The first study to investigate the
relationship between eating fruit and vegetables containing pesticide
residues and the quality of men’s semen has shown a link with lower
sperm counts and percentages of normally-formed sperm.
The study, which is published online
Tuesday in Human Reproduction shows that men who ate the highest amount
of fruit and vegetables with high levels of pesticide residue had a 49
per cent lower sperm count and a 32 per cent lower percentage of
normally-formed sperm than men who consumed the least amount. An
accompanying editorial says the findings have important implications for
human health.
However, the study of 155 men showed
that, overall, the total amount of fruit and vegetables consumed was....
unrelated to changes in any measurements of semen quality in the group
as a whole.
Assistant Professor of Nutrition and
Epidemiology at the Harvard T.H. Chan School of Public Health in Boston,
Jorge Chavarro, said: “These findings should not discourage the
consumption of fruit and vegetables in general. In fact, we found that
total intake of fruit and vegetables was completely unrelated to semen
quality. This suggests that implementing strategies specifically
targeted at avoiding pesticide residues, such as consuming
organically-grown produce or avoiding produce known to have large
amounts of residues, may be the way to go.”
Previous studies have shown that
occupational exposure to pesticides might have an effect on semen
quality, but so far there has been little investigation of the effects
of pesticides in diet.
Prof Chavarro, his student Dr. Yu-Han
Chiu and colleagues analysed 338 semen samples from 155 men attending a
fertility centre between 2007-2012 as part of the ongoing, prospective
“Environment and Reproductive Health” Study. The men were eligible for
the study if they were aged 18-55, had not had a vasectomy, and were
part of a couple planning to use their own eggs and sperm for fertility
treatment.
The men’s diet was assessed by means of a
food frequency questionnaire, and they were asked how often, on
average, they had consumed how many portions of fruit and vegetables,
using standard portion sizes such as one apple, or half an avocado.
The fruit and vegetables were categorised
as being high, moderate or low in pesticide residues based on data from
the annual United States Department of Agriculture Pesticide Data
Programme. Fruit or vegetables that were low in pesticide residues
included peas, beans, grapefruit and onions. Those that had high
residues included peppers, spinach, strawberries, apples and pears.
These data took account of usual practice in food preparation, such as
whether the fruit and vegetables had been peeled and washed.
The researchers divided the men into four
groups, ranging from those who ate the greatest amount of fruit and
vegetables high in pesticides residues (1.5 servings or more a day) to
those who ate the least amount (less than half a serving a day). They
also looked at men who ate fruit and vegetables with low-to-moderate
pesticide residues.
The group of men with the highest intake
of pesticide-heavy fruit and vegetables had an average total sperm count
of 86 million sperm per ejaculate compared to men eating the least who
had an average of 171 million sperm per ejaculate – a 49 per cent
reduction. The percentage of normally formed sperm was an average of 7.5
per cent in men in the group with the lowest intake and 5.1 per cent in
the men with the highest intake – a relative decrease of 32 per cent.
There were no differences seen between
men in the four groups who consumed fruit and vegetables with
low-to-moderate pesticide residues. In fact, there was a significant
trend towards having a higher percentage of normally shaped sperm among
men who consumed the most fruit and vegetables with low pesticide
residues – a relative increase of 37 per cent from 5.7 per cent to 7.8
per cent.
Culled - ScienceDaily
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