CRN: Report finding not enough evidence linking multivitamins to cancer prevention shouldn't obscure their benefits

The report from the United States Preventive Services Task Force looked at a number of different studies and vitamin formulations in their report titled “Vitamin, Mineral and Multivitamin Supplements for the Primary Prevention of Cardiovascular Disease and Cancer.”​​  The report found insufficient evidence to recommend the usage of these substances to prevent these conditions.  But that finding is a far cry from a blanket statement that multivitamins have no value, a headline that Duffy MacKay, ND, executive vice president for the CRN said might pop up in the coming days.

“The task force recognized their report is narrowly focused on heart diease and cancer.  One should not expect a simple multivitamin by itself to prevent these diseases,”​ he told NutraIngredients-USA.

“There conclusions were there were not enough studies to show benefit.  But when you look at the studies that were included, we saw them trending toward benefit.  But that data fell short of meeting their rigorous standards for making a public health recommendation,”​ MacKay said.

“ ‘Not enough evidence’ is a very different finding from ‘no benefit.’ ”​

Multis, single vitamins and minerals​

The review looked at studies done with multivitmain formulations, single and paired vitamins, and vitamins paired with minerals such as vitamin D and calcium.  The report “found inadequate evidence on the effectiveness of multivitamin supplements to prevent cardiovascular disease or cancer. Therefore, the USPSTF concludes that the evidence is lacking and the balance of benefits and harms cannot be determined.”​

The report went on to state that only two substances, beta carotene and vitamin E, had enough data behind them to make a determination.  In the case of beta carotene, the task force found a net harm for the usage of this vitmain, though it modified that finding in response to comments to indicate this is mostly in relation to heavy smokers, an association that MacKay said “has been known for a long time.”  ​And in the case of vitmain E, the report found no benefit.

Weakness of drug-like model​

The large number of formulations covered in the study points out a weakness in applying a single-molecule, drug-like mindset to nutritional studies, MacKay said.  There just isn’t enough apples-to-apples data available, he said.

“This is a giant call out for more research.  If we want to ask questions like cardiovascular disease, we have to embark on a long-term research path that will take us there,”​ MacKay said.

“A critical gap in the evidence is the lack of studies of multivitamin combinations in groups generalizable to the U.S. population. . . Future trials should be more representative of the general population, including women and minority groups, and should have enough power to show whether there are true subgroup differences. Targeting research toward persons who can be identified as high-risk for nutrient deficiency rather than the general population may be more productive,” ​the task force wrote.

General health support​

And that points to a key take away when looking at the study, MacKay said. Most consumers aren’t looking to prevent heart disease and cancer per se when they take a multivitamin or mineral supplement. 

“The reason consumers take their multivitamins is for overall health and to fill nutrient gaps. We know that 52% of Americans take a multivitamin and if you are taking a multi to fill in gaps, this report should do nothing to cahnge that,”​ he said.

“We don’t want that message to be lost in a report that was looking for a magic bullet for heart diesase and cancer,”​ MacKay said.