Taking multivitamins neither increases nor decreases the risk of cancer or cardiovascular disease in women, a study published in the February 2009 issue of the Archives of Internal Medicine has shown.

Over 160,000 women from the Women’s Health Initiative (WHI) took part in the study, nearly half of which used multivitamins on a regular basis.

Dr Marian L Neuhouser of Fred Hutchinson Cancer Research Center in Seattle said: “The main message of our study is that postmenopausal women who take a multivitamin don't increase their risk for cancer or cardiovascular disease, but they don't decrease it, either...These multivitamins are having no effect with regard to these particular disease outcomes."

She added: “Consumers need to decide if they want to continue this practice if they are taking [multivitamins] to prevent getting cancer or CVD...There may be other preventive practices that are better than taking a vitamin supplement, and their money is probably better spent on buying fruit and vegetables or increasing physical activity.”

During the study of 161,808 women, details of use of multivitamins at baseline and follow-up time points were collected. There was an average follow-up period of eight years.

During 2005, disease end points were collected, and this included breast, colon, rectum, endometrium, kidney, bladder, stomach, ovary and lung cancers, as well as cardiovascular diseases and total mortality.

During the follow-up period it was found that there were 9619 cases of cancer, 8751 incidents of cardiovascular diseases and 9865 deaths. However, the research showed that there was no relation between these cases and any risks posed by taking multivitamins.

Neuhouser reported that there was no link between any individual cancer or cardiovascular disease end point, except for "a slightly decreased risk for MI in those who took stress multivitamins.” She also notes that there are only 64 cases of MI amongst the tested women, which is a very small percentage.

She went on to criticise the Dietary Supplement and Health Education Act, which saw the deregulation of vitamin supplements in the US. She said: "We have entire aisles in our grocery stores with all kinds of vitamins, minerals, and so forth. Some are generic or store brand and so not that expensive, but some are extremely expensive. I hate to have consumers spending money on something that may not help them at all, when they could probably better spend it on healthy foods."

The lead study author seems strongly biased against food supplements. To hear the other side of the story, have a look at the article Women’s Multivitamin Study: ‘A little, too late’ study, designed to fail from alliance for natural health.

L.W.