The Effects of a High-Protein Diet on Bone Mineral Density in Exercise-Trained Women: A 1-Year Investigation

Abstract

The effects of long-term high-protein consumption (i.e., >2.2 g/kg/day) are unclear as it relates to bone mineral content. Thus, the primary endpoint of this investigation was to determine if consuming a high-protein diet for one year affected various parameters of body composition in exercise-trained women. This investigation is a follow-up to a prior 6-month study. Subjects were instructed to consume a high-protein diet (>2.2 g/kg/day) for one year. Body composition was assessed via dual-energy X-ray absorptiometry (DXA). Subjects were instructed to keep a food diary (i.e., log their food ~three days per week for a year) via the mobile app MyFitnessPal®. Furthermore, a subset of subjects had their blood analyzed (i.e., basic metabolic panel). Subjects consumed a high-protein diet for one year (mean ± SD: 2.3 ± 1.1 grams per kilogram body weight daily [g/kg/day]). There were no significant changes for any measure of body composition over the course of the year (i.e., body weight, fat mass, lean body mass, percent fat, whole body bone mineral content, whole body T-score, whole body bone mineral density, lumbar bone mineral content, lumbar bone mineral density and lumbar T-score). In addition, we found no adverse effects on kidney function. Based on this 1-year within-subjects investigation, it is evident that a diet high in protein has no adverse effects on bone mineral density or kidney function.

High-Protein Energy-Restriction: Effects on Body Composition, Contractile Properties, Mood, and Sleep in Active Young College Students

“…Mediated by a higher insulin secretion, tryptophan is transported across the blood chain barrier and hence, stimulates the synthesis and function of neurotransmitters (e.g., serotonin) as a dietary precursor (Wurtman et al, 2003). However, there seems to be a ceiling effect as seen in athletes who are used to a steady protein supplementation (Antonio et al, 2019b). With that being said, we conclude that a high-protein moderate energy restriction (ER group) may have beneficial effects on sleeping quality which might be greater by trend than a high-protein intake alone (CG).…”

Recent Perspectives on the Role of Dietary Protein in Physically Active Individuals

“…Once again, the habitual intake of these subjects (1.5±0.2 g/kg) was well above the general recommendation of 0.8 g/kg. A follow-up study was conducted by Antonio and colleagues in which female subjects followed a high (>2.2 g/kg/day) protein diet for one year 31 . In line with the previous study, no significant differences were observed in body composition or bone density for the duration of the study.…”

“…The increased caloric intake reported in these studies was primarily the result of increasing dietary protein intake. It has been theorized the lack of statistically significant differences in body composition and body mass during a hypercaloric diet is due to the thermic effect of protein [27][28][29][30][31][32] . Diet-induced thermogenesis is greatest for protein which contributes to an increase in total daily energy expenditure [32][33][34] .…”

Active Women Across the Lifespan: Nutritional Ingredients to Support Health and Wellness

“…Higher protein diets (> 2.0 g/kg/day) have been shown to be important for maintaining LM and resting energy expenditure under periods of intentional and unintentional caloric restriction [59], which may be more prevalent among active women. Additionally, high-protein diets (> 2.2 g/kg/ day) have not resulted in any adverse effects to bone mineral density or kidney function in healthy women after 6 months [60] or 1 year [61]. As a result of the potentially greater protein oxidation, particularly in the LP, active women should focus on consuming high-quality protein sources (e.g., high biological value, high digestibility, absorption, and EAA content) to minimize muscle soreness and breakdown.…”