April 11, 2012

Is Red Meat Dangerous?

An epidemiological study published a few weeks ago linked the consumption of red meat to a higher risk of death from all causes, cancer, and heart disease. You can read a good summary of it (with a link to the article at the bottom) here:

Science Daily: Red Meat Consumption Linked to Increased Risk of Total, Cardiovascular, and Cancer Mortality.

The study used data from "37,698 men from the Health Professionals Follow-up Study for up to 22 years and 83,644 women in the Nurses' Health Study for up to 28 years who were free of cardiovascular disease (CVD) and cancer at baseline. Diets were assessed through questionnaires every four years."

The study found that "One daily serving of unprocessed red meat (about the size of a deck of cards) was associated with a 13% increased risk of mortality, and one daily serving of processed red meat (one hot dog or two slices of bacon) was associated with a 20% increased risk."

This isn't the first study to link health problems with red meat so we shouldn't be too quick to dismiss its findings. However, given the methodology it used, we also shouldn't be too quick to blame the red meat for the problems it reveals.

Was it the Meat or What's IN the Meat?

The first problem is with the way the nutritional questionnaires are designed that were used in these studies. They ask questions about people's food habits, along the lines of "How many times in the past month did you eat red meat?" and then give multiple choice options for answers like "Less than 5 times" or "6 to 10 times."

What they don't ask is "Where did you eat your red meat?" "Was your Red Meat filled with MSG?" "Was your red meat fried on a grill covered with damaged oils?" "Was Your Red Meat full of pink slime?"

This is important, because you'd have to be delusional to argue that the red meat sold in most chain restaurants is anything but toxic. People who get a daily serving of red meat from a fast food hamburger probably are shortening their lives. Not because of the meat, but because of what else is in the substance they've been sold as "meat."

Did You Get Fries with That?

The second problem with the questionnaires is that they don't ask "what did you eat WITH your red meat? None of us would question that a "red meat" meal that is made up of 3 ounces (cooked) of pink slime on a bun covered with ketchup, sugary pickles, mayo made out of the cheapest oils, and served with a big side of fries cooked in damaged fat, washed down with a 32 oz sugary soda is likely to have severe health consequences, too. But that's how most people at their meat. And if that is the case, the combination of damaged oils and lots of carbs can explain the negative health consequences without any need to demonize red meat.

The Ambivalent Role of Iron

But even so, other research has turned up some significant problems with iron which may also play a part, though as we'll see, we may not be getting the damaging iron from meat since there are other sources of dietary iron to consider.

Iron is essential to life. Without it our blood couldn't transport oxygen to our cells. But too much iron seems to gum up the works. For more than a decade numerous studies have linked higher than normal levels of iron in the brain to the development of Alzheimer's. Too much iron also damages the beta cell, which is why people who have a genetic condition called hemochromatosis where their iron stores grow abnormally large develop diabetes. But high levels of iron also damage the beta cells in people who don't have this gene.

You can read a good review of how iron can cause or worsen diabetes in this article, which also points out that high iron levels contribute to some complications:

The Role of Iron in Diabetes and Its Complications. Sundararaman Swaminathan. Diabetes Care July 2007 vol. 30 no. 7 1926-1933

What Raises our Iron Stores?

So what raises our blood iron stores? Three ounces (cooked) of hamburger are listed as containing 15% of a typical person's daily need for iron. So you'd have to eat a lot of burgers each day to exceed the iron RDA.

Four ounces of rare roast beef contain 43% of your daily need, so if you are eating 12 ounces of roast beef a day, yes, you are eating what could be dangerous amounts of iron if you were doing this day after day.

But it turns out there is almost twice as much iron in a serving of kidney beans as there is in roast beef. (You can find a good listing of the iron content of various foods HERE) And to keep vegetarians from feeling smug, 3 oz of Tofu contains more iron than three ounces of roast beef.

But that's not where the dangerous amounts of iron are coming from, as the link just cited makes plain. Because it also tells us that a cup of "Oatmeal, fortified instant, prepared" contains two and a half times as much iron as a hefty serving of roast beef, clocking in at 10 mg per serving where the 4 oz of roast contains only 4.2 mg.

The key word to note here is "fortified." Because it isn't just your packaged oatmeal that has extra iron in it. Breakfast cereals do. Cheap breads do, too. And of course, you get 100% of your daily iron RDA in any multivitamin not markets as being for "seniors." More iron is absorbed from your food if you consume a lot of vitamin C either from fruits or vitamin pills. The latter fact may have something to do with why large studies have shown that supplementing with vitamin C for a long time raises the risk of death.

But not all the iron in your body comes from your food. You will also get more iron in your food if you cook it in cast iron pans. And cans made out of steel may also contribute iron to your diet, especially if they contain acidic foods. (Details HERE.)

In short, it's very likely that high iron consumption is dangerous. But most of the iron you consume is not coming from the red meat you eat. It might be informative to run a few day's worth of food consumption through some nutritional software to see exactly how much iron you are taking in each day. (This won't, of course account for iron coming in from pans or cans.) If you are consuming a lot of iron, cut back. It might help lower your blood sugar over time.

If your iron intake is high, you might also ask your doctor to measure your ferritin level at your next physical. The hemochromatosis gene is fairly widespread in European populations with 1 in 8 to 12 carrying it and 5 in 1,000 having the two copies that cause damagingly high levels of iron in the blood

it would also be a very good idea for all of us to limit our consumption of red meat to quality meats, avoiding the chemical-laden patties sold in restaurants.

11 comments:

dallyup52 said...

I stopped eating red meat for several years believing blindly what some news reports said about it without thinking. I now believe that if I eat, in moderation, the free range, hormone free, grass feed beef that my sister-in-law raises on her ranch out here in Montana I am going to be just fine. It tastes so much better that any purchased in a retail store.

RLL said...

LOL - that is what blood banks are for. Eat meat, Give Blood!

Gretchen said...

Another viewpoint:

http://healthcorrelator.blogspot.com/2012/04/2012-arch-intern-med-red-meat-mortality.html

Also, heme iron, the iron you get from hemoglobin (red meat), is supposed to be absorbed more easily than the iron you'd get in vitamin pills and beans.

I still eat red meat, however.

Darbro said...

The arguments countering the conclusions of the study are valid. However, at least where cancer risk is concerned, it is fairly well established that cooked (particularly grilled/bbq) red meat contains carcinogens including heterocyclic aromatic amines (e.g. PhIP), nitrosamines, and polycyclic aromatic hydrocarbons. This is even more of a concern for processed meats. However, full blame to red meat isn't valid either, because PhIP is also produced in grilled fish.

Geoffrey Levens said...

What about the effect of "high quality" protein (animal source and soy concentrates and isolates) in raising IGF-1 levels? I know growth hormone increased that way makes muscles grow and speeds recovery from intense exercise. That is why strength athletes want it. But aren't the effects of IGF-1 non-specific, meaning they help all tissues grow faster and recover from stress faster? If that is true, that would mean cancerous cells as well as normal cells. And of course we all have cancer all the time, just that by the time it gets to be more than a few cells, our immune system tags, attacks, and kills it. But if we are increasing IGF-1, isn't that a bit like an arsonist running around the countryside tossing cans of gasoline on all the little brush fires that break out in summer, increasing the risk that one of those fires will grow to be out of control before the fire department can do its job? From what I have read, it does not seem that plant proteins (less "balanced" in amino content), esp in the context of the food they come in, do have this effect?

Geoffrey Levens said...

Oops, no edit button... Meant to say plant proteins do NOT have the IGF-1 raising effect.

Jenny said...

Many of the people in my social circuls who have died of cancer were eating vegetarian "health food" diets. There's so much misinformation put out by the PETA-associated Physicians for Responsible Medicine (PCRM) which spreads lies throughout the media in pursuit of its agenda.

The link between IGF-1 and cancer is far from proven and the link between eating meat and high IGF-1 also varies. One careful study found the skim milk, but not meat intake seemed to raise IGF-1.

Again, the meat-cancer association in most studies comes from questionnaires and don't identify what meats eaten with what else.

Geoffrey Levens said...

Thank you Jenny. It is true that pretty much all of what is labeled "health food" in the stores is crap! Health food to me means mostly the produce and bulk bins and maybe a little grass fed/pasture raised etc.

Unknown said...

On the iron issue: if one is anemic, that is by definition low in iron, or is it? is it how the iron is used? when I take iron for anemia, is it hanging there being dangerous for the other reasons iron is problematic?

Jenny said...

If you are anemic then taking iron could be helpful. The problems come with iron overload.

Sometimes,however, people become anemic because of other factors and eating iron in the form of food or pills doesn't raise the iron level.

Rachel Page said...

The bottom line is, meat is healthy in moderation but people eat too much of it.