Longitudinal Association Between Sodium and Potassium Intake and Physical Performance in Older Adults

The role of nutrition in the prevention of sarcopenia

Sarcopenia is a common skeletal muscle disorder characterized by a loss of muscle mass and impaired muscle function that is associated with poor health outcomes. Although nutrition is considered an important factor in the etiology of sarcopenia, the preventive potential of diet, specifically the extent to which differences in habitual patterns of diet and/or nutrient intakes impact risk of its development, is poorly understood. This narrative review considered research evidence on dietary patterns and nutrient intakes in mid- (<60 y) and young-older (60-70 y) adulthood to evaluate how they relate to age-related changes in muscle mass and function. A key finding was that current evidence on adult diet and sarcopenia risk in older age is limited and fragmented, with different outcomes reported across studies (for example, lean mass, strength) and few reporting links to incident diagnosed sarcopenia. As these outcomes are not interchangeable, it challenges collation of the evidence, leaving many gaps in understanding. There is also limited information about adult (<70 y) diet and few longitudinal studies with repeated dietary assessments to enable definition of cumulative exposures across adulthood. However, despite these limitations, findings from studies of dietary patterns already provide reasonably consistent messages about the benefits of diets of higher quality in earlier adulthood for later physical performance, although whole-diet intervention trials are urgently needed to understand their potential. In comparison, there is little evidence of benefits of higher intakes of individual nutrients in earlier adulthood for later muscle mass and function. Although these gaps need to be addressed in future research, there may already be sufficient data to promote messages about diet quality more widely - that healthier diets of higher quality across adulthood, with known benefits for a range of health outcomes, are also linked to the effective preservation of muscle mass and function.

Minerals and Sarcopenia in Older Adults: An Updated Systematic Review

OBJECTIVE

This systematic review aims to reevaluate the role of minerals on muscle mass, muscle strength, physical performance, and the prevalence of sarcopenia in community-dwelling and institutionalized older adults.

DESIGN

Systematic review.

SETTING AND PARTICIPANTS

In March 2022, a systematic search was performed in PubMed, Scopus, and Web of Sciences using predefined search terms. Original studies on dietary mineral intake or mineral serum blood concentrations on muscle mass, muscle strength, and physical performance or the prevalence of sarcopenia in older adults (average age ≥65 years) were included.

METHODS

Eligibility screening and data extraction was performed by 2 independent reviewers. Quality assessment was performed with the Effective Public Health Practice Project (EPHPP) Quality Assessment Tool for Quantitative Studies. Risk of bias was evaluated using the Risk Of Bias In Non-randomized Studies-of Exposure (ROBINS-E) tool.

RESULTS

From the 15,622 identified articles, a total of 45 studies were included in the review, mainly being cross-sectional and observational studies. Moderate quality of evidence showed that selenium (n = 8) and magnesium (n = 7) were significantly associated with muscle mass, strength, and physical performance as well as the prevalence of sarcopenia. For calcium and zinc, no association could be found. For potassium, iron, sodium, and phosphorus, the association with sarcopenic outcomes remains unclear as not enough studies could be included or were nonconclusive (low quality of evidence).

CONCLUSIONS AND IMPLICATIONS

This systematic review shows a potential role for selenium and magnesium on the prevention and treatment of sarcopenia in older adults. More randomized controlled trials are warranted to determine the impact of minerals on sarcopenia in older adults.

Association of Salt Intake with Muscle Strength and Physical Performance in Middle-Aged to Older Chinese: The Guangzhou Biobank Cohort Study

Older people have higher amounts of sodium accumulation in skeletal muscles than younger people, indicating the possible role of salt intake on muscular and physical function. This large population-based cross-sectional study examined the association of salt intake with muscle strength and physical performance in 4867 participants with an average age of 60.4 (standard deviation = 7.7) years. Information on salt intake was collected from self-reports. Absolute and relative grip strength (AGS and RGS), timed up-and-go test (TUGT), and falls were considered the indicators of muscle strength and physical performance. Linear and logistic regression were used to examine the associations of salt intake with AGS, RGS, TUGT score, and falls, adjusting for demographic and lifestyle factors, body mass index, self-rated health, and self-reported hypertension. Higher salt intake was independently associated with lower grip strength and a higher TUGT score. Versus light salt intake, the adjusted β (95% confidence interval (CI)) of AGS_max, RGS_max, and TUGT scores in those with salty taste were -0.53 (-0.97, -0.08) kg, -0.04 (-0.06, -0.02) kg per kg/m², and 0.08 (0.02, 0.14) s, respectively. A non-significant association was found between salt intake and falls. In sex-stratification analysis, the association remained in women but became non-significant in men. Our results suggest that avoiding high-salt diets may play a role in preserving muscle strength and physical function in the elderly, especially in women.

The World Hypertension League Science of Salt: a regularly updated systematic review of salt and health outcomes studies (Sept 2019 to Dec 2020)

The World Hypertension League Science of Salt health outcomes review series highlights high-quality publications relating to salt intake and health outcomes. This review uses a standardised method, outlined in previous reviews and based on methods developed by WHO, to identify and critically appraise published articles on dietary salt intake and health outcomes. We identified 41 articles published between September 2019 to December 2020. Amongst these, two studies met the pre-specified methodological quality criteria for critical appraisal. They were prospective cohort studies and examined physical performance and composite renal outcomes as health outcomes. Both found an association between increased/higher sodium intake and poorer health outcomes. Few studies meet criteria for high-quality methods. This review adds further evidence that dietary salt reduction has health benefits and strengthens evidence relating to health outcomes other than blood pressure and cardiovascular disease. We observe that most studies on dietary sodium do not have adequate methodology to reliably assess sodium intake and its association with health outcomes.

Prospective association between dietary magnesium intake and physical performance in older women and men

PURPOSE

Magnesium is a profuse intracellular cation with a key role in muscle function and cellular senescence. The aim was to examine the prospective association between 5 year changes in dietary intake of magnesium and changes in physical performance among older men and women.

METHODS

Prospective study conducted over 863 community-dwellers aged ≥ 65 years from the Seniors-ENRICA cohort (Spain). In 2012 and 2017, a validated computerized face-to-face diet history was used to record the consumption of up to 880 foods. From these data, we estimated changes in dietary magnesium intake. The Short Physical Performance Battery (SPPB) was also conducted in both time points and we obtained changes in the score during follow-up, with positive values indicating physical performance improvement.

RESULTS

Over 5 years of follow-up, an increase in magnesium intake was associated with an increment in the SPPB score among older women [multivariate β (95% confidence interval): 1.01 (0.49; 1.52), p-trend: 0.001]. In addition, changes from non-adherence to adherence to both estimated average requirement and recommended dietary allowance during follow-up period were associated with an increment in SPPB score among older women [1.14 (0.36; 1.92) and 0.84 (0.22; 1.47), respectively]. No significant associations between changes in magnesium intake and changes in SPPB score were observed in men.

CONCLUSIONS

Both increase of magnesium intake and change from non-adherence to adherence to dietary reference magnesium intake was prospectively associated with better physical performance among older women, but not among men.