Plant versus Animal Iron

Plant versus Animal Iron.jpeg

It is commonly thought that those who eat plant-based diets may be more prone to iron deficiency, but it turns out that they're no more likely to suffer from iron deficiency anemia than anybody else. This may be because not only do those eating meat-free diets tend to get more fiber, magnesium, and vitamins like A, C, and E, but they also get more iron.

The iron found predominantly in plants is non-heme iron, which isn't absorbed as well as the heme iron found in blood and muscle, but this may be a good thing. As seen in my video, The Safety of Heme vs. Non-Heme Iron, avoidance of heme iron may be one of the key elements of plant-based protection against metabolic syndrome, and may also be beneficial in lowering the risk from other chronic diseases such as heart disease.

The data linking coronary heart disease and the intake of iron, in general, has been mixed. This inconsistency of evidence may be because of where the iron comes from. The majority of total dietary iron is non-heme iron, coming mostly from plants. So, total iron intake is associated with lower heart disease risk, but iron intake from meat is associated with significantly higher risk for heart disease. This is thought to be because iron can act as a pro-oxidant, contributing to the development of atherosclerosis by oxidizing cholesterol with free radicals. The risk has been quantified as a 27% increase in coronary heart disease risk for every 1 milligram of heme iron consumed daily.

The same has been found for stroke risk. The studies on iron intake and stroke have had conflicting results, but that may be because they had never separated out heme iron from non-heme iron... until now. Researchers found that the intake of meat (heme) iron, but not plant (non-heme) iron, was associated with an increased risk of stroke.

The researchers also found that higher intake of heme iron--but not total or plant (non-heme) iron--was significantly associated with greater risk for type 2 diabetes. There may be a 16% increase in risk for type 2 diabetes for every 1 milligram of heme iron consumed daily.

The same has also been found for cancer, with up to 12% increased risk for every milligram of daily heme iron exposure. In fact, we can actually tell how much meat someone is eating by looking at their tumors. To characterize the mechanisms underlying meat-related lung cancer development, researchers asked lung cancer patients how much meat they ate and examined the gene expression patterns in their tumors. They identified a signature pattern of heme-related gene expression. Although they looked specifically at lung cancer, they expect these meat-related gene expression changes may occur in other cancers as well.

We do need to get enough iron, but only about 3% of premenopausal white women have iron deficiency anemia these days. However, the rates are worse in African and Mexican Americans. Taking into account our leading killers--heart disease, cancer, and diabetes--the healthiest source of iron appears to be non-heme iron, found naturally in abundance in whole grains, beans, split peas, chickpeas, lentils, dark green leafy vegetables, dried fruits, nuts, and seeds.

But how much money can be made on beans, though? The processed food industry came up with a blood-based crisp bread, made out of rye flour and blood from cattle and pigs, which is one of the most concentrated sources of heme iron, about two-thirds more than blood from chickens. If blood-based crackers don't sound particularly appetizing, you can always snack on cow blood cookies. And there are always blood-filled biscuits, whose filling has been described as "a dark-colored, chocolate flavored paste with a very pleasant taste." (It's dark-colored because spray-dried pig blood can have a darkening effect on the food product's color.) The worry is not the color or taste, it's the heme iron, which, because of its potential cancer risk, is not considered safe to add to foods intended for the general population.

Previously, I've touched on the double-edged iron sword in Risk Associated With Iron Supplements and Phytates for the Prevention of Cancer. It may also help answer Why Was Heart Disease Rare in the Mediterranean?

Those eating plant-based diets get more of most nutrients since whole plant foods are so nutrient dense. See Nutrient-Dense Approach to Weight Management.

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

Original Link

Plant versus Animal Iron

Plant versus Animal Iron.jpeg

It is commonly thought that those who eat plant-based diets may be more prone to iron deficiency, but it turns out that they're no more likely to suffer from iron deficiency anemia than anybody else. This may be because not only do those eating meat-free diets tend to get more fiber, magnesium, and vitamins like A, C, and E, but they also get more iron.

The iron found predominantly in plants is non-heme iron, which isn't absorbed as well as the heme iron found in blood and muscle, but this may be a good thing. As seen in my video, The Safety of Heme vs. Non-Heme Iron, avoidance of heme iron may be one of the key elements of plant-based protection against metabolic syndrome, and may also be beneficial in lowering the risk from other chronic diseases such as heart disease.

The data linking coronary heart disease and the intake of iron, in general, has been mixed. This inconsistency of evidence may be because of where the iron comes from. The majority of total dietary iron is non-heme iron, coming mostly from plants. So, total iron intake is associated with lower heart disease risk, but iron intake from meat is associated with significantly higher risk for heart disease. This is thought to be because iron can act as a pro-oxidant, contributing to the development of atherosclerosis by oxidizing cholesterol with free radicals. The risk has been quantified as a 27% increase in coronary heart disease risk for every 1 milligram of heme iron consumed daily.

The same has been found for stroke risk. The studies on iron intake and stroke have had conflicting results, but that may be because they had never separated out heme iron from non-heme iron... until now. Researchers found that the intake of meat (heme) iron, but not plant (non-heme) iron, was associated with an increased risk of stroke.

The researchers also found that higher intake of heme iron--but not total or plant (non-heme) iron--was significantly associated with greater risk for type 2 diabetes. There may be a 16% increase in risk for type 2 diabetes for every 1 milligram of heme iron consumed daily.

The same has also been found for cancer, with up to 12% increased risk for every milligram of daily heme iron exposure. In fact, we can actually tell how much meat someone is eating by looking at their tumors. To characterize the mechanisms underlying meat-related lung cancer development, researchers asked lung cancer patients how much meat they ate and examined the gene expression patterns in their tumors. They identified a signature pattern of heme-related gene expression. Although they looked specifically at lung cancer, they expect these meat-related gene expression changes may occur in other cancers as well.

We do need to get enough iron, but only about 3% of premenopausal white women have iron deficiency anemia these days. However, the rates are worse in African and Mexican Americans. Taking into account our leading killers--heart disease, cancer, and diabetes--the healthiest source of iron appears to be non-heme iron, found naturally in abundance in whole grains, beans, split peas, chickpeas, lentils, dark green leafy vegetables, dried fruits, nuts, and seeds.

But how much money can be made on beans, though? The processed food industry came up with a blood-based crisp bread, made out of rye flour and blood from cattle and pigs, which is one of the most concentrated sources of heme iron, about two-thirds more than blood from chickens. If blood-based crackers don't sound particularly appetizing, you can always snack on cow blood cookies. And there are always blood-filled biscuits, whose filling has been described as "a dark-colored, chocolate flavored paste with a very pleasant taste." (It's dark-colored because spray-dried pig blood can have a darkening effect on the food product's color.) The worry is not the color or taste, it's the heme iron, which, because of its potential cancer risk, is not considered safe to add to foods intended for the general population.

Previously, I've touched on the double-edged iron sword in Risk Associated With Iron Supplements and Phytates for the Prevention of Cancer. It may also help answer Why Was Heart Disease Rare in the Mediterranean?

Those eating plant-based diets get more of most nutrients since whole plant foods are so nutrient dense. See Nutrient-Dense Approach to Weight Management.

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

Original Link

What’s the Mediterranean Diet’s Secret?

Why Was Heart Disease Rare in the Mediterranean?.jpg

The Mediterranean Diet is an "in" topic nowadays in both the medical literature and the lay media. As one researcher put it, "Uncritical laudatory coverage is common, but specifics are hard to come by: What is it? Where did it come from? Why is it good? Merits are rarely detailed; possible downsides are never mentioned." So, let's dig in....

After World War II, the government of Greece asked the Rockefeller foundation to come in and assess the situation. Impressed by the low rates of heart disease in the region, nutrition scientist Ancel Keys--after which "K" rations were named--initiated his famous seven countries study. In this study, he found the rate of fatal heart disease on the Greek isle of Crete was 20 times lower than in the United States. They also had the lowest cancer rates and fewest deaths overall. What were they eating? Their diets were more than 90% plant-based, which may explain why coronary heart disease was such a rarity. A rarity, that is, except for a small class of rich people whose diet differed from that of the general population--they ate meat every day instead of every week or two.

So, the heart of the Mediterranean diet is mainly plant-based, and low in meat and dairy, which Keys considered the "major villains in the diet" because of their saturated fat content. Unfortunately, no one is really eating the traditional Mediterranean diet anymore, even in the Mediterranean. The prevalence of coronary heart disease skyrocketed by an order of magnitude within a few decades in Crete, blamed on the increased consumption of meat and cheese at the expense of plant foods.

Everyone is talking about the Mediterranean diet, but few do it properly. People think of pizza or spaghetti with meat sauce, but while "Italian restaurants brag about the healthy measuring in diet, they serve a travesty of it." If no one's really eating this way anymore, how do you study it?

Researchers came up with a variety of Mediterranean diet adherence scoring systems to see if people who are eating more Mediterranean-ish do better. You get maximum points the more plant foods you eat, and effectively you get points deducted by eating just a single serving of meat or dairy a day. So it's no surprise those that eat relatively higher on the scale have a lower risk of heart disease, cancer, and death overall. After all, the Mediterranean diet can be considered to be a "near vegetarian" diet. "As such, it should be expected to produce the well-established health benefits of vegetarian diets." That is, less heart disease, cancer, death, and inflammation; improved arterial function; a lower risk of developing type 2 diabetes; a reduced risk for stroke, depression, and cognitive impairment.

How might it work? I've talked about the elegant studies showing that those who eat plant-based diets have more plant-based compounds, like aspirin, circulating within their systems. Polyphenol phytonutrients in plant foods are associated with a significantly lower risk of dying. Magnesium consumption is also associated with a significantly lower risk of dying, and is found in dark green leafy vegetables, as well as fruits, beans, nuts, soy, and whole grains.

Heme iron, on the other hand--the iron found in blood and muscle--acts as a pro-oxidant and appears to increase the risk of diabetes, whereas plant-based, non-heme iron appears safe. Similarly, with heart disease, animal-based iron was found to significantly increase the risk of coronary heart disease, our number one killer, but not plant-based iron. The Mediterranean diet is protective compared to the Standard American Diet--no question--but any diet rich in whole plant foods and low in animal-fat consumption could be expected to confer protection against many of our leading killers.

Here are some more videos on the Mediterranean Diet:

For more information on heme iron, see Risk Associated With Iron Supplements.

More on magnesium is found in How Do Nuts Prevent Sudden Cardiac Death? and Mineral of the Year--Magnesium.

And more on polyphenols can be seen in videos like How to Slow Brain Aging by Two Years and Juicing Removes More Than Just Fiber.

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: Couleur / Pixabay. This image has been modified.

Original Link

What’s the Mediterranean Diet’s Secret?

Why Was Heart Disease Rare in the Mediterranean?.jpg

The Mediterranean Diet is an "in" topic nowadays in both the medical literature and the lay media. As one researcher put it, "Uncritical laudatory coverage is common, but specifics are hard to come by: What is it? Where did it come from? Why is it good? Merits are rarely detailed; possible downsides are never mentioned." So, let's dig in....

After World War II, the government of Greece asked the Rockefeller foundation to come in and assess the situation. Impressed by the low rates of heart disease in the region, nutrition scientist Ancel Keys--after which "K" rations were named--initiated his famous seven countries study. In this study, he found the rate of fatal heart disease on the Greek isle of Crete was 20 times lower than in the United States. They also had the lowest cancer rates and fewest deaths overall. What were they eating? Their diets were more than 90% plant-based, which may explain why coronary heart disease was such a rarity. A rarity, that is, except for a small class of rich people whose diet differed from that of the general population--they ate meat every day instead of every week or two.

So, the heart of the Mediterranean diet is mainly plant-based, and low in meat and dairy, which Keys considered the "major villains in the diet" because of their saturated fat content. Unfortunately, no one is really eating the traditional Mediterranean diet anymore, even in the Mediterranean. The prevalence of coronary heart disease skyrocketed by an order of magnitude within a few decades in Crete, blamed on the increased consumption of meat and cheese at the expense of plant foods.

Everyone is talking about the Mediterranean diet, but few do it properly. People think of pizza or spaghetti with meat sauce, but while "Italian restaurants brag about the healthy measuring in diet, they serve a travesty of it." If no one's really eating this way anymore, how do you study it?

Researchers came up with a variety of Mediterranean diet adherence scoring systems to see if people who are eating more Mediterranean-ish do better. You get maximum points the more plant foods you eat, and effectively you get points deducted by eating just a single serving of meat or dairy a day. So it's no surprise those that eat relatively higher on the scale have a lower risk of heart disease, cancer, and death overall. After all, the Mediterranean diet can be considered to be a "near vegetarian" diet. "As such, it should be expected to produce the well-established health benefits of vegetarian diets." That is, less heart disease, cancer, death, and inflammation; improved arterial function; a lower risk of developing type 2 diabetes; a reduced risk for stroke, depression, and cognitive impairment.

How might it work? I've talked about the elegant studies showing that those who eat plant-based diets have more plant-based compounds, like aspirin, circulating within their systems. Polyphenol phytonutrients in plant foods are associated with a significantly lower risk of dying. Magnesium consumption is also associated with a significantly lower risk of dying, and is found in dark green leafy vegetables, as well as fruits, beans, nuts, soy, and whole grains.

Heme iron, on the other hand--the iron found in blood and muscle--acts as a pro-oxidant and appears to increase the risk of diabetes, whereas plant-based, non-heme iron appears safe. Similarly, with heart disease, animal-based iron was found to significantly increase the risk of coronary heart disease, our number one killer, but not plant-based iron. The Mediterranean diet is protective compared to the Standard American Diet--no question--but any diet rich in whole plant foods and low in animal-fat consumption could be expected to confer protection against many of our leading killers.

Here are some more videos on the Mediterranean Diet:

For more information on heme iron, see Risk Associated With Iron Supplements.

More on magnesium is found in How Do Nuts Prevent Sudden Cardiac Death? and Mineral of the Year--Magnesium.

And more on polyphenols can be seen in videos like How to Slow Brain Aging by Two Years and Juicing Removes More Than Just Fiber.

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: Couleur / Pixabay. This image has been modified.

Original Link

No More Than a Quart a Day of Hibiscus Tea

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

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

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

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

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

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

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

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

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

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

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

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

In health,
Michael Greger, M.D.

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

Image Credit: mararie / Flickr

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Where are the Lowest Rates of Alzheimer’s in the World?

NF-Nov12 Alzheimer's Disease  Grain Brain or Meathead.jpg

The rates of dementia differ greatly around the world, from the lowest rates in Africa, India, and South Asia, to the highest rates in Western Europe and especially North America. Is it all just genetics? Well, the incidence of dementia and Alzheimer's disease is significantly lower for Africans in Nigeria than for African Americans in Indianapolis, for example--up to five times lower.

Alzheimer's rates of Japanese-Americans living in the U.S. are closer to that of Americans than to Japanese. When people move from their homeland to the United States, Alzheimer's rates can increase dramatically. Therefore, when Africans or Asians live in the United States and adopt a Western diet, their increase in Alzheimer's risk suggests that it's not genetics.

Unfortunately, one doesn't have to move to the West to adopt a Western diet. The prevalence of dementia in Japan has shot up over the last few decades. Mechanisms to explain this in Japan include increases in cholesterol, saturated fat, and iron from increases in the consumption of animal products. Traditional diets are generally weighted toward vegetable products such as grains and away from animal products. But since 1960, the diet in Japan has changed from a more traditional rice-based diet to one with a preponderance of meat. From 1961 to 2008, meat and animal fat increased considerably, whereas the rice supply dropped. The dietary factor most strongly associated with the rise in Alzheimer's disease in Japan was the increased consumption of animal fat.

A similar analysis in China arrived at the same conclusion. As the authors of the Japan study (highlighted in the video, Alzheimer's Disease: Grain Brain or Meathead?) note, on the basis of these findings, the rate of Alzheimer's disease and dementia will "continue to rise unless dietary patterns change to those with less reliance on animal products." This is consistent with data showing those who eat vegetarian appear two to three times less likely to become demented, and the longer one eats meat-free, the lower the associated risk of dementia.

Globally, the lowest validated rates of Alzheimer's in the world are rural India, where they eat low meat, high grain, high bean, high carb diets. It's possible that the apparent protective association between rice and Alzheimer's is due to the fact that the drop of rice consumption was accompanied by a rise in meat consumption, but other population studies have found that dietary grains appear strongly protective in relation to Alzheimer's disease. In other words, perhaps, don't pass on the grain, but "pass the grain to spare the brain."

A few previous videos on Alzheimer's and maintaining cognitive function:

More on the consequences of carbophobia here:

-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: Bob Peters / Flickr

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Dr. Greger’s 2015 Live Year-in-Review Presentation

Food as Medicine

View my new live presentation here: Food as Medicine: Preventing and Treating the Most Dreaded Diseases with Diet

Every year I scour the world's scholarly literature on clinical nutrition, pulling together what I find to be the most interesting, practical, and groundbreaking science on how to best feed ourselves and our families. I start with the thousands of papers published annually on nutrition (27,000 this year--a new record!) and, thanks to a crack team of volunteers (and now staff!), I'm able to whittle those down (to a mere 8,000 this year). They are then downloaded, categorized, read, analyzed, and churned into the few hundred short videos. This allows me to post new videos and articles every day, year-round, to NutritionFacts.org. This certainly makes the site unique. There's no other science-based source for free daily updates on the latest discoveries in nutrition. The problem is that the amount of information can be overwhelming.

Currently I have more than a thousand videos covering 1,931 nutrition topics. Where do you even begin? Many have expressed their appreciation for the breadth of material, but asked that I try to distill it into a coherent summary of how best to use diet to prevent and treat chronic disease. I took this feedback to heart and in 2012 developed Uprooting the Leading Causes of Death, which explored the role diet may play in preventing, arresting, and even reversing our top 15 killers. Not only did it rise to become one of the Top 10 Most Popular Videos of 2012, it remains my single most viewed video to date, watched over a million times (NutritionFacts.org is now up to more than 1.5 million hits a month!).

In 2013 I developed the sequel, More Than an Apple a Day, in which I explored the role diet could play in treating some of our most common conditions. I presented it around the country and it ended up #1 on our Top 10 Most Popular Videos of 2013. Then in 2014 I premiered the sequel-sequel, From Table to Able, in which I explored the role diet could play in treating some of our most disabling diseases, landing #1 on our Top 10 Most Popular Videos of 2014.

Every year I wonder how I'm going to top the year before. Knowing how popular these live presentations can be and hearing all the stories from folks about what a powerful impact they can have on people's lives, I put my all into this new 2015 one. I spent more time putting together this presentation than any other in my life. It took me an entire month, and when you see it I think you'll appreciate why.

This year, I'm honored to bring you Food as Medicine, in which I go through our most dreaded diseases--but that's not even the best part! I'm really proud of what I put together for the ending. I spend the last 20 minutes or so (starting at 56:22) going through a thought experiment that I'm hoping everyone will find compelling. I think it may be my best presentation ever. You be the judge.

You can watch it at no cost online, but it is also available on DVD through my website or on Amazon. If you want to share copies with others, I have a five for $40 special (enter coupon code 5FOR40FAM). All proceeds from the sales of all my books, DVDs, downloads, and presentations go to the 501c3 nonprofit charity that keeps NutritionFacts.org free for all, for all time. If you want to support this initiative to educate millions about eradicating dietary diseases, please consider making a donation.

After you've watched the new presentation, make sure you're subscribed to get my video updates daily, weekly, or monthly to stay on top of all the latest.

-Michael Greger

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Pick Proper Packaging: Why the Whole is Greater than the Sum of Its Parts

You are quite literally what you eat. And there are dramatic differences between the nourishment you receive from whole plant foods and that in which you receive from animal products…   Here is an excerpt from my book, The Vegiterranean Diet: Contrary to popular belief, we don’t eat isolated nutrients. We are not filling our plates …

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Colon Cancer Prevention: Is it the Fiber or the Phytates?

NF - May21 Phytates for the Prevention of Cancer.jpg

Dietary factors are considered the most important environmental risk factors for cancer. Within recent years, a large number of naturally occurring health-enhancing substances of plant origin known as phytonutrients have been recognized to have beneficial effects on certain cancers. Beans, chickpeas, split peas and lentils are packed with all sorts of wonderful nutrients, but the reason they may protect against several degenerative diseases may be due to non-nutritive compounds, or even so-called "antinutrient" compounds like phytates.

Phytates have a somewhat negative reputation for binding to certain minerals (like iron, zinc and manganese) and slowing their absorption. But they have also been found to offer anti-inflammatory health benefits. "The reputation of phytate has had a roller coaster ride ever since its discovery; it has undergone alternate eminence and infamy." (I previously explored the surprising new science about phytates in my video Phytates for the Prevention of Osteoporosis). Could they play a potential role in preventing colon cancer?

In the U.S., colon cancer is the second leading cause of cancer death, but some parts of the world have had just a tiny fraction of our rates, with the highest rates reported in Connecticut, and the lowest in Kampala, Uganda. The famous surgeon Denis Burkitt spent 24 years in Uganda and most of the hospitals he contacted there had never seen a case of colon cancer. Noting they live off diets centered on whole plant foods, he figured that maybe it was the fiber that was so protective.

Some studies have called that interpretation into question. Danes appear to have more colon cancer than Finns, yet Danes consume almost twice the dietary fiber. What else, then, could explain the low cancer rates among plant-based populations? Well, fiber isn't the only thing found in whole plant foods, but missing from processed and animal foods. Maybe it's the phytate.

Dietary phytate, rather than fiber per se, may be the most important variable governing the frequency of colon cancer, as phytate is known to be a powerful inhibitor of the iron-mediated production of hydroxyl radicals, a particularly dangerous type of free radical. So the standard American diet may be a double whammy, the heme iron in muscle meat plus the lack of phytate in refined plant foods to extinguish the iron radicals.

This may account for what researchers found in the Adventist study, highlighted in my video, Phytates for the Prevention of Cancer. They found excess risk of cancer for higher intakes of both red meat and white meat, suggesting all meats contribute to colon cancer formation -- about twice the risk for red meat eaters, and three times the risk for those eating chicken and fish.

Those who eat meat could reduce their risk in two ways: by cutting down on meat or by eating more beans, an excellent source of phytates.

So it's not just how much meat we eat, but our meat to vegetables ratio. Between the two extremes (high-vegetable and low-meat diets versus high-meat and low-vegetable diets) a risk ratio of about eight appears to exist, sufficient to explain a substantial part of the international variation in the incidence of colorectal cancer. Those with the worst of both worlds, high meat and low vegetable, were at eight times the risk.

More on colon cancer in Stool Size Matters.

Here are a few of my latest videos on the latest wonders of the musical fruit:

What about that music, though? See my blog Beans and Gas: Clearing the air.

What about soybeans and cancer? See Breast Cancer Survival and Soy and BRCA Breast Cancer Genes and Soy.

Other ways to mediate the effects of meat intake can be found in my video Reducing Cancer Risk in Meateaters.

For more about how phytates may play a role in both cancer prevention and treatment see Phytates for Rehabilitating Cancer Cells and Phytates for the Treatment of Cancer.

-Michael Greger, M.D.

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

Image Credit: Ton Rulkens / Flickr

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Three Things to Know About Iron Absorption

Iron may be the most abundant mineral on the planet, but it is also the most common and widespread nutritional deficiency in the world. Here are Three Things To Know about iron absorption….in collaboration with Vegan Street… Although you may take in plenty of iron, absorption may be impaired by the intake of phytates, tannic …

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