Rates in younger adults rose sharply; which lifestyle factors really help?
When we’re young we feel immortal, and cancer seems like a distant threat.
But an alarming new report from the American Cancer Society reveals a sharp spike in colorectal cancer rates among Generation X and Millennial Americans (Siegel RL et al. 2017).
Since 2000, rates of colorectal cancer among Gen X’ers under 50 and Millennials have risen by a pretty shocking 22 percent.
Most sources define Millennials as people born between 1982 and 2004 and Gen X’ers as those born from the early 1960s through the early 1980s.
About one in 21 (4.7%) men and one in 23 (4.4%) women will get colorectal cancer at some point, and inflammatory bowel disease (IBD) is a risk factor.
Colorectal cancer is the third most common kind, and the second leading cause of cancer death, projected to kill about 50,000 people in 2017.
It’s not clear why rates are rising among Americans under 50, but the American Cancer Society speculates that it may be due to lifestyle.
As ACS researcher Rebecca Siegel told the Washington Post, “… one explanation might be a complex interaction involving the same factors that have contributed to the obesity epidemic — changes in diet, a sedentary lifestyle, excess weight and low fiber consumption.”
What is colorectal cancer and how is it diagnosed?
The colon absorbs water and salt from food after it passes through the small intestine.
Any remaining waste passes into the rectum — the last six inches of your digestive system — before exiting the body.
Colon cancers and rectal cancers share many features, and afflict connected areas, so they're often lumped together as "colorectal" cancer (CRC).
Cancer is a condition in which cells begin to grow out of control, and in CRC, this process starts as a polyp (growth) on the lining of the colon or rectum. Some polyps, called adenomas, become cancerous, while many remain unchanged.
Since it can take up to 10-15 years for a polyp to become cancerous, regular screening can prevent colorectal cancer by finding and removing polyps while they’re still benign.
When CRC is found before it has a chance to spread, the five-year survival rate is about 90 percent.
Rates of CRC in adults over 50 have dropped nearly one-third since 2000 — probably thanks to rising use of colonoscopy exams, which can detect risky growths (polyps) and enable immediate removal.
However, many people who need screening fail to get it, and survival rates become lower if the cancer is more advanced or has spread.
Newer CRC screening tests look for blood, antibodies, and/or DNA related to cancerous cells in waste matter collected at home and mailed to a lab.
These so-called “multi-target stool DNA” tests — approved by the FDA in 2014 — look about as effective as colonoscopies for detecting cancer and pre-cancerous growths.
Detection of risks via stool tests must be followed up with a colonoscopy, and removal of any threatening growths.
Seven ways to help protect yourself
Obviously, no one thing can prevent colorectal cancer.
But lifestyle decisions can lower (or increase) your risk over time, especially if you combine protective measures and reduce risk factors.
Let’s see what the evidence suggests you can do to protect yourself with lifestyle choices.
#1 Stay active: Regular exercise (similar in intensity to a brisk walk) lowers your risk of colorectal cancer, and more vigorous activity may have an even stronger benefit.
#2 Maintain a healthy weight and reasonably flat belly: Being overweight increases your risk of colorectal cancer, with the link being somewhat stronger for men than women. And the risk grows along with belly fat. In other words, as your waistline expands so does your risk for CRC.
#3 Quit tobacco smoking: Smoking or chewing tobacco is linked to higher risk for CRC, as well as lung and stomach cancers. There’s no evidence that nicotine — as opposed to various other chemicals in tobacco — is carcinogenic. So it seems unlikely that vaping would raise the risk for CRC.
#4 Drink alcohol moderately: One to two drinks a day appears to help reduce the risk of CRC, but heavy alcohol consumption — four or more drinks per day — is linked to higher risk.
#5 Coffee may be your friend: The evidence that coffee may help prevent CRC is fairly strong, but the same can't be said for tea.
#6 Favor fish, fruits, veggies, and whole grains: Diets high in these foods may reduce your risk for CRC ... see Fish + Veggies Diet = Lowest Colon Risk.
Overall, the evidence that eating lots of fruits and vegetables prevents CRC is mixed. That said, some studies link diets high in fruits and/or green leafy vegetables to significantly reduced risk.
The evidence on dietary fiber is mixed, but generally suggest that high-fiber foods protect against CRC, while fiber supplements don’t seem to help.
Several studies have shown that fish — and the vitamin D3 and omega-3 fatty acids that abound only in seafood — may help to prevent, delay, or hinder CRC.
(For an overview of the evidence, and links to related reports, see Can Fish Curb Colon Cancer?.)
In 2005, the huge EPIC study found that — compared with eating less than one-third ounce of fish per day — diets averaging three ounces of fish or more per day were linked to a 30 percent lower risk ... see Fish Cuts Risk of Colorectal Cancer, Red Meat Raises It.
Why would that be? The anti-inflammatory and other properties of omega-3 fatty acids in seafood may curb the conversion of benign polyps into more dangerous cells.
One study examined whether fish oil affected patients with a history of colon polyps. The researchers tested fish oil unusually high in EPA versus DHA, which is the other major omega-3 fatty acid in fish.
Before and after the study, small samples of the lining of the colon were taken, which allowed the researchers to measure how quickly new cells were proliferating, and the rate at which cells were being removed via apoptosis.
The results — see Fish Oil May Curb Onset of Colorectal Cancer — were encouraging:
- The rate at which bowel-lining cells formed (proliferation) fell by almost 25 percent in the subjects who took the high-EPA fish oil, compared to those who received no treatment.
- The rate at which proliferating cells were eliminated by apoptosis (cellular "suicide") more than doubled in the patients who took the high-EPA fish oil, and there was no significant change in the untreated control group.
- The levels of omega-3 EPA in the cells of the treated participants were twice as high as in the control group.
A similar 2006 study — see Fish and Omega-3s May Reduce Colon Cancer Risk — found that, compared with men who ate fish less than once a week:
- CRC risk was 20 percent lower among men who ate fish two to five times a week.
- CRC risk was 40 percent lower among men who ate fish five times a week or more.
And the results of a clinical trial in people with pre-cancerous colorectal tumors (adenomas) showed that omega-3 EPA — which occurs only in fish and fish oil — halted tumor cell growth and raised the rate of cancer cell apoptosis or “suicide” (see Omega-3 Curbs Colon Cancer in Clinical Trial).
Finally, a Harvard study linked high omega-3 blood levels to reduced risk for colorectal cancer, with the resulting preventive effect comparable to that of aspirin’s proven benefit: see Omega-3s May Cut Colon Cancer Risk by Two-Thirds.
#7 Don’t overdo red meats: The evidence from population studies, while mixed, generally links higher intakes of red and processed meats to higher risk for CRC.
For example, the very large EPIC study from Europe suggested that diets averaging six ounces of processed and red meats or more per day raise the risk by 35 percent, versus diets averaging less than an ounce per day.
Poultry consumption doesn’t raise or lower the risk for CRC, judging by the results of epidemiological (population) studies, including the EPIC investigation.
Pills for prevention
Vitamin D may be an ally against the disease: see Vitamin D Again Linked to Lower Colon Risk.
So it makes sense to eat plenty of fatty fish like salmon, tuna, and sardines — the richest food sources, by far — take omega-3 fish or krill oil and supplemental vitamin D3, and seek moderate sun exposure.
Aspirin or other non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (Advil) and naproxen (Aleve) can lower the risk of colorectal cancer and polyps.
But NSAIDs can cause serious, even fatal gastric bleeding, so most experts don’t recommend taking them to reduce CRC risk unless your family history or genetic makeup puts you in a high-risk group.
Curcumin offers a natural alternative that works in some of the same ways as NSAIDs — but safely — and this well-researched antioxidant blend from turmeric root shows promise as an aid to prevention: see Curcumin May Curb Colon Cancer and Curry Spices versus Colorectal Cancer.
Standard curcumin extracts are poorly absorbed, so be sure to seek out a highly absorbed curcumin supplement.
The bottom line? Take this threat seriously
People under 50 — including folks under 30 — should heed the implications of the sharply rising rates of CRC in their age cohorts.
Taking the threat seriously means eating in ways that reduce risk, exercising routinely, and getting yourself tested — sooner rather than later!
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