Is It Time to Reconsider the U.S. Recommendations for Dietary Protein and Amino Acid Intake?

Since the U.S. Institute of Medicine's recommendations on protein and amino acid intake in 2005, new information supports the need to re-evaluate these recommendations. New lines of evidence include: (1) re-analysis/re-interpretation of nitrogen balance data; (2) results from indicator amino acid oxidation studies; (3) studies of positive functional outcomes associated with protein intakes higher than recommended; (4) dietary guidance and protein recommendations from some professional nutrition societies; and (5) recognition that the synthesis of certain dispensable amino acids may be insufficient to meet physiological requirements more often than previously understood. The empirical estimates, theoretical calculations and clinical functional outcomes converge on a similar theme, that recommendations for intake of protein and some amino acids may be too low in several populations, including for older adults (≥65 years), pregnant and lactating women, and healthy children older than 3 years. Additional influential factors that should be considered are protein quality that meets operational sufficiency (adequate intake to support healthy functional outcomes), interactions between protein and energy intake, and functional roles of amino acids which could impact the pool of available amino acids for use in protein synthesis. Going forward, the definition of "adequacy" as it pertains to protein and amino acid intake recommendations must take into consideration these critical factors.

Opportunities for Adding Undernutrition and Frailty Screening Measures in US National Surveys.

Both undernutrition and frailty adversely affect the health and functional outcomes of the older adult population. Timely and accurate national data are necessary to assess those at risk of these debilitating but often preventable conditions, to correct them and support healthy aging. The objective was to identify relevant measures in undernutrition and frailty screening tools and determine if these measures are collected in recent protocols for US national surveys sampling older adults and which measures could be added to be able to better assess risk of undernutrition and frailty. Commonly used undernutrition and frailty screening tools were evaluated to identify measures that were unique or common to both. US national surveys were examined to determine whether they included older adults in their survey sample, collected health measures from participants, in what form, and whether they were functional indexes or survey questions. A comparative analysis of survey protocols was performed to determine which surveys collected data related to the measures of undernutrition and frailty. Of the 8 national surveys, only 3 provided ≥1 physical measurement (i.e., height/weight, grip strength, balance). Most surveys included self-reported data on height/weight, physical functioning/mobility, disability, and psychological components. Whereas 6 included questions on food security/food program participation, only 1 collected data on dietary intake. Currently national surveys include only limited health measures that can be used to identify undernutrition and frailty risk in older adults. Adding a few simple screening measures already included in popular screening tools, such as grip strength, unintentional weight loss, and loss of appetite, to national surveys which monitor older Americans would facilitate estimation of the prevalence of undernutrition and frailty risk, better estimate those at risk, provide an opportunity to set national goals to reduce their risk, and help implement strategies for improved health outcomes.

Plant Proteins: Assessing Their Nutritional Quality and Effects on Health and Physical Function.

Consumer demand for plant protein-based products is high and expected to grow considerably in the next decade. Factors contributing to the rise in popularity of plant proteins include: (1) potential health benefits associated with increased intake of plant-based diets; (2) consumer concerns regarding adverse health effects of consuming diets high in animal protein (e.g., increased saturated fat); (3) increased consumer recognition of the need to improve the environmental sustainability of food production; (4) ethical issues regarding the treatment of animals; and (5) general consumer view of protein as a "positive" nutrient (more is better). While there are health and physical function benefits of diets higher in plant-based protein, the nutritional quality of plant proteins may be inferior in some respects relative to animal proteins. This review highlights the nutritional quality of plant proteins and strategies for wisely using them to meet amino acid requirements. In addition, a summary of studies evaluating the potential benefits of plant proteins for both health and physical function is provided. Finally, potential safety issues associated with increased intake of plant proteins are addressed.

Screening Community-Living Older Adults for Protein Energy Malnutrition and Frailty: Update and Next Steps.

Protein-energy malnutrition (PEM)/undernutrition and frailty are prevalent, overlapping conditions impacting on functional and health outcomes of older adults, but are frequently unidentified and untreated in community settings in the United States. Using the World Health Organization criteria for effective screening programs, we reviewed validity, reliability, and feasibility of data-driven screening tools for identifying PEM and frailty risk among community-dwelling older adults. The SCREEN II is recommended for PEM screening and the FRAIL scale is recommended as the most promising frailty screening tool, based on test characteristics, cost, and ease of use, but more research on both tools is needed, particularly on predictive validity of favorable outcomes after nutritional/physical activity interventions. The Malnutrition Screening Tool (MST) has been recommended by one expert group as a screening tool for all adults, regardless of age/care setting. However, it has not been tested in US community settings, likely yields large numbers of false positives (particularly in community settings), and its predictive validity of favorable outcomes after nutritional interventions is unknown. Community subgroups at highest priority for screening are those at increased risk due to prior illness, certain demographics and/or domiciliary characteristics, and those with BMI < 20 kg/m2 or < 22 if > 70 years or recent unintentional weight loss > 10% (who are likely already malnourished). Community-based health professionals can better support healthy aging by increasing their awareness/use of PEM and frailty screening tools, prioritizing high-risk populations for systematic screening, following screening with more definitive diagnoses and appropriate interventions, and re-evaluating and revising screening protocols and measures as more data become available.