Improvements in iron status and cognitive function in young women consuming beef or non-beef lunches

Abstract

Iron status is associated with cognitive performance and intervention trials show that iron supplementation improves mental function in iron-deficient adults. However, no studies have tested the efficacy of naturally iron-rich food in this context. This investigation measured the hematologic and cognitive responses to moderate beef consumption in young women. Participants (n=43; age 21.1±0.4 years) were randomly assigned to a beef or non-beef protein lunch group [3-oz (85 g), 3 times weekly] for 16 weeks. Blood was sampled at baseline, and weeks 8 and 16, and cognitive performance was measured at baseline and week 16. Body iron increased in both lunch groups (p<0.0001), with greater improvement demonstrated in women with lower baseline body iron (p<0.0001). Body iron had significant beneficial effects on spatial working memory and planning speed (p<0.05), and ferritin responders (n=17) vs. non-responders (n=26) showed significantly greater improvements in planning speed, spatial working memory strategy, and attention (p<0.05). Lunch group had neither significant interactions with iron status nor consistent main effects on test performance. These findings support a relationship between iron status and cognition, but do not show a particular benefit of beef over non-beef protein consumption on either measure in young women.

Figure 1

Volunteer flow diagram.

Figure 2

Change in response time by ferritin response group; Change (endpoint-baseline) in One-Touch Stockings of Cambridge latency to first choice for move categories 1–6 for ferritin responders (n = 17) and non-responders (n = 26). Main effect of responder group, p = 0.007.

Figure 3

Change in strategy by ferritin response group; change (endpoint-baseline) in Spatial Working Memory strategy score for six- and eight-box problems in ferritin responders (n = 17) and non-responders (n = 26). A lower score and larger negative change indicate better strategy. Main effect of responder group, p = 0.007; * p < 0.05 between-group comparison for eight-box problem.