How Much Water Should We Drink Every Day?

How Much Water Should We Drink Every Day?.jpeg

More than 2000 years ago Hippocrates (460-377 BCE) said, "If we could give every individual the right amount of nourishment and exercise, not too little and not too much, we would have found the safest way to health." What does that mean when it comes to water? Water has been described as a neglected, unappreciated, and under-researched subject, and further complicating the issue, a lot of the papers extolling the need for proper hydration are funded by the bottled water industry.

It turns out the often quoted "drink at least eight glasses of water a day" dictum has little underpinning scientific evidence . Where did that idea come from? The recommendation was traced to a 1921 paper, in which the author measured his own pee and sweat and determined we lose about 3% of our body weight in water a day, or about 8 cups (see How Many Glasses of Water Should We Drink in a Day?). Consequently, for the longest time, water requirement guidelines for humanity were based on just one person.

There is evidence that not drinking enough may be associated with falls and fractures, heat stroke, heart disease, lung disorders, kidney disease, kidney stones, bladder and colon cancer, urinary tract infections, constipation, dry mouth, cavities, decreased immune function and cataract formation. The problem with many of these studies is that low water intake is associated with several unhealthy behaviors, such as low fruit and vegetable intake, more fast-food, less shopping at farmers markets. And who drinks lots of water? People who exercise a lot. No wonder they tend to have lower disease rates!

Only large and expensive randomized trials could settle these questions definitively. Given that water cannot be patented, such trials seem unlikely; who's going to pay for them? We're left with studies that find an association between disease and low water intake. But are people sick because they drink less, or are they drinking less because they're sick? There have been a few large prospective studies in which fluid intake is measured before disease develops. For example, a Harvard study of 48,000 men found that the risk of bladder cancer decreased by 7% for every extra daily cup of fluid we drink. Therefore, a high intake of water--like 8 cups a day--may reduce the risk of bladder cancer by about 50%, potentially saving thousands of lives.

The accompanying editorial commented that strategies to prevent the most prevalent cancers in the West are remarkably straightforward in principle. To prevent lung cancer, quit smoking; to prevent breast cancer, maintain your ideal body weight and exercise; and to prevent skin cancer, stay out of the sun. Now comes this seemingly simple way to reduce the risk of bladder cancer: drink more fluids.

Probably the best evidence we have for a cut off of water intake comes from the Adventist Health Study, in which 20,000 men and women were studied. About one-half were vegetarian, so they were also getting extra water by eating more fruits and vegetables. Those drinking 5 or more glasses of water a day had about half the risk of dying from heart disease compared to those who drank 2 or fewer glasses a day. Like the Harvard study, this protection was found after controlling for other factors such as diet and exercise. These data suggest that it was the water itself that was decreasing risk, perhaps by lowering blood viscosity (blood thickness).

Based on all the best evidence to date, authorities from Europe, the U.S. Institute of Medicine, and the World Health Organization recommend between 2.0 and 2.7 liters (8 to 11 cups) of water a day for women, and 2.5 to 3.7 liters (10 to 15 cups) a day for men. This includes water from all sources, not just beverages. We get about a liter from food and the water our body makes. So this translates into a recommendation for women to drink 4 to 7 cups of water a day and men 6 to 11 cups, assuming only moderate physical activity at moderate ambient temperatures.

We can also get water from all the other drinks we consume, including caffeinated drinks, with the exception of stronger alcoholic drinks like wines and spirits. Beer can leave you with more water than you started with, but wine actively dehydrates you. However, in the cancer and heart disease studies I mentioned above, the benefits were only found with increased water consumption, not other beverages.

I've previously touched on the cognitive benefits of proper hydration here: Does a Drink Of Water Make Children Smarter?

Surprised tea is hydrating? See my video Is Caffeinated Tea Dehydrating?

Surprised that the 8-a-day rested on such flimsy evidence? Unfortunately, so much of what we do in medicine has shaky underpinnings. That's the impetus behind the idea of evidence-based medicine (what a concept!). Ironically, this new movement may itself undermine some of the most effective treatments. See Evidence-Based Medicine or Evidence-Biased?

How else can we reduce our risk of bladder cancer? See Raw Broccoli and Bladder Cancer Survival.

What kind of water? I recommend tap water, which tends to be preferable from a chemical and microbial contamination standpoint. What about buying one of those fancy alkalizing machines? See Alkaline Water: a Scam?

It's so nice to have data on such a fundamental question. We have much to thank the Adventists for. You will see their studies cropping up frequently. See, for example, Plant-Based Diets and Diabetes, The Okinawa Diet: Living to 100, and Evidence-Based Eating.

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: Sally Plank / Flickr. Image has been modified.

Original Link

Are the Benefits of Organic Food Underrated or Overrated?

Vegsource.jpeg

Pesticides have been classified as probable carcinogens for 25 years. Different pesticides have been associated with different cancers through a variety of mechanisms, including genetic damage--direct hits to our DNA or chromosomes--and epigenetic modification, changes in the way our genes are expressed. These effects have been documented in workers who are spraying the pesticides, but exposure to pesticide residues that remain on food is much smaller.

More recently, higher cancer rates have also been noted in people who live in areas where pesticides are heavily sprayed, but what about the food we buy at the store? Organic fruits and vegetables have fewer pesticides, but even the levels on conventional produce are generally well below acceptable limits. There is still scientific controversy about the safety of some pesticides even under the regulatory limits, however, given the possible additive effects of the mixture of pesticides to which we're exposed. The pesticide approval process also doesn't take into account toxic breakdown products such as dioxins that can form once pesticides are released into the environment.

Cadmium is another issue. In the largest review to date, involving hundreds of studies, not only did organic foods have more antioxidant phytonutrients, but lower concentrations of cadmium. Cadmium is one of three highly toxic heavy metals (along with lead and mercury) found in the food supply. Cadmium accumulates in the body, so we should try to keep intake as low as possible. Organic crops only have about half the cadmium, which is thought to come from the phosphate fertilizers that are added to conventional crops.

Of course, not all organic foods are healthy. The organic food industry is now worth tens of billions of dollars, and they didn't get that way just selling carrots. We can now buy pesticide-free potato chips and organic jelly beans. Organic foods can be even worse because, for example, people falsely judge organic Oreo cookies to have fewer calories than conventional Oreos, and so may eat more. Forgoing exercise was deemed more acceptable when the person had just chosen an organic dessert rather than a conventional one. In fact, leniency toward forgoing exercise was slightly greater after choosing an organic dessert than after eating no dessert at all--organic cookies were effectively viewed as having negative calories! Organic junk food is still junk food.

Not only do people tend to overestimate the nutritional benefits of organic foods, they also overestimate the risks of pesticides. People think that as many people die from pesticide residues on conventional food as die in motor vehicle accidents in the United States. Surveys have found organic food buyers may think eating conventional produce is almost as bad as smoking a pack of cigarettes. That kind of thinking is dangerous because it could potentially lead to a decrease in overall fruit and vegetable consumption.

If just half of the U.S. population were to increase fruit and vegetable consumption by a single serving a day, an estimated 20,000 cancer cases might be avoided each year. That's how powerful produce may be. But, because the model was using conventional fruits and veggies, the pesticide burden from those extra fruits and vegetables might result in 10 additional cancer cases. So overall, if half of us ate one more serving, we'd just prevent 19,990 cases of cancer a year.

Now that was a paper written by scientists-for-hire paid for by the Alliance for Food and Farming, which is a bunch of conventional produce growers, so they probably exaggerated the benefits and minimized the risks, but I think the bottom line is sound. We get a tremendous benefit from eating conventional fruits and vegetables that far outweighs whatever tiny bump in risk we may get from the pesticides. Why not reap the benefits without the risk and choose organic? Great! But we should never let concern about pesticides stop us from stuffing our face with as many fruits and vegetables as possible.

My video, Are the Benefits of Organic Food Underrated or Overrated?, was the final installment of a 5-part series on organics. The first four videos are:

I've covered the issue of cadmium in our diet before in Cadmium and Cancer: Plant vs. Animal Foods and Male Fertility and Diet. Heavy metals are found concentrated in seafood and organ meats, but can also be found in certain supplements and protein powders.

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: Sally Plank / Flickr. This image has been modified.

Original Link

Are the Benefits of Organic Food Underrated or Overrated?

Vegsource.jpeg

Pesticides have been classified as probable carcinogens for 25 years. Different pesticides have been associated with different cancers through a variety of mechanisms, including genetic damage--direct hits to our DNA or chromosomes--and epigenetic modification, changes in the way our genes are expressed. These effects have been documented in workers who are spraying the pesticides, but exposure to pesticide residues that remain on food is much smaller.

More recently, higher cancer rates have also been noted in people who live in areas where pesticides are heavily sprayed, but what about the food we buy at the store? Organic fruits and vegetables have fewer pesticides, but even the levels on conventional produce are generally well below acceptable limits. There is still scientific controversy about the safety of some pesticides even under the regulatory limits, however, given the possible additive effects of the mixture of pesticides to which we're exposed. The pesticide approval process also doesn't take into account toxic breakdown products such as dioxins that can form once pesticides are released into the environment.

Cadmium is another issue. In the largest review to date, involving hundreds of studies, not only did organic foods have more antioxidant phytonutrients, but lower concentrations of cadmium. Cadmium is one of three highly toxic heavy metals (along with lead and mercury) found in the food supply. Cadmium accumulates in the body, so we should try to keep intake as low as possible. Organic crops only have about half the cadmium, which is thought to come from the phosphate fertilizers that are added to conventional crops.

Of course, not all organic foods are healthy. The organic food industry is now worth tens of billions of dollars, and they didn't get that way just selling carrots. We can now buy pesticide-free potato chips and organic jelly beans. Organic foods can be even worse because, for example, people falsely judge organic Oreo cookies to have fewer calories than conventional Oreos, and so may eat more. Forgoing exercise was deemed more acceptable when the person had just chosen an organic dessert rather than a conventional one. In fact, leniency toward forgoing exercise was slightly greater after choosing an organic dessert than after eating no dessert at all--organic cookies were effectively viewed as having negative calories! Organic junk food is still junk food.

Not only do people tend to overestimate the nutritional benefits of organic foods, they also overestimate the risks of pesticides. People think that as many people die from pesticide residues on conventional food as die in motor vehicle accidents in the United States. Surveys have found organic food buyers may think eating conventional produce is almost as bad as smoking a pack of cigarettes. That kind of thinking is dangerous because it could potentially lead to a decrease in overall fruit and vegetable consumption.

If just half of the U.S. population were to increase fruit and vegetable consumption by a single serving a day, an estimated 20,000 cancer cases might be avoided each year. That's how powerful produce may be. But, because the model was using conventional fruits and veggies, the pesticide burden from those extra fruits and vegetables might result in 10 additional cancer cases. So overall, if half of us ate one more serving, we'd just prevent 19,990 cases of cancer a year.

Now that was a paper written by scientists-for-hire paid for by the Alliance for Food and Farming, which is a bunch of conventional produce growers, so they probably exaggerated the benefits and minimized the risks, but I think the bottom line is sound. We get a tremendous benefit from eating conventional fruits and vegetables that far outweighs whatever tiny bump in risk we may get from the pesticides. Why not reap the benefits without the risk and choose organic? Great! But we should never let concern about pesticides stop us from stuffing our face with as many fruits and vegetables as possible.

My video, Are the Benefits of Organic Food Underrated or Overrated?, was the final installment of a 5-part series on organics. The first four videos are:

I've covered the issue of cadmium in our diet before in Cadmium and Cancer: Plant vs. Animal Foods and Male Fertility and Diet. Heavy metals are found concentrated in seafood and organ meats, but can also be found in certain supplements and protein powders.

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: Sally Plank / Flickr. This image has been modified.

Original Link

Antioxidant- and Folate-Rich Foods for Depression

Antioxidant- and Folate-Rich Foods for Depression.jpeg

According to the Centers for Disease Control and Prevention, the rates of all of our top 10 killers have fallen or stabilized except for one, suicide. As shown in my video, Antioxidants & Depression, accumulating evidence indicates that free radicals may play important roles in the development of various neuropsychiatric disorders including major depression, a common cause of suicide.

In a study of nearly 300,000 Canadians, for example, greater fruit and vegetable consumption was associated with lower odds of depression, psychological distress, self-reported mood and anxiety disorders and poor perceived mental health. They conclude that since a healthy diet comprised of a high intake of fruits and vegetables is rich in anti-oxidants, it may consequently dampen the detrimental effects of oxidative stress on mental health.

But that study was based on asking how many fruits and veggies people ate. Maybe people were just telling the researchers what they thought they wanted to hear. What if you actually measure the levels of carotenoid phytonutrients in people's bloodstreams? The same relationship is found. Testing nearly 2000 people across the United States, researchers found that a higher total blood carotenoid level was indeed associated with a lower likelihood of elevated depressive symptoms, and there appeared to be a dose-response relationship, meaning the higher the levels, the better people felt.

Lycopene, the red pigment predominantly found in tomatoes (but also present in watermelon, pink grapefruit, guava and papaya) is the most powerful carotenoid antioxidant. In a test tube, it's about 100 times more effective at quenching free radicals than a more familiar antioxidant like vitamin E.

Do people who eat more tomatoes have less depression, then? Apparently so. A study of about a thousand older men and women found that those who ate the most tomato products had only about half the odds of depression. The researchers conclude that a tomato-rich diet may have a beneficial effect on the prevention of depressive symptoms.

Higher consumption of fruits and vegetables has been found to lead to a lower risk of developing depression, but if it's the antioxidants can't we just take an antioxidant pill? No.

Only food sources of antioxidants were protectively associated with depression. Not antioxidants from dietary supplements. Although plant foods and food-derived phytochemicals have been associated with health benefits, antioxidants from dietary supplements appear to be less beneficial and may, in fact, be detrimental to health. This may indicate that the form and delivery of the antioxidants are important. Alternatively, the observed associations may be due not to antioxidants but rather to other dietary factors, such as folate, that also occur in plant-rich diets.

In a study of thousands of middle-aged office workers, eating lots of processed food was found to be a risk factor for at least mild to moderate depression five years later, whereas a whole food pattern was found to be protective. Yes, it could be because of the high content of antioxidants in fruits and vegetables but could also be the folate in greens and beans, as some studies have suggested an increased risk of depression in folks who may not have been eating enough.

Low folate levels in the blood are associated with depression, but since most of the early studies were cross-sectional, meaning a snapshot in time, we didn't know if the low folate led to depression or the depression led to low folate. Maybe when you have the blues you don't want to eat the greens.

But since then a number of cohort studies were published, following people over time. They show that a low dietary intake of folate may indeed be a risk factor for severe depression, as much as a threefold higher risk. Note this is for dietary folate intake, not folic acid supplements; those with higher levels were actually eating healthy foods. If you give people folic acid pills they don't seem to work. This may be because folate is found in dark green leafy vegetables like spinach, whereas folic acid is the oxidized synthetic compound used in food fortification and dietary supplements because it's more shelf-stable. It may have different effects on the body as I previously explored in Can Folic Acid Be Harmful?

These kinds of findings point to the importance of antioxidant food sources rather than dietary supplements. But there was an interesting study giving people high dose vitamin C. In contrast to the placebo group, those given vitamin C experienced a decrease in depression scores and also greater FSI. What is FSI? Frequency of Sexual Intercourse.

Evidently, high dose vitamin C improves mood and intercourse frequency, but only in sexual partners that don't live with one another. In the placebo group, those not living together had sex about once a week, and those living together a little higher, once every five days, with no big change on vitamin C. But for those not living together, on vitamin C? Every other day! The differential effect for non-cohabitants suggests that the mechanism is not a peripheral one, meaning outside the brain, but a central one--some psychological change which motivates the person to venture forth to have intercourse. The mild antidepressant effect they found was unrelated to cohabitation or frequency, so it does not appear that the depression scores improved just because of the improved FSI.

For more mental health video, see:

Anything else we can do to enhance our sexual health and attractiveness? 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:

Image Credit: Sally Plank / Flickr. This image has been modified.

Original Link

Antioxidant- and Folate-Rich Foods for Depression

Antioxidant- and Folate-Rich Foods for Depression.jpeg

According to the Centers for Disease Control and Prevention, the rates of all of our top 10 killers have fallen or stabilized except for one, suicide. As shown in my video, Antioxidants & Depression, accumulating evidence indicates that free radicals may play important roles in the development of various neuropsychiatric disorders including major depression, a common cause of suicide.

In a study of nearly 300,000 Canadians, for example, greater fruit and vegetable consumption was associated with lower odds of depression, psychological distress, self-reported mood and anxiety disorders and poor perceived mental health. They conclude that since a healthy diet comprised of a high intake of fruits and vegetables is rich in anti-oxidants, it may consequently dampen the detrimental effects of oxidative stress on mental health.

But that study was based on asking how many fruits and veggies people ate. Maybe people were just telling the researchers what they thought they wanted to hear. What if you actually measure the levels of carotenoid phytonutrients in people's bloodstreams? The same relationship is found. Testing nearly 2000 people across the United States, researchers found that a higher total blood carotenoid level was indeed associated with a lower likelihood of elevated depressive symptoms, and there appeared to be a dose-response relationship, meaning the higher the levels, the better people felt.

Lycopene, the red pigment predominantly found in tomatoes (but also present in watermelon, pink grapefruit, guava and papaya) is the most powerful carotenoid antioxidant. In a test tube, it's about 100 times more effective at quenching free radicals than a more familiar antioxidant like vitamin E.

Do people who eat more tomatoes have less depression, then? Apparently so. A study of about a thousand older men and women found that those who ate the most tomato products had only about half the odds of depression. The researchers conclude that a tomato-rich diet may have a beneficial effect on the prevention of depressive symptoms.

Higher consumption of fruits and vegetables has been found to lead to a lower risk of developing depression, but if it's the antioxidants can't we just take an antioxidant pill? No.

Only food sources of antioxidants were protectively associated with depression. Not antioxidants from dietary supplements. Although plant foods and food-derived phytochemicals have been associated with health benefits, antioxidants from dietary supplements appear to be less beneficial and may, in fact, be detrimental to health. This may indicate that the form and delivery of the antioxidants are important. Alternatively, the observed associations may be due not to antioxidants but rather to other dietary factors, such as folate, that also occur in plant-rich diets.

In a study of thousands of middle-aged office workers, eating lots of processed food was found to be a risk factor for at least mild to moderate depression five years later, whereas a whole food pattern was found to be protective. Yes, it could be because of the high content of antioxidants in fruits and vegetables but could also be the folate in greens and beans, as some studies have suggested an increased risk of depression in folks who may not have been eating enough.

Low folate levels in the blood are associated with depression, but since most of the early studies were cross-sectional, meaning a snapshot in time, we didn't know if the low folate led to depression or the depression led to low folate. Maybe when you have the blues you don't want to eat the greens.

But since then a number of cohort studies were published, following people over time. They show that a low dietary intake of folate may indeed be a risk factor for severe depression, as much as a threefold higher risk. Note this is for dietary folate intake, not folic acid supplements; those with higher levels were actually eating healthy foods. If you give people folic acid pills they don't seem to work. This may be because folate is found in dark green leafy vegetables like spinach, whereas folic acid is the oxidized synthetic compound used in food fortification and dietary supplements because it's more shelf-stable. It may have different effects on the body as I previously explored in Can Folic Acid Be Harmful?

These kinds of findings point to the importance of antioxidant food sources rather than dietary supplements. But there was an interesting study giving people high dose vitamin C. In contrast to the placebo group, those given vitamin C experienced a decrease in depression scores and also greater FSI. What is FSI? Frequency of Sexual Intercourse.

Evidently, high dose vitamin C improves mood and intercourse frequency, but only in sexual partners that don't live with one another. In the placebo group, those not living together had sex about once a week, and those living together a little higher, once every five days, with no big change on vitamin C. But for those not living together, on vitamin C? Every other day! The differential effect for non-cohabitants suggests that the mechanism is not a peripheral one, meaning outside the brain, but a central one--some psychological change which motivates the person to venture forth to have intercourse. The mild antidepressant effect they found was unrelated to cohabitation or frequency, so it does not appear that the depression scores improved just because of the improved FSI.

For more mental health video, see:

Anything else we can do to enhance our sexual health and attractiveness? 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:

Image Credit: Sally Plank / Flickr. This image has been modified.

Original Link

What Do All the Blue Zones Have in Common?

Do Flexitarians Live Longer.jpg

What accounts for the benefits of a Mediterranean-style diet? An anatomy of health effects was published, and the single most important component was the high consumption of plant foods. In contrast, fish and seafood consumption, the only animal foods promoted in the Mediterranean diet, did not seem to help.

If you look at four of the major dietary quality scoring systems, which have all been associated with extending lifespan and lowering heart disease and cancer mortality, they all share only four things in common: more fruit, more vegetables, more whole grains and more nuts and beans. They are all built on a common core of a diet rich in plant foods, whereas opposite food patterns, rich in animal foods and poor in plant-based foods (in other words, the Western diet), is associated with higher risks. So we need to optimize the food environment to support whole grains, vegetables, fruit and plant-based proteins.

That's one of the things all the so-called Blue Zones have in common: the longest living populations have not only social support and engagement and daily exercise, but nutritionally they all center their diets around plant foods, reserving meat mostly for special occasions. In fact, the population with perhaps the highest life-expectancy in the world, the California Adventist vegetarians, doesn't eat any meat at all.

So if the primary benefits of the Mediterranean diet are due to all the whole plant foods, what if you went back to the famous PREDIMED study and created a "provegetarian" scoring system? We know vegetarians live longer, but because a pure vegetarian diet might not easily be embraced by many individuals, maybe it would be easier to swallow if we just tell people more plant-based foods and less animal-based foods. But would just moving along the spectrum towards more plants actually enable people to live longer? Researchers thought of this food pattern as a "gentle approach" to vegetarianism, figuring that if it improved survival it would be an easily understandable message for health promotion: more plant foods, less animal foods.

On this scoring system, you get points for eating fruit, vegetables, nuts, grains, beans, olive oil and potatoes, but get docked points for any animal fats, eggs, fish, dairy or any type of meat or meat products. Of course that means you get a higher score the more potato chips and French fries you eat. That's why I prefer the term "whole-food, plant-based diet" since it's defined by what you eat, not by what you don't eat. When I taught at Cornell I had "vegan" students who apparently were trying to live off French fries and beer; vegan does not necessarily mean health-promoting.

But did the provegetarian scoring system work? Regardless of healthy versus unhealthy, if you give points to people for any kind of plant food, processed or not, and detract points for any kind of animal product consumption, people with higher scores live longer. The maximum provegetarian score is 60, but even just scoring 40 or more was associated with a 40 percent drop in mortality. In fact, there were so few deaths in the highest category of adherence to the provegetarian diet, they had to merge the two upper categories for their analysis. This is evidence that simple advice to increase the consumption of plant-derived foods with reductions in the consumption of foods from animal sources confers a survival advantage. You can view the graph in my video Do Flexitarians Live Longer?

The researchers conclude, "this modest change is realistic, affordable, and achievable because a sizable proportion of their population was already eating that way. So one can get significant survival benefit without a radical shift to the exclusive consumption of plant foods, a more gradual and gentle approach which is more easily translatable into public policy." A 41 percent drop in mortality rates in the United States would mean saving the lives of hundreds of thousands of Americans every year.

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

I've done a few videos on the health of so-called semi-vegetarians or flexitarians ("flexible" vegetarians). See how they rate in:

The Provegetarian Score reminds me of the animal to vegetable protein ratio in Prostate Cancer Survival: The A/V Ratio. My favorite dietary quality index is the one in Calculate Your Healthy Eating Score. How do you rate? Even the healthiest among us may be able to continue to push the envelope.

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: Sally Plank / Flickr. This image has been modified.

Original Link

What Do All the Blue Zones Have in Common?

Do Flexitarians Live Longer.jpg

What accounts for the benefits of a Mediterranean-style diet? An anatomy of health effects was published, and the single most important component was the high consumption of plant foods. In contrast, fish and seafood consumption, the only animal foods promoted in the Mediterranean diet, did not seem to help.

If you look at four of the major dietary quality scoring systems, which have all been associated with extending lifespan and lowering heart disease and cancer mortality, they all share only four things in common: more fruit, more vegetables, more whole grains and more nuts and beans. They are all built on a common core of a diet rich in plant foods, whereas opposite food patterns, rich in animal foods and poor in plant-based foods (in other words, the Western diet), is associated with higher risks. So we need to optimize the food environment to support whole grains, vegetables, fruit and plant-based proteins.

That's one of the things all the so-called Blue Zones have in common: the longest living populations have not only social support and engagement and daily exercise, but nutritionally they all center their diets around plant foods, reserving meat mostly for special occasions. In fact, the population with perhaps the highest life-expectancy in the world, the California Adventist vegetarians, doesn't eat any meat at all.

So if the primary benefits of the Mediterranean diet are due to all the whole plant foods, what if you went back to the famous PREDIMED study and created a "provegetarian" scoring system? We know vegetarians live longer, but because a pure vegetarian diet might not easily be embraced by many individuals, maybe it would be easier to swallow if we just tell people more plant-based foods and less animal-based foods. But would just moving along the spectrum towards more plants actually enable people to live longer? Researchers thought of this food pattern as a "gentle approach" to vegetarianism, figuring that if it improved survival it would be an easily understandable message for health promotion: more plant foods, less animal foods.

On this scoring system, you get points for eating fruit, vegetables, nuts, grains, beans, olive oil and potatoes, but get docked points for any animal fats, eggs, fish, dairy or any type of meat or meat products. Of course that means you get a higher score the more potato chips and French fries you eat. That's why I prefer the term "whole-food, plant-based diet" since it's defined by what you eat, not by what you don't eat. When I taught at Cornell I had "vegan" students who apparently were trying to live off French fries and beer; vegan does not necessarily mean health-promoting.

But did the provegetarian scoring system work? Regardless of healthy versus unhealthy, if you give points to people for any kind of plant food, processed or not, and detract points for any kind of animal product consumption, people with higher scores live longer. The maximum provegetarian score is 60, but even just scoring 40 or more was associated with a 40 percent drop in mortality. In fact, there were so few deaths in the highest category of adherence to the provegetarian diet, they had to merge the two upper categories for their analysis. This is evidence that simple advice to increase the consumption of plant-derived foods with reductions in the consumption of foods from animal sources confers a survival advantage. You can view the graph in my video Do Flexitarians Live Longer?

The researchers conclude, "this modest change is realistic, affordable, and achievable because a sizable proportion of their population was already eating that way. So one can get significant survival benefit without a radical shift to the exclusive consumption of plant foods, a more gradual and gentle approach which is more easily translatable into public policy." A 41 percent drop in mortality rates in the United States would mean saving the lives of hundreds of thousands of Americans every year.

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

I've done a few videos on the health of so-called semi-vegetarians or flexitarians ("flexible" vegetarians). See how they rate in:

The Provegetarian Score reminds me of the animal to vegetable protein ratio in Prostate Cancer Survival: The A/V Ratio. My favorite dietary quality index is the one in Calculate Your Healthy Eating Score. How do you rate? Even the healthiest among us may be able to continue to push the envelope.

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: Sally Plank / Flickr. This image has been modified.

Original Link

Reversal of Chronic Disease Risk Even Late in Life

NF-Oct18 Never too Late to Start Eating Healthier.jpeg

A hundred years ago, the New York Times reported on a rather sophisticated study for the time: 4,600 cases of cancer appearing over a seven year period, suggesting that the increased consumption of animal foods was to blame. A century later, the latest review on the subjects concluded that mortality from all causes put together, ischemic heart disease, circulatory, and cerebrovascular diseases was significantly lower in those eating meat-free diets, in addition to less cancer and diabetes.

I'm surprised they found such significant results given that people in these studies typically didn't stop eating meat until late in life. For example, in the largest study done up until recently, up to a third of subjects ate vegetarian for less than five years, yet they still ended up with lower rates of heart disease whether they were under 60 or over 60, normal weight or overweight, used to smoke or never smoked; those that had stopped eating meat had lower risk, suggesting that decades of higher risk dietary behavior could be reversed within just years of eating healthier.

If you look at countries that switched from eating traditional, more plant-based diets to more Westernized diets, it may take 20 years for cancer rates to shoot up. It takes decades for most tumors to grow. For example, if you look at Asia, their dietary shift was accompanied by a remarkable increase in mortality rates of breast, colon, and prostate cancers. The same thing can be shown with migration studies. Men moving from rural China to the U.S. experience a dramatic increase in cancer risk, but tumors take time to grow.

So it's remarkable to me that after most of a lifetime eating the standard Western diet, one can turn it around and reverse chronic disease risk with a healthier diet, even late in the game... as discussed in my video, Never Too Late to Start Eating Healthier.

So, "should we all start eating vegetarian?" asked an editorial that accompanied the results from the largest study ever published on Americans eating plant-based diets, which found vegetarian diets to be associated with lower all-cause mortality, meaning those who started eating vegetarian live, on average, longer lives. This analysis included so-called semi-vegetarians, who ate meat at least once a month (but no more than once a week), so it's not yet clear how harmful eating meat a few times a month is. What we can all agree on, though, is that we should limit our intake of junk food and animal fat, and eat more fruits and vegetables. Most authorities will also agree that diets should include whole grains, beans, and nuts. Instead of fighting over whose diet is the best, it's time to acknowledge these common features of diets associated with less disease, and instead focus our attention on helping patients avoid the intense commercial pressures to eat otherwise.

How amazing the human body is if we just treat it right! For more on lifestyle medicine, see:

So please don't allow the perfect to become the enemy of the good. Any movement we can make towards improving our diet can help. Though the earlier the better: See Heart Disease Starts in Childhood and Back in Circulation: Sciatica and Cholesterol.

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--2013: Uprooting the Leading Causes of Death, More Than an Apple a Day, 2014: From Table to Able: Combating Disabling Diseases with Food, 2015: Food as Medicine: Preventing and Treating the Most Dreaded Diseases with Diet, and my latest, 2016: How Not To Die: The Role of Diet in Preventing, Arresting, and Reversing Our Top 15 Killers.

Image Credit: victorpr / 123RF

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Are Raisins a Good Snack Choice?

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Raisins, like all fruits, have a variety of health benefits, but dried fruit is higher in calories per serving than fresh, so might they contribute to weight gain? A study done by the University of Connecticut helped set people's minds at ease. Men and women were assigned to consume a cup of raisins a day for six weeks and were able to successfully offset the consumption of other foods in their diets such that they experienced no significant change in weight or waist circumference. What about in kids? I explore that in the video, Are Raisins Good Snacks for Kids?.

Leave it to the California Raisin Marketing Board to dream up a study titled, "An after-school snack of raisins lowers cumulative food intake in young children." Sounds good, right? They compared raisins to potato chips and chocolate chip cookies. They gave kids raisins, grapes, chips or cookies and said they could eat as much as they wanted and surprise surprise kids ate less fruit and more junk, but I guess naming the paper "Kids Prefer Cookies" would not have garnered the same kind of sponsor approval.

This reminds me of another study they did showing that regular consumption of raisins may reduce blood sugar levels... compared to fudge cookies and Oreos. Another study showed raisins caused less of a blood sugar spike than Coca-cola and candy bars. Though you can tell it was not funded by Big Raisin by their conclusion, "whether the general public should be advised to snack on fruit rather than on candy bars requires further debate and investigation."

Comparing raisins to chips and cookies was similarly unhelpful. Luckily, a less biased study was published by researchers at the University of Toronto. Nine to eleven year old boys and girls were told to eat all the grapes or raisins they wanted 30 minutes before a meal in which they could eat all the pizza they wanted. If you just gave them the meal, no snack, they ate 837 calories worth of pizza. If you gave them all-you-can-eat grapes before the meal, they ate 128 calories of grapes, but that seemed to fill them up a bit, so they ended up eating less pizza. But because they ate the snack and the meal they ended up getting more calories over all. Still, grape calories are better than pizza calories, but when given raisins instead, they ate even more snack calories, but the raisins were evidently so satiating that they ate so much less pizza that they ate fewer calories over all.

Now I know as parents there's a concern that if our kids eat snacks it might spoil their dinner, but when the snacks are fruit and the meal is a pepperoni and three cheese pizza, the more we can ruin their appetite, the better.

Raisin marketers aren't the only one's trying game the scientific method. Check out:

How to help get our kids to eat their fruits and veggies:

More dried fruit studies (my fave is dried mango):

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--2013: Uprooting the Leading Causes of Death, More Than an Apple a Day, 2014: From Table to Able: Combating Disabling Diseases with Food, 2015: Food as Medicine: Preventing and Treating the Most Dreaded Diseases with Diet, and my latest, 2016: How Not To Die: The Role of Diet in Preventing, Arresting, and Reversing Our Top 15 Killers.

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What About Eating Just a Little Meat?

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As you can see in my video, Plant-Based Diets and Diabetes, we've known for decades that a plant-based diet may be protective against diabetes. Studies going back half a century found that those eating meat one or more days a week had significantly higher rates of diabetes, and the more frequently meat was eaten, the more frequent the disease. And this is after controlling for weight, so even at the same weight, those eating more plant-based had but a fraction of the diabetes rates. If anything, vegetarians should have had more diabetes just because they appear to live so much longer, so they had more time to develop these kinds of chronic diseases; but no, apparently lower rates of death and disease.

Fast forward 50 years to the Adventist-2 study, looking at 89,000 people, and we see a stepwise drop in the rates of diabetes as one eats more and more plant-based, down to a 78% lower prevalence among those eating strictly plant-based. Protection building incrementally as one moved from eating meat daily, to eating meat weekly, to just fish, to no meat, and then to no eggs and dairy either. Followed over time, vegetarian diets were associated with a substantially lower incidence of diabetes, indicating the potential of these diets to stem the current diabetes epidemic.

We see the same step-wise drop in rates of another leading killer, high blood pressure. The greater the proportion of plant foods, the lower the rates of hypertension, and the same with excess body fat. The only dietary group not on average overweight were those eating diets composed exclusively of plant foods, but again there was the same incremental drop with fewer and fewer animal products. This suggests that it's not black and white, not all or nothing, any steps we can make along this spectrum of eating healthier may accrue significant benefits.

What about eating a really healthy diet with just a little meat? Is it better to eat none at all? We have new insight last year from Taiwan. Asian diets in general tend to be lower in meat and higher in plant foods compared with Western diet, but whether a diet completely avoiding meat and fish would further extend the protective effect of a plant-based diet wasn't known, until now.

Traditionally, Asian populations have had low rates of diabetes, but a diabetes epidemic has since emerged, and appears to coincide with increased meat, animal protein, and animal fat consumption, but the Westernization of Asian diets also brought along a lot of fast food and junk, and so these researchers at the national university didn't want to just compare those eating vegetarian to typical meateaters. So, they compared Bhuddist vegetarians to Bhuddist non-vegetarians, eating traditional Asian diets. Even the omnivores were eating a predominantly plant-based diet, consuming little meat and fish, with the women eating the equivalent of about a single serving a week, and men eating a serving every few days. That's just 8% of the meat intake in the U.S., 3% for the women. The question: is it better to eat 3% or 0%?

Again, both groups were eating healthy; zero soda consumption, for example, in any group. Despite the similarities in their diet, and after controlling for weight, family history, exercise, and smoking, the men eating vegetarian had just half the rates of diabetes, and the vegetarian women just a quarter of the rates. So even in a population consuming a really plant-based diet with little meat and fish, true vegetarians who completely avoided animal flesh, while eating more healthy plant foods, have lower odds for prediabetes and diabetes after accounting for other risk factors. They wanted to break it up into vegan versus ovo-lacto like in the Adventist-2 study, but they couldn't because there were no cases at all of diabetes found within the vegan group.

More on preventing and treating this terrible disease:

The reason I keep going back to that Adventist-2 study is that it's not only the biggest study of those eating plant based diets in North America, but the largest such study anywhere anytime. We owe those investigators a great debt (not to mention the 96,741 participants!). One thing I'm happy my tax dollars are going towards (via the National Cancer Institute and National Institutes of Health). More from the Adventists in Caloric Restriction vs. Animal Protein Restriction.

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--2013: Uprooting the Leading Causes of Death, More Than an Apple a Day, 2014: From Table to Able: Combating Disabling Diseases with Food, 2015: Food as Medicine: Preventing and Treating the Most Dreaded Diseases with Diet, and my latest, 2016: How Not To Die: The Role of Diet in Preventing, Arresting, and Reversing Our Top 15 Killers.

Image Credit: Reisek / Flickr

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