Since the beginning of civilization, humans have used fragrances to enhance their daily lives and enhance special occasions. Up until the mid-nineteenth century, all fragrances were naturally derived. But in the early 1830's scientists learned how to isolate and identify the chemicals responsible for aromas. The first of these were cinnamic aldehyde from cinnamon oil and benzaldehyde from bitter almond oil. In the 1920's, the first completely synthetic perfume, Chanel No.5, was marketed and from there the synthetic perfume industry skyrocketed.
At present, natural fragrances and essential oils are making a strong comeback in the fragrance industry. This is due in part to the emerging science and art of aromatherapy and the rising incidence rates of chemical sensitivities, allergies, and asthma. Consumers and scientists now believe there is a connection between the proliferation of fragrance chemicals of all kinds and these maladies. The cosmetics industry has responded with a dizzying array of products — unscented, fragrance-free, made with essential oils or naturally scented — to meet the needs of a variety of consumers. What do we know about the science of smelling and what do terms such as "fragrance free," "made with essential oils," and "naturally scented" mean?
Olfactory Science
Our sense of smell and our emotions appear to be inextricably linked. The olfactory bulb that controls our sense of smell is juxtaposed with the limbic system (a.k.a. "emotion central") making our nasal passages one of the most direct connections to our brains. However, studying exactly how this direct link affects our health has proven challenging. Compared to our vision and our hearing, our sense of smell is not well understood. Furthermore, the human perception of smells is subjective and people suffering from symptoms associated with a fragrance may have great difficulty in distinguishing between psychological irritation from an unpleasant odor and physical sensory irritation from volatile chemicals. Some skeptical researchers believe that people fear negative consequences when the offensive odor may actually be benign. Finding the extent to which fragrance chemicals irritate or otherwise harm us is a difficult task. According to Betty Bridges of the Fragranced Products Information Network, the fragrance industry does not have a centralized program for collecting data on fragrances. In addition, the regulation of fragrances is split among at least three different government agencies: FDA, Consumer Products Safety Commission and EPA.
Current research is underway to explain the link between our sense of smell and sensory irritation and allergies. Researchers from the University of California at San Diego are trying to establish the levels at which chemicals first become odorants and then progress to irritants. So far they have succeeded in finding threshold levels for several chemical mixtures. They have also found some evidence to support the notion that chemicals in combination are more irritating at lower levels than single compounds. The problem with sorting out the effects of fragrances is that they can stimulate both the olfactory nerve and the trigeminal nerve. The trigeminal nerve is responsible for mediating physiological irritation (causing sensations of stinging, burning, and tingling). These symptoms are often mistaken for allergic reactions, but are really irritation reactions. A true allergy causes a generalized immune response in the body and includes the production of antibodies. An irritation is typically localized and is not accompanied by a system response in the body. This distinction is important because the allergies and irritation reactions may require different treatments. Additional data from a study following 112 people with Multiple Chemical Sensitivities (MCS) found evidence that MCS involves two distinct phases: a high level chemical exposure that is exacerbated by later exposure to everyday chemicals. This suggests that for people with MCS, fragrances can be very problematic.
The following definitions can help clarify the labeling of household and body care products so that consumers can select the most beneficial, as well as least problematic, products for their individual needs.
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