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

How a Gluten-Free Diet Can Be Harmful

NF-Feb23 Gluten-Free Diets - Separating the Wheat from the Chat .jpeg

Until only a few years ago, almost the whole of the scientific world maintained that the wheat protein gluten would provoke negative effects only in people with rare conditions such as celiac disease or wheat allergies. But by the early part of 2013, it was largely becoming accepted that some non-celiac patients could suffer from gluten or wheat sensitivity. Indeed, a consensus panel of experts now officially recognizes three gluten-related conditions, wheat allergy, celiac disease and gluten sensitivity.

What percentage of the population should avoid wheat? About 1 in a 1,000 may have a wheat allergy, and nearly 1 in a 100 may have celiac disease. Celiac disease appears to be on the rise, though there's still less than about a 1 in 10,000 chance an American will be diagnosed with celiac in a given year. Our best estimate for wheat sensitivity is in the same general range as celiac, slightly higher than 1 percent. That's still potentially millions of people who may have been suffering for years who could have been cured by simple dietary means, yet who were unrecognized and unaided by the medical profession.

Although gluten sensitivity continues to gain medical credibility, we still don't know how it works. We don't know how much gluten can be tolerated, if it's reversible or not, or what the long-term complications might be of not sticking to a gluten-free diet. Considering the lack of knowledge, people with gluten sensitivity should consider reintroducing gluten back into their diet every year to see if it's still causing problems.

The reason health professionals don't want to see people on gluten-free diets unless absolutely necessary is that, for the 98 percent of people that don't have gluten issues, whole grains--including the gluten grains wheat, barley and rye--are health promoting, linked to reduced risk of coronary heart disease, cancer, diabetes, obesity and other chronic diseases.

Because some people have a peanut allergy doesn't mean everyone should avoid peanuts. There is no evidence to suggest that following a gluten-free diet has any significant benefits in the general population. Indeed, there is some evidence to suggest that a gluten-free diet may adversely affect gut health in those without celiac disease, gluten sensitivity, or wheat allergy. A study out of Spain, highlighted in my video, Gluten-Free Diets: Separating the Wheat from the Chat, found that a month on a gluten-free diet may hurt our gut flora and immune function, potentially setting those on gluten-free diets up for an overgrowth of harmful bacteria in their intestines. Why? Because the very components wheat sensitive people have problems with, like FODMAP and fructans, may act as prebiotics and feed our good bacteria.

Gluten, itself, may also boost immune function. After less than a week on added gluten protein, subjects experienced significantly increased natural killer cell activity, which could be expected to improve our body's ability to fight cancer and viral infections. Another study found that high gluten bread improved triglyceride levels better than regular gluten bread.

Ironically, one of the greatest threats gluten-free diets pose may be the gluten itself. Self-prescription of gluten withdrawal may undermine our ability to pick up celiac disease, the much more serious form of gluten intolerance. The way we diagnose celiac is by looking for the inflammation caused by gluten in celiac sufferers, but if they haven't been eating a lot of gluten, we might miss the disease. Hence, rather than being on a gluten-free diet, we want celiac suspects to be on a gluten-loaded diet. We're talking 4-6 slices of gluten packed bread every day for at least a month so we can definitively diagnose the disease.

Why does it matter to get a formal diagnosis if you're already on a gluten-free diet? Well, it's a genetic disease, so you'll know to test the family. But most importantly, many people on gluten-free diets are not actually on gluten-free diets. Even 20 parts per million can be toxic to someone with celiac. Many on "gluten-free diets" inadvertently eat gluten. Sometimes gluten-free products are contaminated, so even foods labeled "gluten-free" may still not be safe for celiac sufferers.

As editorialized in the Lancet, the irony of many celiac patients not knowing their diagnosis, while millions of non-sufferers banish gluten from their lives, can be considered a public health farce.


Though the medical profession now recognizes wheat sensitivity as a discrete entity, it's still not clear if it's actually the gluten to which people are reacting. For a review of the controversy, see Is Gluten Sensitivity Real?

In How to Diagnose Gluten Intolerance, I go step by step how someone may want to proceed who suspects they might be sensitive to gluten-containing grains.

More on the benefits of whole grains in general in Whole Grains May Work As Well As Drugs and Alzheimer's Disease: Grain Brain or Meathead?

More on keeping our gut flora happy in videos such as Prebiotics: Tending Our Inner Garden and How to Change Your Enterotype.

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: Whatsername? / Flickr

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