WEIGHT LOSS OR GAIN
Weight fluctuations are common in CFS/ME. In the acute phase of the illness, and during relapses, weight loss is the rule, while in long-term cases there is a tendency to gain weight easily.
There are many competing theories to explain weight fluctuation in people with CFS/ME. Increases and decreases in weight can occur as the result of faulty cell metabolism, immune system overactivation, hypothyroidism or hypoadrenalism, loss of appetite due to excess catecholamine production (adrenaline), gastrointestinal upset, and carnitine deficiency. Hypothalamic dysregulation is, in all likelihood, the prime reason for weight fluctuation. The hypothalamus regulates the autonomic nervous system, which is responsible for all the unconscious aspects of maintaining homeostasis.
Essentially, the non-enteric aspects of the autonomic nervous system are divided into two components, sympathetic and parasympathetic. Sympathetic activation increases “fight or flight” responses, through the action of norepinephrine, while parasympathetic activation allows for digestion, slows heart rate, and facilitates the necessary resting activities of the body. There is evidence that weight loss is characterized by increased sympathetic activity, while weight gain is characterized by increased parasympathetic activity. Another function of the hypothalamus is to release leptin, the hormone that signals the body when it has eaten enough. Damage to the hypothalamus, or resistance to leptin, could result in continuing hunger, even after a meal has been eaten.
Experiments performed on rats over 50 years ago demonstrated that damage to the ventro-medial hypothalamus resulted in obesity, whereas electrical stimulation to the same region produced anorexia. More recent research has proposed that alterations in neurotransmitter activity in the hypothalamus, (specifically norepinephrine), are ultimately responsible for appetite.
The hypothalamus also controls thyroid and adrenal function, which have been shown to be abnormal in CFS/ME patients, as well as regulating aspects of the immune system. Since hypothalamic dysfunction is central in producing many other CFS/ME anomalies, there is good reason to suspect its involvement in appetite disorder and weight problems associated with this illness.
The sudden weight loss common in the acute stages of CFS/ME can be dramatic. First, surface fat reserves, then muscles seem to simply disappear. The reasons for the rapid weight loss are multiple. Many symptoms common in the acute stage (loss of appetite, gastrointestinal upset, changes in taste perception, exhaustion, difficulty swallowing, nausea, vomiting) are related to stimulation of the sympathetic nervous system. This results in a profound reduction in caloric intake. Lowered intake reduces the supply of available vitamin B complex, which in turn diminishes appetite. As intake is further reduced, nutritional deficiencies become established, leading to continuation of the vicious cycle.
Lack of food intake is not the only reason people lose weight in this stage. Immune system overactivity, in particular the expression of tumor necrosis factor (TNF), a cytokine released by activated T cells, causes severe weight loss. Dr. Nancy Klimas has found increased expression of tumor necrosis factor in patients with CFS/ME ( Journal of Chronic Fatigue Syndrome , 1995). In theory, the acute stage of the illness, when the immune system is overactive, may produce sudden weight loss due to the increased production of tumor necrosis factor. This is true even for patients who eat copious amounts of food.
CFS/ME patients have remarked that when their weight loss ends, and they begin to regain some of the weight they have lost, they see a general improvement in symptoms. Perhaps, this is due to the fact that regaining weight signals the end of the acute phase of the illness and the beginning of more stable metabolic processes.
Treatments that have been helpful in acute-stage weight loss include alpha ketoglutarate (a citric acid metabolite that halts wasting syndrome), L-carnitine, vitamin B complex, and general nutritional supplementation. Ensure, protein powders, and shakes are also effective in increasing weight. Antidepressants, mild tranquilizers (benzodiazepines), stress-reduction techniques (hypnosis, meditation) can all help increase appetite. Acupuncture is particularly effective in increasing appetite, and may be an attractive alternative to supplements for those with digestive system problems.