Certain vitamin supplements may increase lung cancer risk, especially in smokers

Feb 29, 2008

Vitamin supplements do not protect against lung cancer, according to a study of more than 77,000 vitamin users. In fact, some supplements may even increase the risk of developing it.

“Our study of supplemental multivitamins, vitamin C, vitamin E and folate did not show any evidence for a decreased risk of lung cancer,” wrote the study’s author, Christopher G. Slatore, M.D., of the University of Washington, in Seattle. “Indeed, increasing intake of supplemental vitamin E was associated with a slightly increased risk of lung cancer.”

The findings were published in the first issue for March of the American Thoracic Society’s American Journal of Respiratory and Critical Care Medicine.

Dr. Slatore and colleagues selected a prospective cohort of 77,126 men and women between 50 and 76 years of age in the Washington state VITAL (VITamins And Lifestyle) study, and determined their rate of developing lung cancer over four years with respect to their current and past vitamin usage, smoking, and other demographic and medical characteristics.

Of the original cohort, 521 developed lung cancer, the expected rate for a low-risk cohort such as VITAL. But among those who developed lung cancer, in addition to the unsurprising associations with smoking history, family history, and age, there was a slight but significant association between use of supplemental vitamin E and lung cancer.

“In contrast to the often assumed benefits or at least lack of harm, supplemental vitamin E was associated with a small increased risk of lung cancer,” said Dr. Slatore.

When modeled continuously, the increased risk was equivalent to a seven percent rise for every 100 mg/day. “This risk translates into a 28 percent increased risk of lung cancer at a dose of 400 mg/day for ten years,” wrote Dr. Slatore. The increased risk was most prominent in current smokers.

The idea that vitamin supplements are healthy, or at the very least, do no harm, comes from the desire of many people to mimic the benefits of a healthy diet with a convenient pill says Tim Byers, M.D., M.P.H., of the University of Colorado School of Medicine in an editorial in the same issue of the journal. However, he points out, “fruits contain not only vitamins but also many hundreds of other phytochemical compounds whose functions are not well understood.”

The World Cancer Research Fund and the American Cancer Society recommend two servings of fruit each day, based on a study that previously found a 20 percent increase in cancer risk among people who ate the least amount of fruit. This recommendation “would likely lead to a reduced risk for lung cancer, as well as reduced risk of several other cancers and cardiovascular disease,” writes Dr. Byers. “However, any benefit to the population of smokers from increasing fruit intake to reduce cancer risk by 20 percent would be more than offset if even a small proportion of smokers decided to continue tobacco use in favor of such a diet change.”

These findings have broad public health implications, given the large population of current and former smokers and the widespread use of vitamin supplements. “Future studies may focus on other components of fruits and vegetables that may explain the decreased risk [of cancer] that has been associated with fruits and vegetables,” writes Dr. Slatore. “Meanwhile,” he says, “our results should prompt clinicians to counsel patients that these supplements are unlikely to reduce the risk of lung cancer and may be detrimental.”

Source: American Thoracic Society

Explore further: Spicy treatment the answer to aggressive cancer?

Related Stories

How anthrax spores grow in cultured human tissues

Jun 23, 2015

Cultured human lung cells infected with a benign version of anthrax spores have yielded insights into how anthrax grows and spreads in exposed people. The study, published in the Journal of Applied Microbiology, will h ...

Low-cost pollution detectors to tackle air quality

Jun 02, 2015

Pollution causes 30,000 people a year in the UK to die early yet most of us are unaware of the degree to which we are exposed to it. Low-cost pollution detectors could provide the answer.

Three problems with the way we think about nuclear power

Jun 01, 2015

The future does not exist, at least not in the same way the past exists. From an evolutionary perspective, one might say there is no future in looking too far ahead. And perhaps not surprisingly, we are not ...

A turning point in the physics of blood

May 07, 2015

Mike Graham knows that fluid dynamics can reveal much about how the flow of blood helps and hinders individual blood cells as they go about their work.

Automated counting of tumor cells in blood

May 04, 2015

Biological and medical scientists have been using flow cytometry to count cancer cells for the past 40 years. But the large instruments are expensive and can only be operated by trained personnel. By contrast ...

Recommended for you

Spicy treatment the answer to aggressive cancer?

15 hours ago

It has been treasured by food lovers for thousands of years for its rich golden colour, peppery flavour and mustardy aroma…and now turmeric may also have a role in fighting cancer.

Cancer survivors who smoke perceive less risk from tobacco

Jul 02, 2015

Cancer survivors who smoke report fewer negative opinions about smoking, have more barriers to quitting, and are around other smokers more often than survivors who had quit before or after their diagnosis, according to a ...

Melanoma mutation rewires cell metabolism

Jul 02, 2015

A mutation found in most melanomas rewires cancer cells' metabolism, making them dependent on a ketogenesis enzyme, researchers at Winship Cancer Institute of Emory University have discovered.

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

SDMike
not rated yet Mar 01, 2008
So, E smoking increases cancer risk. "The increased risk was most prominent in current smokers. " I've taught statistics for years and don't recall the term "prominent". What is the relationship between E and cancer in non smokers?

Lousy reporting!

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.