(RxWiki News) We're told to eat lots of vegetables and whole grains. They should be the staple of our diet. A new study finds that the way these foods are produced impacts our risk of cancer - slightly - but still the risk is there.
A naturally occurring toxic metal that's used in a variety of fertilizers may increase the risk of breast cancer. Cadmium is found both in the environment and in the plants humans consume. It has estrogen-like activity and may promote malignancies driven by estrogen, including breast cancer.
"Eating a healthy diet is always your best defense."
According to Swedish scientists, cadmium contamination of farmland soil through atmospheric deposits and fertilizer use increases the amount of the metal found in plants.
The most common sources of dietary cadmium are cereals, bread, root crops, potatoes and vegetables, says Agneta Åkesson, Ph.D., associate professor at Karolinska Institutet in Sweden.
Akesson and colleagues followed nearly 56,000 women for more than 12 years. Dietary cadmium exposure was estimated with a questionnaire asking how often certain types of foods were consumed.
Consumption of cadmium was divided into three groups, comparing the highest and lowest levels of consumption. Women who were exposed to the highest levels of cadmium had a nearly two-fold higher consumption of whole grain and vegetables than those who consumed the lowest levels.
During the 12-year study, 2,112 women developed breast cancer.
Researchers found that among these women, those who consumed higher levels of cadmium had a 21 percent increased risk of breast cancer, compared to women with the lowest intake.
Some of the foods with the highest cadmium levels, namely whole grains and vegetables, have also been found in some studies to have anti-cancer effects.
The authors write, "It could be hypothesized that the observed association between dietary cadmium exposure and breast cancer in the present study may partly be masked by the consumption of whole grain and vegetables, as adjusting the models for these foods resulted in a considerable increase of the risk estimates for dietary cadmium intake."
According to Akesson, women who ate more whole grains and vegetables had lower breast cancer risks than women who were exposed to cadmium from other foods.
Akesson concluded, “It’s possible that this healthy diet to some extent can counteract the negative effect of cadmium, but our findings need to be confirmed with further studies.”
This research was published in Cancer Research, a journal of the American Association for Cancer Research.
The study was supported by The Swedish Cancer Society and the Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning and by the Swedish Research Council/Research Infrastructures.
No potential conflicts of interest were disclosed.