Nutritional needs of a person vary according to energy expenditure and not merely as a function of age. A sedentary adult needs 25kcal/kg/day while an acutely ill older person under moderate stress may need more than 40kcal/kg/day. Intake and pattern of food sources tend to change with age. Older adults may need fewer calories to maintain their weight, but still need the same amounts (or even more) of vitamins and minerals as they did in their younger years as digestive changes can affect the way the body absorbs certain nutrients.
Cachexia in Dementia
There are many reasons why a person with advanced dementia might lose weight. Studies have shown that once dementia reaches its final stages, one in every two or three affected people will experience severe weight loss. Weight loss may occur despite the person with advanced dementia being given all the food they want. The cachexia anorexia syndrome is a complex metabolic syndrome associated with dementia and has been defined as involuntary weight loss involving both fat and muscle, due to shifts in metabolism. It is characterized by-
- Severe weight loss
- Severe decrease in fat-free mass
- Increased metabolic rate
- Physical activity decreased
- Increased proteolysis
- Insulin resistance
- Increased cytokines
Investigators hypothesize that chronic production of negative regulatory cytokines can explain the nonspecific responses resulting in cachexia. Recently, cytokine immunotherapy with genetically engineered substances for viral diseases, cancer, and autoimmune diseases has also provided confirmation of the involvement of cytokines in anorexia. Cytokines are cell-associated proteins produced and secreted by inflammatory cells that have the capacity to act at low concentrations on other cells both locally and systematically via specific cell receptors.
In muscles, they lead to decreased protein synthesis and increased activity of the ubiquitin-proteasome system and catabolism. In liver, decreased albumin synthesis, decreased lipoprotein lipase activity, hyperlipidemia and increased acute phase reactants e.g. CRP are observed. The gastrointestinal tract also shows decreased gastric emptying & decreased intestinal mobility while central nervous system is marked by Anorexia and cognitive dysfunction.
Quantifying nutritional intake is best preformed by a dietitian. Different methods can be used. Twenty-four hour recall is commonly used and is based on an interview during which the patient recalls all food consumed in the previous 24 hours.The main disadvantages are that it represents only food intake for 1 day and may not represent a patient’s typical intake. Data can also be affected if the patient has cognitive impairment. Food records for 7 days for all food and drink consumed can be used and help eliminate day-to-day variations.
A large number of clinical signs indicate nutritional deficiencies. The general impression is a wasted, thin individual with dry scaly skin and poor wound healing. The hair is thin and nails are spooned and depigmented. Patients complain of bone and joint pain and edema. Specific nutritional deficiencies are associated with specific clinical signs
Many older people do not have their own teeth – 59% aged 65 to 74 use dentures according to one survey. Poor dentition and ill-fitting dentures may limit the type and quantity of food they eat. Chewing problems are associated with a greater likelihood of poor health and decreased quality of life. Depression is common in older people and can present in 2% to 10% of the community. One of the most common presentations is loss of appetite and weight loss. It has been documented that 30% to 36% of weight loss seen in outpatients and the nursing home is due to depression. An inverse relationship between energy intake and cognition has been shown in hospital patients with dementia. Weight loss and changed behavior are associated with late stage disease. Fifty percent of patients with Alzheimer’s cannot feed themselves 8 years after their diagnosis. Also olfactory changes occur in Alzheimer’s which may affect food intake. Older people living on their own and socially isolated tend to eat less. These same people eat up to 50% more with company.