Heme iron and cardiovascular disease

[nomadreid]

TL;DR Summary

Heme iron is claimed in a research study (cited in text) to be associated with a 27% increased risk of cardiovascular disease; is this credible?

In the "Results" section of the Abstract of https://pubmed.ncbi.nlm.nih.gov/23708150/, (due to a paywall, I get no further) there is the following "The dose-response RR of CHD for an increase in heme iron intake of 1 mg/day was 1.27" (CHD being coronary heart disease).
Is the paraphrasing in https://gamechangersmovie.com/dr-loomis-beef-with-mens-health-review-of-the-film/ of this result: "one additional milligram per day of heme iron — found exclusively in animal foods — is associated with a 27% increased risk of cardiovascular disease"? If so,
is such a percentage credible?

 

[Ygggdrasil]

Summary:: Heme iron is claimed in a research study (cited in text) to be associated with a 27% increased risk of cardiovascular disease; is this credible?

In the "Results" section of the Abstract of https://pubmed.ncbi.nlm.nih.gov/23708150/, (due to a paywall, I get no further) there is the following "The dose-response RR of CHD for an increase in heme iron intake of 1 mg/day was 1.27" (CHD being coronary heart disease).
Is the paraphrasing in https://gamechangersmovie.com/dr-loomis-beef-with-mens-health-review-of-the-film/ of this result: "one additional milligram per day of heme iron — found exclusively in animal foods — is associated with a 27% increased risk of cardiovascular disease"? If so,
is such a percentage credible?

I think the paraphrasing you quote does accurately portray the findings from the article cited. However, it is important to note that the finding is an association and that correlation does not necessarily imply causation. The data analyzed in the paper all comes from observational studies not randomized controlled trials. There could be systematic differences between people who choose to eat more heme iron that contribute to the increased risk of CVD and heme iron is not necessarily the culprit. For example, foods rich in heme iron (primarily animal proteins) are also rich in saturated fats and cholesterol which also are thought to contribute to CVD. People who avoid animal proteins may also be more health conscious than the general population and thus have decreased risk of CVD because of other actions that are not directly connected to heme consumption. (Here's a nice article on some of the difficulties of performing research on linking nutrition to health outcomes: https://fivethirtyeight.com/features/you-cant-trust-what-you-read-about-nutrition/).

I think it is pretty well established that diets rich in red meats and processed meats are associated with a variety of health problems (e.g. CVD and cancer). What exact components of these meats that cause the health problems is still an active area of research. For reference, here's what the American Heart Association has to say about the subject:

Dietary patterns rich in red meat have been associated with higher CVD incidence and mortality,58–62 and body mass index and waist circumference, as well.63,64 Several systematic reviews and meta-analyses have documented a direct association between red meat intake and CVD incidence and mortality, although the magnitude of the association is less strong than that for processed meat.58,65,66 Substitution analyses based on large cohort studies found that the replacement of red and processed meat with alternative foods such as unprocessed poultry, fish, nuts, and legumes was associated with a lower risk of total and CVD mortality.62 The potential adverse effect of red meat on CVD risk has been attributed to a combination of factors, including saturated fat and heme iron content, and gut microbiota metabolism of l-carnitine and phosphatidylcholine.45,67,68

2021 Dietary Guidance to Improve Cardiovascular Health: A Scientific Statement From the American Heart Association
https://www.ahajournals.org/doi/10.1161/CIR.0000000000001031

 

[nomadreid]

Thank you very much, Ygggdrasil