Dietary fructose may contribute to cancer tumor growth, a study in animal models suggests.
- Fructose
is a natural sugar found in fruits, vegetables, and honey.
- Fructose
can be bad for your health when consumed as part of high-fructose corn
syrup in processed foods.
- Past
studies have linked high-fructose corn syrup intake to many diseases,
including cancer.
- Researchers
from Washington University in St. Louis has found that dietary fructose
may promote tumor growth in animal models of melanoma, breast cancer, and
cervical cancer.
Fructose is
the natural sugar found in fruits, as well as some vegetables and honey. When
consumed from a natural source such as an apple or dates, fructose
is not considered harmful to a person’s health.
However, when fructose
is consumed as part of high-fructose corn syrup via
processed foods like soda and packaged baked goods, then it can become a health
concern.
Past studies link the
consumption of fructose or high-fructose corn syrup to an increased risk
for Alzheimer’s disease, type 2
diabetes, fatty liver
disease, kidney
disease, and cancer..
“Fructose occurs
naturally in some fruits and vegetables — so humans have always been exposed to
it,” Gary Patti, PhD, the Michael and Tana Powell Professor of
Chemistry, Genetics, and Medicine at Washington University in St. Louis,
told Medical News Today.
“What has changed over
the past four to five decades is that we started using it as an artificial
sweetener in processed foods. As a result, many people are exposed to much
higher levels than ever before. It is important to understand what impact this
has on human health,” he added.
Patti is the senior
author of a new study recently published in Nature. that has found that dietary fructose may promote
tumor growth in animal models of melanoma, breast cancer, and cervical
cancer.
Why look at fructose in relation to cancer?
For this study,
researchers used an animal model of cancer tumors. During the study, the
animals were fed a diet rich in fructose.
“It has been well
established for over a century that cancer cells are addicted to glucose,” Patti
said. “We take advantage of this in the clinic all the time. Patients are given
a radioactive form of glucose that shows up in PET scans.
Because cancer cells take up more glucose than most other healthy cells, they
light up in the images.”
“Glucose and fructose are made up of the exact same
atoms,” he continued. “The only difference between them is the way in which the
atoms are arranged. Given the avidity that cancer cells have for glucose, it’s
compelling to imagine that they might use fructose in a similar way.”
Fructose, lipids, and tumor growth
Upon analysis, Patti and
his team found that the body’s liver converts fructose into a type of lipid. called lysophosphatidylcholines
(LPCs)., which are associated with
inflammation.
When cancer cells
divide, they require a large amount of lipids. Having a larger amount of LPCs
in the bloodstream aids cancer cell replication, thus helping tumors grow.
“When you eat an
excessive amount of food, your body converts it into fat,” Patti explained.
“That is your body’s way of storing energy. High levels of dietary fructose
induce a similar process. The fructose is converted into a precursor of fat in
the liver, called lipids. Those lipids can then feed the tumor.”
“Cancer cells are unique from most other cells in
the body because they are rapidly dividing, which is what allows tumors to grow
larger,” he continued. “For a cancer cell to divide into two, it has to make a
new set of cellular contents. That requires a lot of nutrients, which
ultimately come from the diet. It is therefore intuitive to imagine that
dietary modifications could influence the process of tumor growth.”
“The complication is
that there are a lot of variables to think about such as where the tumor is in
the body, which oncogenes it has, what drugs the patient is using, what dietary
components are transformed into prior to reaching the tumor, etc,” Patti added.
“Our understanding of these issues is only at its very early stages, but there
are an increasing number of studies starting to illuminate important details. I
hope our study will be part of that equation.”
Processed foods’ effect on cancer risk: Understanding
the mechanisms
MNT spoke with Anton Bilchik, MD, PhD, surgical oncologist, chief of medicine
and Director of the Gastrointestinal and Hepatobiliary Program at Providence
Saint John’s Cancer Institute in Santa Monica, CA, about this study.
“We’ve been suspicious
for quite a while that certain food supplements such as sweeteners and
processed food increase the risk of getting cancer, but we’ve never really
known the mechanism,” Bilchik, who was not involved in the research, pointed
put.
“This
is one of the few studies that provides a possible mechanism for fructose,
which is found in corn syrup, processed food, and sweeteners, a mechanism that
may cause a variety of different cancers. So there may be some truth to the fact
that people need to be very cautious about using sweeteners or using sugars
that are not from fruits and vegetables, but are in processed foods.”– Anton
Bilchik, MD, PhD
“Fructose is in so many
food products that we eat, and we’re now seeing a massive uptick in young
people being diagnosed with certain cancers, such as colorectal cancer,
and that is being linked to processed food,” he continued.
“And we know that
processed food has high contents of fructose in them, so this just provides a
possible mechanism. I think that we need to see some clinical studies in people
that take sweeteners versus natural sugars to see whether there’s any
difference in cancer. So I think to translate this to the clinical world would
be most beneficial,” said Bilchik.
How can you decrease fructose intake?
MNT also spoke with Monique
Richard, MS, RDN, LDN, a registered dietitian nutritionist and owner
of Nutrition-In-Sight, about this study for ways on which readers can
potentially lower the amount of fructose they consume.
Richard said a simple
way — though not always possible or easy — to avoid excessive or less
beneficial types of fructose is to eat more foods that do not have packaging or
labels such as produce.
“Say yes to fructose in
fruit and ‘no, thank you’ to the fructose [in] the fruit roll-up,” she advised.
“The
fiber and vitamins and minerals that naturally accompany the carbohydrates such
as fructose in fruit and vegetables is less likely to be over-consumed,
although portions do still matter. The fiber and nutrients are also beneficial
for our gut
microbiota, which we are also observing being affected by excessive
fructose consumption from ultra-processed foods.”– Monique Richard, MS, RDN,
LDN
“Reading labels and
understanding ingredients is another key to knowing what you’re consuming,”
Richard continued. “There are numerous names for sugar. Educate yourself about
the types and names of sugar so that you’re not trading one for an equal or
similar product.“
“Food manufacturers
understand how to market to make money. A label could say ‘no high fructose
corn syrup’ but could have just as much or more fructose, glucose, or sucrose
(table sugar), just to name a few. I see this often in crackers, cookies, soft
drinks, and juices,” she told us.
“Keep in mind, there is
no reason to be obsessive and never include these items — hello holidays,
Halloween, and favorite treats. But knowing how much, how often, and making
sure that real food is not replaced in lieu of these things is the most
important for our daily dietary patterns and enjoyment of life,” Richard
advised.
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