Dietary Iron Intake and Body Iron Stores Are Associated with Risk of Coronary Heart Disease in a Meta-Analysis of Prospective Cohort Studies

Abstract

The link between iron intake as well as body iron stores and coronary heart disease (CHD) has been contentiously debated, and the epidemiologic evidence is inconsistent. We aimed to quantitatively summarize the literature on the association between dietary iron intake/body iron stores and CHD risk by conducting a meta-analysis of prospective cohort studies. PubMed was used to find studies published through June 2013 in peer-reviewed journals. Embase or a hand search of relevant articles was used to obtain additional articles. The pooled RRs of CHD incidence and mortality with 95% CIs were calculated by using either a random-effects or fixed-effects model, as appropriate. Twenty-one eligible studies (32 cohorts) including 292,454 participants with an average of 10.2 y of follow-up were included. Heme iron was found to be positively associated with CHD incidence (RR: 1.57; 95% CI: 1.28, 1.94), whereas total iron was inversely associated (RR: 0.85; 95% CI: 0.73, 0.999). Neither heme-iron nor total iron intakes were significantly associated with CHD mortality. Both transferrin saturation and serum iron were inversely related to CHD incidence [RR (95% CI): 0.76 (0.66, 0.88) and 0.68 (0.56, 0.82), respectively], but only transferrin saturation was inversely associated with CHD mortality (RR: 0.85; 95% CI: 0.73, 0.99). In conclusion, total iron intake and serum iron concentrations were inversely associated with CHD incidence, but heme iron intake was positively related to CHD incidence. Elevated serum transferrin saturation concentration was inversely associated with both CHD incidence and mortality. Future research is needed to establish the causal relation and to elucidate potential mechanisms.

Hydroxytyrosol supplementation increases vitamin C levels in vivo. A human volunteer trial

“…Body iron stores (ferritin) have been associated with increased risk of CVD [34], [35] while depletion may be a cardioprotective mechanism [36], [37]. But this is highly controversial because iron deficiency too has been associated with increased cardiovascular risk [38].…”

Dietary intake of heme iron and risk of cardiovascular disease: A dose–response meta-analysis of prospective cohort studies

“…Moreover, many of the studies in this meta-analysis had large sample sizes and long follow-up durations, which provided high statistical power to our quantitative assessment of the correlation between dietary iron intake and the risk of CVD. In comparison to the similar study by Hunnicutt et al, the quality of our meta-analysis was increased by generating doseeresponse curves in addition to the comparisons of the highest and lowest categories [15]. Finally, the relatively large number of studies regarding heme iron intake and total iron intake enabled us to perform subgroup analyses based on gender, study location, number of participants, and follow-up duration.…”

“…One recent meta-analysis by Hunnicutt et al investigated the correlation between dietary iron intake and the risk of coronary heart disease (ICD-9 codes 410e414 and ICD-10 codes I 2 0e I 2 5); however, this study did not categorically cover all cardiovascular diseases (i.e. codes 390e459 and I01eI99) [15]. Thus, to the best of our knowledge, no meta-analysis has been performed to examine the specific association between dietary heme iron intake and CVD risk.…”

Increased iron levels and lipid peroxidation in a Mediterranean population of Spain

“…Elevated iron levels have been associated with several chronic diseases such as cardiovascular disease [1], metabolic syndrome [2], type 2 diabetes [3], cancer [4] as well as neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD) [5]. It has been speculated that these relationships are mediated by oxidative stress, a condition characterized by an imbalance between the generation of reactive oxygen species (ROS) and response from the antioxidant defence systems [6] In fact, certain pathologies, characterized by iron excess, such as b-thalassaemia [7] or hereditary haemochromatosis (HH) [8], have been associated with increased oxidative stress.…”