June 16, 2021

Unintentional Weight Loss — A Symptom of Malnutrition in the Elderly

Written by: Maki Palad, M.D.
Reviewed by: Mubashar Rehman, PHD

Aging is an unavoidable process that puts the elderly individual at risk for disease and nutritional deficiency. Malnutrition, according to the World Health Organization, encompasses the imbalances in a person’s intake of energy and nutrition and includes three broad groups: undernutrition, micronutrient-related malnutrition, and overweight or obesity; however, malnutrition is often used interchangeably with undernutrition and in this article, we will focus on undernutrition in the elderly.

Nutrition is an interplay between several factors, including health problems and diminished organ system reserve; baseline level of activity and energy expenditure, caloric requirements; and socioeconomic factors such as food preference and access to a nutritional diet. Compromising any of these factors puts the elderly at risk for undernutrition, leading to frailty and higher mortality.
The prevalence of malnutrition in the elderly varies among sub-groups with around 6% among outpatients, community dwellers and rises to almost 30% among those in rehabilitation and long-term care facilities. Malnutrition, particularly disease-associated malnutrition, also poses an economic burden. In the United States, it is estimated that the annual cost is over $15.5 billion.
Malnutrition often goes unrecognized because of the common assumption that undernutrition in the elderly is inevitable and is just part of aging. However, spotting early symptoms of malnutrition contributes to the overall improvement of the physiologic and functional status of the aging population. Unfortunately, it is quite challenging to spot early signs of malnutrition because it is a gradual and insidious process.

Unintentional weight loss is a telltale sign! 

Unintentional weight loss is a telltale sign of malnutrition in the elderly. It reflects an individual’s nutritional status along with other factors that contribute to the decrease in nutritional adequacy. Studies show that weight loss, especially when it is unintentional, is associated with increased mortality. A clinically significant weight loss would be at least a 2% decrease of baseline body weight in one month, more than 5% decrease in three months, or more than 10% decrease in six months. A common initial sign is that their clothes, jewelry, and even shoes are getting loose. There are several factors leading to unintentional weight loss, including: 


Inadequate food intake 

• Social factors such as financial constraints affecting their ability to acquire a nutritious meal contribute to inadequate food intake. For example, those with limited income may have to spend their money on medications and bills rather than on food. 

• Malignancy and depression are the most important medical and psychiatric causes of weight loss in the elderly. 

 • Age-related decrease in physiologic function contributes to weight loss. For example, as we age, our taste and smell sensitivity decreases, digestion is delayed, we become full right away, and our natural regulation of food intake is impaired. 


Decrease in appetite

Because of the changes in taste and smell sensitivity in the elderly population, the desire to eat and the pleasure of good food decreases. They also have a decrease in energy needs; hence, much of their intake is reduced. 


Loss of muscle mass 

Even without an underlying medical condition, the elderly are prone to loss of muscle mass. This can be due to a low level of physical activity, changing metabolic function and hormones, and decreased protein intake. 


Underlying illness

An underlying medical condition, whether chronic or acute, greatly contributes to unintentional weight loss. 
Cachexia is a term to describe the complex mechanism of dysregulated metabolic processes that lead to muscle breakdown with or without fat loss. 


Clinical investigation and evaluation are important when you first notice unintentional weight loss in the elderly. Management of malnutrition is usually targeted when an underlying cause has been identified. Nutritional repletion is also equally provided. Some of the common interventions include lifting any dietary restriction as much as possible, assuring the quality of the food they eat and giving daily multivitamin and mineral supplements. 

Malnutrition, especially in the elderly, is largely under-recognized, and the burden it brings to the health system is actually preventable. However, given the detrimental impact it has on the aging population, plus the rising health costs to the economy, interventions should be given early on. 



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  2. Goates S, Du K, Braunschweig CA, Arensberg MB. Economic Burden of Disease-Associated Malnutrition at the State Level. PLoS One. 2016;11(9):e0161833. Published 2016 Sep 21. doi:10.1371/journal.pone.0161833
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  5. World Health Organization. What is malnutrition? 2016. www.who.int/features/qa/malnutrition/en (Accessed on May 13, 2021).


Article written by Maki Palad, M.D.
Maki is a medical doctor from Manila, Philippines.She also majored in Biology prior to pursuing a medical career. When she is not working, she does freelance writing for health blogs and websites. She also does volunteer work for telehealth consultations and onsite charity clinics. During her free time, she likes to spend it at home reading, binge-watching her favorite shows and working out.

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