a native hydrous magnesium silicate, sometimes with a small amount of aluminum silicate; used as a dusting powder. The inhalation of talc is associated with a wide variety of respiratory disorders.
Factors contributing to poor sleep include vitamin and mineral deficiencies. Magnesium deficiency can cause insomnia; lack of potassium can lead to difficulty staying asleep; and vitamin D deficiency has been linked to excessive daytime sleepiness.
In response, other studies propose that increasing vitamin D levels with supplements may reduce depressive symptoms. But new research, published in the journal Psychosomatic Medicine, has found no evidence that vitamin D supplements reduce depression.