“Hearst Magazines and Yahoo may earn commission or revenue on some items through these links.”
-
New research suggests good vitamin D levels may lower the risk of developing colorectal cancer.
-
This isn’t the first study to find a link between vitamin D and colorectal cancer risk.
-
Experts recommend staying on top of your vitamin D status
An estimated 1.4 million Americans live with colorectal cancer, and rates of the disease have been increasing in younger people for years. While there’s been a lot of emphasis on colorectal cancer screenings, many people also want to do what they can to lower the risk of developing this form of cancer in the first place. Now, new research suggests that your vitamin D levels may play a role in how likely you are to develop colorectal cancer.
And, as 18% of Americans have inadequate vitamin D levels, the findings are eyebrow-raising. Of course, colorectal cancer is a complicated disease, and it’s hard to say that low vitamin D alone would cause someone to develop it. But the study is part of a growing body of data that has found a link between vitamin D and colorectal cancer.
Meet the experts: Wael Harb, M.D., a medical oncologist at MemorialCare Cancer Institute at Orange Coast and Saddleback Medical Centers in Orange County, CA; Jessica Cording, R.D., C.D.N., author of The Little Book of Game-Changers; Scott Keatley, R.D., of Keatley Medical Nutrition Therapy; Veronika Fedirko, Ph.D., associate professor of cancer prevention at The University of Texas MD Anderson Cancer Center; Mónika Fekete, Ph.D., lead study author and professor in the Institute of Preventive Medicine and Public Health at Semmelweis University.
Here’s what the study found, plus what experts want you to know.
What did the study find?
The study, which was published in the journal Nutrients, analyzed data from 50 studies on adults who had colorectal cancer, who had a documented vitamin D deficiency, or who were given a vitamin D supplement.
The researchers found that vitamin D deficiency is strongly linked to a higher risk of developing colorectal cancer. “Maintaining optimal vitamin D levels and adequate dietary intake is crucial in preventing colorectal cancer and improving patient prognosis,” the researchers wrote in the study.
Is there a link between vitamin D deficiency and colorectal cancer?
Vitamin D deficiency and colorectal cancer have been linked in the past. One study of more than 12,000 people found that those who have lower levels of vitamin D in their blood had a 31% higher risk of developing colorectal cancer than those with better vitamin D levels.
Another study found that people who had high levels of vitamin D in their diet had a 25% lower risk of developing colorectal cancer. Data from the Nurses’ Health Study also discovered that women with the highest vitamin D intake had a 58% lower risk of developing colorectal cancer compared with people who had lower levels of vitamin D.
“These findings are reinforced by a substantial body of epidemiological data, making vitamin D one of the most biologically plausible and extensively studied nutritional factors in colorectal cancer risk reduction,” says Veronika Fedirko, Ph.D., associate professor of cancer prevention at The University of Texas MD Anderson Cancer Center. “While some randomized clinical trials have shown mixed results—often due to factors such as dosage, timing, or baseline vitamin D concentrations—the association demonstrated in observational studies remains consistent and strongly supported by biological evidence.”
Why might vitamin D deficiency raise the risk of colorectal cancer?
There are a few things that could be behind this, according to Wael Harb, M.D., a medical oncologist at MemorialCare Cancer Institute at Orange Coast and Saddleback Medical Centers in Orange County, CA. A big factor is that vitamin D impacts your immune system, he says.
“Vitamin D modulates immune responses,” he says. Specifically, vitamin D interacts with the vitamin D receptor (VDR), which is in colon tissue, explains Scott Keatley, R.D., of Keatley Medical Nutrition Therapy. “When activated, VDR can influence gene expression related to cell proliferation, differentiation, and apoptosis, which are all central processes in cancer development,” he says. “Low vitamin D levels may weaken these protective effects, allowing abnormal cells in the colon to survive and multiply.”
Vitamin D may also help reduce inflammation in the body (and gut), “which could potentially impact tumor development,” Dr. Harb says. On the flip side, having lower levels of vitamin D can let inflammation in your intestines go unchecked, raising the risk that colorectal cancer will develop, he explains.
“While vitamin D is not a substitute for screening or a healthy lifestyle, it is an important and relatively modifiable factor worth paying attention to—especially in individuals at higher risk of deficiency, such as older adults, people with limited sun exposure, those with darker skin, or individuals with chronic illnesses,” says Mónika Fekete, Ph.D., lead study author and professor in the Institute of Preventive Medicine and Public Health at Semmelweis University.
How much vitamin D do you need?
The recommended daily allowance (RDA) of vitamin D varies by person and age, but most adults should get 600 international units (IU) daily, according to the National Institutes of Health (NIH). Adults aged 70 and up should have 800 IU of vitamin D, per the NIH.
How do I know if I’m getting enough vitamin D?
There are a few symptoms that can suggest you’re low on vitamin D. According to Jessica Cording, R.D., C.D.N., author of The Little Book of Game-Changers, the most common ones she sees are:
-
Fatigue
-
Brain fog
-
Low mood
-
Poor immune system function (i.e. getting sick a lot)
-
Bone fractures (in severe cases)
Still, Keatley says that most people with low vitamin D levels don’t have symptoms. That’s why it’s important to ask your doctor about checking your vitamin D levels. “A blood test is the most reliable way to get a sense of whether you have adequate vitamin D levels,” Cording says.
How to get enough vitamin D
Most people get vitamin D from exposure to the sun, but you can also get it from foods. The biggest food sources of vitamin D are cod liver oil, trout, salmon, mushrooms, fortified milk, and fortified cereal, according to the NIH. However, Cording says that some people can benefit from a vitamin D supplement.
Dr. Harb says we aren’t at the level yet in colorectal cancer prevention of recommending that everyone take a vitamin D supplement. However, he says that your vitamin D levels should be checked during your annual check-up to make sure they’re OK.
“Testing is especially important if you have limited sun exposure or frequent use of sunscreen (which is important for skin cancer prevention), darker skin, digestive disorders, chronic health conditions, older age, or are overweight or obese,” Dr. Fedirko says. “The test is simple and can be arranged through your healthcare provider.”
If your levels of vitamin D are low, Keatley recommends looking for supplements with vitamin D3 (cholecalciferol). “It’s more effective at raising blood levels than D2,” he says. A dose of 1,000–2,000 IU daily is common, per Keatley, but it’s important to talk to your doctor about dosing recommendations before taking a vitamin D supplement.
Vitamin D3 – 5000 IU
$19.00 at amazon.com
Vitamin D3 and K2
$30.95 at amazon.com
Vitamin D3 K2
$18.50 at amazon.com
Bone Strength Organic Calcium + Vitamin D3 + K2
$42.34 at amazon.com
Wondering when’s the best time to take vitamin D? “Vitamin D is fat-soluble, so take it with a meal that contains fat for better absorption,” Keatley says.
If you’re concerned about your vitamin D status or your colorectal cancer risk, talk to your doctor. They should be able to answer your questions and provide personalized guidance from there.
Dietary supplements are products intended to supplement the diet. They are not medicines and are not intended to treat, diagnose, mitigate, prevent, or cure diseases. Be cautious about taking dietary supplements if you are pregnant or nursing. Also, be careful about giving supplements to a child, unless recommended by their healthcare provider.
You Might Also Like
-
Can Apple Cider Vinegar Lead to Weight Loss?
-
Bobbi Brown Shares Her Top Face-Transforming Makeup Tips for Women Over 50
