on June 25, 2026
Aging is one of the major demographic changes of our time and poses new challenges for preventive and nutritional medicine. Among these, one of the most common and often underestimated conditions is malnutrition.
When people talk about malnutrition, they tend to think instinctively of extreme food deprivation or contexts of severe poverty. In reality, the clinical meaning of the term is much broader and includes all situations in which the body receives, uses, or metabolizes nutrients inadequately in relation to its needs.
This means that a person can be malnourished both because they eat too little and because their diet is unbalanced or does not provide adequate amounts of essential nutrients.
In older people, malnutrition is particularly complex because seemingly opposing conditions often coexist: overweight, obesity, muscle loss, frailty, and declining nutritional status.
Understanding the mechanisms that lead to malnutrition means developing effective strategies to preserve independence, physical strength, and quality of life.
What is malnutrition?
Malnutrition is defined as a condition characterized by changes in body composition and biological functions due to an imbalance between:
- the body’s needs;
- nutritional intake;
- nutrient utilization.
The consequences can affect:
- body structure;
- metabolism;
- the immune system;
- muscle function;
- clinical recovery;
- survival.
According to the international GLIM (Global Leadership Initiative on Malnutrition) criteria, diagnosis requires the integration of clinical data, weight loss, reduced muscle mass, and assessment of associated pathological conditions.
Why older people are more vulnerable to malnutrition
Older age brings physiological changes that make it harder to maintain adequate nutritional balance.
Among the most significant factors are:
Reduced appetite
With age, the body’s physiological hunger signals weaken.
This phenomenon is known as anorexia of aging.
Contributing factors include:
- hormonal changes;
- slower gastric emptying;
- neuroendocrine changes.
Changes in taste and smell
Reduced sensory perception diminishes the enjoyment of meals and often leads people to eat less.
Dental problems and chewing difficulties
Tooth loss or poorly fitting dentures can limit the consumption of nutrient-rich foods.
Chronic diseases
Many conditions increase nutritional risk:
- diabetes;
- heart failure;
- respiratory failure;
- cancer;
- neurological diseases.
Polypharmacy
Taking several medications at the same time can affect:
- appetite;
- intestinal absorption;
- taste perception.
Reduced independence
Financial difficulties, social isolation, or functional limitations can make meal preparation difficult.
Overweight and obesity in older people: the malnutrition paradox
A little-known fact is that overweight and obesity do not rule out malnutrition.
An older person may have:
- excess body fat;
- reduced muscle mass;
- nutritional deficiencies.
This condition is defined as sarcopenic obesity.
Italian data from the Passi d’Argento surveillance system have shown that more than half of people aged 64 and over are overweight.
With increasing age, however, the prevalence of unintentional weight loss and underweight increases.
The consequences of excess weight in older adults
Excess weight has consequences that go beyond a simple increase in body weight.
Reduced mobility
Increased body load makes it more difficult:
- to walk;
- to stand up;
- to maintain balance.
Respiratory deterioration
Excess body fat increases the work of breathing and promotes exertional dyspnea.
Musculoskeletal overload
The joints, already affected by age-related changes, are subjected to greater mechanical stress.
Increased cardiovascular risk
Excess body fat contributes to:
- hypertension;
- dyslipidemia;
- diabetes;
- atherosclerosis.
When the opposite problem prevails: undernutrition and sarcopenia
In older age, the picture often changes.
The following become more frequent:
- unintentional weight loss;
- reduced muscle mass;
- decreased strength.
Sarcopenia is one of the main consequences of protein-energy malnutrition.
When the body does not receive sufficient nutrients, it uses muscle as its main metabolic reserve.
Muscle mass and aging
Muscle does not only perform a motor function.
It participates in:
- glucose metabolism;
- energy balance;
- immune function;
- myokine production;
- bone health.
With the passing of the years, muscle develops a reduced sensitivity to nutritional stimuli, a phenomenon defined as anabolic resistance.
This makes an adequate protein intake necessary.
Nutrition in older adults: principles of prevention
The diet should be:
varied;
complete;
easy to chew;
nutrient-rich.
Key elements:
vegetables;
fruit;
legumes;
whole grains;
extra virgin olive oil and omega-3-rich vegetable oils;
fish;
eggs;
high biological value protein sources.
Particular attention should be paid to the quality of the proteins.
The role of proteins
The main scientific societies suggest:
about 1.0–1.2 g/kg/day of protein in healthy older adults;
1.2–1.5 g/kg/day in the presence of frailty or chronic diseases.
Distributing protein across different meals can help support muscle protein synthesis.
Particular interest is focused on essential amino acids and leucine, which is involved in activating protein synthesis.
Physical activity and nutrition: an integrated strategy
Nutrition alone is not enough.
Regular physical activity:
- stimulates the maintenance of muscle mass;
- improves metabolism;
- reduces the risk of falls;
- preserves autonomy.
Age-adapted exercises can also produce clinically relevant benefits.
Malnutrition in older adults is a complex condition that includes both nutritional excess and deficiency.
Early recognition of weight loss, reduced strength, changes in appetite, and changes in body composition allows for intervention before frailty and loss of autonomy develop.
Adequate nutrition, combined with physical activity and monitoring of nutritional status, is one of the most important tools for promoting active and healthy aging.
Bibliography
Cederholm T et al. GLIM criteria for the diagnosis of malnutrition. Clinical Nutrition. 2019.
Volkert D et al. ESPEN guideline on clinical nutrition and hydration in geriatrics. Clinical Nutrition. 2019.
Cruz-Jentoft AJ et al. Sarcopenia: revised European consensus on definition and diagnosis. Age Ageing. 2019.
Cruz-Jentoft AJ, Sayer AA. Sarcopenia. Lancet. 2019.
Morley JE. Anorexia of aging. Physiological Reviews. 2001.
Deutz NEP et al. Protein intake and exercise for optimal muscle function with aging. Clinical Nutrition. 2014.
Bauer J et al. Evidence-based recommendations for dietary protein intake in older people. JAMDA. 2013.
Houston DK et al. Dietary protein intake and lean mass change in older adults. American Journal of Clinical Nutrition. 2008.
Landi F et al. Protein intake and muscle health in old age. Nutrients. 2016.
Passi d’Argento. Elderly Surveillance System. Istituto Superiore di Sanità.
