Do Vitamins Increase Mortality?
Chester J. Zelasko, Ph.D. | July 8, 2008

A reader recently sent me a link to a lecture by Larry Norton, MD, Deputy Physician-in-Chief for Breast Cancer Programs at Sloan-Kettering Cancer Center (1). The reader was concerned because he’s a leading expert on cancer treatment and said he wouldn’t recommend taking vitamins because research has shown an increased mortality rate. Needless to say, that’s a provocative statement so I decided to listen to the discussion about supplements and provide my analysis of his comments. Before I do, let me say upfront that Dr. Norton is a brilliant physician; I wouldn’t hesitate to recommend him to anyone seeking cancer treatment. But it’s always the rest of the story where things get muddy. Let’s take a look.

Are Vitamins Dangerous?
Dr. Norton made a statement that people who take vitamins die sooner. He based that on a study published in Lancet in 2003 (2). The study was not a double-blind, placebo-controlled trial (DBPC). Rather, it was a meta-analysis of seven DBPC trials on vitamin E and eight DBPC trials on beta-carotene supplementation that included a combined total of 200,000 subjects. The objective of the individual studies was to see whether supplementation with these antioxidants reduced morbidity and mortality. Vitamin E had no positive or negative effect; beta-carotene resulted in a slight increased risk of overall mortality and an increased risk of death from heart disease.

The problem is that this statistical study combined studies that used varying amounts of the supplements, used mostly synthetic sources of the vitamins, and lasted varying lengths of time from 1.4 to 12 years. Even with no background in statistics, you can see the problem--too many different types of studies are being combined. In a review of the problems with meta-analysis, Dr. Craig Coleman who did a similar type of meta-analysis on the efficacy of echinacea said, “It’s not that we are comparing apples and oranges. Rather, we’re comparing different types of apples (3).” But that doesn’t lend itself to an accurate analysis.

There’s one more issue and that’s related to the number of subjects. Whenever the number of subjects gets so high, it increases the probability that differences will be found; an analysis of the data confirms that risk. While there was a statistically significant increase in mortality for those who used beta-carotene, the numbers work out to an additional four deaths per 1,000 subjects over 12 years. People are not dropping in the street from taking beta-carotene as Dr. Norton implied. He acknowledged that some people who are already sick might be attracted to taking vitamins. With so few deaths, that’s a more reasonable explanation than saying that vitamins are bad in general. Vitamins are not a substitute for a healthy lifestyle and quality health care--they complement it.

Why Would You Say That?
Dr. Norton was asked about the use of substances such as curcumin and coenzyme Q10 during cancer treatment. He replied with a question: “Why would you say that?” What he was after was the research: are there randomized DBPC trials done on those supplements in human trials during cancer treatment? Not test-tube or rodent studies and not theories based on logic--human trials. Have those data been accepted for publication in a peer-reviewed journal? If it passes those criteria, then he’d consider it.

But Dr. Norton violated his own criteria. He made the statement that cancer cells are more metabolically active and therefore, will need the vitamins more than the normal cells; the vitamins could therefore increase the tumor’s ability to defend itself and grow. So let’s ask him the same question: “Why would you say that?”

Are there published randomized DBPC trials on cancer patients undergoing treatment who were given antioxidants and had an increase in mortality or tumor growth? The answer is no. There are test-tube studies on antioxidants and isolated tumor cells, but that doesn’t fit his criteria. Neither does his logic when he states that cancer cells are dividing fast and thus must need more antioxidants. There are only test-tube studies showing that may be possible but nothing in human trials. In fact, there are a small number of DBPC trials on human subjects undergoing cancer treatment who were given antioxidants with beneficial effects (4).

Bottom Line
This was not an attempt to catch Dr. Norton making an error. Rather, it’s to demonstrate that we don’t know everything about antioxidants and cancer treatment. If a well-respected doctor makes a statement, he must back it up with research, not logic. So if you’re undergoing cancer treatment and your doctor says, “I don’t want you to take any vitamins during treatment,” I would start by asking one question: “Why would you say that?”

  1. Larry Norton, MD. The Changing Face of Breast Cancer: Where We Are, Where We Are Going, and How.

  2. Vivekananthan DP, et al. Use of Antioxidant Vitamins for the Prevention of Cardiovascular Disease: Meta-Analysis of Randomized Trials. Lancet. 2003; 361:2017-23.

  3. Carey, John. When Medical Studies Collide: Contradictory reports? Meta-analysis may make things more confusing. BusinessWeek. August 6, 2007. Page 38.

  4. Better Life Newsletter. Vitamin C and Cancer Treatment. March 16, 2007.
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