The Two Most Active Ingredients of the Mediterranean Diet

Which Parts of the Mediterranean Diet Extended Life.jpg

Olives and nuts are plant foods, and as such, are packed with antioxidants, raising the antioxidant level of our bloodstream resulting in lower fat oxidation and free radical DNA damage, but what's happening inside people's arteries?

Researchers measured the amount of atherosclerotic plaque in the neck arteries going to the brain in folks who for years were eating added nuts, added extra virgin olive oil or neither to their daily diets. In the control group, the plaque got worse, which is what happens when one continues to eat an artery-clogging diet, but there were no significant changes in the added extra virgin olive oil group, and the plaque in the added nut group appeared to get better. The nuts appeared to induce a regression of the disease, or at least a significant delay in the progression. The nut group was still suffering strokes, but only half as many, perhaps because the reduction in plaque height within the arteries on extra nuts was indicating a stabilization of the plaque, rendering them less likely to rupture. You can see these results in my video Which Parts of the Mediterranean Diet Extended Life?

Adding nuts to our diet may also improve endothelial function, boosting the ability of our arteries to dilate naturally by about 30 percent. If you look at the baseline adherence to Mediterranean diet principles and control for things like smoking and exercise, there were only two factors significantly associated with reduced heart attack and stroke risk: more vegetables and more nuts. No significant association with the olive oil, wine, fish or cutting back on soda and cookies. Among the individual components, only increased consumption of vegetables and nuts were related to reduced cardiovascular events.

On the one hand, cutting stroke risk in half just by eating a handful of nuts a day is pretty amazing, but those in the added nut group didn't appear to live any longer overall. This is in contrast to other studies that suggested that frequent nut consumption may extend life. For example, the Harvard health professionals studies, involving a whopping three million person-years of follow-up over decades, found nut consumption associated with fewer deaths from cancer, heart disease, respiratory disease and most importantly fewer deaths overall. This was confirmed by all the other big major prospective studies in a recent review.

So what's going on here with the study showing no longevity benefit from nuts? Did they just not wait long enough? Just because people were randomized to the nut group didn't mean they actually ate more nuts, and those randomized to the other groups didn't necessarily stay away.

If you re-analyze the data comparing the death rates of those who actually ate more nuts to those who actually didn't, nut consumption was indeed associated with significantly reduced risk of death. If you do the same kind of post hoc analysis with olive oil, even with the extra virgin, there is no benefit in terms of living longer. This is consistent with how Ancel Keys, the so-called Father of the Mediterranean diet, viewed olive oil. He thought of its benefit more as a way of just replacing animal fats; anything to get people to eat less lard and butter.

What is the best kind of nut? The greatest benefits were attributed to walnuts, particularly for preventing cancer deaths. Those eating more than three servings of walnuts a week appeared to cut their risk of dying from cancer in half.

Now it's just a matter of communicating the research to the public. All the major cancer groups emphasize a more plant-based diet, remarkably consistent with the World Health Organization guidelines for healthy eating. The far-reaching positive effects of a plant-based diet--including walnuts--may be the most critical message for the public.

Here are some of my previous videos on the Mediterranean diet:

Think the effects of adding a few nuts to one's daily diet are too good to believe? Check out my video Four Nuts Once a Month. For more on Walnuts and Artery Function check out the video, and for more on nuts and cancer prevention, see Which Nut Fights Cancer Better?

Nuts May Help Prevent Death and so may beans; see Increased Lifespan from Beans. What about Fruits and Longevity: How Many Minutes per Mouthful?

More on protecting ourselves from "brain attacks" in Preventing Strokes with Diet.

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: garlandcannon / Flickr. This image has been modified.

Original Link

The Two Most Active Ingredients of the Mediterranean Diet

Which Parts of the Mediterranean Diet Extended Life.jpg

Olives and nuts are plant foods, and as such, are packed with antioxidants, raising the antioxidant level of our bloodstream resulting in lower fat oxidation and free radical DNA damage, but what's happening inside people's arteries?

Researchers measured the amount of atherosclerotic plaque in the neck arteries going to the brain in folks who for years were eating added nuts, added extra virgin olive oil or neither to their daily diets. In the control group, the plaque got worse, which is what happens when one continues to eat an artery-clogging diet, but there were no significant changes in the added extra virgin olive oil group, and the plaque in the added nut group appeared to get better. The nuts appeared to induce a regression of the disease, or at least a significant delay in the progression. The nut group was still suffering strokes, but only half as many, perhaps because the reduction in plaque height within the arteries on extra nuts was indicating a stabilization of the plaque, rendering them less likely to rupture. You can see these results in my video Which Parts of the Mediterranean Diet Extended Life?

Adding nuts to our diet may also improve endothelial function, boosting the ability of our arteries to dilate naturally by about 30 percent. If you look at the baseline adherence to Mediterranean diet principles and control for things like smoking and exercise, there were only two factors significantly associated with reduced heart attack and stroke risk: more vegetables and more nuts. No significant association with the olive oil, wine, fish or cutting back on soda and cookies. Among the individual components, only increased consumption of vegetables and nuts were related to reduced cardiovascular events.

On the one hand, cutting stroke risk in half just by eating a handful of nuts a day is pretty amazing, but those in the added nut group didn't appear to live any longer overall. This is in contrast to other studies that suggested that frequent nut consumption may extend life. For example, the Harvard health professionals studies, involving a whopping three million person-years of follow-up over decades, found nut consumption associated with fewer deaths from cancer, heart disease, respiratory disease and most importantly fewer deaths overall. This was confirmed by all the other big major prospective studies in a recent review.

So what's going on here with the study showing no longevity benefit from nuts? Did they just not wait long enough? Just because people were randomized to the nut group didn't mean they actually ate more nuts, and those randomized to the other groups didn't necessarily stay away.

If you re-analyze the data comparing the death rates of those who actually ate more nuts to those who actually didn't, nut consumption was indeed associated with significantly reduced risk of death. If you do the same kind of post hoc analysis with olive oil, even with the extra virgin, there is no benefit in terms of living longer. This is consistent with how Ancel Keys, the so-called Father of the Mediterranean diet, viewed olive oil. He thought of its benefit more as a way of just replacing animal fats; anything to get people to eat less lard and butter.

What is the best kind of nut? The greatest benefits were attributed to walnuts, particularly for preventing cancer deaths. Those eating more than three servings of walnuts a week appeared to cut their risk of dying from cancer in half.

Now it's just a matter of communicating the research to the public. All the major cancer groups emphasize a more plant-based diet, remarkably consistent with the World Health Organization guidelines for healthy eating. The far-reaching positive effects of a plant-based diet--including walnuts--may be the most critical message for the public.

Here are some of my previous videos on the Mediterranean diet:

Think the effects of adding a few nuts to one's daily diet are too good to believe? Check out my video Four Nuts Once a Month. For more on Walnuts and Artery Function check out the video, and for more on nuts and cancer prevention, see Which Nut Fights Cancer Better?

Nuts May Help Prevent Death and so may beans; see Increased Lifespan from Beans. What about Fruits and Longevity: How Many Minutes per Mouthful?

More on protecting ourselves from "brain attacks" in Preventing Strokes with Diet.

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: garlandcannon / Flickr. This image has been modified.

Original Link

How to Prevent Ulcerative Colitis with Diet

Preventing Ulcerative Colitis with Diet.jpg

What has driven the dramatic increase in prevalence of the inflammatory bowel disease Crohn's disease in societies that rapidly westernized--a disease practically unknown just a century ago? What has changed in our internal and external environment that has led to the appearance of this horrible disease?

Japan suffered one of the most dramatic increases, and out of all the changing dietary components, animal protein appeared to be the strongest factor. There was an exponential increase in newly diagnosed Crohn's patients and daily animal protein intake, whereas the greater the vegetable protein, the fewer the cases of Crohn's, which is consistent with data showing a more plant-based diet may be successful in both preventing and treating Crohn's disease (See Preventing Crohn's Disease With Diet and Dietary Treatment of Crohn's Disease). But what about other inflammatory bowel diseases?

In the largest study of its kind, shown in my video Preventing Ulcerative Colitis with Diet, 60,000 people were followed for more than a decade. Researchers found that high total protein intake--specifically animal protein--was associated with a significantly increased risk of the other big inflammatory bowel disease, ulcerative colitis. It wasn't just protein in general, but the "association between high protein intake and inflammatory bowel disease risk was restricted to animal protein."Since World War II, animal protein intake has increased not only in Japan but also in all developed countries. This increase in animal protein consumption is thought to explain some of the increased incidence of inflammatory bowel disease in the second half of the 20th century.

Other studies found this as well, but why? What's the difference between animal protein and plant protein? Animal proteins tend to have more sulfur containing amino acids like methionine, which bacteria in our gut can turn into the toxic rotten egg smell gas, hydrogen sulfide. Emerging evidence suggests that sulfur compounds may play a role in the development of ulcerative colitis, a chronic inflammatory disease of the colon and rectum characterized by bloody diarrhea.

The first hint as to the importance of our gut flora was in the 1970's when "analysis of stools showed that their bulk was made up of mostly bacteria, not undigested material." We're pushing out trillions of bacteria a day and they just keep multiplying and multiplying. They do wonderful things for us like create the protective compound, butyrate, from the fiber we eat, but unfortunately, the bacteria may also elaborate toxic products from food residues such as hydrogen sulfide "in response to a high-meat diet."

Hydrogen sulfide is a bacterially derived cell poison that has been implicated in ulcerative colitis. We had always assumed that sulfide generation in the colon is driven by dietary components such as sulfur-containing amino acids, but we didn't know for sure until a study from Cambridge was published. Researchers had folks eat five different diets each with escalating meat contents from vegetarian all the way up to a steak each day. They found that the more meat one ate, the more sulfide; ten times more meat meant ten times more sulfide. They concluded that "dietary protein from meat is an important substrate for sulfide generation by bacteria in the human large intestine."

Hydrogen sulfide can then act as a free radical and damage our DNA at concentrations way below what our poor colon lining is exposed to on a routine basis, which may help explain why diets higher in meat and lower in fiber may produce so-called "fecal water" that causes about twice as much DNA damage. Fecal water is like when researchers make a tea from someone's stool.

The biology of sulfur in the human gut has escaped serious attention until recently. Previously it was just thought of as the rotten egg smell in malodorous gas, but the increase in sulfur compounds in response to a supplement of animal protein is not only of interest in the field of flatology--that is, the formal study of farts--but may also be of importance in the development of ulcerative colitis.

I have several videos on our microbiome, including:

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: illustrator © 123RF.com. This image has been modified.

Original Link

How to Prevent Ulcerative Colitis with Diet

Preventing Ulcerative Colitis with Diet.jpg

What has driven the dramatic increase in prevalence of the inflammatory bowel disease Crohn's disease in societies that rapidly westernized--a disease practically unknown just a century ago? What has changed in our internal and external environment that has led to the appearance of this horrible disease?

Japan suffered one of the most dramatic increases, and out of all the changing dietary components, animal protein appeared to be the strongest factor. There was an exponential increase in newly diagnosed Crohn's patients and daily animal protein intake, whereas the greater the vegetable protein, the fewer the cases of Crohn's, which is consistent with data showing a more plant-based diet may be successful in both preventing and treating Crohn's disease (See Preventing Crohn's Disease With Diet and Dietary Treatment of Crohn's Disease). But what about other inflammatory bowel diseases?

In the largest study of its kind, shown in my video Preventing Ulcerative Colitis with Diet, 60,000 people were followed for more than a decade. Researchers found that high total protein intake--specifically animal protein--was associated with a significantly increased risk of the other big inflammatory bowel disease, ulcerative colitis. It wasn't just protein in general, but the "association between high protein intake and inflammatory bowel disease risk was restricted to animal protein."Since World War II, animal protein intake has increased not only in Japan but also in all developed countries. This increase in animal protein consumption is thought to explain some of the increased incidence of inflammatory bowel disease in the second half of the 20th century.

Other studies found this as well, but why? What's the difference between animal protein and plant protein? Animal proteins tend to have more sulfur containing amino acids like methionine, which bacteria in our gut can turn into the toxic rotten egg smell gas, hydrogen sulfide. Emerging evidence suggests that sulfur compounds may play a role in the development of ulcerative colitis, a chronic inflammatory disease of the colon and rectum characterized by bloody diarrhea.

The first hint as to the importance of our gut flora was in the 1970's when "analysis of stools showed that their bulk was made up of mostly bacteria, not undigested material." We're pushing out trillions of bacteria a day and they just keep multiplying and multiplying. They do wonderful things for us like create the protective compound, butyrate, from the fiber we eat, but unfortunately, the bacteria may also elaborate toxic products from food residues such as hydrogen sulfide "in response to a high-meat diet."

Hydrogen sulfide is a bacterially derived cell poison that has been implicated in ulcerative colitis. We had always assumed that sulfide generation in the colon is driven by dietary components such as sulfur-containing amino acids, but we didn't know for sure until a study from Cambridge was published. Researchers had folks eat five different diets each with escalating meat contents from vegetarian all the way up to a steak each day. They found that the more meat one ate, the more sulfide; ten times more meat meant ten times more sulfide. They concluded that "dietary protein from meat is an important substrate for sulfide generation by bacteria in the human large intestine."

Hydrogen sulfide can then act as a free radical and damage our DNA at concentrations way below what our poor colon lining is exposed to on a routine basis, which may help explain why diets higher in meat and lower in fiber may produce so-called "fecal water" that causes about twice as much DNA damage. Fecal water is like when researchers make a tea from someone's stool.

The biology of sulfur in the human gut has escaped serious attention until recently. Previously it was just thought of as the rotten egg smell in malodorous gas, but the increase in sulfur compounds in response to a supplement of animal protein is not only of interest in the field of flatology--that is, the formal study of farts--but may also be of importance in the development of ulcerative colitis.

I have several videos on our microbiome, including:

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: illustrator © 123RF.com. This image has been modified.

Original Link

How to Protect Our Telomeres with Diet

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In my video, Does Meditation Affect Cellular Aging?, I discussed how stress reduction through meditation might be able to lengthen telomeres, the protective caps at the tips of our chromosomes that tend to deplete as we age.

What about exercise? We can't always change our situation in life, but we can always go out for a walk. London researchers studied 2,400 twins, and those who exercised more may have pumped up their telomeres along with their muscles. Apparently it doesn't take much either. The "heavy" exercise group was only averaging about a half-hour a day.

These were mostly folks in their 40's, but does it still work in your 50's? Yes. A study out of South Korea found that people in their 50's who work out three hours a week had longer telomeres.

In my video, Telomeres: Cap It All Off with Diet, you can see the telomere lengths of young healthy regular folk controls at around age 20, and then at age 50. As we'd expect, the older subjects' telomeres were significantly shorter. What about athletes? The young athletes started out in the same boat, with nice, long, young, healthy telomeres capping all their chromosomes. The older athletes, in contrast to the controls, appeared to still have the chromosomes of 20-year-olds. But these were marathon runners, triathletes running 50 miles a week for 35 years.

What was it about the Ornish intervention that so powerfully protected telomeres after just three months? We saw that stress management seems to help, but what about diet and exercise? Was it the plant-based diet, was it the walking 30 minutes a day, or was it just because of the weight loss? In 2013 a study was published that can help us anser just that question.

The researchers took about 400 women and randomized them into four groups: a portion-controlled diet group, an exercise group, a portion controlled diet and exercise group, and a control group for a full year. In the video, you can see a comparison of the length of each group's telomeres. After a year of doing nothing, there was essentially no change in the control group, which is what we'd expect. The exercise group was 45 minutes of moderate-to-vigorous exercise like jogging. After a year of that, they did no better. What about just weight loss? Nothing. The same thing for exercise and weight loss, no significant change either.

So as long as we're eating the same diet, it doesn't appear to matter how small our portions are, or how much weight we lose, or how hard we exercise. After a year, the subjects saw no benefit. On the other hand, the Ornish group on the plant-based diet, who lost the same amount of weight after just three months and exercised less than half as hard, saw significant telomere protection.

It wasn't the weight loss or the exercise: it was the food.

What aspects of a plant-based diet make it so protective? Studies have associated more vegetables and fruit, and less butter, with longer telomeres. From the latest review, foods high in fiber and vitamins are strongly related to longer telomeres. However, the key may be avoiding saturated fat. Swapping just 1% of saturated fat calories in our diet for anything else can add nearly a whole year of aging's worth of length onto our telomeres.

Saturated fats like palmitic acid, the primary saturated fat in salmon, and found in meat, eggs, and dairy in general, can be toxic to cells. This has been demonstrated in heart cells, bone marrow cells, pancreatic cells, and brain cells. The toxic effects on cell death rates happen right around what you'd see in the blood stream of people who eat a lot of animal products. It may not be the saturated fat itself, however, as saturated fat may just be a marker for the increased oxidative stress and inflammation associated with those foods.

With this link to saturated fat, it's no wonder that lifelong low cholesterol levels have been related to longer telomeres and a smaller proportion of short telomeres--in other words, markers of slower biological aging. In fact, there's a rare congenital birth defect called progeria syndrome, where children age 8-10 times faster than normal. It seems associated with a particular inability to handle animal fats.

The good news is that "despite past accumulated injury leading to shorter telomere lengths, current healthy behaviors might help to decrease a person's risk of some of the potential consequences like heart disease." Eating more fruit and vegetables and less meat, and having more support from friends and family, attenuate the association between shorter telomeres and the ravages of aging.

To summarize: inflammation, oxidation, damage and dysfunction are constantly hacking away at our telomeres. At the same time, our antioxidant defenses, healthy diet, exercise and stress reduction are constantly rebuilding them.


I've asked this diet versus exercise question in a few other contexts. See:

Though dietary change appears more impactful, I'm a big fan of walking. See Longer Life Within Walking Distance and for my personal favorite exercise, Standing Up for Your Health.

For more on the role saturated fat may play in disease, see, for example, my videos Heart Disease Starts in Childhood and Treating Multiple Sclerosis with the Swank MS Diet.

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: AJC ajcann.wordpress.com / Flickr

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How Many Minutes of Daily Meditation to Combat Stress?

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In the film The Holiday, Cameron Diaz exclaims "Severe stress ... causes the DNA in our cells to shrink until they can no longer replicate." Did Hollywood get the science right?

The enzyme that builds and maintains the caps at the tips of our chromosomes (called telomeres) appear to slow the aging of our cells. Do people who are stressed have shorter telomeres? To answer that question, researchers from the University of California, San Francisco measured the telomere lengths in mothers of chronically ill children--what could be more stressful than that? The longer a woman had spent being the main caretaker of her ill child, the shorter her telomeres. The extra telomere shortening in the most stressed mothers was equivalent to that caused by at least a decade of aging. We see the same thing in caregivers of Alzheimer's patients and those suffering severe work-related exhaustion. Even those abused as children may grow up with shorter telomeres.

There's not much we can do about our past, but if we manage our stress now, can we grow some telomeres back? If we go on a meditation retreat and meditate for 500 hours, we can indeed boost our telomerase activity (the enzyme that restores our telomeres)--but there's got to be a quicker fix.

In an exciting study from UCLA and UC San Francisco (highlighted in my video, Does Meditation Affect Cellular Aging?, caregivers of family members with dementia were randomized to just 12 minutes of daily meditation for eight weeks, or just about ten hours in total. The meditators experienced significant benefit, including better mental and psychological function accompanied by an increase in telomerase activity, suggesting an improvement in stress-induced cellular aging.

Here's a link to the backgrounder video that presents the original Ornish study: Research Into Reversing Aging. I cover the comparable effects of diet and exercise in my video Telomeres - Cap It All Off with Diet.

I have a few videos on using aromatherapy and other modalities to help deal with stress:

For life extension in general, 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: Nickolai Kashirin / Flickr

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Hummus for a Healthy Heart

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I've talked previously about the anti-diabetic and anti-obesity effects of various phytonutrients in beans, but beans have protective effects on the cardiovascular system as well. As one academic review suggested, plant-specific compounds can have a remarkable impact on the health care system and may provide therapeutic health benefits, including the prevention and treatment of diseases and disorders. Plants have antioxidant effects, anti-inflammatory effects, protect our livers, lower cholesterol and blood pressure, and help prevent aging, diabetes, osteoporosis, DNA damage, heart disease and other disorders. Those without legumes in their daily diet, for example, may be at quadruple the odds of suffering high blood pressure.

Legumes such as chickpeas have been used to treat high blood pressure and diabetes for thousands of years. And they can also lower cholesterol levels. Researchers placed people in Northern India on high fat diets to raise their cholesterol levels up to that of the Western world (up around 206 mg/dL) and swapped in chickpeas for some of the grains they were eating. In five months, their cholesterol levels dropped to about 160, almost to the target of around 150. Cholesterol was reduced more than 15 percent in most of the subjects. In a randomized crossover trial, highlighted in my video, Beans, Beans, They're Good for Your Heart, two servings a day of lentils, chickpeas, beans, or split peas cut cholesterol levels so much that many participants moved below the range for which statin drugs are typically prescribed.

In the India study, although the subjects' cholesterol levels were comparable to the Western world at the start of the treatment with chickpeas, before the studym the participants were eating a low-fat diet. So low that their cholesterol levels started out at 123, well within the safe zone. Only after packing their diets with saturated fat were the researchers able to boost their cholesterol up to typical American levels, which could then be ameliorated by adding chickpeas. So it would be better if they just ate healthy in the first place. Or even better, healthy with hummus: a healthy diet with lots of legumes.


Beans dips like hummus are among my favorite go-to snacks. I like to dip snap peas and red bell pepper slices in them. I'd love to hear everyone's favorite recipe. You show me yours and I'll show you mine :)

Canned Beans or Cooked Beans? Click the link to find out!

Beans can help us live longer (Increased Lifespan from Beans), control our blood sugars (Beans and the Second Meal Effect), and help prevent and treat diabetes (Preventing Prediabetes By Eating More and Diabetics Should Take Their Pulses).

What about the purported "anti-nutrient" phytates in beans? You mean the Phytates for the Prevention of Cancer, the Phytates for Rehabilitating Cancer Cells, and the Phytates for the Treatment of Cancer? Phytate-containing foods may also help protect our bones (Phytates for the Prevention of Osteoporosis).

Why not just take cholesterol pills every day for the rest of our life? See my videos Statin Muscle Toxicity and Statin Cholesterol Drugs and Invasive Breast 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 Uprooting the Leading Causes of Death, More Than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: homami / Flickr

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Making Your Own Mouthwash

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The effects of a vegetarian diet on systemic diseases like cancer, diabetes, and heart diseases have been studied and have revealed predominantly less systemic diseases in those eating plant-based diets. However, there have only been a few studies on oral health, which I covered in my videos Plant-Based Diets: Oral Health and Plant-Based Diets: Dental Health.

What's the latest? In a study of 100 vegetarians compared to a 100 non-vegetarians, the vegetarians had better periodontal conditions, showing less signs of inflammation like gum bleeding, less periodontal damage, and better dental home care, brushing and flossing 2.17 times a day compared to 2.02 times a day. The difference in home hygiene is not that large, though, so maybe it was something about their diet. However, vegetarians may have a healthier lifestyle overall beyond just avoiding meat. The researchers controlled for smoking, but other factors like obesity can adversely affect oral health, so there may be confounding factors. What we need is an interventional study, where researchers take people eating the standard Western diet, improve their diets, and see what happens. But no such study existed... until now.

With professional support of nutritionists, the participants of the study (highlighted in my video What's the Best Mouthwash?) with existing periodontal disease changed their dietary patterns to so-called "wholesome nutrition," a diet emphasizing veggies, fruits, whole grains, potatoes, beans, peas, lentils, and spices, with water as the preferred beverage. To make sure any changes they witnessed were due to the diet, researchers made subjects maintain their same oral hygiene before and after the dietary change. What did they find? They found that eating healthier appeared to lead to a significant reduction of probing pocket depth, gingival inflammation, and levels of inflammatory cytokines, which mediate the tissue destruction in periodontal disease. Therefore, the researchers conclude that wholesome nutrition may improve periodontal health.

Why might diet help? Plant-based diets have a number of nutritional benefits in terms of nutrient density, but it also may be about improving balance between free radicals and our antioxidant defense system. Traditionally, dietary advice for oral health was just about avoiding sugar, which feed the bad bacteria on our teeth. We now realize that some foods and beverages, like green tea, possess antimicrobial properties to combat the plaque producing bacteria directly.

If plaque is caused by bacteria, why not use antibiotics? Many such attempts have been made, however undesirable side-effects such as "antibiotic resistance, vomiting, diarrhea and teeth stains have precluded their use." In a petri dish, green tea phytonutrients effectively inhibit the growth of these bacteria, but what about in our mouths? Researchers found that rinsing with green tea strongly inhibited the growth of the plaque bacteria on our teeth within minutes. Seven minutes after swishing with green tea, the number of harmful bacteria in the plaque scraped from people's teeth was cut nearly in half.

If you swish sugar water in your mouth, within three minutes the pH on our teeth can drop into the cavity formation danger zone. But if 20 minutes before swishing with sugar water, you swished with some green tea, you wipe out so many plaque bacteria that the same sugar water hardly has any effect at all. The researchers conclude that using green tea as a mouthwash or adding it to toothpaste could be a cost effective cavity prevention measure, especially in developing countries.

In the "civilized world," we have antiseptic mouthwashes with fancy chemicals like chlorhexidine, considered the gold standard anti-plaque agent. If only it didn't cause genetic damage. DNA damage has been detected in individuals who rinsed their mouths with chlorhexidine-containing mouthwashes, and not just to cells in the mouth. 13 volunteers rinsed their mouths with the stuff for a few weeks, and there was an increase in DNA damage both in the cells lining their cheeks as well as in their peripheral blood cells, suggesting that chlorhexidine was absorbed into their bodies. It reduced plaque better than other antiseptic chemicals, but it's doubtful whether chlorhexidine can still be considered the golden standard considering how toxic it is to human cells.

Are we left with having to decide between effectiveness and safety? How about a head to head test between chlorhexidine and green tea? Researchers found that green tea worked better than chlorhexidine at reducing plaque. Using green tea as a mouthwash may be cheaper, safer, and better. If, as a bonus, you want to sprinkle some amla powder (dried Indian gooseberry powder) into it, you may make it an even better plaque buster. Amla evidently shows an outstanding cavity-stopping potential not by killing off the bacteria like green tea, but by actually suppressing the bacteria's plaque forming abilities.

I now keep a mason jar filled with cold-steeped green tea (Cold Steeping Green Tea) with a spoonful of amla in the fridge and swish and swallow a few times a day. For extra credit you can gargle a bit with it too (see my video Can Gargling Prevent the Common Cold?).

Green tea shouldn't be the primary beverage of children, though, as the natural fluoride content may cause cosmetic spots on the teeth. For more check out my video Childhood Tea Drinking May Increase Fluorosis Risk.

Another reason we may want to avoid antibacterial mouthwashes is that they can kill off the good bacteria on our tongue that are instrumental in enhancing athletic performance with nitrate-containing vegetables (See Don't Use Antiseptic Mouthwash). For more on this, check out my video from yesterday, Antibacterial Toothpaste: Harmful, Helpful, or Harmless?

Need a reminder what amla is? More on dried Indian gooseberry powder power in:

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: Norio Nakayama / Flickr

Original Link

Bile Acids and Breast Cancer

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Why do constipated women appear to be at higher risk for breast cancer? The results of a 1989 study out of the American Journal of Public Health suggested a slight increased risk of breast cancer for both decreased frequency of bowel movements and firm stool consistency. Women who had three or more bowel movements a day appeared to cut their risk of breast cancer in half. This could be because constipation means a greater contact time between our waste and our intestinal wall, which may increase the formation and absorption of fecal mutagens--substances that cause DNA mutations and cancer--into our circulation, eventually ending up in breast tissue.

The concept that more frequent bowl movements decrease breast cancer risk dates back more than a century, where severe constipation, so-called "chronic intestinal stasis," was sometimes dealt with surgically. Figuring that the colon was an inessential part of the human anatomy, why not cure constipation by just cutting it out? After the surgery, they noticed that potentially precancerous changes in the breasts of constipated women seemed to disappear.

It would take another 70 years before researchers followed up on the clues by those distinguished surgeons who claimed breast pathology cleared when constipation was corrected. A 1981 study published in The Lancet investigated the relation between potentially precancerous changes in the breast and the frequency of bowl movements in nearly 1,500 women (See Breast Cancer and Constipation). The researchers found that the risk of precancerous changes was four times greater in women reporting two or fewer bowel movements a week compared to more than once daily.

We know that even the non-lactating breast actively takes up chemical substances from the blood. We also know that there are mutagens in feces. It is not unreasonable to suggest that potentially toxic substances derived from the colon have damaging or even carcinogenic effects upon the lining of the breast. Toxic substances like bile acids. Bile acids were first shown to promote tumors in mice in 1940, but subsequent experiments on rats led to the mistaken belief that bile acids just promoted existing cancers and couldn't initiate tumors themselves. However, there is a fundamental difference between the rodent models and human cancer. Rats only live a few years while humans can live dozens, so the opportunity for cancer causing mutations may be at least 30 times greater in humans. We now have at least 15 studies that show that bile acids can damage DNA, strongly suggesting they can initiate new cancers as well.

Bile acids are formed as a way of getting rid of excess cholesterol. Our liver dumps bile acids into the intestine for disposal, assuming our intestines will be packed with fiber to trap it and flush it out of the body. But if we haven't been eating enough fiber-rich whole plant foods, bile acids can be reabsorbed back into the body and build up in the breast.

Carcinogenic bile acids are found concentrated in the fluid of breast cysts at up to a hundred times the level found in the bloodstream. By radioactively tagging bile acids, researchers were able to show that intestinal bile acids rapidly gain access to the breast, where they can exert an estrogen-like cancer-promoting effect on breast tumor cells. This would explain why we see 50% higher bile acid levels in the bloodstream of newly diagnosed breast cancer victims. These findings support the concept of a relationship between intestinally-derived bile acids and risk of breast cancer. So how can we facilitate the removal of bile acids from our body?

Slowed colonic transit can increase bile acid levels. Therefore, to decrease absorption of bile acids, we can speed up the so-called "oro-anal transit time," the speed at which food goes from mouth to toilet, by eating lots of fiber. A diet packed with plants greatly increases bile acid excretion.

Fiber can bind up and remove other toxic elements like lead and mercury as well as cholesterol and bile acids. But plants can bind bile acids even independent of fiber. Vegan diets bind significantly more bile acid than lacto-ovo or non-vegetarian diets even at the same fiber intake, which could explain why individuals eating vegetarian might excrete less mutagenic feces in the first place.

I touched on this in my live presentation From Table to Able: Combating Disabling Diseases with Food, but what I didn't get to discuss is the relative bile acid binding abilities of different foods. I cover that in my video Which Vegetable Binds Bile Best?

What intestinal transit time should we be shooting for? See Food Mass Transit. That may be why Stool Size Matters. Also, How Many Bowel Movements Should You Have Every Day? We can improve speed and size by Bulking Up on Antioxidants and eating lots of whole plant foods (Prunes vs. Metamucil vs. Vegan Diet).

Fiber may also help women remove excess estrogen from their body. See my video Fiber vs. Breast Cancer. For more on the wonders of fiber, see Dr. Burkitt's F-Word Diet.

For more of my latest videos on breast cancer prevention and survival, 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, and Food as Medicine.

Image Credit: Photocapy / Flickr

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Coffee for Hepatitis C

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Decades ago, researchers in Norway came upon an unexpected finding. Alcohol consumption was associated with liver inflammation (no surprise), but a protective association was found for coffee consumption. These findings were replicated in the U.S. and around the world. Those at risk for liver disease--who drank a lot of alcohol or were overweight--appeared to cut their risk in half if they drank more than two cups of coffee a day.

Liver cancer is one of the most feared complications of liver inflammation. Hepatocellular carcinoma is the third leading cause of cancer death, and the incidence has been rapidly rising in the United States and Europe, largely driven by the burden of hepatitis C infection and fatty liver disease. Putting together all the best studies done to date, those drinking the most coffee had half the risk of liver cancer compared to those that drank the least. Since the meta-analysis was published, a new study found that male smokers may be able to cut their risk of liver cancer more than 90% by drinking four or more cups of coffee a day. (Of course, they could also stop smoking!). It's similar to heavy drinkers of alcohol: drinking more coffee may decrease liver inflammation, but not as much as drinking less alcohol.

Liver cancers are among the most avoidable cancers, through hepatitis B vaccination, control of hepatitis C transmission, and reduction of alcohol drinking. These three measures could, in principle, wipe out 90% of liver cancers worldwide. It remains unclear whether coffee drinking has an additional role on top of that, but in any case such a role would be limited compared to preventing liver damage in the first place. But what if you already have hepatitis C or are among the 30% of Americans with non-alcoholic fatty liver disease due to obesity, which may quadruple one's risk of dying from liver cancer? Coffee seems to help with hepatitis C, reducing liver damage, disease activity, and mortality. It was only the lack of randomized, interventional studies on the topic that prevented us from concluding that coffee has a protective effect.

But in 2013 we got such a study, a randomized controlled trial on the effects of coffee consumption in chronic hepatitis C (highlighted in my video, Preventing Liver Cancer with Coffee). Forty patients with chronic hepatitis C were randomized into two groups: the first consumed four cups of coffee/day for 30 days, while the second remained coffee "abstinent." Then the groups switched for the second month. Two months is too soon to detect changes in cancer rates, but the researchers were able to demonstrate that coffee consumption reduces oxidative DNA damage, increases the death of virus infected cells, stabilizes chromosomes, and reduces fibrosis, all of which could explain the role coffee appears to play in reducing the risk of disease progression and of evolution to cancer.

Is it time to write a prescription for coffee for those at risk for liver disease? Some say no: "[A]lthough the results are promising, additional work is needed to identify which specific component of coffee is the contributing factor in reducing liver disease and related mortality." There are, after all, more than 1000 compounds that could be responsible for its beneficial effects. But that's such a pharmacological worldview. Why do we have to know exactly what it is in the coffee bean before we can start using them to help people? Yes, more studies are needed, but in the interim; moderate, daily, unsweetened coffee ingestion is a reasonable adjunct to therapy for people at high risk such as those with fatty liver disease.

Daily consumption of caffeinated beverages can lead to physical dependence. Caffeine withdrawal symptoms can include days of headache, fatigue, difficulty with concentration, and mood disturbances. But this dependence could be a good thing: "The tendency for coffee to promote habitual consumption may ultimately be advantageous if its myriad potential health benefits are confirmed."

More on coffee in:

Broccoli can boost the liver's detoxifying enzymes (Prolonged Liver Function Enhancement from Broccoli) but one can overdo it (Liver Toxicity Due to Broccoli Juice?).

What other foods might reduce DNA damage? See:

-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: Matthew Wicks / Flickr

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