Prospective controlled research on red meat, haem iron, and blood pressure
The recent report of Tzoulaki and colleagues [1] on a large cross-
sectional epidemiological international collaborative study on macro-
/micronutrients and blood pressure (INTERMAP) indicated that blood
pressure was negatively associated with non-haem iron ingestion and
positively associated with red meat intake. Both this paper and the
accompanying editorial noted the need for confirmation of such findings
with prospective controlled studies. I am writing to draw attention to a
relevant small, but well-controlled prospective study from our laboratory.
We reported no change in the systolic or diastolic resting blood
pressure of 21 healthy premenopausal women who consumed weighed
experimental lacto-ovo-vegetarian and meat-containing diets (with
equivalent food energy) for 8 wk each in a randomized cross-over design
[2]. These two diets contained 0 and 184 g meat/d, respectively. Three-
quarters of this meat was beef, with chicken as the remainder. As
described in a subsequent paper emphasizing iron content and
absorption/bioavailability [3], the two diets contained 12.6 and 13.6 mg
total iron, and 0 and 1.2 mg haem iron/d, respectively. Compared to the
meat-containing diet, the lacto-ovo-vegetarian diet resulted in
substantially lower non-haem and total iron absorption [3]. This small
study with controlled diets for 8 wk each does not support a positive
association of red meat or haem iron intake with blood pressure, under
conditions of equivalent energy consumption.
REFERENCES
[1] Tzoulaki I, Brown IJ, Chan Q, Van Horn L, Ueshima H, Zhao L, et
al. Relation of iron and red meat intake to blood pressure: cross
sectional epidemiological study. Bmj 2008;337:a258.
[2] Hunt JR, Matthys LA, Johnson LK. Zinc absorption, mineral
balance, and blood lipids in women consuming controlled lactoovovegetarian
and omnivorous diets for 8 wk. Am J Clin Nutr 1998;67:421-430.
[3] Hunt JR, Roughead ZK. Nonheme-iron absorption, fecal ferritin
excretion, and blood indexes of iron status in women consuming controlled
lactoovovegetarian diets for 8 wk. Am J Clin Nutr 1999;69:944-52.
Competing interests:
Author has received some research funding from the National Cattlemen's Beef Association in the USA.
Competing interests:
No competing interests
04 August 2008
Janet R Hunt
Research Nutritionist
USDA-ARS Grand Forks Human Nutrition Research Center, Grand Forks, ND 58202
Rapid Response:
Prospective controlled research on red meat, haem iron, and blood pressure
The recent report of Tzoulaki and colleagues [1] on a large cross-
sectional epidemiological international collaborative study on macro-
/micronutrients and blood pressure (INTERMAP) indicated that blood
pressure was negatively associated with non-haem iron ingestion and
positively associated with red meat intake. Both this paper and the
accompanying editorial noted the need for confirmation of such findings
with prospective controlled studies. I am writing to draw attention to a
relevant small, but well-controlled prospective study from our laboratory.
We reported no change in the systolic or diastolic resting blood
pressure of 21 healthy premenopausal women who consumed weighed
experimental lacto-ovo-vegetarian and meat-containing diets (with
equivalent food energy) for 8 wk each in a randomized cross-over design
[2]. These two diets contained 0 and 184 g meat/d, respectively. Three-
quarters of this meat was beef, with chicken as the remainder. As
described in a subsequent paper emphasizing iron content and
absorption/bioavailability [3], the two diets contained 12.6 and 13.6 mg
total iron, and 0 and 1.2 mg haem iron/d, respectively. Compared to the
meat-containing diet, the lacto-ovo-vegetarian diet resulted in
substantially lower non-haem and total iron absorption [3]. This small
study with controlled diets for 8 wk each does not support a positive
association of red meat or haem iron intake with blood pressure, under
conditions of equivalent energy consumption.
REFERENCES
[1] Tzoulaki I, Brown IJ, Chan Q, Van Horn L, Ueshima H, Zhao L, et
al. Relation of iron and red meat intake to blood pressure: cross
sectional epidemiological study. Bmj 2008;337:a258.
[2] Hunt JR, Matthys LA, Johnson LK. Zinc absorption, mineral
balance, and blood lipids in women consuming controlled lactoovovegetarian
and omnivorous diets for 8 wk. Am J Clin Nutr 1998;67:421-430.
[3] Hunt JR, Roughead ZK. Nonheme-iron absorption, fecal ferritin
excretion, and blood indexes of iron status in women consuming controlled
lactoovovegetarian diets for 8 wk. Am J Clin Nutr 1999;69:944-52.
Competing interests:
Author has received some research funding from the National Cattlemen's Beef Association in the USA.
Competing interests: No competing interests