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By Dr. Mercola
Colon cancer has been in the news as of late after the
International Agency for Research on Cancer (IARC), which is part of the World
Health Organization (WHO), concluded in late 2015 that processed meat can cause
colorectal cancer in humans, classifying it as a Group 1 carcinogen.
Colorectal cancer, which includes both cancers of the colon
and rectum, is the third most common cancer diagnosed in the U.S. (not
including skin cancers). In 2016, it’s estimated there will be more than 95,000
new cases of colon cancer (and more than 39,000 cases of rectal cancer)
diagnosed.1
Your colon, also known as your large intestine, plays an
incredibly important role in your health. As food passes through your colon,
liquid and salt are removed to prepare it for elimination.
Aside from
helping to form, store and eliminate waste, your colon contains billions of
bacteria, a healthy balance of which is essential for optimal health.
Many Cases of Colon Cancer Are Preventable
Colorectal cancer is the second leading cause of cancer
deaths in the U.S., but, like many types of cancer, it is often preventable.
Research published in Pharmaceutical Research suggested that
only 5 percent to 10 percent of cancer cases are due to genetic defects, while
the rest are linked to environment and lifestyle factors.2
The researchers estimated that up to 35 percent of
cancer-related deaths may be due to diet, another 30 percent due to tobacco, 20
percent due to infections and the rest due to other environmental factors
including exposure to radiation, stress, physical activity levels and
environmental pollution.
The American Institute for Cancer Research (AICR) also stated
that about one-third of the most common U.S. cancer cases are preventable
through a healthy diet, being physically active and maintaining a healthy
weight.
In the
case of colorectal cancer, the percentage that could be prevented via these
lifestyle factors rises to 50 percent.3
Top Tips to Prevent Colon Cancer
Today can be the day you start making healthy changes to
lower your risk of this potentially deadly disease. Top steps include the
following.
1. Eat More Vegetables and Some Fruits
Vegetables contain an array of antioxidants and other
disease-fighting compounds that are very difficult to get anywhere else – like
magnesium.
Results from one meta-analysis indicated that for every
100-milligram increase in magnesium intake, the
risk of colorectal tumor decreased by 13 percent, while the risk of colorectal
cancer was lowered by 12 percent.4
The researchers noted magnesium’s anti-cancer effects may be
related to its ability to reduce insulin resistance, which may positively
affect the development of tumors.
Beyond magnesium, plant chemicals called phytochemicals can
reduce inflammation and eliminate carcinogens, while others regulate the rate
at which your cells reproduce, get rid of old cells and maintain DNA.
Vegetables are also one of the best forms of dietary fiber.
Studies have repeatedly shown that people with higher vegetable intake have
lower rates of cancer.5
Cruciferous vegetables may be particularly beneficial due to
the sulforaphane they contain. Sulforaphene, a naturally occurring derivative
of sulforaphne, has been found to suppress growth of colon cancer-derived
tumors, for example.6
If you’re
healthy, consuming some fruit in moderation may also be beneficial. According
to one study, dried plums (i.e. prunes) may lower your risk of colon cancer by
building your gut bacteria.7
2. Eat More Fiber
Dietary fiber has been associated with a reduced risk of
colorectal cancer, particularly incident colorectal adenoma and distal colon
cancer.8 Further,
for every 10 grams of fiber you add to your daily diet, your risk of colon
cancer decreases by 10 percent.9
A 2005 study similarly revealed that dried plums “favorably
altered … colon cancer risk factors” in rats, possibly due to their high
content of dietary fiber and polyphenolics.10
Fortunately,
if you follow the tip above and eat more vegetables, you’ll naturally be eating
more fiber from the best possible source— vegetables. Psyllium seed
husk, flax seeds, hemp seeds and chia seeds also provide valuable sources of
soluble and insoluble fiber.
3. Optimize Your Vitamin D Levels
Vitamin D deficiency is a risk factor for colorectal cancer.
In one study published in the journal Gut, people with higher blood levels of
vitamin D were less likely to develop colorectal tumors.11
This may be because vitamin D is beneficial for your immune
system, which in turn may help to limit the growth of cancerous tumors.
According to the researchers:12
“Evidence suggests protective effects of vitamin D and antitumour
immunity on colorectal cancer risk.
Immune cells in tumour microenvironment can convert
25-hydroxyvitamin D [25(OH)D] [vitamin D] to bioactive 1α,25-dihydroxyvitamin
D3, which influences neoplastic and immune cells
… High plasma 25(OH)D level
is associated with lower risk of colorectal cancer with intense immune
reaction, supporting a role of vitamin D in cancer immunoprevention through
tumour–host interaction.”
Regular
sun exposure, use of a high-quality tanning bed and/or supplementation with a
vitamin D3 supplement can get your vitamin D levels into the optimal range of
50-70 ng/ml. You’ll need to monitor your levels to be sure you stay within this
target range.
4. Avoid Processed Meats
Processed meats are those preserved by smoking, curing,
salting, or the addition of chemical preservatives.
This includes bacon, ham, pastrami, salami, pepperoni, hot
dogs, some sausages, and hamburgers (if they have been preserved with salt or
chemical additives) and more. Particularly problematic are the nitrates that
are added to these meats as a preservative, coloring and flavoring.
The
nitrates found in processed meats are frequently converted into nitrosamines,
which are clearly associated with an increased risk of certain cancers. AICR
warns that "there is no safe threshold" for eating processed meats.13
5. Be Knowledgeable About Red Meat Consumption
Research suggests that people who eat the most red meat (in
one study this was five ounces a day) have a 24 percent greater risk of
colorectal cancer than those who eat the least.14
Red meat is likely not the problem in and of itself, however,
but the way it’s cooked, and the source it comes from, likely play a role.
Grass-fed beef, for instance, contains cancer-fighting compounds.
On the other hand, it’s known that glyphosate, the active
ingredient in Roundup herbicide, can have a detrimental impact on healthy gut
bacteria and is
carcinogenic. CAFO animals are typically fed grains contaminated with glyphosate.
Red meat cooked at high temperatures (such as barbecued or
fried) may also contain carcinogenic cooking byproducts like heterocyclic
amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs).
When it comes
to meats, I recommend eating organically raised grass-fed meats only and cooking them only lightly (rare, not well-done).
For the record, I believe most people need some animal protein to be optimally
healthy, but most eat far more protein than is
necessary (or healthy).
6. Exercise
There is convincing evidence that regular exercise can
significantly reduce your risk of colon cancer.15 One study
revealed that physically active men and women have about a 30 percent to 40
percent reduction in the risk of developing colon cancer compared with inactive
persons, for instance.16
For starters, exercise drives your insulin levels down, and
controlling insulin levels is one of the most powerful ways to reduce your
cancer risk. It's also been suggested that apoptosis (programmed cell death) is
triggered by exercise, causing cancer cells to die.
Exercise
also improves the circulation of immune cells in your blood. The job of these
cells is to neutralize pathogens throughout your body, as well as destroy
precancerous cells before they become cancerous. The better these cells
circulate, the more efficient your immune system is at defending itself against
infections and diseases like cancer.
7. Maintain a Healthy Weight and Control Belly Fat
A number of studies have linked obesity to an increased risk
for about a dozen different cancers, including cancer of the colon. In a 2014
study that analyzed data from more than 5 million people over the age of 16,
every 11-pound increase in body weight was associated with an increased risk
for 10 types of cancer.17
If you’re
overweight or obese, even small amounts of weight loss can lead to significant benefits for your health. In
terms of cancer prevention, losing excess belly fat is particularly important, as belly fat is linked to
an increased risk of colon cancer regardless of your body weight.
8. Limit Your Alcohol Intake and Quit Smoking
Both excessive alcohol intake and smoking are associated with an increased risk of colorectal cancer. When it
comes to alcohol, I generally define "moderate" alcohol intake (which
is allowed in thebeginner phase of my nutrition plan)
as a 5-ounce glass of wine, a 12-ounce beer or 1 ounce of hard liquor, with a
meal, per day.
As you
progress further in the nutrition plan, I do recommend eliminating all forms of
alcohol. If you’re a smoker, you can find
tips for quitting here.
9. Eat Garlic
Garlic has been shown to kill cancer cells in laboratory
studies, as well as shown promise when consumed via your diet. One study showed
that women who regularly ate garlic (along with fruits and vegetables) had a 35
percent lower risk of colon cancer.18
Those who consume high amounts of raw garlic also appear to
have a lower risk of stomach and colorectal cancers.19 Furthermore,
among people with inoperable forms of colorectal, liver, or pancreatic cancer,
taking an extract of aged garlic for six months helped to improve immune
function, which suggests it may be useful for helping your immune system during
times of stress or illness.20
When you add raw garlic in your diet the fresh clove must be
crushed or chopped in order to stimulate the release of an enzyme called
alliinase, which in turn catalyzes the formation of allicin.
Allicin,
in turn, rapidly breaks down to form a number of different organosulfur
compounds. So to “activate” garlic’s medicinal properties, compress a fresh
clove with a spoon prior to swallowing it, chop it finely to add to a salad, or
put it through your juicer to add to your vegetable juice.
