Vitamin D May Decrease Risk of Colorectal Cancer

Vitamin D May Decrease Risk of Colorectal Cancer

  • The National Cancer Institute (NCI) reported that the rate of colon cancer has nearly doubled since the 1990s among people younger than 50 years old.
  • New research finds evidence that vitamin D might be an inexpensive and easy way to help prevent young onset colorectal cancer.
  • Notably, the findings didn’t indicate a significant association between total vitamin D intake and risk of colorectal cancer diagnosed after age 50.
  • Experts say that it’s difficult to get enough vitamin D from diet alone, and most people consume too little.

According to the Centers for Disease Control and Prevention (CDC)Trusted Source, colorectal cancer is the third most common cancer in men and women and the third leading cause of cancer-related deaths in the United States.

The National Cancer Institute (NCI) reported that the rate of colon cancer has nearly doubled since the 1990s among people younger than 50 years old.

However, new research published in the journal Gastroenterology finds compelling evidence that vitamin D might be an inexpensive and easily accessible addition to screening tests as a colorectal cancer prevention strategy for young-onset colorectal cancer.

“There is abundant laboratory data that vitamin D may possess anti-cancer activity,” Kimmie Ng, MD, co-senior author of the study and director of the Young-Onset Colorectal Cancer Center at Dana-Farber Cancer Institute in Boston, told Healthline.

She added that multiple epidemiologic studiesTrusted Source has also found higher vitamin D status is associated with decreased risk of colorectal cancer.

Participants were part of the Nurse’s Health Study II

Researchers calculated total vitamin D intake from dietary sources and supplements of 94,205 women participating in the Nurses’ Health Study II (NHS II).

NHS II participants are followed up every 2 years with questionnaires on demographics, diet and lifestyle factors, medical, and other health-related information.

Ng and her team focused on a primary endpoint — young-onset colorectal cancer diagnosed before age 50. They also used follow-up questionnaires to determine whether participants had had a colonoscopy or sigmoidoscopy, where colorectal polyps were found.

Getting vitamin D through our diet might be best

From 1991 to 2015, researchers documented 111 cases of young-onset colorectal cancer and 3,317 colorectal polyps. Analysis revealed that higher total vitamin D intake was associated with a significantly reduced risk of early-onset colorectal cancer.

“We found that total vitamin D intake of 300 IU per day or more – roughly equivalent to three 8 oz. glasses of milk – was associated with an approximately 50% lower risk of developing young-onset colorectal cancer,” Ng said in a 2021 article published by the Dana-Farber Cancer Institute.

Also, there was a link between higher vitamin D intake and reduced risk of colon polyps detected before age 50.

Researchers also found the association was stronger for dietary vitamin D, especially from dairy products, rather than vitamin D supplements. According to study authors, this might be due to chance or unknown factors.

Notably, the findings didn’t indicate a significant association between total vitamin D intake and the risk of colorectal cancer diagnosed after age 50.

“Although there were a large number of participants in our study, we still had a limited number of young-onset colorectal cancer cases,” said Ng. “Therefore, our findings should be confirmed in larger cohorts.”

She added that because the study population consisted of female nurses, most of whom are white, “further studies are needed in other population subgroups.” RESOURCETRANSFORM: Health Equity

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Getting enough vitamin D from diet can be difficult

Elena A. Ivanina, DO, director of Neurogastroenterology and Motility at Lenox Hill Hospital in New York, said getting enough vitamin D from natural food sources alone is difficult.

She noted that the average intake of vitamin D through diet is only 204 international units (IU) for men and 168 IU for women – significantly below the recommended daily allowance. The recommended daily amountTrusted Source of vitamin D is 400 IU for children up to age 12 months, 600 IU for people 1 to 70 years old, and 800 IU for people over age 70.

She recommended discussing the risk of vitamin D deficiency with your doctor, checking your levels, and considering a supplement.

“Especially in breastfed infants, older adults, people with limited sun exposure, dark-skinned individuals, people with conditions that limit fat absorption, and those who are obese or have undergone gastric bypass surgery,” advised Ivanina.

The importance of screening and prevention

Ivanina emphasized that over 75 percent of colorectal cancers happen to people with no known risk factors.

“Which is why screening and prevention is so important,” she continued. “People at highest risk include those with close relatives with colorectal cancer and hereditary cancer syndromes as well as those with a personal history of polyps or inflammatory bowel disease.”

According to Theodore Strange, MD, interim chair of Medicine at Staten Island University Hospital, diet is always important. He added that there’s a lot of data to show that a high-fat diet is a risk for colon cancer, but it’s one area where you can make changes – although genetic risk factors require other proactive measures.

“There are genetic predispositions to colon cancer,” he explained. “So there are people who have certain types of polyps in their system or may have colitis. Certain types of colitis, like ulcerative colitis, can predispose you to colon cancer. Frequent screenings of those people would be very important.”

Not all polyps are dangerous

Strange said there are three major types of polyps. A physician can determine which ones are potentially dangerous.

“One type is the hyperplastic polyp that basically comes from the suction of the device going in – that’s non-worrisome. Then there’s a villous adenoma, that’s worrisome, and then there’s something called a tubulovillous adenoma, and that’s something that’s in-between,” Strange explained.

“If it’s on a stalk, looking like a mushroom almost, then any gastroenterologist can clip it out, and if the margin of the stalk is free of cancer, then it’s pretty OK,” he continued.

However, Strange cautioned that if the polyp is flat, “sticking to the colon wall where you can’t lift it,” that’s more concerning because that means it can go through the layers of the colon.

The bottom line

Research finds that a higher intake of dietary vitamin D is associated with a reduced risk of young-onset colorectal cancer, which develops before age 50.

Experts say most people consume too little vitamin D and say it’s difficult to get enough vitamin D from diet alone. They recommend that people talk with their doctor about their vitamin D levels and consider taking a supplement.

Experts also say that routine screening and following a nutritious diet are important preventive measures, especially for people with a family history of the disease and other risk factors.

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