Donating Blood to Prevent Cancer?

Donating Blood to Prevent Cancer?
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Prioritizing plant-based sources of iron may be more effective than giving blood at reducing the risk of potentially “ferrotoxic” (iron-related) diseases such as cancer and diabetes.

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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.

If cancer is, indeed, a so-called “ferrotoxic disease,” a consequence, in part, of iron toxicity, that would explain not only the dramatic drop in cancer rates after blood donations, but also why people with higher levels of iron in their blood “had an increased risk of dying from cancer,” why women who bleed into their ovaries are at high risk for ovarian cancer, and why those suffering an iron overload disease, called hemochromatosis, have up to 200 times the risk of cancer. There’s even been a call to go back and look at some of the chemotherapy trials that kept taking blood from the chemo group to check for side effects. Maybe, just the iron removal from the blood draws accounted for some of the apparent chemo benefits.

Iron may be a double-edged sword. “Iron deficiency causes anemia, whereas excessive iron [may increase] cancer risk, presumably by” acting as a pro-oxidant, generating free radicals. Iron-deficiency anemia is a serious problem in the developing world, but “[i]n meat-eating countries,…iron excess may be more of a problem than iron deficiency.” Body iron stores accumulate insidiously with ageing, due to the fact that intake exceeds loss,” and our body has no good way of getting rid of excess iron.

Ferritin is a blood test measure of our backup iron stores. The normal range is 12 to 200, but just because it’s normal doesn’t mean it’s ideal. In the blood donor study, those who developed cancer were up to here. The average for men may be over 100.

This suggests that “normal,” “ambient levels of iron stores may be noxious and constitute a…problem that affects large segments of the population.” So, “[t]here may be a need to redefine the normal range…based on…disease risk,” rather than just following a bell curve. “Thus, iron deficiency may exist when ferritin levels decline to less than about 12 ng/mL; whereas, ferrotoxic disease may [start to] occur with levels greater than about 50 ng/mL.”

Harvard recently looked at blood donations and colorectal cancer, and found no connection. But, the range of ferritin levels they were looking at were like from here, to about here, right? And those were the ones who reported giving blood like 30 or more times.

So, maybe instead of draining our blood to reduce excess iron stores, why not just prevent the iron overload in the first place? If you measure the iron stores of men that stay away from heme iron— that get all their iron from plants—their levels come in right around where the cancer-free donor group came in, which may help explain why those eating plant-based diets tend to have less cancer, and other diseases associated with iron overload, such as pre-diabetes, as well as diabetes.

Please consider volunteering to help out on the site.

Image credit: Steel Wool via flickr. Image has been modified.

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.

If cancer is, indeed, a so-called “ferrotoxic disease,” a consequence, in part, of iron toxicity, that would explain not only the dramatic drop in cancer rates after blood donations, but also why people with higher levels of iron in their blood “had an increased risk of dying from cancer,” why women who bleed into their ovaries are at high risk for ovarian cancer, and why those suffering an iron overload disease, called hemochromatosis, have up to 200 times the risk of cancer. There’s even been a call to go back and look at some of the chemotherapy trials that kept taking blood from the chemo group to check for side effects. Maybe, just the iron removal from the blood draws accounted for some of the apparent chemo benefits.

Iron may be a double-edged sword. “Iron deficiency causes anemia, whereas excessive iron [may increase] cancer risk, presumably by” acting as a pro-oxidant, generating free radicals. Iron-deficiency anemia is a serious problem in the developing world, but “[i]n meat-eating countries,…iron excess may be more of a problem than iron deficiency.” Body iron stores accumulate insidiously with ageing, due to the fact that intake exceeds loss,” and our body has no good way of getting rid of excess iron.

Ferritin is a blood test measure of our backup iron stores. The normal range is 12 to 200, but just because it’s normal doesn’t mean it’s ideal. In the blood donor study, those who developed cancer were up to here. The average for men may be over 100.

This suggests that “normal,” “ambient levels of iron stores may be noxious and constitute a…problem that affects large segments of the population.” So, “[t]here may be a need to redefine the normal range…based on…disease risk,” rather than just following a bell curve. “Thus, iron deficiency may exist when ferritin levels decline to less than about 12 ng/mL; whereas, ferrotoxic disease may [start to] occur with levels greater than about 50 ng/mL.”

Harvard recently looked at blood donations and colorectal cancer, and found no connection. But, the range of ferritin levels they were looking at were like from here, to about here, right? And those were the ones who reported giving blood like 30 or more times.

So, maybe instead of draining our blood to reduce excess iron stores, why not just prevent the iron overload in the first place? If you measure the iron stores of men that stay away from heme iron— that get all their iron from plants—their levels come in right around where the cancer-free donor group came in, which may help explain why those eating plant-based diets tend to have less cancer, and other diseases associated with iron overload, such as pre-diabetes, as well as diabetes.

Please consider volunteering to help out on the site.

Image credit: Steel Wool via flickr. Image has been modified.

Doctor's Note

What “blood donor study”? See Donating Blood to Prevent Heart Disease?, the prequel to this video.

For more on diet and iron levels, see The Safety of Heme vs Non-Heme Iron and Risk Associated with Iron Supplements.

Interested in other examples of normal lab values not being necessarily ideal? Check out:

Even though a plant-based diet may be preferable for personal disease risk, that doesn’t mean we shouldn’t all give blood. Join me in supporting the Red Cross.

If you haven’t yet, you can subscribe to my videos for free by clicking here.

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