People are familiar with vanilla flavor through foods, cosmetics, household products and some medicines. Vanilla flavoring agents usually contain vanillin or its analogue ethyl vanillin.

Previous data suggest that the inhalation of eugenol, which contains a vanillyl group, has the potential to enhance appetite. Additionally, the inhalation of aroma compounds containing the vanillyl group or its analogues tend to increase food intake in experimental models.

In a study by Ogawa and colleagues, researchers noted that vanillin, ethyl vanillin and eugenol had appetite-enhancing effects, while isoeugenol and safrole did not have such effects. The appetite-enhancing effects could be attributed to the vanillyl group and could possibly be affected by the position of the double bond in the aliphatic chain.

The results of intraperitoneal administration of eugenol and vanillin have also shown that their appetite-enhancing effects could occur through the stimulation of olfactory receptors.

Source: Ogawa K, Tashima A, Sadakata M, Morinaga O. Appetite-enhancing effects of vanilla flavours such as vanillin. Journal of Natural Medicines 2018;72:798–802.