Page 39 - Summer2018

HISTAMINE AND ALLERGIES break down histamine in the gut. Histamine
Most people have heard of histamine be- Another confounding issue can be low becomes
cause it is known to “cause” allergies. In fact, levels of the enzyme that we naturally produce
the body’s defense reaction to foreign proteins to break down histamine. This enzyme, called problematic
in the blood is what causes allergies. Part of diamine oxidase (DAO), is responsible for when people
that reaction includes the release of histamine breaking down histamine in the gut, the liver have too
from mast cells (a type of white blood cell and other tissues. Some people are low in this
that releases histamine and other substances). enzyme due to genetic variations. Others may be much
Although mast cells also release many other low due to GI disorders such as small intestine histamine in
pro-inflammatory substances, histamine gets a bacterial overgrowth (SIBO), hormonal imbal- their blood
particularly bad rap. ances or any kind of persistent inflammation.
Histamine becomes problematic when Excess estrogen levels also can increase circu- or tissue
people have too much histamine in their blood lating histamine because estrogen suppresses even though
or tissue even though no allergic reaction is DAO activity and stimulates mast cells. no allergic
occurring. In the absence of true allergies (im- In addition to the breakdown by DAO, hista-
munoglobulin E [IgE] reactions), there are es- mine needs to be methylated in the liver before reaction is
sentially two major scenarios in which this can excretion by the kidneys. Methylation refers to occurring.
take place. The first and probably most common the process of any molecule being transformed
scenario, typically known as “histamine intol- by the addition of a methyl group (CH3)—three
erance,” is when someone either absorbs too hydrogen atoms bonded to a carbon atom.
much histamine from the GI tract or does not Histamine is methylated to a molecule called
break it down well in the liver (or both). Many methylhistamine, which renders it much less
foods contain histamine, and if the histamine toxic and ready for disposal through the urine. 1
is not successfully broken down in the gut, it Low DAO activity in the GI tract and liver
can get absorbed in excessive amounts. Proper due to genetic variants, combined with gut
liver function is required to break down the inflammation, excess estrogen and insufficient
histamine to be excreted as waste. When one or levels of methyl groups can create a perfect
both of these functions is not working properly, storm for some people, causing major histamine
histamine builds up in the blood. overload. The approach to deal with this situa-
In the second, much more complex and tion must be multifaceted.
insidious scenario, called “mast cell activation
syndrome” (MCAS), dysfunctional mast cells MAST CELL ACTIVATION SYNDROME
release too much histamine. In some people, of When mast cells are activated, they release
course, both things are happening, and there are histamine, tryptase and other pro-inflammatory
other factors that can affect histamine levels as mediators. This is great when the mast cells are
well. Any serious conversation about histamine protecting us from pathogens or are involved
“overload” thus needs to address the origin of in healing wounds. Sometimes, however, mast
the excess histamine. When the overload is due cells show up in excess (a rare condition known
to improper breakdown of histamine in the gut as mastocytosis), or, as in MCAS, they over-
or liver, the protocol will differ from when it produce these pro-inflammatory molecules,
originates from the mast cells. flooding the system with them and mimicking
an allergic response.
HISTAMINE INTOLERANCE MCAS is not fully understood, and its
There are at least two possible reasons why treatments are even less clear. I like to think
someone would absorb excess histamine from of MCAS as akin to an autoimmune condition
the gut. First, dysbiosis (or a disordered micro- because it involves mast cells (immune cells)
biome), so common these days, can certainly that are overactive and somewhat trigger-happy
contribute to this problem and, in fact, is the in releasing their contents. Unfortunately, this
leading cause of histamine intolerance. Micro- can really wreak havoc in the body. Dr. Law-
bial imbalance can inhibit the body’s ability to rence Afrin and Dr. Theoharis Theoharides

SUMMER 2018 Wise Traditions 37