Menopause and muscle mass: Study highlights need for increased protein intakes

Furthermore, post-menopausal women (POST-M) had significantly higher levels of pro-inflammatory marker tumour necrosis factor-α, suggesting higher levels of inflammation.

"Reduced oestradiol (E2) and dietary protein intake in POST-M women occurs in conjunction with increased levels of biomarkers of NMJ [neuromuscular junction] degradation, inflammation and muscle proteolysis, which may be associated with reduced motor unit activation and muscle quality," researchers from the University of Mary Hardin-Baylor in Belton, TX wrote in the journal Nutrients.​

Menopause and muscle​

Menopause is accompanied by decreased production of the female oestrogenic hormone E2, which plays an essential role​ in the maintenance of neuromuscular function through its antioxidant properties​. Thus, menopause has been associated​ with increased sarcopenia risk, as well as increased oxidative stress and production of pro-inflammatory mediators, which also negatively impact muscle mass and function.

Deterioration of muscle is common as people age, yet it has also been associated​ with inadequate protein consumption in older adults.

As such, the researchers sought to investigate further the effects of lower circulating levels of E2 in POST-M compared to PRE-M women to evaluate axonal and NMJ degeneration, pro-inflammatory status and protein degeneration.

Study details​

The study included 12 healthy women within a cross-sectional design, six of whom were pre-menopausal and six post-menopausal. Blood, urine and dietary data were collected from the participants, in addition to measures of body composition, motor unit activation and muscle performance.

The researchers reported that POST-M women had significantly lower levels of E2, motor unit activity, muscle quality and muscle performance compared to PRE-M women. In addition, they noted that POST-M women consumed inadequate amounts of protein at 0.81 g/kg/day, considerably less than the 1.47 g/kg/day consumed in the PRE-M group.

In contrast, levels of c-terminal fragment of agrin and urinary titin were higher in the POST-M group, however, inflammatory marker tumour necrosis factor-α was also significantly elevated.

"We conclude that reductions in E2, protein intake and antioxidant effects most likely up-regulated TNF-α levels, which subsequently (1) increased the activity of NT to degrade agrin to CAF and (2) up-regulated the activity of NF-кB to instigate muscle proteolysis, thereby resulting in increased TNTF," the researchers explained. 

"We also conclude that the culminating effects of this inflammatory and proteolytic cascade conceivably had a detrimental impact on NMJ integrity, motor unit activation and [muscle quality] compared to the pre-menopausal women, who displayed normal levels of E2," they added.

The study called for further research to validate the findings in a larger sample of women more representative of the overall population.

Source: Nutrients​
doi: doi.org/10.3390/nu16020197​
“Decreased Neuromuscular Function and Muscle Quality along with Increased Systemic Inflammation and Muscle Proteolysis Occurring in the Presence of Decreased Estradiol and Protein Intake in Early to Intermediate Post-Menopausal Women”
Authors: Darryn S. Willoughby et al.