With age, the physiological responses to occasional or regular stressors from a broad range of functions tend to change and adjust at a different pace, restoring these functions in the normal healthy range becomes increasingly challenging. Even if this natural decline is somehow unavoidable, opportunities exist to slow down and mitigate the impact of advancing age on major physiological processes, which, when weakened, constitute the hallmarks of ageing.
Nutrition is a modifiable factor affecting the quality of life and independence of older people. The physiological, psychological and social changes during ageing affect their dietary choices. The physiological, psychological and social changes during ageing affect the dietary choices of older people.
The loss of skeletal muscle mass and the concomitant increase in body fat mass that occur with ageing are accompanied by weakness, low physical activity and a lower resting metabolic rate. Moreover, the natural loss of taste and smell may lead to decreased appetite and poor dietary habits. Age-related diseases and polypharmacy often interfere with the ingestion, absorption and metabolism of food; in addition, dental conditions influence the dietary habits of older adults and potentially further compromise their nutritional status.
Furthermore, eating habits are strongly influenced by social and psychological changes that occur with ageing. Low income or poverty, together with the need to buy medications, can mean that some older persons are financially unable to meet their nutritional needs. Loneliness and the increased likelihood of eating alone influence dietary intake, as older adults who eat with other people tend to consume more than those who eat alone. Finally, age-related psychological factors, such as depression, which is extremely common in the older population, are important determinants of energy balance.
Nutrition is a modifiable factor that influences the incidence as well as the progression of chronic diseases and has a major role in quality of life. Clinicians should support older adults to ensure that their energy and nutrient needs are met. Modifying the ageing trajectory may be achieved by identifying a series of important players in the ageing process and targeting them through interventions such as diet and lifestyle modifications, which would help curb the functional decline in different biological systems.
Nutritional strategies to promote healthy ageing:
Improving nutrient intake and metabolism: Interventions to improve hunger in the elderly have been shown to increase energy and nutrient intake and reduce age-associated weight loss. These interventions include serving smaller energy-enriched portions, favouring liquid versus solid textures (e.g. smoothies), or even improving the meal environment. Micronutrient supplementation has also shown benefits in improving micronutrient status in older adults
Supporting digestion and nutrient absorption: Maintaining a healthy gut microbial environment, known to promote an anti-inflammatory state and consequently promote digestion and absorption of nutrients, constitutes a relevant target to increase nutrient availability from the gut.
Optimising energy metabolism: Age-related anabolic resistance, especially in the postprandial state, leads to blunted postprandial muscle protein synthesis, which, if sustained, results in lower muscle mass and strength
Limiting inflammation: Low-grade inflammation is a ubiquitous condition in older adults related to multiple age-associated factors, namely oxidative stress, DNA damage, infection history and dysbiosis. Inflammageing is a main contributing factor to tissue damage and the decline in immunity, mobility, brain, heart, and gut health.
Mitigating oxidative stress: High ROS production in the gut is associated with increased inflammation, low SCFA production, and dysbiosis, all deleterious to gut and systemic immunity. Oxidative stress is also a major contributor to the loss of bone mass and strength.
Promoting gut microbiota balance: Improving microbiota composition or the balance between beneficial microbiota and pathobionts thus represents a central target for the maintenance of gut barrier integrity, immunity, and subsequently, general health and wellbeing.