Foods feed both matter and mind.
"Dhanwantari, deity of Ayurveda"
by Menno Dijkhuys
(Click the picture for a larger image)
The seven dhatus are the principle constituents of the body, literally the "body tissues." They need nourishment and give form to the physical body. Rasa as plasma or "nutritive juice" is the most essential dhatu that is derived from food, and all other dhatus are derived from it. The plasma is the watery solution that carries the free chemicals in our blood, among which are the neurotransmitters and many substances that affect neurotransmitter activity. The science of Ayurveda regards plasma as both the carrier of essential nourishment and the promoter of happiness.
According to Ayurveda, foods affect our emotions through the direct effect of taste (rasa), through the effect during digestion (virya), and the effect after digestion (vipaka). The resulting doshas and gunas stimulate the occurrence of particular Rasas. Thus all foods are moodfoods.
Some foods may have toxic effects on our emotional well-being. Meat is emotionally toxic primarily because it contains large amounts of neurotransmitters created by the fear and pain of the dying animal. Eating organic foods is another way to avoid emotionally toxic substances.
Bad digestion means that many toxins are being produced inside the intestines. The organs of the digestive system are heavily loaded with receptors as well as production centers for information molecules that affect our emotions without our being conscious of it.
"Moodfoods" - as foods that have particularly high effects on the emotions - are becoming more and more popular. There is nothing wrong with eating in accordance with this approach as long as it is applied honestly and in moderation. Ayurvedic knowledge regarding the effects of specific moodfoods may be used to control specific Rasas, keeping in mind that such an approach is absolutely secondary to eating properly balanced food.
Many moodfoods give people the idea that happiness can be bought. The stronger these mood products become, the more they contribute to the creation of a culture of drug addiction. The use of antidepressants, calming agents, and stimulating agents is already extremely high in Western society, even though it is often legally limited to prescription by doctors. Less powerful mood products and moodfoods easily escape legal prescription, leaving the doors wide open for abuse. Products that are designed to alter moods (as all products are, even without their makers being conscious of it) should be really mild.
The above texts on moodfoods were extracted from the book "The Yoga of the Nine Emotions", which fully explains these subjects.