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

The Best Diet to Prevent Kidney Stones

The Best Diet to Prevent Kidney Stones.jpeg

In my video How to Prevent Kidney Stones With Diet you can see what the jagged surface of a kidney stone looks like under a microscope. Imagine one of those scraping down your urinary canal! Kidney stones affect approximately 1 in 11 people in the United States. Twenty years ago it was only 1 in 20, representing a dramatic increase in the prevalence of the disease that started rising after World War II. Our first clue as to why was a study published in the 70's, which found a striking relationship between stone incidence and the consumption of animal protein. This was a population study, though, so it couldn't prove cause and effect.

That study inspired researchers in Britain to do an interventional study, adding animal protein to subjects' diets, such as an extra can of tuna fish a day, and measuring stone-forming risk factors in their urine. Participants' overall probability of forming stones increased 250% during those days they were eating that extra fish. And the so-called "high animal protein diet" was just enough to bring intake up to that of the average American. So Americans' intake of meat appears to markedly increase the risk of kidney stones.

What about consuming no meat at all? By the late 70's we knew that the only dietary factor consistently associated with kidney stones was animal protein. The higher the intake of animal protein, the more likely the individual was to not only get their first kidney stone, but to then suffer from subsequent multiple stones. This effect was not found for high protein intake in general, but specifically high animal protein intake. Conversely, a diet low in animal protein may dramatically reduce the overall probability of forming stones. This may explain the apparently low incidence of stones in vegetarian societies, so researchers advocated "a more vegetarian form of diet" as a means of reducing the risk.

It wasn't until 2014 that vegetarian kidney stone risk was studied in detail, though. Using hospital admissions data, researchers found that vegetarians were indeed at a lower risk of being hospitalized for kidney stones. It's not all or nothing, though. Among meat-eaters, increasing meat intake is associated with a higher risk of developing kidney stones, whereas a high intake of fresh fruit, fiber, and magnesium may reduce the risk.

Which animal protein is the worst? People who form kidney stones are commonly advised to restrict the intake of red meat to decrease stone risk, but what about chicken and fish? Despite compelling evidence that excessive animal protein consumption enhances the risk of stone formation, the effect of different sources of animal protein had not been explored until another study in 2014. Researchers compared the effects of salmon and cod, chicken breast meat, and burger and steak. In terms of uric acid production, they found that gram for gram fish may actually be worse. However, the overall effects were complex. Basically, stone formers should be counseled to limit the intake of all animal proteins, and not by just a little bit. Only those who markedly decrease their animal protein intake may expect to benefit.

Making our urine more alkaline can also help prevent the formation of kidney stones (and even dissolve and cure uric acid stones). How can you tell the pH of your urine? See my video Testing Your Diet with Pee & Purple Cabbage.

For more on kidney stones, see How to Treat Kidney Stones with Diet and Do Vitamin C Supplements Prevent Colds but Cause Kidney Stones?. And check out my overview of kidney health in How Not to Die from Kidney Disease.

Uric acid can also crystallize in our joints, but the good news is that there are natural treatments. See Gout Treatment with a Cherry on Top and Treating Gout with Cherry Juice.

Kidney stones are just one more reason that Plant Protein is Preferable.

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

The Best Diet to Prevent Kidney Stones

The Best Diet to Prevent Kidney Stones.jpeg

In my video How to Prevent Kidney Stones With Diet you can see what the jagged surface of a kidney stone looks like under a microscope. Imagine one of those scraping down your urinary canal! Kidney stones affect approximately 1 in 11 people in the United States. Twenty years ago it was only 1 in 20, representing a dramatic increase in the prevalence of the disease that started rising after World War II. Our first clue as to why was a study published in the 70's, which found a striking relationship between stone incidence and the consumption of animal protein. This was a population study, though, so it couldn't prove cause and effect.

That study inspired researchers in Britain to do an interventional study, adding animal protein to subjects' diets, such as an extra can of tuna fish a day, and measuring stone-forming risk factors in their urine. Participants' overall probability of forming stones increased 250% during those days they were eating that extra fish. And the so-called "high animal protein diet" was just enough to bring intake up to that of the average American. So Americans' intake of meat appears to markedly increase the risk of kidney stones.

What about consuming no meat at all? By the late 70's we knew that the only dietary factor consistently associated with kidney stones was animal protein. The higher the intake of animal protein, the more likely the individual was to not only get their first kidney stone, but to then suffer from subsequent multiple stones. This effect was not found for high protein intake in general, but specifically high animal protein intake. Conversely, a diet low in animal protein may dramatically reduce the overall probability of forming stones. This may explain the apparently low incidence of stones in vegetarian societies, so researchers advocated "a more vegetarian form of diet" as a means of reducing the risk.

It wasn't until 2014 that vegetarian kidney stone risk was studied in detail, though. Using hospital admissions data, researchers found that vegetarians were indeed at a lower risk of being hospitalized for kidney stones. It's not all or nothing, though. Among meat-eaters, increasing meat intake is associated with a higher risk of developing kidney stones, whereas a high intake of fresh fruit, fiber, and magnesium may reduce the risk.

Which animal protein is the worst? People who form kidney stones are commonly advised to restrict the intake of red meat to decrease stone risk, but what about chicken and fish? Despite compelling evidence that excessive animal protein consumption enhances the risk of stone formation, the effect of different sources of animal protein had not been explored until another study in 2014. Researchers compared the effects of salmon and cod, chicken breast meat, and burger and steak. In terms of uric acid production, they found that gram for gram fish may actually be worse. However, the overall effects were complex. Basically, stone formers should be counseled to limit the intake of all animal proteins, and not by just a little bit. Only those who markedly decrease their animal protein intake may expect to benefit.

Making our urine more alkaline can also help prevent the formation of kidney stones (and even dissolve and cure uric acid stones). How can you tell the pH of your urine? See my video Testing Your Diet with Pee & Purple Cabbage.

For more on kidney stones, see How to Treat Kidney Stones with Diet and Do Vitamin C Supplements Prevent Colds but Cause Kidney Stones?. And check out my overview of kidney health in How Not to Die from Kidney Disease.

Uric acid can also crystallize in our joints, but the good news is that there are natural treatments. See Gout Treatment with a Cherry on Top and Treating Gout with Cherry Juice.

Kidney stones are just one more reason that Plant Protein is Preferable.

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 Canned Beans as Healthy as Home Cooked?

NF-Sep18 Are Canned Beans as Healthy as Cooked Beans?.jpg

Beans are an essential part of any healthful diet. The federal government recommends about half a cup a day of beans, counting them as both a protein and a vegetable since they have the best of both worlds. Beans are excellent sources of fiber, folate, plant protein, plant iron, vitamin B1, and minerals such as magnesium, phosphorus, potassium, and copper, all while being naturally low in sodium.

Yet Americans don't know beans! 96% of Americans don't even meet the measly minimum recommended intake of beans, chickpeas, split peas or lentils. The same percentage of Americans don't eat their greens every day. Two of the healthiest foods on the planet are greens and beans, but hardly anyone even consumes the minimum recommended amount. As a team of researchers from the National Cancer Institute noted, this is just another "piece added to the rather disturbing picture that is emerging of a nation's diet in crisis."

But how should we get our beans? Canned beans are convenient, but are they as nutritious as home-cooked? And if we do used canned, should we drain them or not? A recent study published in Food and Nutrition Sciences spilled the beans.

In addition to their health benefits, beans are cheap. The researchers did a little bean counting, and a serving of beans costs between ten cents and, if we want to go crazy, 40 cents.

The researchers compiled a table, which you can see in my video, Canned Beans or Cooked Beans?, of the cost per serving of beans, both canned and cooked. Canned beans cost about three times more than dried beans, but dried beans can take hours to cook, so my family splurges on canned beans, paying the extra 20 cents a serving. Nutrition-wise, cooked and canned are about the same, but the sodium content of canned beans can be 100 times that of cooked. Draining and rinsing the canned beans can get rid of about half the sodium, but you're also draining and rinsing away some of the nutrition. I recommend, when buying canned beans, to instead get the no-salt added varieties, and to keep and use the bean juice.

The bottom line is that beans, regardless of type or form, are a nutrient rich food and should be encouraged as part of an overall healthy diet.

Concerned about gas? See my blog post Beans and Gas: Clearing the air.

-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: Caro Wallis / Flickr

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The Healthiest Diet for Weight Control

NF-Sep4 Why Plant-Based Might be the Healthiest Diet for Weight Control.jpg

We know that vegetarians tend to be slimmer, but there's a perception that veg diets may somehow be deficient in nutrients. So how's this for a simple study, profiled in my video Nutrient-Dense Approach to Weight Management: an analysis of the diets of 13,000 people, comparing the nutrient intake of those eating meat to those eating meat-free.

They found that those eating vegetarian were getting higher intakes of nearly every nutrient: more fiber, more vitamin A, more vitamin C, more vitamin E, more of the B vitamins (thiamin, riboflavin, & folate), more calcium, more magnesium, more iron, and more potassium. At the same time, they were also eating less of the harmful stuff like saturated fat and cholesterol. And yes, they got enough protein.

And some of those nutrients are the ones Americans really struggle to get enough of--like fiber, vitamins A, C, and E, calcium, magnesium, potassium--and those eating vegetarian got more of all of them. Even so, just because they did better than the standard American diet isn't saying much--they still didn't get as much as they should have. Those eating vegetarian ate significantly more dark green leafy vegetables, but that comes out to just two more teaspoons of greens than meat eaters on average every day.

In terms of weight management, the vegetarians were consuming, on average, 363 fewer calories every day. That's what people do when they go on a diet and restrict their food intake--but it seemed like that is how vegetarians just ate normally.

How sustainable are more plant-based diets long term? They are among the only type of diet that has been shown to be sustainable long-term, perhaps because not only do people lose weight but they often feel so much better.

And there's no calorie counting or portion control. In fact, vegetarians may burn more calories in their sleep. Those eating more plant-based diets appear to have an 11% higher resting metabolic rate. Both vegetarians and vegans seem to have a naturally revved up metabolism compared to those eating meat.

Having said that, the vegetarians in the first study mentioned were also eating eggs and dairy, so while they were significantly slimmer than those eating meat, they were still, on average, overweight. As profiled in my video, Thousands of Vegans Studied, the only dietary pattern associated on average with an ideal body weight was a strictly plant-based one. But at least the study helps to dispel the myth that meat-free diets are somehow nutrient-deficient. In fact, the editor-in-chief of the Journal of the American Dietetic Association asked, "What could be more nutrient dense than a vegetarian diet?"

Anyone can lose weight in the short term on nearly any diet, but diets don't seem to work in the long-term. That's because we don't need a "diet"; we need a new way of eating that we can comfortably stick with throughout our lives. If that's the case, then we better choose to eat in a way that will most healthfully sustain us. That's why a plant-based diet may offer the best of both worlds. It's the only diet, for example, shown to reverse heart disease-our number one killer-in the majority of patients, as described in my video: One in a Thousand: Ending the Heart Disease Epidemic.

There are a number of theories offered as to why those eating plant-based are, on average, so much slimmer. Check out these videos for more information:

-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.

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Latest Science on Rooibos & Nettle Tea

 

 

 

 

 

 

 

 

 

Rooibos, or red tea, is anecdotally reported to aid stress-related symptoms, but it has none of the mood-altering phytonutrients thought responsible for the increased calm and decreased stress after drinking green tea (see Dietary Brain Wave Alteration). So why do some people feel less stressed drinking red tea?

Researchers recently found that human adrenal gland cells in a petri dish produce about 4 times fewer steroid hormones in the presence of red tea. This could certainly result in lower stress hormone levels if it happened within the body, but the effect was so dramatic the researchers were concerned it might adversely effect the production of sex steroid hormones as well. Thankfully, that’s not what they found when they tested it in human subjects. The same, however, may not be true of nettle tea.

Nettle is used to relieve the symptoms of prostate enlargement by boosting estrogen levels, but case reports show men drinking too much may grow breasts and women may actually start lactating. Nettle tea is safe as long as you 1) don’t drink too much, 2) don’t mistake it for deadly nightshade if you forage it, and 3) don’t put the leaves in your mouth fresh. They don’t call them stinging nettles for nothing! In my 3-min video Herbal Tea Update: Rooibos & Nettle I show a close-up of the impalement of a nettle spicule in the skin.

My go-to herbal tea is hibiscus (see my last post Hibiscus Tea: The Best Beverage?). But nettle tea is touted for being packed with minerals. This always seemed a bit strange to me. Yes, if you boil dark green leafy vegetables long enough, you do lose minerals into the cooking water, but how many minerals could we be getting if you just steep some tea? We never knew because it hadn’t been tested, until now.

Researchers compared the mineral content of nettle tea to chamomile tea, mint tea, St. John’s Wort, and sage. Nettle tea didn’t seem to have much more than any of the others, but maybe they’re all really high?

One cup of nettle tea has the same amount of iron in a dried apricot, the zinc found in a single pumpkin seed, one-twentieth of a mushroom’s worth of copper, and 4 peanuts’ worth of magnesium and a fig’s worth of calcium. I agree with the researchers that a cup of herbal tea may not be an important source of minerals, but it’s not negligible. Greens are so packed with nutrition that we can benefit by just drinking some hot water they’ve been soaking in for a few minutes.

The fact that so much nutrition leaches into the water in nettle tea is a reason we don’t want to boil greens unless we’re making soup or otherwise consuming the cooking water. See Best Cooking Method for more tips on preserving nutrients.

-Michael Greger, M.D.

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

Image credit: chumsdock / Flickr

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