YSM Issue 91.1

genetics
FEATURE
IMMUNE TO OUR FOOD
Fast food, slow recovery
BY LESLIE SIM
IMAGE COURTESY OF THE LATZ LAB
Dr. Latz and Dr. Christ of the Latz Lab at University of Bonn.
Our world is plastered with weight-loss advertisements.
For every McDonald’s commercial, there is another one
for Lean Cuisine or Weight Watchers. In America, obesity
and health have become national concerns, as over a
third of the adult population is obese—a record high. It
seems that unhealthy eating habits don’t just contribute
to obesity; they also have long-term consequences that
originate from our immune systems and DNA.
Our immune systems have a memory similar to that of
our muscles and brains. For example, our immune systems
are able to recognize pathogens such as the influenza
virus so that in the case of a second infection, we
know how to fight the infection. This evolutionary advantage
in humans allows us to ward off infections and
illnesses on the daily. Without our innate immune system’s
memory, we would die from the common cold.
The Latz lab at University of Bonn, in which postdoctoral
fellow Anette Christ has researched the immune
system, has delved into these health concerns with a scientific
mindset. By pairing a problem we see in society
with curiosities about the innate immune system and its
response to certain types of diets, the researchers discovered
that the immune system responds similarly to the
typical Western fast food diet—high in fat, high in sugar,
and low in fiber—as it does to pathogens and infections.
The experiment was performed on three groups of
mice: one was fed a standard healthy chow diet, a second
was fed a Western diet, and a third group was given
a Western fast food diet and then switched over to the
chow diet after a period of time. After performing genetic
analyses on the different groups’ bone marrow cells, the
Latz lab discovered the presence of signatures linked to
inflammation and immune cell differentiation called inflammasomes
that release inflammatory messengers in
the group of mice on a Western diet. Inflammasomes are
usually only triggered by bacterial infections in order to
keep the immune system ready for a subsequent infection.
These signatures were originally observed in the group
that had switched diets, but they later disappeared after
the mice were put onto chow diet. Although still curious
about how exactly these signatures recognize characteristics
of the Western fast food diet, the lab was surprised
to discover that the immune system may treat high-sugar,
high-fat foods the way it treats bacterial infections.
Furthermore, they found that the Western fast food
diet affects histone-packaging in the DNA, which means
certain portions of the DNA unwind to cause a change in
the expression of genetic material of the cell. These epigenetic
changes coupled with inflammation have been
shown to play a major role in the development of atherosclerosis,
diabetes, and heart disease in the mice. This
finding suggests that nutrition and diet choices can have
major consequences on our health.
The next step in this research is determining whether
it applies to humans. In the near future, Christ hopes to
conduct a clinical study in which healthy volunteers will
be exposed to different diets for several different time
periods. While this study will have more variables, she
believes that it will produce results similar to those of the
study she has already performed with the Latz lab.
As health gurus and health movements are on the rise,
we often find ourselves wondering which diets are the
best for us: vegan? vegetarian? A raw diet? The answer
is probably none of the above. “There is no ‘correct’ diet
out there for us,” Christ said. Everyone is different—due
to different food resources and traditional cuisines, people
from different races or geographical locations may
have varied intestinal environments and genetic makeups
that complicate the answer. It’s nonetheless important
for people to be informed about what types of foods
they should choose for themselves in an attempt to live
a healthy life. We are what we eat, and our immune systems
agree.
www.yalescientific.org
March 2018
Yale Scientific Magazine
27