Question: About what percentage of people are sensitive to biogenic amines, such as histamines?
About the article "Yeast", section "Wine".

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Yeast is used in winemaking, where it converts the sugars present in grape juice (must) into ethanol.
Yeast is normally already present on grape skins.
Fermentation can be done with this endogenous "wild yeast," but this procedure gives unpredictable results, which depend upon the exact types of yeast species present.
For this reason, a pure yeast culture is usually added to the must; this yeast quickly dominates the fermentation.
The wild yeasts are repressed, which ensures a reliable and predictable fermentation.
Most added wine yeasts are strains of "S. cerevisiae", though not all strains of the species are suitable.
Different "S. cerevisiae" yeast strains have differing physiological and fermentative properties, therefore the actual strain of yeast selected can have a direct impact on the finished wine.
Significant research has been undertaken into the development of novel wine yeast strains that produce atypical flavour profiles or increased complexity in wines.
The growth of some yeasts, such as "Zygosaccharomyces" and "Brettanomyces", in wine can result in wine faults and subsequent spoilage.
"Brettanomyces" produces an array of metabolites when growing in wine, some of which are volatile phenolic compounds.
Together, these compounds are often referred to as ""Brettanomyces" character", and are often described as "antiseptic" or "barnyard" type aromas.
"Brettanomyces" is a significant contributor to wine faults within the wine industry.
Researchers from University of British Columbia, Canada, have found a new strain of yeast that has reduced amines.
The amines in red wine and Chardonnay produce off-flavors and cause headaches and hypertension in some people.
About 30% of people are sensitive to biogenic amines, such as histamines.
Amines are organic compounds and functional groups that contain a basic nitrogen atom with a lone pair.
Amines are derivatives of ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group.
Important amines include amino acids, biogenic amines, trimethylamine, and aniline; see :Category:Amines for a list of amines.
Inorganic derivatives of ammonia are also called amines, such as chloramine (NClH2); see :Category:Inorganic amines.
Compounds with the nitrogen atom attached to a carbonyl of the structure R–CO–NR′R″ are called amides and have different chemical properties from amines. 
There is a distinction between endogenous and exogenous biogenic amines.
Endogenous amines are produced in many different tissues (for example: adrenaline in adrenal medulla or histamine in mast cells and liver).
The amines are transmitted locally or via the blood system.
The exogenous amines are directly absorbed from food in the intestine.
Alcohol can increase the absorption rate.
Monoamine oxidase (MAO) breaks down biogenic amines and prevents excessive resorption.
MAO inhibitors (MAOIs) are also used as medications for the treatment of depression to prevent MAO from breaking down amines important for positive mood. 
TAAR6 belongs to the trace amine-associated receptor family.
Trace amines are endogenous amine compounds that are chemically similar to classic biogenic amines like dopamine, norepinephrine, serotonin, and histamine.
Trace amines were thought to be 'false transmitters' that displace classic biogenic amines from their storage and act on transporters in a fashion similar to the amphetamines, but the identification of brain receptors specific to trace amines indicates that they also have effects of their own. 
Trace amines and common biogenic monoamines.
Trace amines are those found in 0.1-10 nM concentrations, constituting less than 1% of total biogenic amines in the mammalian nervous system.
The endogenous trace amines are para/meta-tyramine, tryptamine, phenylethylamine, and para/meta-octopamine.
These share structural similarities with the three common monoamines: serotonin, dopamine, and norepinephrine.
Each ligand has a different potency, measured as increases cyclic AMP (cAMP) concentration after the binding event.
The currently accepted rank order of ligand affinity for brain hTAAR1 is as follows: p-tyramine → PEA → octopamine → m-tyramine → dopamine → tryptamine → histamine → serotonin → norepinephrine.
The EC50 values for cAMP production caused by p-tyramine and PEA binding events are 214 and 324 nM, respectively.
Dopamine and serotonin have a 5 to 25-fold lower potency than either p-tyramine or PEA.
The discrepancies in ligand potency may act to balance the differences in monoamine concentrations, common amines being less potent than trace amines.