This 12-week ONS supplementation trial demonstrated significant improvements in several physical functioning and activity parameters in the test group in comparison to the controls. These included HGS, KES, gait speed, and Barthel index scores, as well as physical activity levels measured by the PASE and the IPAQ. Interestingly, all outcome measures also exhibited a notable enhancement in the IG compared to their respective pre-intervention results.
The increase in life expectancy worldwide has led to a growing elderly population, and the prevalence of malnutrition among older individuals is a global issue [1]. The proportion of people aged 60 or above was 9.8% in 2017 in South East Asia. It is predicted to increase to 13.7% and 20.3% by 2030 and by 2050, respectively [1] respectively. Sri Lanka is one of the South Asian countries with a rapidly aging population, undergoing a rapid epidemiological and nutritional transition. With the improvement of healthcare facilities in Sri Lanka, the elderly population has been increasing gradually during the past few decades. It is estimated that one in four Sri Lankans will be an elderly person by the year 2041 making Sri Lankans the oldest population in South Asia [27]. It has also been reported that over 50% of elders in some elderly care institutions in Sri Lanka are malnourished [28]. The same research publication has stated that a considerably higher proportion (59.1%) of elderly people living in elderly homes in Kandy were at risk of being malnourished while 3.8% were malnourished [28]. According to another study conducted in a community dwelling in Kandy district, 12.5% of the adults were malnourished whereas about half (52.4%) were at risk of malnutrition [3]. A similar kind of community-based study in relation to nutritional status in Galle district has stated that 0.5% elderly were malnourished and 30.8% were at risk of malnutrition [29].
Although, regions across the world are experiencing similar demographic shifts, the prevalence of malnutrition in older adults varied considerably due to variations in both the tool used for its assessment and the respective population [30]. The prevalence, factors contributing to malnutrition and the strategies to address may be influenced by a multitude of factors across various geographic and socio-economic contexts, cultural practices and healthcare infrastructures. Meanwhile, our study was aimed to assess the impact of ONS in addressing malnutrition among older adults in Sri Lanka.
Weak grip strength, which is indicative of sarcopenia, has been consistently associated with poor health outcomes [31]. Our study findings are consistent with the significant improvements reported in HGS on ONS in previous literature. For example, a 12-week supplementation of a mixture of nutrients, including HMB, arginine, and lysine, resulted in a notable enhancement of HGS and positive trends in FFM [32]. These findings indicated that this ONS positively impacts functionality, strength, FFM, and protein synthesis among the elderly [32].
HGS is also an important marker of the health of the arm muscles, so important in ADLs [33] such as opening medication containers, carrying grocery bags, pushing doors, and using kitchen utensils. Many tasks become markedly more challenging when HGS is diminished and can lead to further restrictions in ADLs, including reducing the frequency one can leave their home and negatively impacting their functional, psychological, and social well-being [34]. An optimal hand grip strength is not only of great importance in activities related to feeding, and personal hygiene tasks, like bathing and grooming, but also in leisure-time hobbies. Recreational pursuits including playing a musical instrument, painting, knitting, or gardening, may be impacted by poor overall health as reflected by grip strength. This also extends to handling household tools like hammers, screwdrivers, or wrenches during simple repairs or maintenance around the house [34]. Hence, it is crucial to maintain HGS, as it is also related to joint mobility and muscle strength, and ultimately contributes to an improved QOL among the elderly population [35].
A significant finding was that participants who received ONS demonstrated the greatest improvement in KES. This result also aligns with findings from the trial conducted by Yamada and co-workers. Participants undergoing a 12-week program of resistance exercise, protein supplementation, and vitamin D supplementation achieved the most substantial improvement in muscle quality and strength, among sarcopenic or dynapenic older adults [36]. A study by Liao and colleagues investigated the efficacy of a combined intervention involving resistance exercise training and protein supplementation in promoting the recovery of walking speed among individuals with knee osteoarthritis and sarcopenia [37] and found that the 12-week treatment enhanced the therapeutic effects by accelerating the time required for walking speed recovery to a level equal to or greater than 1.0 m/s. This improvement in walking speed not only helps reduce the severity of the disease but also has the potential to minimize the risk of sarcopenia in these patients [37]. In another RCT, performing thirty minutes of heavy-load strength training three times per week, along with protein supplementation, resulted in increased leg lean mass, as well as improvements in strength and functional capacity among older adults with limited mobility [38].
Perhaps the most striking finding of the current study was the substantial increase in the physical activity level measured by the PASE and the IPAQ among the IG participants in comparison to the CG. This result can be attributed to an improvement in muscular strength due to the implementation of the ONS intervention. Similar outcomes were observed in a trial conducted by Yoshimura and team [39], wherein a group of elderly individuals in a rehabilitation hospital underwent a combination of resistance training and ONS for a period of 2 - 6 months. Another parallel study examining the effects of a hyperproteic, hypercaloric ONS combined with a standardized physical intervention on the functional status and QOL of frail institutionalized older adults [40] also yielded promising results. Improvements were observed in the level of physical functionality measured using the Short Physical Performance Battery and the Short-Form Late-Life Function and Disability Instrument. Additionally, participants exhibited enhanced QOL, particularly among those with greater frailty criteria, lower functional levels, lower vitamin D levels, and poorer nutritional status. Researchers concluded that the 12-week intervention involving ONS alongside physical exercise not only improves function and muscle strength but also enhances their overall QOL.