Comparisons of vegetarian and beef-containing diets on hematological indexes and iron stores during a period of resistive training in older men

Abstract

Objective-To test the hypothesis that older men who consumed a vegetarian (lacto-ovo) diet would develop a lower iron status compared with older men who consumed a beef-containing diet during a period of resistive training (RT). Design-Experimental, repeated measures study.Subjects-Twenty-one healthy men aged 59 to 78 years, with a BMI range of 24 to 33 kg/m 2 , completed the study.Intervention-All men consumed a vegetarian diet for 2 weeks (baseline). After this, the men were randomly assigned to one of two dietary groups. Eleven men consumed a beef-containing diet, and 10 men continued to consume a vegetarian diet for 12 weeks. During this time all subjects participated in RT three days per week, designated as RT1 to RT12.Main outcome measures-Serum ferritin and serum iron concentrations, transferrin saturation, transferrin receptor, total iron binding capacity, and selected hematological variables, as well as Address correspondence to: Wayne W. Campbell, PhD, Department of Foods and Nutrition, Purdue University, 700 West State St, West Lafayette, IN 47907. E-mail: campbellw@cfs.purdue.edu. Consumption of a beef-containing diet, having greater iron bioavailability, increases hematological parameters during resistive training; however, consumption of a lacto-ovo vegetarian diet did not adversely affect hematological profile NIH Public Access NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript selected nutrient intakes and estimated iron bioavailability from three-day diet records, were determined at baseline, RT5, and RT12.Statistical analyses-A general linear model repeated-measures ANOVA was used to examine the effects of group, time, and group×time interactions for iron status and dietary data.Results-Total iron intake was not different between the two groups; however, the beef group had a three to four times greater intake of bioavailable iron (P<.01) than the vegetarian group. Serum iron, total iron binding capacity, transferrin saturation, and transferrin receptor were not significantly different between the beef and vegetarian groups, or changed over time with RT. Serum ferritin decreased over time in both the beef and vegetarian groups during RT (P<.01). Re-introduction of beef into the diets of the beef group increased hemoglobin concentration and hematocrit compared with the vegetarian group during the 12 weeks of RT (group×time, P<.05). These changes were within clinically normal limits.Applications/Conclusions-Older men who consume a beef-containing, higher-bioavailableiron diet, compared with a vegetarian, lower-bioavailable-iron diet, have an increased hematological profile during a 12-week period of RT. Older men who consume either a beef-containing or a vegetarian diet maintain a hematological profile within clinically normal limits during 12 weeks of RT.In the absence of disease or blood loss, iron status is primarily controlled by dietary iron absorption (1,2), which is regulated by current iron stores and the iron bioavailability of the diet (2,3). Iron bioavail...

Vegetarian and Omnivorous Nutrition—Comparing Physical Performance

“…For instance, several papers examined muscular power and strength (Campbell et al, 1999;Haub et al, 2005;Wells et al, 2003), four assessed anaerobic and aerobic performance (Baguet et al, 2011;Hanne et al, 1986;Hietavala et al, 2012;Raben et al, 1992) whilst one investigated immune parameters (Richter et al, 1991) in relation to a vegetarian-based diet. In addition, most papers used different physical testing and/or biomarkers.…”

“…Campbell et al (1999) did, however, report resistance training induced changes in whole body composition (p = 0.014) and an increase in mean type II muscle fibre area size between groups (p = 0.005). Similarly, Wells et al 2003, described haemoglobin and haematocrit were significantly increased in the meat group (p < 0.01) though this did not affect strength testing.…”

“…The studies were unified regarding muscular strength. All three studies found no significant difference in muscular strength or power between the LOV groups and the omnivorous groups except in Wells et al (2003) where the LOV group displayed a significant increase in strength for knee extensions (p<0.01), yet both groups revealed significant improvements in muscular strength and power. Campbell et al (1999) did, however, report resistance training induced changes in whole body composition (p = 0.014) and an increase in mean type II muscle fibre area size between groups (p = 0.005).…”

“…Three studies examined the difference between a LOV diet and a typical beefcontaining western diet and its effect on Resistance Training (RT) in elderly men (Campbell et al, 1999;Haub et al, 2005;Wells et al, 2003). The studies were unified regarding muscular strength.…”

“…In two out of the three studies texturised vegetable protein was used frequently in the LOV diets with breakfast patties, grillers, chick[pea] patties and veggie dogs highly prominent (Haub et al, 2005;Wells et al, 2003). Products such as these often contain food colour, pH modifier, surface-active substrates, emulsifiers and surfactants (Asgar et al, 2010).…”