Enhancing central and peripheral insulin activity as a strategy for the treatment of endogenous depression--an adjuvant role for chromium picolinate?
Depression is often associated with insulin resistance, owing to cortisol overproduction; conversely, many studies suggest that diabetics are at increased risk for depression. Recent evidence indicates that insulin is transported through the blood-brain barrier and influences brain function via widely distributed insulin receptors on neurons. These receptors are particularly dense on catecholaminergic synaptic terminals, and, while effects are variable dependent on brain region, several studies indicate that insulin promotes central catecholaminergic activity, perhaps by inhibiting synaptic re-uptake of norepinephrine. Additionally, it is well known that insulin enhances serotonergic activity in increasing blood-brain barrier transport of tryptophan. Since impaired monoaminergic activity in key brain pathways is believed to play an etiological role in depression, techniques which promote effective insulin activity, both centrally and peripherally, may be therapeutically beneficial in this disorder. This may rationalize anecdotal reports of improved mood in clinical depressives and diabetics receiving the insulin-sensitizing nutrient chromium picolinate. This nutrient, perhaps in conjunction with other insulin-sensitizing measures such as low-fat diet and aerobic exercise training (already shown to be beneficial in depression), should be tested as an adjuvant for the treatment and secondary prevention of depression.
Nutrition 21, San Diego, California 92109.
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D001921:Brain / Q000378:metabolism; D017024:Chemotherapy, Adjuvant; D003863:Depression / Q000188:drug therapy* / Q000517:prevention & control; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D010848:Picolinic Acids / Q000627:therapeutic use*; D011972:Receptor, Insulin / Q000378:metabolism
D007328:Insulin; D010848:Picolinic Acids; D011972:Receptor, Insulin; C030614:picolinic acid