Study linking multivits and breast cancer “fundamentally flawed”

A study linking regular use of multivitamins with an increased breast cancer risk has been dismissed as “fundamentally flawed” by industry and consumer groups.

The decade-long study (published in the American Journal of Clinical Nutrition) of more than 35,000 Swedish women was carried out by scientists at the Karolinska Institute in Stockholm. The researchers found that women who reported multivitamin use at the study’s start were 19 percent more likely than non-users to develop breast cancer. That was with factors like age, family history of breast cancer, weight, fruit and vegetable intake, and exercise, smoking and drinking habits taken into account.

The researchers conclude that it might be biologically plausible that multivitamins could have such an effect, and say the potential link “merits further investigation”.

But the Health Food Manufacturers Association and Consumers for Health Choice have criticized both the research and the way it has been reported in the media (

“This research linking multivitamins with breast cancer is fundamentally flawed,” said Graham Keen, executive director of the HFMA. “The study was not designed to establish cause and effect, and the researchers themselves agree that the findings do not prove that vitamins are to blame for incidence of breast cancer.

“The study has other limitations – the details about multivitamin use were obtained by a self-administered questionnaire, which is prone to inaccuracies, and details of the particular constituents of the multivitamins used were not available.

“Vitamins and minerals are not just useful for good health and wellbeing, they’re essential.  In an ideal world, our diet would provide us with all the vitamins and minerals that our body needs for good health. But evidence from the FSA’s latest National Diet and Nutrition Survey shows that a significant proportion of the UK population simply doesn’t achieve nutritional sufficiency through diet alone*.

“The best solution for most people is to eat as healthy a diet as possible, combined with other health-related lifestyle changes. For those looking to safeguard their nutritional intake, daily multivitamin supplements provide essential nutritional insurance for millions of consumers. In fact, the HFMA’s latest research confirms that 17m people now consume food supplements at least four times a week.”

Women’s health expert Dr Marilyn Glenville added: “The findings from this research are in sharp contrast to a study published in 2009 which looked at the survival of patients with end-stage cancer.  They were given supplements containing folic acid, selenium, vitamin C, coenzyme Q10 and beta-carotene over nine years.  Those taking the supplements survived 40% longer than the predicted survival time. So if supplementation really was a problem then it should have reduced survival time not increased it.”

Sue Croft, director of Consumers for Health Choice, told NP: “You would think that on the day the General Election was announced that media would have better things to do than report than an insipid new study into multi-vitamins.  But no, yet another article inadequately reported and even less understood pushes supplements back into the negative spotlight once again.

“I’m glad CHC was able to work with HFMA on this one.  The story didn’t just run in the newspaper — it made it onto the radio. Between us we managed to have the story dismissed on the BBC Radio 2 Jeremy Vine show early on and replaced with a discussion on multi-vitamins with Dr Sarah Jarvis that leaned towards the positive side. Teamwork!”