Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
Based on a study of nearly half a million people followed for eight years, higher consumption of unprocessed red meat and processed meat was associated with higher risks of the #1 killer of men and women, heart disease, as well as pneumonia, diverticular disease—outpouchings of the colon wall—colon polyps, and diabetes. Higher poultry intake was associated with higher risks of gastroesophageal reflux disease—acid reflux, gastritis, and duodenitis, which is inflammation of the stomach lining and intestines, as well as diverticular disease of the colon, gallbladder disease, and diabetes.
And all these were after taking into account a vast array of other factors, including age/sex/class/education/employment/smoking/exercise, even dietary factors, like total fruit and vegetable intake, and how much fiber they may be getting from whole grains, for instance, to help account for dietary quality. So, the higher rates of disease really did seem to be linked to the amount of meat they were eating, instead of other factors. The researchers even adjusted for BMI, meaning it wasn’t just because those eating meat tend to be heavier.
The bottom line is that higher consumption of meat, including chicken, is associated with higher risks of several common disease conditions. But higher meat consumption was also significantly associated with a lower risk of one condition: iron deficiency anemia. In a previous video, I talked about how vegetarians might be right in the ferritin sweet spot, with iron stores low enough to help prevent iron toxicity-related diseases like diabetes and cancer, but high enough to avoid iron deficiency anemia. So, they appear to have the best of both worlds. Low iron stores to keep free radicals down, but not enough to result in higher rates of anemia. At least, that’s what we used to think until this study of British vegetarians was published.
Based on the anemia rates of hundreds of thousands of regular red-meat eaters, those eating red meat only a few times a week, or the thousands of people who stuck to poultry, to fish, were vegetarian, versus hundreds of vegans. Among white men, only the fish eaters appeared to have significantly higher rates of anemia. Among premenopausal women, the infrequent red-meat eaters had higher rates than the regular red-meat eaters, and those who skipped red meat altogether had higher rates, except the vegans. About 9% of regular meat-eating menstruating women had anemia, compared to 10% of those who ate red meat less frequently, compared to about 13% of those who didn’t eat red meat at all. But only 8% of vegans were anemic. And postmenopausal women showed the same trend, about 3% higher anemia rates in most of those who skipped red meat. British Indian participants had higher anemia rates across the board, with significantly higher rates in vegetarian men and older women, though not necessarily among reproductive age women. But the rates were extremely high regardless. The prevalence among American women is more like 9%.
Iron deficiency anemia can have serious consequences, like this young vegan woman who temporarily lost part of her vision due to a severe case of it. She started out with low iron stores from her diet, then experienced menorrhagia, meaning excessively heavy menstrual bleeding, which is in fact the most common cause of iron deficiency anemia, regardless of diet––heavy menstrual bleeding. There are lots of hormonal and nonhormonal medical treatments to treat the cause of anemia by lightening menstrual flow. But in terms of treating anemia, oral iron supplements are considered the first line treatment, though in serious cases, rapid repletion of blood levels using IV iron can be used.
Intravenous iron may also be used in the setting of inflammatory bowel disease, since oral iron can be toxic to the lining of the intestines, potentially worsening the disease process. However, iron supplements may result in adverse gastrointestinal effects in everybody, such as abdominal pain, constipation, or nausea. Nearly 75% of patients taking iron supplements experience side effects, which ultimately result in one in four ceasing treatment, predominantly due to gastrointestinal problems. Even if you don’t experience symptoms, iron supplements may exacerbate inflammation or hurt your microbiome, reducing the abundance of beneficial microbes, while increasing the abundance of deleterious ones. And, of course, iron supplements are a short-term strategy, while dietary interventions can be considered a more long-term strategy. And indeed, you can successfully treat iron-deficiency anemia with diet alone, usually by increasing consumption of iron-rich foods like iron-fortified grains, along with vitamin C-rich foods or beverages that help with iron absorption. The healthiest iron sources are legumes (beans, split peas, chickpeas, and lentils), whole grains, dark green leafy vegetables, certain fruits, like dried apricots, and nuts and seeds. Although non-iron dietary factors, such as not drinking tea with meals or adding vitamin C-rich foods, don’t have as much effect on iron absorption as we used to think, it can’t hurt to drink tea separately, and include vitamin C-rich foods, such as citrus, tropical fruits, bell peppers, and broccoli with your meals.
If you do need iron supplements, the optimal dosing may be 60 to 120 mg of ferrous iron— so, like ferrous sulfate, or ferrous gluconate, ferrous lactate, ferrous fumarate, or ferrous succinate— though ferrous bisglycinate may have at least twice the bioavailability. So, you can take half the dose and thereby suffer fewer side effects, given with vitamin C on alternate days. So, every other day rather than taken every day. Oral iron should generally be taken on an empty stomach, at least an hour before meals.
Now, if taking it on an empty stomach causes pain and nausea, you can take it with meals, which may reduce side effects, but may also reduce absorption. Similarly, taking vitamin C with the iron increases its absorption, but at the same time increases the incidence of gastrointestinal side effects. So, only do it if you can tolerate it.
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