Phenolics is a general term that applies to groups of chemicals having a common structure that occur naturally in humans, plants or animals. They are compounds that colour, flavour, and preserve foods and living organisms both naturally and as additives. Included in this group are hormones and neurotransmitters. These chemical compounds give us most of our sensory perceptions about the world around us. Three aromatic phenolic compounds are always found in proteins. They are phenylalanine, tyrosine and tryptophan. Degradation of these amino acids produces such chemicals as histamine, serotonin, tyramine and dopamine. Some phenolics are present in virtually every plant source. Phenolics play a major role in allergies, hypersensitivity, intolerances, behaviour and learning disorders and many chronic degenerative disease processes. Many people suffering from food sensitivities only partially improve when eliminating the food they are sensitive to rather than the implicated phenolic, because some phenolics occur in up to seventy different foods. For people with widespread food sensitivities, desensitizing phenolic compounds allows them to gradually return to a full diet. Some hormones and neurotransmitters can also be rebalanced by this method. Desensitizing hormones or neurotransmitters does not involve increasing or decreasing amounts naturally present in the body. It means reducing sensitivity and negative reactions to these chemicals.

From a list of 43, here are the ones Luke is sensitive to, and was desenstized to them:

Chlorogenic Acid: derivative of cinnamic acid that forms a dark plant pigment, siad to be responsible for the blackening of cut or cooked potatotes. Absence of chlorogenic acid causes bruising in apples. The second most widespread plant phenolic next to caffeic acid. Symptoms are asthma, hayfever, congestion and headaches, skin rashes, allergies to dust, pollens and molds

Epinephrine: hormone secreted by adrenal gland. Symptoms include asthmas, anxiety, tachycardia, vasoconstriction, insomnia

Gallic Acid: is a constituent of tannins and is found in 80% of all foods and food colouring. Symptoms include but are not limited to bowel problems, itching allergic rhinitis, migraines, sciatica, diarrhea, constipation, food allergies, sugar craving and sleep disturbance

Gliadin: protein found in gluten grains wheat, rye, spelt. Symptoms include diarrhea, constipation, Chrone's disease and Celiac disease.

L-Dopa: precursor of the neurotransmitter dopamine, used as a drug in the treatment of Parkinson's disease. Symptoms of sensitivity are Parkinson's, anxiety, depression and arrhythmia.

Lithium Benzoate: chemical element used as a lubricant in pressing tablets and as a drug used in the treatment of mania. Symptoms are cardiovascular, renal and nervous system related.

Serotonin: hormone an neurotransmitter found in blood platelets, intestinal mucosa, pineal body and nervous system, that influences sensory perception, temperature regulation and peristaltic motion. Sensitivity symptoms are insomnia, memory loss, aggression, dyslexia, obsessive-compulsive behaviour.