Factors affecting aging, as indicated by stakeholders

Socioeconomic status. Poverty affects many older adults. In 2020, 8.9% of older adults were living below the poverty level, which increased to 10.3% in 2021 per the Official Poverty Measure ⁶. Of this proportion of older adults living below the poverty line, people of color had higher percentages of poverty. Among Black, Asian, and Hispanic populations, the poverty rates were roughly 18%, 9.3%, 17.1% compared to 6.8% among White, not Hispanic⁶. Compared to men, older women are also more likely to be classified as living in a state of poverty in almost all racial/ethnic groups with 10.3% vs. 7.7% in White, 19.1% vs. 16% in Black, 14.9% vs. 11.2% in Asian, 19.8% vs. 17.3% in Hispanic⁷. Limited income adversely affects the nutrition intake of older adults⁸.

Food and nutrition insecurity. Food insecurity and hunger can have profound impacts on nutritional status and health-related quality of life (QOL). Although food insecurity and hunger are often used interchangeably, the two are different degrees of the same indicators. Food insecurity is characterized by having inconsistent access and uncertainty in obtaining food, putting individuals at higher risk for malnutrition, chronic disease, and low QOL 24. The threat of food insecurity and hunger among older adults is rapidly increasing with about 15.8%⁹ being food insecure and 14.7% facing the threat of hunger ¹⁰. Older adults at greatest risk include those with a low income, those under the age of 70 years, being a person of color, and residing in the southern states ¹⁰. Food insecurity is correlated with lower energy and nutrient intakes, poor health outcomes, increased risk of early mortality and increased health care expenditures ^{11, 12, 10}. Food insecurity and hunger affect more aging women than aging men ¹⁰. In addition, food insecurity is associated with higher likelihood of having limitations performing activities of daily living (ADLs) ¹³. Older adults who were facing the threat of hunger are 30% more likely to report at least one ADL limitation¹⁰. In turn, due to food-related physical functional limitations such as food purchase and food preparation, the risk of food insecurity is increased. While food security is about economic and physical access to a certain quantity of food, nutrition security considers food quality. This concept is currently being developed.

The USDA NE-1939 Multistate Project “Changing the Health Trajectory for Older Adults through Effective Diet and Activity Modifications” team has conducted various studies to examine the determinants and outcomes of food security. In addition, the USDA Food Security tool was enhanced by developing, testing and validating a physical function food security tool to assess the full extent of food security among older adults attributed not only to economic causes but to physical function limitations as well. Further work is ongoing to examine the quality of the diet of individuals who are food insecure due to economic and physical functional limitations.

Nutritional Risk.  Nutritional risk increases with age. This is due to a variety of factors such as decreased appetite, chewing and swallowing difficulties, physical limitations, limited income, reduced social interaction, and chronic diseases. Nutritional risk encompasses both ends of the health spectrum, undernutrition and overnutrition, each with equally detrimental health consequences. The prevalence of malnutrition among older adults is problematic. A nutrient-poor diet is related to morbidity and mortality, physical impairments, functional disability and a greater frequency of admittance to hospitals and other long-term care facilities ¹⁴. The USDA NE-1939 Multistate Project “Changing the Health Trajectory for Older Adults through Effective Diet and Activity Modifications” team has conducted various studies examining the dietary practices of older adults. A three-state study revealed that 80.1% of older adults electing to take part in community nutrition programs were classified as “at nutritional risk” or “at possible nutritional risk” ¹⁵. Poor diets can have a profound effect on cell physiology altering inflammatory markers and oxidative stress, which contribute to telomere erosion and cellular senescence. Our work demonstrates the need for better understanding of the bidirectional relationships between the nutritional status of aging and the impact of nutritional status on health outcomes. An interdisciplinary approach would enable researchers to examine these issues at the cellular, individual and societal levels.

Dietary Intakes. A primary factor affecting the nutritional status of older adults is inadequate food and nutrient intakes. MyPlate recommendations suggest adults over age 50 years consume 1½ to 2 cups of fruits, 2 to 2½ cups of vegetables, 5 to 6 ounce-equivalents of grains, 5 to 5½ ounce-equivalents of protein and 3 cups of dairy daily ¹⁶. However, based on the Healthy Eating Index, only 18% of adults age 60+ years meet grain recommendations, 32% meet recommendations for vegetables, 34% meet total fat recommendations and between 23-27% consume the recommended amount of meat, dairy and fruit ¹⁷. Inadequate food intakes and aging can affect micronutrient status. For example, it is estimated that selenium status in 10% of Americans aged 40 or older is sub-optimal. These levels of marginal deficiency increase the susceptibility to age-related degeneration later in life. High dietary selenium intake has also been reported to increase muscle protein levels by 10-14% in adult pigs¹⁸. Inversely, whether or not a high protein diet affects body selenium status among aging adults is unknown. 

As people age, blood levels of the cardioprotective fatty acid, linoleate (18:2n6) decreases. The decrease in blood levels of linoleic status parallels the loss of skeletal and cardiac muscle function and lean mass¹⁹.  In addition, diminished linoleate status in older individuals coincides with diminished mitochondrial function in skeletal muscle that accompanies aging ^{20, 21}.  Exercise and a balanced diet may prevent muscle atrophy by targeting mitochondria ²².   

A dietary intake frequency assessment conducted by the NE-1939 multistate team revealed that the majority of community-residing older adults surveyed were consuming low intake frequencies of protein-rich foods, produce and whole grains ³⁹. In addition to examining whole food consumption among aging adults, the NE-1939 team is exploring specific nutrients including selenium and fatty acids.

Physical Activity. Physical activity is a key modifiable behavior that can attenuate chronic disease risk and improve physical functioning in older adults ²³. It also builds “physical reserves” so that if physical function declines resulting from illness or injury, individuals with greater physical reserves would be less likely to fall below the threshold for disability ²⁴. Thus, physical activity is a key component of healthy aging. Unfortunately, the vast majority of older adults are not engaging in the recommended levels of physical activity ²³.

Muscular Skeletal Health & Body Composition.  Adults can experience a 3 to 8% decline in muscle mass per decade beginning in their 40s and 50s; ²⁵muscle mass traditionally declines 30% to 50% between the ages of 40 and 80 years ²⁶. For this project, we use the definition of the Foundation for the National Institutes of Health Sarcopenia Project (FNIH-SP) that uses lean mass (absolute or relative to body mass) and physical function cut points to define sarcopenia ²⁷. The cut points have been shown to be independent predictors of incident mobility impairment in men and women ²⁸. Sarcopenia-related health care costs are substantial, with estimates ranging from $11.8 to $26.2 billion 32. A 10% reduction in sarcopenia prevalence could save upward of $1.1 billion annually in the U.S. ²⁹. Nearly half (46.6%) of these savings would occur if 10% of those with severe sarcopenia were able to improve to a moderate level of sarcopenia while the remaining 56.4% would occur if 10% of those classified with “moderate sarcopenia” moved to “normal” ²⁹. If sarcopenia were to be eradicated, about 26% of disability cases would be eliminated ²⁹.

Lifestyle practices of older adults, in particular physical inactivity and poor nutritional intake, and weight status (obesity) increase sarcopenia risk ³⁰. This provides a unique challenge when designing community-based exercise and nutrition programs. An effective sarcopenia prevention/treatment program must increase physical activity and promote healthy eating while preventing an energy deficit that promotes weight loss, which can adversely affect sarcopenia ³⁰. Establishing successful interventions that preserve and/or improve lean mass and physical function is crucial. There has been a significant effort to determine the most effective and efficacious interventions for treating sarcopenia and its associated symptoms ³¹; however, many efforts are not easily transferable to the community setting.

A study conducted as part of the NE-1939 project demonstrated that a 12-week periodized resistance training intervention strategy was effective in retaining appendicular lean muscle mass and improving muscle strength in women ages 65-84 years ³². The renewal project will further develop this work into a larger-scale, multistate intervention.

Importance of Work

Through our collaborative efforts, we identified community supports for increasing produce consumption among older adults ³³ and decreasing nutritional deficiencies that place aging adults at increased sarcopenia risk and nutritional risk in general ¹⁵. For example, we found that dietary selenium insufficiency induces age-related diabetes-like symptoms in association with accelerated telomere shortening ^{33, 34}. Other dietary interventions, such as fortifying diets with high-quality oils rich in linoleic acid appear to impact skeletal muscle mass ³⁵.  Additionally, we identified exercise modalities that offer promise in lowering sarcopenia risk and severity ³² and that nutritional risk is associated with shorter telomeres, a biological marker of aging ³⁶.

Building on our previous effort, a project renewal will provide the opportunity to expand on the work completed thus far by the members of the USDA NE-1939 Multistate Project “Changing the Health Trajectory for Older Adults through Effective Diet and Activity Modifications” from 2014 to the present. Further work can build on these findings to ascertain if shortened telomeres and the corresponding increase in cellular senescence contribute to sarcopenia.

The renewal project will focus on three objectives: (1) to identify biomarkers and molecular mechanisms contributing to healthspan, (2) to conduct multidimensional assessments of food security, nutritional status, physical activity and related factors affecting the aging population, and (3) to develop, implement and evaluate interventions that improve health in aging populations. Given the diversity of the current team, which includes experts from metabolic nutrition to Extension and Outreach researchers, our team is well-positioned to address the health and well-being of community-residing older adults from the laboratory to community. This provides a unique opportunity to work from the metabolic level to translational science.

We will also expand our reach to include those 40 years and older. This expansion of age inclusion is based on our present work that has illustrated the need to start interventions earlier than age 60 when applicable ^{37, 38, 32.}

The technical feasibility of the research.

Our team has a long-standing interest and a strong research record in the areas of lifestyle risk factors, dietary patterns, nutritional status, exercise/physical activity, physiology and health promotion. Each has extensive experience in one of five areas: metabolic nutrition, epidemiology, nutrition and/or physical activity interventions, qualitative research, nutritional science, and cell physiology. The proposed research is strengthened by our interdisciplinary approach that embodies translational research, taking it from the lab to the community. The project team has a successful work history, including project development, data collection, evaluation, and dissemination.

 The advantages for doing the work as a multistate effort.

This multistate aspect will provide the opportunity for team members to reach a diverse group of aging adults from around the United States. The multistate and institutional aspect allows us to collect data from a range of socioeconomic and ethnically diverse populations across rural, suburban and urban geographical areas. This multistate group currently covers the northeast, mid-Atlantic, Southern, and upper Midwest regions of the country. Second, the multistate nature of the project, which entails the utilization of standardized assessment tools used by all researchers, lends itself to establishing a large data set from which additional analyses can be conducted. Additionally, the collaborative nature of the proposed work will allow a better utilization of research funding on larger-scale, multi-purpose, comprehensive projects that embody translational research (lab to community).

Anticipated Impacts

The proposed multistate research team will train undergraduate and graduate students in qualitative research (e.g., conducting focus groups, analyzing focus group transcripts), quantitative research (e.g., data collection, data analysis), professional and scientific writing, laboratory skills, anthropometric measures, nutritional status assessment, dietary intake assessment, and physical function. The team will submit collaborative grant applications to external funding organizations and publish research findings in joint publications. The work conducted through our independent and collaborative efforts will (1) provide a better understanding of the dietary and physical activity needs of at-risk aging adults, (2) develop and implement effective strategies to address these needs, and (3) identify biomarkers related to the health of aging adults. Overall, these combined efforts will improve understanding of dietary intakes, physical function, quality of life (QOL), and food and nutrition security, lower sarcopenia risk, and reduce age-related diseases such as type 2 diabetes.