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

Which Works Better: Adding Beans or Portion Control?

NF-Dec24 Preventing Prediabetes By Eating More.jpg
People who eat the most legumes appear to only have a fraction of the risk for a type of prediabetes known as metabolic syndrome. Legumes are beans, split peas, chickpeas, and lentils. In one studyout of Iran, people who ate three or more servings of beans a week only had about a quarter of the odds of the disease, compared to those who ate one serving or less.

Bean consumption is associated with lower body weight, a slimmer waist, less obesity and lower blood pressure in population studies, but whether the association of bean consumption with healthier body weight and risk factors of metabolic syndrome is due to physiological effects of the beans themselves or is simply an indicator of a healthy lifestyle is uncertain. Anyone smart enough to eat beans may be smart enough to eat all sorts of other healthy foods, so maybe bean consumption is just a marker for a healthy diet.

A study out of the British Journal of Nutrition put this to the test (highlighted in my video, Preventing Prediabetes by Eating More). The researchers note that reducing belly fat may be the best way to treat metabolic syndrome and reduce the risk of prediabetes turning into full-blown diabetes. "Energy restriction has been the cornerstone of most weight-loss strategies; however, evidence suggests that the majority of individuals who lose weight [by calorie-cutting] regain it during subsequent months or years." Starving ourselves almost never works long-term. Therefore, they conclude that "it is important to identify foods that can be easily incorporated into the diet and spontaneously lead to the attainment and maintenance of a healthy body weight and improved metabolic control."

So, for the first time ever, the researchers did a head-to-head test: beans versus caloric restriction. The bean group was asked to eat five cups of lentils, chickpeas, split peas, or navy beans a week, and the caloric restriction group was asked to reduce energy intake. In other words, the bean group was asked to eat more food and the cutting calories group was asked to eat less food. Not-so-surprisingly, the more-food group won. Not only was regular bean consumption as effective as portion control in reducing prediabetes risk factors like slimming waistlines and better blood sugar control, but the bean diet led to additional benefits beyond just calorie reduction, presumably due to some functional properties of the beans and peas.

The researchers concluded that five cups a week of beans, chickpeas, split peas and lentils in an ad libitum diet (meaning subjects weren't told to change their diet in any other way), reduced risk factors of metabolic syndrome. These effects were equivalent, and in some instances stronger, than telling people to cut 500 calories from their daily diet. These results are encouraging news for individuals with or at risk for type 2 diabetes since they indicate that simple diet changes, such as the inclusion of beans, can have a positive impact on blood sugar control.

What is metabolic syndrome? See: Metabolic Syndrome and Plant-Based Diets.

More on plants versus calorie restriction in:

More on magic beans:

What about treating full-blown diabetes with beans? All in my video: Diabetics Should Take Their Pulses.

-Michael Greger, M.D.

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

Image Credit: homami / Flickr

Original Link

Where Do You Get Your Fiber?

NF-Sep29 Do Vegetarians get enough Protein?.jpg

Vegetarians and vegans are all too familiar with the question: Where do you get your protein?

Well, we can finally put to rest the question of whether vegetarians get enough protein thanks to a large study that compared the nutrient profiles of about 30,000 non-vegetarians to 20,000 vegetarians and about 5,000 vegans, 5,000 flexitarians (vegetarian most of the time), and 5,000 pescetarians (no meat except fish). The average requirement is 42 grams of protein a day. As you can see in the graph in the video, Do Vegetarians Get Enough Protein, meat eaters get way more than they need, and so does everyone else. Vegetarians and vegans average 70% more protein than the recommendation every day.

It's surprising that there's so much fuss about protein in this country when less than 3% of adults don't make the cut, presumably because they're on extreme calorie-restricted diets and aren't eating enough food period. But 97% of Americans get enough protein.

There is a nutrient, though, for which 97% of Americans are deficient. That nutrient is fiber.

Less than 3% of Americans get even the recommended minimum adequate intake of fiber. That's something we really have to work on.

On average, we get only about 15 grams a day. The minimum daily requirement is 31.5, so we get less than half the minimum. Men are particularly deficient. If we break down intake by age and gender, after studying the diets of 12,761 Americans, the percent of men between ages 14 and 50 getting the minimum adequate intake is zero. (The only nutrient Americans may be more deficient in than fiber is potassium. See 98% of American Diets Potassium Deficient.)

This deficit is stunning in that dietary fiber has been protectively associated in population studies with the risk of diabetes, metabolic syndrome, cardiovascular disease, obesity, and various cancers as well high cholesterol, blood pressure, and blood sugars. Therefore, it is not surprising that fiber is listed as a nutrient of concern reported by the Dietary Guidelines Advisory Committee. Protein is not.

One problem is that most people have no idea what's in their food; more than half of Americans think steak is a significant fiber source. By definition, fiber is only found in plants. There is no fiber in meat, dairy or eggs, and little or no fiber in junk food. Therein lies the problem. Americans should be eating more beans, vegetables, fruits, and whole grains--but how are they doing?

96% of Americans don't eat the minimum recommended daily amount of beans, 96% don't eat the measly minimum for greens, and 99% don't get enough whole grains. Nearly the entire U.S. population fails to eat enough whole plant foods.

Even semi-vegetarians make the fiber minimum, though. Those eating completely plant-based diets triple the average American intake. When closing the fiber gap, you'll want to do it gradually though, no more than about five extra grams a day each week until you can work your way up. But it's worth it. "Plant-derived diets tend to contribute significantly less fat, saturated fat, cholesterol, and food-borne pathogens, while at the same time offering more fiber, folate, vitamin C, and phytochemicals, all essential factors for disease prevention, optimal health, and well being." And the more whole plant foods the better. If we compare the nutritional quality of vegan versus vegetarian, semi-vegetarian, pesco-vegetarian and omnivorous diets, traditional healthy diet indexing systems consistently indicate that the most plant-based diet is the healthiest one.

For more on how S.A.D. the Standard American Diet is, see Nation's Diet in Crisis.

Americans eating meat-free diets average higher intakes of nearly every nutrient. See my video Nutrient-Dense Approach to Weight Management.

Isn't animal protein higher quality protein though? See my videos:

For more on protein, see: Plant Protein Preferable and Prostate Cancer Survival: The A/V Ratio.

And for a few on 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 Uprooting the Leading Causes of Death, More Than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: Nathan Rupert / Flickr

Original Link

Dietary Cholesterol Affects Blood Cholesterol Levels

NF-Aug18 Debunking Egg Industry Myths.jpg

In my video, Eggs vs. Cigarettes in Atherosclerosis, I profiled a study showing that both smoking and eating eggs can harm our arteries. But even egg yolks alone were associated with artery-clogging plaque buildup nearly two thirds as bad as smoking.

This certainly ruffled some feathers.

Yes, eggs are by far the number one source of cholesterol in the American diet, but some letters to the editor protested that dietary cholesterol may have very little impact on blood cholesterol levels, citing a study published in 1971 performed on eight people. But if one looks at dozens of studies together, covering hundreds of study subjects, we find that blood cholesterol concentration is "clearly increased by added dietary cholesterol." In my video, Debunking Egg Industry Myths, there is an extreme example just to illustrate: a year in the life of a study subject taken on and off eggs. First, the researchers take him off eggs, putting him on a cholesterol-free diet, and his blood cholesterol plummets within just three weeks. Then they give him lots of eggs, and his cholesterol shoots back up, stays high until they take the eggs away and put him back on the cholesterol free diet, and so on and so forth. The researchers were essentially turning his high blood cholesterol on and off like a light switch (made out of eggs).

Of course the only reason we care our about our cholesterol levels or how much plaque is building up inside our arteries is because we want to avoid the consequences, like a heart attack. So do eggs increase our risk of cardiovascular disease? The latest meta-analysis, the latest compilation of all the best studies on egg consumption and risk of heart disease going back to 1930, found that, overall, those who ate the most eggs had a 19% increased risk of cardiovascular disease, a 68% increased risk of diabetes, and, once you have diabetes, an even greater 85% increased risk of heart disease. It didn't take much; less than a single egg a day was associated with a significantly increased risk of heart disease. Just over half an egg a day may increase heart disease risk 6% (40% in separated diabetes patients), and the risk of diabetes by 29%. The researchers conclude that their findings support the American Heart Association dietary guidelines, which advise restricted egg consumption in adults for preventing cardiometabolic disease, like diabetes, our seventh leading cause of death, and heart disease, our number one killer.

More on the diabetes connection in Eggs and Diabetes and Bacon, Eggs, and Gestational Diabetes During Pregnancy.

More on eggs and the egg industry in general:

There's more to heart disease than just cholesterol buildup. In my video, Eggs and Arterial Function, I explore what effect egg consumption has on endothelial function, the ability of our arteries to relax normally.

In health,
Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my videos for free by clicking here and watch my full 2012 - 2015 presentations Uprooting the Leading Causes of Death, More than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: Rebecca Siegel / Flickr

Original Link

Why Would Eating Fish Increase Diabetes Risk?

NF-Jul23 Fish and Diabetes.jpg

In the past two years, six separate meta-analyses have been published on the relationship between fish consumption and type 2 diabetes. The whole point of a meta-analysis is to compile the best studies done to date and see what the overall balance of evidence shows. The fact that there are six different ones published recently highlights how open the question remains. One thread of consistency, though, was that fish consumers in the United States tended to be at greater risk for diabetes.

If we include Europe, then fish eaters appeared to have a 38% increased risk of diabetes. On a per serving basis, that comes out to be about a 5% increase in risk for every serving of fish one has per week. To put that into perspective, a serving of red meat per day is associated with 19% increase in risk. Just one serving per day of fish would be equivalent to a 35% increase in risk. But why might fish be worse than red meat?

Fish intake may increase type 2 diabetes risk by increasing blood sugar levels, as a review of the evidence commissioned by the U.S. government found. The review found that blood sugars increase in diabetics given fish oil. Another possible cause is that omega 3's appear to cause oxidative stress. A recent study, highlighted in my video, Fish and Diabetes, found that the insulin producing cells in the pancreas don't appear to work as well in people who eat two or more servings of fish a week. Or it may not be related to omega 3's at all but rather the environmental contaminants that build up in fish.

It all started with Agent Orange. We sprayed 20 million gallons of the stuff on Vietnam, and some of it was contaminated with trace amounts of dioxins. Though the Red Cross estimates that a million Vietnamese were adversely affected, what about all the servicemen who were exposed spraying it across the countryside? Reports started showing up that veterans exposed to Agent Orange appeared to have higher diabetes rates than unexposed veterans, a link that's now officially recognized.

These so-called "persistent organic pollutants" are mainly man-made industrial chemicals and are among the most hazardous compounds ever synthesized. They include dioxins, PCBs, and certain chlorine-containing pesticides, all of which are highly resistant to breakdown in the environment.

Initially condemned for their deleterious effect on reproductive function and their ability to cause cancer, there is now a growing body of evidence showing that exposure to these pollutants leads to metabolic diseases such as diabetes. This is a breakthrough that "should require our greatest attention."

For more on the role industrial pollutants may play in our diabetes epidemic, see Diabetes and Dioxins and Pollutants in Salmon and Our Own Fat.

More on the changing views surrounding fish oil supplements in Is Fish Oil Just Snake Oil?

Other foods associated with diabetes risk include processed meat and eggs. See Bacon, Eggs, and Gestational Diabetes During Pregnancy and Eggs and Diabetes, while Indian gooseberries and flaxseeds may help (Amla Versus Diabetes and Flaxseed vs. Diabetes).

Other videos on how polluted our oceans now are include:

-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: Gideon / Flickr

Original Link

Why We Should Eat More Beans

NF-Mar11 Why You Should Eat More Beans.jpg

We’ve known for decades that beans have an exceptionally low glycemic index. You give someone cooked beans, peas, or lentils and they don’t even get half the blood sugar spike that they would get with the same amount of carbs in the form of bread, pasta, or potatoes. So if you’re going to eat some high glycemic food like white rice, consider having some beans with it, and the more beans the better. If you check out my 3-min video Beans and the Second Meal Effect, you can see that as the subjects’ bean to rice ratio increases, cardiometabolic risk factors continually improve. Substituting one serving of beans for one serving of white rice was associated with a 35 percent lower risk of metabolic syndrome (pre-diabetes).

Why do beans have such a low glycemic index? Maybe it’s because they’ve got so much fiber that absorption is just slower or something? It was this study that blew everyone’s minds.

It started about as expected. Give people bread for breakfast, and they get big spikes in blood sugar and insulin levels, but give the same amount of carbs in lentil form and you blunt the effect. (Lentils for breakfast? Well, the Brits like baked beans on their toast, but I’ve started using a handful of sprouted lentils in my breakfast smoothie. See A Better Breakfast and Antioxidants Sprouting Up). What they did different, though, was follow through to lunch.

For lunch both groups got the same meal; they both got bread. Those that had lentils for breakfast, though, had less of a glycemic reaction to the bread. At the time they called it the “lentil effect,” but subsequent studies found chickpeas appear to work just as well. It has since been dubbed the “second meal effect.” Eat lentils for dinner, and then for breakfast, even if forced to drink sugar water, we have better glycemic control. Beans moderate your blood sugar not just at the meal we eat them, but even hours later or the next day.

How is that even possible? The mystery has since been solved. Remember what our gazillions of gut bacteria do with fiber? They produce compounds like propionate with it (see Fawning Over Flora and Boosting Good Bacteria in the Colon Without Probiotics) that get absorbed into our system and slow down gastric emptying—the rate at which food leaves our stomach—so we don’t get as much of a sugar rush. It’s like symbiosis. We feed our good bacteria and they feed us back. So, we have a bean burrito for supper and by the next morning it’s time for our gut bacteria to eat that same burrito and the by-products they create may affect how our breakfast is digested.

Researchers figured this out by giving people rectal infusions of the amount of propionate your good bacteria might make from a good burrito, and the stomach relaxes within minutes. I guess if you forgot to eat any kind of beans for supper and need to blunt the effect of your breakfast doughnut, it’s theoretically not too late—but in general I encourage people to administer their food orally.

What about the gas? Check out my blog post Beans and Gas: Clearing the Air.

Which beans are most antioxidant packed? See The Best Bean and The Healthiest Lentil (hint: skip the jelly variety). Which lower cholesterol the most? See Soy Worth a Hill of Beans?

What other superpowers do beans posses? They are packed with potassium (Preventing Strokes with Diet), mad with magnesium (Mineral of the Year—Magnesium), and a preferred source of protein (Plant Protein Preferable). They improve breast cancer survival (Breast Cancer Survival and Soy), reduce hot flashes (Soy Foods & Menopause), delay premature puberty (The Effect of Soy on Precocious Puberty), and they’re a great bargain to boot (Eating Healthy on a Budget).

-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: Renee Suen 孫詩敏 / Flickr

Original Link