Odor Associated with Aging

Human body odor is generated by waste materials present on the skin surface and secretions from the sweat and sebaceous glands. These waste materials are converted to characteristic odorous compounds through oxidative degradation or metabolism by skin microbes. Changes in body odor due to aging relate to the amount and composition of sweat and sebum secreted, as well as gland activity. 2-Nonenal has an unpleasant, greasy, grassy odor and is mainly detected in people aged over 40 years. Generation of 2-nonenal is related to oxidative degradation of ω7 unsaturated fatty acids. Given that body odor may function as a barometer indicating the body's overall health, further understanding of this odor's makeup is important. Here, we define several types of body odor and describe changes in body odor, with a specific focus on 2-nonenal, an odor characteristically associated with aging.