Plant Protein but Not Animal Protein Consumption Is Associated with Frailty through Plasma Metabolites

Plant and Animal Protein Intake and Transitions From Multimorbidity to Frailty and Mortality in Older Adults

BACKGROUND

Multimorbidity is the most common chronic condition experienced among older adults. It is unknown which amount and source of protein influences the development of frailty and mortality in patients with multimorbidity. We aimed to examine the association of plant and animal sources of protein intake with frailty and mortality among this type of patients.

METHODS

This longitudinal study included 1868 participants aged ≥ 60 years from the Seniors-ENRICA cohort in Spain with multimorbidity, defined as having 2 or more clinician-diagnosed chronic diseases. Habitual diet was assessed at baseline (2008-2010) with a validated computerized diet history. Participants underwent repeated physical examinations (in 2013, 2015 and 2017) for assessment of frailty (≥ 3 criteria from the frailty phenotype: low physical activity, slow walking speed, muscle weakness, weight loss and exhaustion). All-cause mortality was assessed up to January 2022. Analyses were conducted using Cox proportional hazard models and multistate models adjusted for sociodemographic, lifestyle and other dietary factors.

RESULTS

Mean consumption of protein was 90.2 (standard deviation [SD]: 26.8) g/day, which represents 18.7% of the total energy intake and 1.23 (0.39) g per kg of body weight per day. Plant protein represented 6.16% of the energy intake, while animal protein represented 12.5%. During a median follow-up of 12.9 (range: 11.7-13.9) years, we documented 196 incident cases of frailty and 490 deaths; of these mortality cases, 83 individuals died after a frailty diagnosis. Higher intake of total protein was associated with decreased risk of frailty (hazard ratio [HR] for tertile 3 vs. tertile 1: 0.66; 95% confidence interval [CI]: 0.45, 0.96; p trend: 0.03). In multistate models, higher fish protein intake decreased the risk in the progression from multimorbidity to frailty (HR per 1-SD increment: 0.81 [95% CI: 0.68, 0.97]), and higher plant protein decreased the risk of progressing from multimorbidity to mortality (0.86 [0.75, 0.98]). In the progression from frailty to mortality, estimates for total, plant and animal protein showed increased risk (HR for 1 SD increment in total protein: 1.38 [1.05, 1.81]; HR for plant protein: 1.29 [1.01, 1.67]; HR for animal protein: 1.41 [1.04, 1.92]). No significant associations were found between meat protein and dairy protein in any transition.

CONCLUSIONS

In individuals with multimorbidity, higher protein intake, especially fish protein, was associated with lower risk of subsequent frailty, whereas plant protein intake was associated with lower risk of mortality. Higher total protein intake, however, might be detrimental in patients with multimorbidity and frailty.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02804672.

Nutritional specificity of frailty: from epidemiological and clinical evidence to potential mechanisms

PURPOSE OF REVIEW

Considering the ageing of the population, age-related syndromes, such as frailty, are prominent. In this context, nutrition is a modifiable factor considered a key nonpharmacological approach to prevention and treatment. Yet, its contribution to the frailty pathophysiology is conflicting in the literature. This paper discusses the recent literature (January 2023-June 2024) on the implication of nutrition in frailty management.

RECENT FINDINGS

Malnutrition is one of the main frailty risk factors. Proteins are the targeted macronutrient for their effects on muscle anabolism, not only in terms of quantity consumed but also in terms of sources. The diversity in plant and animal sources demonstrates better results than relying on a single source. More globally, anti-inflammatory and antioxidant diets are associated with a lower risk of frailty, like the Mediterranean Diet and specific food groups, like seafood, nuts, and seeds. Nutrition is pivotal in frailty prevention and treatment, and multidomain interventions providing exercises seem to yield even better results.

SUMMARY

Diverse protein sources and anti-inflammatory and antioxidant diets associated with exercises are the primary recommendations for frailty prevention and treatment. However, there is a need to evaluate how to achieve and maintain this healthy behaviour in real life.

Plant proteins: are they a good alternative to animal proteins in older people?

PURPOSE OF REVIEW

This review provides the latest insight into the impact of consuming plant-based protein for older people.

RECENT FINDINGS

According to the latest data, a healthy diet rich in plant-based-protein-rich-food could promote healthy aging. This health effect is partly because of the amino acid composition of proteins, as well as to the important constituents such as fiber and bioactive compounds found in the matrix. Furthermore, even though animal protein is more effective at stimulating muscle protein synthesis, a high consumption of plant protein (beyond 31 g/day) appears to enhance physical performance and reduce the risk of frailty in older individuals.

SUMMARY

Recent literature highlights numerous health benefits for older people associated with a substantial intake of plant-based vs. animal-based protein, both in preventing and mitigating chronic age-related diseases and reducing the risk of all-cause mortality. However, a high intake of plant-based protein-rich products could pose risks of malnutrition and fiber-related intestinal intolerances. Further research is needed to assess the risk-benefit ratio of a high consumption of plant proteins in older individuals before we can make robust recommendations on how far animal proteins can be healthfully replaced with plant proteins.