intake is associated with increased risk, whereas high fiber foods appear to be protective. The reason fat intake may be associated with GERD symptoms and erosive esophagitis is because when we eat fatty foods, the sphincter at the top of the stomach that's supposed to keep the food down becomes relaxed, so more acid can creep up into the esophagus. In my video Diet & GERD Acid Reflux Heartburn, you can see a study in which researchers fed volunteers a high-fat meal--a McDonald's sausage and egg McMuffin--compared to a low-fat meal (McDonald's hot cakes), and there was significantly more acid squirted up in the esophagus after the high-fat meal.

In terms of later stages of disease progression, over the last twenty years 45 studies have been published in the association between diet and Barrett's esophagus and esophageal cancer. In general, they found that meat and high-fat meals appeared to increase cancer risk. Different meats were associated with cancers in different locations, thoughj. Red meat was more associated with cancer in the esophagus, whereas poultry was more associated with cancer at the top of the stomach. Plant-based sources of protein, such as beans and nuts, were associated with a significantly decreased risk of cancer.

Those eating the most antioxidant-rich foods have half the odds of esophageal cancer, while there is practically no reduction in risk among those who used antioxidant vitamin supplements, such as vitamin C or E pills. The most protective produce may be red-orange vegetables, dark green leafies, berries, apples, and citrus. The benefit may come from more than just eating plants. Eating healthy foods crowds out less healthy foods, so it may be a combination of both.

Based on a study of 3,000 people, the consumption of non-vegetarian foods (including eggs) was an independent predictor of GERD. Egg yolks cause an increase in the hormone cholecystokinin, which may overly relax the sphincter that separates the esophagus from the stomach. The same hormone is increased by meat, which may help explain why plant-based diets appear to be a protective factor for reflux esophagitis.

Researchers found that those eating meat had twice the odds of reflux-induced esophageal inflammation. Therefore, plant-based diets may offer protection, though it's uncertain whether it's attributable to the absence of meat in the diet or the increased consumption of healthy foods. Those eating vegetarian consume greater amounts of fruits and vegetables containing innumerable phytochemicals, dietary fiber, and antioxidants. They also restrict their consumption of animal sources of food, which tend to be fattier and can thus relax that sphincter and aggravate reflux.

GERD is common; its burdens are enormous. It relapses frequently and can cause bleeding, strictures, and a deadly cancer. The mainstay of treatment is proton pump inhibitor drugs, which rake in billions of dollars. We spend four billion dollars on Nexium alone, three billion on Prevacid, two billion on Protonix, one billion on Aciphex. These drugs can cause nutrient deficiencies and increase the risk for pneumonia, food poisoning, and bone fractures. Thus, it is important to find correctable risk factors and correct them. Known correctable risk factors have been things like obesity, smoking and alcohol consumption. Until recently, though, there hadn't been studies on specifically what to eat and what to avoid, but now we have other correctable factors to help prevent this disease.

For more on GERD, see: Diet & Hiatal Hernia, Coffee & Mortality, and Club Soda for Stomach Pain & Constipation.

I also have a video about esophageal cancer, detailing the extraordinary reversal of the kinds of precancerous changes that lead to the devastating condition--with nothing but strawberries: Strawberries versus Esophageal Cancer.

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: PDPics / Pixabay. Image has been modified.

Original Link

Best Foods for Acid Reflux

Best Foods for Acid Reflux.jpeg

Gastroesophageal reflux disease (GERD) is one of the most common disorders of the digestive tract. The two most typical symptoms are heartburn and regurgitation of stomach contents into the back of the throat, but GERD is not just burning pain and a sour taste in your mouth. It causes millions of doctor visits and hospitalizations every year in the United States. The most feared complication is cancer.

You start out with a normal esophagus. If the acid keeps creeping up, your esophagus can get inflamed and result in esophagitis. Esophagitis can transform into Barrett's esophagus, a precancerous condition which can then turn into adenocarcinoma (a type of cancer). To prevent all that, we need to prevent the acid reflux in the first place.

In the last three decades, the incidence of this cancer in the US has increased six-fold, an increase greater than that of melanoma, breast, or prostate cancer. This is because acid reflux is on the rise. In the United States, we're up to about 1 in 4 people suffering at least weekly heartburn and/or acid regurgitation, compared to around 5% in Asia. This suggests that dietary factors may play a role.

In general, high fat intake is associated with increased risk, whereas high fiber foods appear to be protective. The reason fat intake may be associated with GERD symptoms and erosive esophagitis is because when we eat fatty foods, the sphincter at the top of the stomach that's supposed to keep the food down becomes relaxed, so more acid can creep up into the esophagus. In my video Diet & GERD Acid Reflux Heartburn, you can see a study in which researchers fed volunteers a high-fat meal--a McDonald's sausage and egg McMuffin--compared to a low-fat meal (McDonald's hot cakes), and there was significantly more acid squirted up in the esophagus after the high-fat meal.

In terms of later stages of disease progression, over the last twenty years 45 studies have been published in the association between diet and Barrett's esophagus and esophageal cancer. In general, they found that meat and high-fat meals appeared to increase cancer risk. Different meats were associated with cancers in different locations, thoughj. Red meat was more associated with cancer in the esophagus, whereas poultry was more associated with cancer at the top of the stomach. Plant-based sources of protein, such as beans and nuts, were associated with a significantly decreased risk of cancer.

Those eating the most antioxidant-rich foods have half the odds of esophageal cancer, while there is practically no reduction in risk among those who used antioxidant vitamin supplements, such as vitamin C or E pills. The most protective produce may be red-orange vegetables, dark green leafies, berries, apples, and citrus. The benefit may come from more than just eating plants. Eating healthy foods crowds out less healthy foods, so it may be a combination of both.

Based on a study of 3,000 people, the consumption of non-vegetarian foods (including eggs) was an independent predictor of GERD. Egg yolks cause an increase in the hormone cholecystokinin, which may overly relax the sphincter that separates the esophagus from the stomach. The same hormone is increased by meat, which may help explain why plant-based diets appear to be a protective factor for reflux esophagitis.

Researchers found that those eating meat had twice the odds of reflux-induced esophageal inflammation. Therefore, plant-based diets may offer protection, though it's uncertain whether it's attributable to the absence of meat in the diet or the increased consumption of healthy foods. Those eating vegetarian consume greater amounts of fruits and vegetables containing innumerable phytochemicals, dietary fiber, and antioxidants. They also restrict their consumption of animal sources of food, which tend to be fattier and can thus relax that sphincter and aggravate reflux.

GERD is common; its burdens are enormous. It relapses frequently and can cause bleeding, strictures, and a deadly cancer. The mainstay of treatment is proton pump inhibitor drugs, which rake in billions of dollars. We spend four billion dollars on Nexium alone, three billion on Prevacid, two billion on Protonix, one billion on Aciphex. These drugs can cause nutrient deficiencies and increase the risk for pneumonia, food poisoning, and bone fractures. Thus, it is important to find correctable risk factors and correct them. Known correctable risk factors have been things like obesity, smoking and alcohol consumption. Until recently, though, there hadn't been studies on specifically what to eat and what to avoid, but now we have other correctable factors to help prevent this disease.

For more on GERD, see: Diet & Hiatal Hernia, Coffee & Mortality, and Club Soda for Stomach Pain & Constipation.

I also have a video about esophageal cancer, detailing the extraordinary reversal of the kinds of precancerous changes that lead to the devastating condition--with nothing but strawberries: Strawberries versus Esophageal Cancer.

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: PDPics / Pixabay. Image has been modified.

Original Link

Sweet Beet Salad

This beet salad is very easy to make and full of flavor. It calls for only six ingredients and is really pretty, perfect for a special occasion or just when you want a break from the standard green salad. Enjoy! Print Sweet Beet Salad Prep time:  10 mins Cook time:  15 mins Total time:  25...

Read More »

The post Sweet Beet Salad appeared first on Straight Up Food.

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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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Rinse Your Mouth After Sour Foods and Drinks

NF-May10 Protecting Teeth From Hibiscus Tea.jpeg

Hibiscus tea has been found to be as effective at lowering blood pressure as a leading hypertension drug without the potential side-effects (which include everything from lack of strength to impotence, including rare cases of potentially fatal liver damage). Hibiscus, though, may have adverse effects of its own.

As I've reviewed previously in Plant-Based Diets: Oral Health, people who eat plant-based diets appear to have superior periodontal health, including less gum disease and fewer signs of inflammation, like bleeding. However, they also have twice the prevalence of dental erosions, areas on the teeth where the enamel has thinned due to more frequent consumption of acidic fruits and vegetables. Therefore, after we eat something like citrus, we should swish our mouths with water to clear the acid from our teeth.

This includes beverages. I'm a big fan of hibiscus tea, but it's not called "sour tea" for nothing. In a study highlighted in my video, Protecting Teeth from Hibiscus Tea, researchers at the University of Iowa dental school tested 25 different popular teas and found two with a pH under 3 (as acidic as orange juice or coca cola): Tazo's passion and Bigelow's red raspberry, both of which contain hibiscus as their first ingredient.

To see if these teas could actually dissolve teeth, the researchers took 30 extracted molars from people and soaked them in different teas. And indeed, out of the five teas tested, the greatest erosion came from the tea with the most hibiscus. The researchers left the tooth sitting in the tea for 25 hours straight, but this was to simulate a lifetime of exposure. The bottom line is that herbal teas are potentially erosive, particularly fruity and citrusy teas like hibiscus. To minimize the erosive potential, we can use a straw to drink the beverage. And as I mentioned above, after consuming an acidic food or drink we should also rinse our mouth with water to help neutralize the acid.

For more on the effects of hibiscus on blood pressure, see the previous video, Hibiscus Tea vs. Plant-Based Diets for Hypertension.

Are there other potential downsides to tea drinking? That's the topic of my videos: Is There Too Much Aluminum in Tea? and How Much Hibiscus Tea is Too Much?

For more on avoiding drug side-effects by choosing more natural treatments can be found in videos like:

For more on diet and oral health, see:

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: T.Kiya / Flickr

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Treating Asthma With Plants vs. Pills

NF-July7 Treating Asthma with Plants vs. Supplements.jpg

In my video Treating Asthma With Fruits and Vegetables, I highlighted a landmark study on manipulating antioxidant intake in asthma. The study found that just a few extra fruits and vegetables a day can powerfully reduce asthma exacerbation rates. If the antioxidants in the plants are ameliorating asthma, then why can't we take antioxidant pills instead? Because antioxidant pills don't appear to work.

Studies using antioxidant supplements on respiratory or allergic diseases have mostly shown no beneficial effects. This discrepancy between data relating to fruit and vegetable intake compared with those using antioxidant supplements may indicate the importance of the whole food, rather than individual components. For example, in the Harvard Nurse's Health Study, women who got the most vitamin E from their diet appeared to be at half the risk for asthma, (which may help explain why nut consumption is associated with significantly lower rates of wheezing), but vitamin E supplements did not appear to help.

Men who eat a lot of apples appear to have superior lung function, as do kids who eat fresh fruit every day, as measured by FEV1 (basically how much air you can forcibly blow out in one second). The more fruit, salad, and green vegetables kids ate, the greater their lung function appeared.

Researchers are "cautious about concluding which nutrient might be responsible." There's vitamin C in fruits, salads, and green vegetables, but there are lots of other antioxidants, such as "vitamin P," a term used to describe polyphenol phytonutrients found in grapes, flax seeds, beans, berries, broccoli, apples, citrus, herbs, tea, and soy. Polyphenol phytonutrients can directly bind to allergenic proteins and render them hypoallergenic, allowing them to slip under our body's radar. If this first line of defense fails, polyphenols can also inhibit the activation of the allergic response and prevent the ensuing inflammation, and so may not only work for prevention, but for treatment as well.

Most of the available evidence is weak, though, in terms of using supplements containing isolated phytonutrients to treat allergic diseases. We could just give people fruits and vegetables to eat, but then we couldn't perform a double-blind study to see if they work better than placebo. Some researchers decided to use pills containing plant food extracts. Plant extracts are kind of a middle ground. They are better than isolated plant chemicals, but are not as complete as whole foods. Still, since we can put whole foods in a capsule, we can compare the extracts to fake sugar pills that look and feel the same to see if they have an effect.

The first trial involved giving people extracts of apple skins. I've talked about the Japan's big cedar allergy problem before (See Alkylphenol Endocrine Disruptors and Allergies), so apple extract pills were given every day for a few months starting right before pollen season started. The results were pretty disappointing. They found maybe a little less sneezing, but the extract didn't seem to help their stuffy noses or itchy eyes.

What about a tomato extract? A randomized, double-blind, placebo-controlled eight-week trial was performed on perennial allergic rhinitis, this time not for seasonal pollen, but for year-round allergies to things like dust-mites. There are lots of drugs out there, but you may have to take them every day year-round, so how about some tomato pills instead? After oral administration of tomato extract for eight weeks, there was a significant improvement of total nasal symptom scores, combined sneezing, runny nose and nasal obstruction, with no apparent adverse effects.

Would whole tomatoes work even better? If only researchers would design an experiment directly comparing phytonutrient supplements to actual fruits and vegetables head-to-head against asthma, but such a study had never been done... until now. The same amazing study, highlighted in my video, Treating Asthma with Plants vs. Supplements?, that compared the seven-fruit-and-vegetables-a-day diet to the three-fruit-and-vegetables-a-day diet, after completion of its first phase, commenced a parallel, randomized, controlled supplementation trial with capsules of tomato extract, which boosted the power of five tomatoes in one little pill, and the study subjects were given three pills a day.

Who did better, the group that ate seven servings of actual fruits and vegetables a day, or the group that ate three servings a day but also took 15 supposed serving equivalents in pill form? The pills didn't help at all. Improvements in lung function and asthma control were evident only after increased fruit and vegetable intake, which suggests that whole-food interventions are most effective. Both the supplements and increased fruit and vegetable intake were effective methods for increasing carotenoid concentrations in the bloodstream, but who cares? Clinical improvements--getting better from disease--were evident only as a result of an increase in plant, not pill, consumption. The results provide further evidence that whole-food approaches should be used to achieve maximum efficacy of antioxidant interventions.

And if this is what a few more plants can do, what might a whole diet composed of plants accomplish? See Treating Asthma and Eczema with Plant-Based Diets.

I also dealt with preventing asthma in the first place: Preventing Asthma With Fruits and Vegetables.

The theme of whole foods being more efficacious than supplements seems to come up over and over again. See for example:

More on "vitamin P" in How to Slow Brain Aging by Two Years.

The anti-inflammatory effects of nuts may explain the Harvard Nurse's Health Study finding: Fighting Inflammation in a Nut Shell.

-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, and From Table to Able.

Image Credit: Mike Mozart / Flickr

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Orange Aromatherapy for Anxiety

NF-Mar31 Does Orange Aromatherapy Reduce Anxiety?.jpg

Aromatherapy -- the use of concentrated essential oils extracted from plants to treat disease -- is commonly used to treat anxiety symptoms. Anxiety disorders are the most prevalent class of psychiatric disorders in the general population. However, their treatment is challenging, because the drugs used for the relief of anxiety symptoms can have serious side effects.

Thankfully, credible studies that examine the effect of essential oils on anxiety symptoms are gradually starting to appear in the medical literature. However, in most of these studies, exposure to the essential oil odor was accompanied by massage. This makes it difficult to draw firm conclusions about the effect of the aroma itself.

A typical example includes this study where patients in the intensive care unit the day after open-heart surgery got foot massages with orange-scented oil. Why not back massages? Because they just had their chests cracked open so they have huge sternotomy wounds. Patients showed a significant psychological benefit from the aromatherapy massage.

But how do we know the essential oil had anything to do with it? Maybe it was just the massage. If that's the case, then great--let's give people massages! I'm all for more ICU foot rubs. "There is considerable evidence from randomized trials that massage alone reduces anxiety, so if massage is effective, then aromatherapy plus massage is also effective." One study where cancer patients got massaged during chemo and radiation even found that the massage without the fragrance may be better. The researchers thought it might be a negative Pavlovian response: the patient smells the citrus and their body thinks, "Oh no, not another cancer treatment!"

More recently the ambient odor of orange was tested in a dental office to see if it reduces anxiety and improves mood. Ambient odor of orange was diffused in the waiting room and appeared to have a relaxant effect--less anxiety, better mood, and more calmness--compared to a control group where there was no odor in the air. No odor, that is, except for the nasty dentist office smell. Maybe the orange scent was just masking the unpleasant odors. Maybe it had nothing to do with any orange-specific molecules. More research was necessary.

So in another study, highlighted in my video, Orange Aromatherapy for Anxiety, researchers exposed some graduate students to an anxiety-producing situation and tested the scent of orange, versus a non-orange aroma, versus no scent at all. The orange did appear to have an anxiety-reducing effect. Interestingly, the observed anxiety-reducing effects were not followed by physical or mental sedation. On the contrary, at the highest dose, the orange oil made the volunteers feel more energetic. So orange aromatherapy may potentially reduce anxiety without the downer effect of Valium-type drugs. Does that mean we can get the benefits without the side effects? I've talked about the concerns of using scented consumer products before, even ones based on natural fragrances (Throw Household Products Off the Scent), and there have been reports of adverse effects of aromatherapy.

Alternative medicine isn't necessary risk-free. For example, there are dozens of reported cases of people having their hearts ruptured by acupuncture. Ouch.

But the adverse effects of aromatherapy were mostly from skin irritation from essential oils being applied topically, or even worse swallowed. Certain citrus oils can also make your skin sensitive to sunlight.

Lavender may also help for both anxiety (Lavender for Generalized Anxiety Disorder) and migraines (Lavender for Migraine Headaches).

The only other aromatherapy-related video is Wake Up and Smell the Saffron, though I have others on natural ways do reduce anxiety, including:

Natural, though, doesn't always mean safe. See, for example:

Of course eating citrus is good too! I have videos on Reducing Muscle Fatigue With Citrus and Keeping Your Hands Warm With Citrus, but Tell Your Doctor If You Eat Grapefruit.

-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, and From Table to Able.

Image Credit: Tim Sackton / Flickr

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