Can Calcium And Vitamin D Supplements Increase The Risk Of Polyps? Let’s find out the truth
There is some talk going on that calcium and vitamin D supplements can increase the risk of polyps in the colon and rectum region (2). This came out when a trial study was conducted regarding the role of calcium and vitamin D in preventing polyps. Older studies regarding the effect of calcium and vitamin D supplements on prevention of polyp have given inconsistent results.
According to recent studies, it has been found that calcium with and without vitamin D increased the risk of colorectal polyps about 5 to 10 years after the supplements have been started (2).
According to these studies, there is evidence supporting that use of calcium supplements either with or without vitamin D supplements, can increase the risk of formation of precancerous growths or some forms of polyps in the colon or rectum for about a few years after a person has started taking the supplements.
Researchers also say that more studies are needed to confirm the results and if the studies prove right, then it can be an important discovery regarding assessment and prevention of colorectal cancer.
What is Colorectal Cancer?
Colorectal cancer is a malignant medical condition where cancerous cells multiply uncontrollably resulting in abnormal growth developments in the rectum or colon.
Polyp Precedes Colorectal Cancer
Polyp is a noncancerous growth and colorectal cancer often starts as a polyp in the lining of the rectum or colon (1, 3, 4). The growth of the polyps tends to be very slow, sometimes taking even up to two decades to form (5).
There are various types of polyps, distinguished according to their size, shape and characteristics of the tissue. Adenoma is the most common type of polyp and is known as adenomatous polyp (6).
Studies were also done on serrated polyps that are not as common as adenomatous polyps; however, have the same potential for becoming cancerous.
Preventing Colorectal Cancer
According to clinical point of view, when a patient is undergoing regular colonoscopic screening and if there are any suspicious polyps viewed, then removing them is the best way to decrease the chances of colorectal cancer.
Other than screening, chemoprevention using different agents has frequently been researched for reducing the rate of colorectal cancer.
The different agents researched for prevention of colorectal cancer consist of: Folic acid, aspirin, non-aspirin non-steroidal anti-inflammatories; calcium and vitamin D supplements.
Increased Risk of Polyps with Calcium Supplementation: The Ongoing Research
A recent analysis of the studies conducted regarding the chemoprevention trial of calcium and vitamin D in more than 2,000 patients with ages between 45 to 75 revealed that patients already had removal of at least single adenomatous polyp in colon and rectum region during a baseline screening. These patients were also supposed to have a follow-up colonoscopy in about 3 to 5 years.
After separating those patients who have a family history of rectal/ colon cancer, IBS or other serious diseases, the remaining patients were randomly assigned to 4 different treatment groups.
- The first group of patients was given calcium supplements daily.
- The second group was given vitamin D supplements daily.
- The third group was given both the supplements daily.
- The fourth group of patients was not given any supplements at all.
These four groups of patients were in the treatment stage till next follow-up screening colonoscopy in about 3 to 5 years. Patients after undergoing the second colonoscopy then underwent an observation stage where they were given no supplementations, after which a third screening colonoscopy was done, actually about 6 to 10 years after the patients were given the supplementation.
The results of the colonoscopy after the conclusion of the treatment stage revealed that neither calcium nor vitamin D affected the percentage of the cases of serrated polyps.
However, third colonoscopy that was done about 6 to 10 years after the patients initially started the supplementation showed an increased percentage of serrated polyps in the patients taking calcium alone or with vitamin D (2).
Any association for vitamin D alone was not found. Individuals who smoked were at increased risk for development of serrated polyps after taking calcium supplements.
Thus, at the end of these studies, it was concluded that more studies are needed for conclusive results and this can have an important affect on screening and prevention of colorectal cancer.
In the meantime, it has been recommended that individuals having a history of precancerous serrated polyps; especially women and people who smoke should avoid taking calcium and vitamin D supplements.