A new study is being reported in the media as suggesting a link between eggs and prostate cancer.
The findings of the study – that men who ate 2.5 or more eggs a week compared to men who ate less than half an egg week were 82% more likely to develop fatal prostate cancer – are certainly interesting.
But on their own they are not reliable enough to warrant men cutting back on eggs to reduce risk of prostate cancer.
For one thing, out of the 27,607 men followed as part of the study, only 199 died of prostate cancer during the course of the study. This number is too small to be confident that any associations between lifestyle and fatal prostate cancer are not simply down to chance.
Another problem with the study is that the lifestyles of the men who ate the most eggs also differed in other ways. For example, these men tended to be older, had a higher body mass index, were more likely to smoke and ate more red meat and dairy foods.
The researchers took some of these into account when they analysed the data, but this was not the case for dairy consumption.
This is a problem because our landmark report on cancer prevention, the most comprehensive ever published, found strong evidence that diets high in calcium (an indicator of dairy consumption) increase risk of prostate cancer (although because of contradictory evidence on bowel cancer, we do not make any recommendations on dairy one way or the other).
So it is possible the higher dairy consumption among the men who ate a lot of eggs may have skewed the results.
This means more research is needed before we can confidently say that eggs and prostate cancer really are linked. Our cancer prevention report did not conclude there was strong evidence that eggs affect risk of any type of cancer, including prostate cancer.
The researchers who have carried out this study have suggested the findings mean that “caution in egg intake may be warranted for adult men” but we would not recommend men cutting back on egg consumption to reduce their prostate cancer risk until there is more evidence.
But men – and women – who do want to reduce their risk of cancer can do so by making the kind of lifestyle changes for which there is already strong evidence. This includes maintaining a healthy weight, being regularly physically active and by having more plant foods such as fruits and vegetables and cutting down on alcohol, salt, and red and processed meat.