Catabolic Wasting - Cachexia and Sarcopenia
Dietary and Lifestyle Considerations
Exercise is critical for maintaining muscle mass in those with cachexia and sarcopenia and is most effective when coupled with proper nutrition (Churchward 2013; Solheim 2012; Penna 2011; Schols 2002). A review of 49 published studies of resistance training programs of ≥ 8 weeks in adults ≥ 50 years reported an average lean weight gain of 2.4 pounds (Peterson 2011). Some studies have reported that weight training is effective even in very old people. A study of 10 frail, aging adults (average age 90 years) reported that an 8-week weight resistance training program was associated with an average 174% gain in muscle strength and an average 9% increase in the mid-thigh muscle area (Fiatarone 1990).
Exercise is also useful for patients with muscle wasting due to HIV/AIDS, cancer, or other severe illnesses. A review of 9 published studies of HIV-positive subjects reported that resistance exercise was associated with an average weight gain of 11 pounds (Fillipas 2010). Another study of HIV-positive patients >60 years old reported that a weight training program (2 times weekly for a year) was associated with average strength gains of 52-133% and significantly faster walking speeds (de Souza 2011).
Researchers reviewed 16 published studies on the effects of exercise on muscle strength/mass in cancer patients. Most of these studies involved patients with cancers of the breast, prostate, or blood (such as leukemia); most patients had low to moderate stage cancers. The studies demonstrated that compared to usual care, resistance exercise improves upper and lower body muscle strength (Stene 2013).
Multiple studies have reported that many types of resistance and aerobic exercises are useful for maintaining muscle mass in the elderly (Montero 2013). However, there is little information comparing muscle building effects of various forms of exercise in elderly individuals (eg, land-based versus water exercises). Research is currently underway to develop optimal exercise strategies for people with muscle wasting (de Souza 2013).
While exercise is best, research has also been undertaken to determine whether electrical stimulation can be useful in maintaining muscle mass in the elderly. Electromyostimulation is often useful for bedridden persons or those with limited mobility who have difficulty walking or doing standard exercise. Electromyostimulation or electrical muscle stimulation involves stimulating muscle contraction with low level electrical impulses applied to the muscles by electrodes. One study used electromyostimulation 3 times bi-weekly for 54 weeks on a group of 76 aging women (average age 75 years). After 54 weeks, the electromyostimulation-treated women gained an average of 0.8% of lean mass while control women lost an average of 0.8% (Kemmler 2013).
Another method to increase muscle mass and strength in people who find traditional exercise difficult is whole-body vibration (WBV) training. In WBV, oscillations are transmitted vertically from the feet to the rest of the body by using vibrating platforms. This recently-established training method was shown to stimulate muscle strength and power in healthy individuals and to improve gait and balance in older people (Chanou 2012). A study of 13 older women (average age 79 years) reported that WBV training for 10 weeks (3-5 times weekly for 7 to 22 minutes) significantly increased thigh muscle cross-sectional area and strength compared to 13 matched control women (Machado 2010).
For very ill people, regular exercise may be impossible. However, they should be encouraged to move if possible; even if only to sit up and walk a short distance to the bathroom. Total bed rest impairs protein synthesis in older adults (Drummond 2012).
Avoiding smoking and secondhand tobacco smoke is important in preventing and treating catabolic wasting. A number of studies have reported that smoking significantly increases the risk of sarcopenia. Smoking and exposure to toxins associated with smoking increase the risk for muscle wasting in at least 4 ways: 1) reducing appetite, 2) inhibiting protein synthesis, 3) increasing protein breakdown, and 4) increasing the body’s levels of myostatin (ie, a natural protein that inhibits muscle growth) (Petersen 2007; Rom 2012).
Consume Adequate Protein and Amino Acids
Older adults may need more protein than current government guidelines indicate. The recommended dietary allowance (RDA) of protein for adults 19 years and older is 0.8 g/kg (1 kg = 2.2 pounds) of body weight daily (Mithal 2013). A number of studies have reported that consuming less than the 0.8 g/kg is associated with significantly lower lean mass in older adults (Scott 2010; Houston 2008). It is now generally recommended that older adults consume from 1.0 to 1.2 g/kg body weight of protein daily (Mithal 2013; Wolfe 2008). This corresponds to 70-84 g protein for a 70 kg (154 pound) person. However, there are some concerns that a higher protein intake may be harmful to those with kidney disease (Martin 2005). People with depressed kidney function should consult with a physician before consuming supplements with protein and amino acids.
Moderate consumption of lean meat and fish may also be useful for people with muscle wasting. A study of 19 elderly men enrolled in a weight training program reported that consuming a “mixed” diet containing meat and fish and an average of 91 g of protein daily for 12 weeks was associated with larger gains in muscle strength and mass compared to a group eating a lacto-ovo vegetarian diet containing milk and eggs but no meat or fish (average 71 g of protein daily) (Campbell 1999).
Individuals with sarcopenia may need higher levels of protein and amino acids in their diet to overcome “anabolic resistance” (ie, a condition in which the body becomes less efficient in converting dietary protein into body protein). Anabolic resistance is common in older individuals with sarcopenia or people with HIV/AIDS- or cancer-related cachexia. Higher levels of dietary or supplemental protein and amino acids are needed to overcome anabolic resistance. The branched-chain amino acid leucine plays a critical role in stimulating protein synthesis in sarcopenic people (Dardevet 2012). Leucine is found in greatest concentrations in animal proteins, especially whey from milk (Hayes 2008; Phillips 2009). Leucine is also readily available as a dietary supplement.
Other Nutrition-Related Factors
Ensuring cachectic patients consume adequate calories each day is of paramount importance. Caloric needs vary with body size, and individuals with similar degrees of weight loss as a result of different diseases may have different caloric needs. Generally, evidence suggests that caloric needs of most cachectic patients can be satisfied by consuming between 25 and 35 calories per kg (2.2 pounds) of ideal body weight per day (Bonet Saris 2011; Jiménez Jiménez 2011b; Nicolini 2013; Diaz 2004).
Difficulties chewing and swallowing can also negatively impact nutrition in people with catabolic wasting. Dental implants have been very helpful, and dentures supported by mandibular implants have been associated with increased nutritional intakes compared to standard dentures (de Oliveira 2004; Hutton 2002). Speech and swallowing therapy has been useful in many people with swallowing difficulties. Many individuals who cannot eat food by mouth and must be tube fed have been able to resume normal eating after speech and swallowing therapy (Logemann 2007).
Social support and eating meals with others can significantly increase nutrient consumption in frail, muscle-wasted elderly individuals (Wright 2006). Good mealtime ambiance (eg, good china/tableware, flowers, background music) has also been associated with better food intake in elderly individuals (Mathey 2001). Sufficient water should be consumed to avoid dehydration (Morley 2006).