Пиколинат хрома, депрессия и контроль массы тела

A Duke University study validated that adding chromium supplements to diet significantly improved symptoms of atypical depression, and patients’ tendency to overeat. In the study, 75 people with atypical depression, most of whom were overweight or obese, received either 600 mcg per day of chromium (as chromium picolinate) or a placebo for eight weeks. The proportion of people who improved by at least 50% (responders) was greater in the chromium group than in the placebo group (54% versus 36%), although this difference was not statistically significant. However, significant differences were seen when the analysis was restricted to those people who reported that they had severe carbohydrate craving (a possible indicator of abnormal glucose metabolism). In that subset, the proportion of responders was 65% in the chromium group and only 33% in the placebo group, a statistically significant difference. No significant side effects were observed in people taking chromium.

 Chromium, Depression, and Weight Management

Булимия, блуждающий нерв, опиоидные и серотониновые рецепторы

The first major breakthrough in the treatment of bulimia came with the era of SSRI antidepressant medications. The initial motivation was a perceived link between bulimia and depression, which commonly exist as co-morbid disorders. Serotonin was clearly involved in some way in the mechanisms of active bulimia. In 1997, Prozac became the first drug ever licensed by the FDA for the treatment of bulimia nervosa. The drug’s formal approval was based on clinical studies showing median reductions in binging of as much as 67 per cent for Prozac, compared with 33 per cent for placebo. Vomiting was reduced by 56 per cent, compared to 5 per cent for female placebo users. (About 10 per cent of diagnosed bulimics are males.) While cure is too strong a word, the benefits were quite dramatic in some cases.

What about the roughly 50% of bulimics who do not respond to serotonin-boosting medications? Recent research covered by the science blog Neurotopia points the finger at a long nerve running through the cranium. The tenth cranial nerve, better known as the vagus nerve, branches through the neck, thorax and abdomen, and is involved in breathing, tasting, swallowing, and digestion. Most of the signal traffic carried by the vagus nerve is one way: from the body to the brain. Suspicion fell on the vagus nerve because of its direct involvement with one of bulimia’s most salient traits — the inability to feel normal levels of fullness, or satiety.

Bulimics must eat more at a sitting than non-bulimics in order to feel satisfied. There is evidence of vagus nerve involvement in meal satiation, portion size, and, notably, control of vomiting. Researchers have suggested that bulimics have a relatively insensitive vagus nerve, made even less sensitive by the debilitating cycle of overeating and vomiting. Hence, bulimia patients need greater vagus nerve stimulation in order to stop eating. Interestingly, studies have also shown that people suffering from bulimia have high pain thresholds, compared to non-bulimics.

This dysregulation of the vagus nerve responds to the drug ondansetron, according to recent research published in Physiology & Behavior by Patricia L. Faris and colleagues. The antiemetic effects of ondansetron, which reduce vagus nerve activity by acting on the 5-HT3 serotonin receptor, seem to decrease vomiting while increasing the number of normal meals eaten.

Finally, a third path toward treatment has been sparked by research on opioid receptors. Decreased endogenous opioid activity may also underpin bulimia. A small 2005 study by Johns Hopkins University School of Medicine analyzed the results of brain MRIs on eight bulimic women and eight controls. Bulimics showed decreased opioid receptor binding in the insula, another area of the brain implicated in MRI studies of addiction. The insula has been called the brain’s “gustatory cortex,” and it may be that the repeating cycle of binge and purge activates the opioid system. Opioid receptors are involved in the processing of the reward value of food. This suggests that a drug like naltrexone, which blocks opiate receptors, might also have a role to play in the treatment of bulimia.

Drugs for Bulimia