Meta-study confirms that carrots protect against breast cancer
A few days ago we wrote about a study from the last century, in which carrots protected against breast cancer. Okay, of course, one study doesn't say much. One study is no study. But in 2018, Chinese researchers at Ningbo University published a meta-study in Medicine with the same outcome.
The Chinese collected 10 epidemiological studies, in which a total of 141,187 women had participated. Of those women, 13,747 had been diagnozed with breast cancer.
The group of women with the highest carrot intake has 21 percent less chance of developing breast cancer than the group with the lowest intake.
Click on the figure below for a larger version.
There is a tendency in epidemiological nutritional science that interesting effects lose their luster as more researchers start studying the effect. A first study triumphantly concludes that food X or substance Y protects against disease Z, a second study is a little less cheering, a third study again a little less, a fputh study doesn't find any effect at all - and when we are fifteen years further, the conclusion of that first positive study has been put to rest.
The outcomes of the hopeful first study often turn out to be a fluke. Or they were a result of a methodological error.
This may not be the case with the protective effect of carrots, the Chinese discovered. The figure below shows that, in the period between 1986 and 2016, in which the 10 studies are published in succession, the protective effect of carrots remains intact.
Click on the figure above for a larger version.
The Chinese also determined whether it matters where the study was conducted. Not so. Whether the women lived in Europe, the US or the Asian continent, carrots protected against breast cancer.
The quality of the studies was also not a factor. Meticulously conducted studies concluded just as often that carrots protected as not so well-executed epidemiological studies.
"The results of the current meta-analysis indicated that high carrot intake was associated with decreased risk of breast cancer," the researchers write.
"These findings could have important public health implications given the high incidence and large burden of breast cancer. However, this evidence is mainly derived from case-control studies and further data from large cohorts are warranted to confirm the results."
Medicine (Baltimore). 2018 Sep;97(37):e12164.
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