Peppermint, a source of small amounts of menthol, is believed to work by acting on receptors in the nasal mucous membranes, leading to a reduction of nasal stuffiness. Eucalyptus oil is often used in a steam inhalation to help clear nasal and sinus congestion.
Vitamin D is essential for maintenance of bone mineralization through the regulation of calcium and phosphorus homeostasis. Vitamin D also exhibits many non-skeletal effects, particularly on the immune, endocrine, and cardiovascular systems.
While calcium is necessary to build and maintain strong bones, it's vitamin D that aids in it's absorption. If you're not getting enough vitamin D, your bones could become weak, brittle, and even misshapen. A combination of vitamin D and calcium is necessary to prevent osteoporosis in older adults.