March 31, 2015

expert reaction to study investigating fruit and vegetables, pesticides and semen quality

A study published in the journal Human Reproduction has examined a potential link between consumption of fruit and vegetables containing pesticide residues and semen quality. The authors suggest that the consumption of high levels of pesticide residues in fruit and vegetables is associated with a lower overall sperm count and lower percentage of morphologically normal sperm among men visiting a fertility clinic.

Prof. Sheena Lewis, Professor of Reproductive Medicine, Queen’s University Belfast, said:

“This is an interesting study but its results must be taken in context.  The study includes a relatively small number of 155 men. The men were all having infertility investigations so their semen may be more vulnerable to pesticide insult than the general population. The sperm counts and morphology of the highest pesticide residue group, although lower than the lowest quartile of intake, were still within the normal range according to WHO recommendations.  The authors’ conclusion is correct that more studies are needed NOT that we should stop eating our 5-a-day.”

Dr Jackson Kirkman-Brown, Science Lead, Birmingham Women’s Fertility Centre, said:

“The paper highlights a growing body of evidence that diet can affect male fertility and sperm quality.

“The data do not really allow us to assess whether it is actual pesticide residue or simply choice of vegetable type which may be affecting the sperm parameters – pesticide itself was not measured and indeed some patients could have been eating organic fruit and vegetables – as it was published general average levels that were used to assess how much individuals may have consumed. Therefore this paper may cause unnecessary worry.

“Men wishing to optimise their sperm quality should still eat a healthy balanced diet until more data is available.”

Prof. Allan Pacey, Professor of Andrology, University of Sheffield, said:

“This is a very interesting paper that raises the possibility that pesticide residues in our food may be a contributory factor in male infertility, at least in some men. The idea has been raised before, but to my knowledge this is the first paper that has investigated this question in a systematic way. That said, whilst the results are tantalising, they should be interpreted with caution as the study is not without its flaws and limitations.

“This is not a criticism of the authors because this kind of work is challenging, but as they acknowledge themselves they did not measure the pesticide residues in the actual food the men ate but rather inferred this from other data. Also, this is an observational study and on the basis of the data in the paper, we cannot discount that it is another aspect of the men’s diet or lifestyle that is actually the cause of the effects seen.

“I think it would be important that the newspaper headlines that accompany this article don’t discourage men from eating their quota of fresh fruit and vegetables each day as this is important for other health reasons. There is also no evidence at present that switching to organic fruit and vegetables will improve semen quality, although it will obviously do no harm. But I hope that this paper will encourage other studies to take place in this area, so that we might be able to answer the question once and for all.”

‘Fruit and vegetable intake and their pesticide residues in relation to semen quality among men from a fertility clinic’ by Y.H. Chiu et al. published in Human Reproduction at 00:05 UK time on Tuesday 31 March 2015.

All our previous output on this subject can be seen at this weblink: http://www.sciencemediacentre.org/tag/sperm/

Declared interests

Prof. Sheena Lewis is CEO of Lewis Fertility Testing Ltd, a university spin-out company marketing a test for male infertility: www.spermcomet.com.

Prof. Allan Pacey: Chairman of the advisory committee of the UK National External Quality Assurance Schemes in Andrology and Editor in Chief of Human Fertility (both unpaid). Also, recent work for the World Health Organisation, Merck Sharp and Dohme Ltd (Finland), Ferring Pharmaceuticals Ltd (paid consultancy with all monies going to University of Sheffield). Co-applicant on a research grant from the Medical Research Council (ref: MR/M010473/1).