No Cancer Benefit From Vitamin B, Omega-3 Supplements in Heart Patients

MONDAY, Feb. 13 (HealthDay News) — Patients with a history of
heart disease will most likely not reduce their risk for developing cancer
by taking vitamin B and/or omega-3 fatty acid supplements, a new French
analysis suggests.

“In the population we studied, we found no beneficial effects of either
B vitamins or omega-3 fatty acids taken over five years on cancer
occurrence or cancer-related death,” noted study author Valentina
Andreeva, who is with the nutritional epidemiology research unit at the
University of Paris XIII in Bobigny, France.

Andreeva and her colleagues report their findings in the Feb. 13 online
edition of the Archives of Internal Medicine.

To explore the protective potential of B vitamins and fatty acid
supplements, the authors did a secondary analysis of data that had been
collected in a previous study involving almost 2,000 French men and 500
women.

All were between 45 and 80 years of age, and all had experienced
cardiac trouble (heart attack, unstable angina or ischemic stroke) in the
year leading up to the start of the study.

In turn, the participants were divided into one of four different
groups that consumed a daily supplement regimen involving various types of
vitamin B and omega-3 fatty acids at “relatively low supplementation
doses.”

By the end of the original five-year study, 7 percent of the
participants had gone on to develop some form of cancer, and just over 2
percent ultimately died of cancer. The vast majority of cancer cases
(including prostate, lung, bladder and colorectal cancer) and deaths
occurred among men (81 percent and 83 percent, respectively).

The team unearthed no evidence that any form of vitamin B or omega-3
fatty acid supplement improved cancer outcomes in any way.

The investigators noted that there were some indications that cancer
risk might have actually gone up, specifically among women taking vitamin
B and/or omega-3 fatty acid supplementation. However, the authors stressed
that this observation was based on too few cases to substantiate a firm
conclusion, and called for further research involving a larger pool of
participants.

“The results of our study suggest that individuals should exercise
caution when deciding to take dietary supplements, especially over a long
period of time and without a physician’s advice,” advised Andreeva. “Such
supplements constitute active substances and might have adverse effects in
some populations. To be on the safe side, individuals should strive to
achieve dietary recommendations via healthy, balanced diets.”

Joseph Su, the Washington, D.C.-based program director of the division
of cancer control and population science within the U.S. National Cancer
Institute’s epidemiology and genomics research program, said that nothing
about the findings struck him as surprising.

“So far, study findings have been very inconsistent,” he noted. “But
most supplement studies, if anything, have shown no beneficial effect
whatsoever. Just like this one. So, I don’t think there’s anything that
can really back up the idea that these supplements can prevent
cancer.”

However, Vicky Stevens, strategic director of laboratory services at
the American Cancer Society in Atlanta, expressed some reservations about
the French analysis.

“Compared with other trials, they used much lower levels of
supplements,” she noted. “From the B-vitamin point of view, dramatically
lower. So, it could be argued that they just weren’t using high enough
levels of supplements to see any effects,” Stevens suggested.

“And they used a natural form of folate [vitamin B supplement], whereas
other trials use a synthetic form,” Stevens added. “But the real problem
in being able to evaluate the effects they do see is that they don’t have
enough people. And it’s not really a long enough follow-up period to
really see an effect of these supplements on cancer onset. Five years
isn’t really enough. It can take 10 or 20 years in most cases. So, what
they may be seeing is an effect on preexisting abnormalities, but not the
impact on cancer onset itself.”

Duffy MacKay, a naturopathic doctor and vice president of scientific
and regulatory affairs for the Council for Responsible Nutrition in
Washington, D.C., agreed.

“When you look at an intervention like this, you’re definitely not
looking at the role of the supplements at preventing tumors, because the
tumors likely started well before the trial,” he noted. “So really what
the trial is about is giving vitamin B and omega 3 and seeing if they
altered the outcome, the progression, of these cancers,” MacKay
explained.

“And with that you have to realize that cancer is a very complex
multi-factorial disease,” MacKay stressed. “And two supplements would
never be expected to be a successful treatment on their own. I would say,
however, that proper nutrition is one of your best allies in terms of
wellness, period. And while no one ever claimed these were cancer drugs,
if you will, supplements make sense, cancer or no cancer.”

More information

For more on vitamins and cancer, visit the American Cancer Society.

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