magnesium: A trace mineral used to make body tissue, especially bone.

manganese : A trace mineral that is found in your body’s glands and bones. It helps metabolize carbohydrates and synthesize fats, including cholesterol.

mercury: A heavy metal that is toxic to humans and commonly found in fish from polluted waters.

metabolic rate : The pace at which your body uses calories.

minerals : Nutrients composed of only one kind of atom. They’re inorganic, meaning that they don’t contain the carbon, hydrogen, and oxygen atoms found in all organic compound.

monounsaturated fat: A fat such as olive oil with a one carbon double bond. Such fats are liquid at room temperature, but thicken when chilled. Monounsaturated fats are known to reduce bad cholesterol.

mucous membranes: The moist tissues that line the eyes, mouth, nose, throat, vagina, and rectum.

myelin: The fatty material that sheathes nerve cells and makes it possible for them to fire the electrical messages that enable you to think, see, speak, move, and perform the multitude of tasks natural to a living body; brain tissue also is rich in fat.