Consumption of pesticides treated fruits and vegetables linked with reduced fertility in women

Regular dietary consumption of fruits and vegetables treated with pesticides is linked to lower probability of live births and success rates of ARTs according to a study from Harvard T.H. Chan School of Public Health published October 30, 2017 in JAMA.

Animal exposure to pesticides at environmentally relevant concentrations is known to decrease the number of live births. Whether this holds good for humans is topic for research in recent years, the effects of high dose exposure causing reproductive injuries is already known.

More than 600 different pesticides chemicals, resulting into 1000s of combinations are available in US market with more than 450 kg applied every year.

Occupational exposure to high dose of some older pesticides are known to cause reproductive injury in exposed males causing infertility and azoospermia.

This prospective epidemiological study uses sophisticated biological markers to identify the effects of subclinical everyday exposure pesticide residues in fruits and vegetables on female fertility.

The study recruited 325 women undergoing infertility treatment as part of the Environment and Reproductive Health (EARTH) study. The women filled out study questionnaire about the daily consumption of fruits and vegetables. Women’s exposure to pesticides was calculated based on US government database of average pesticide residues on fresh fruits and vegetables.

The study found that women who ate more than two servings (2.3) of high-pesticide fruits or vegetables each day, compared with women who ate an average of one each day, were 18% less likely to become pregnant and 26% less likely to have a live birth than women with the lowest exposure.

If you can exchange one high-pesticide fruit or vegetable a day for a low-pesticide one, your odds of pregnancy are increased by 79% and live birth by 88% say the researchers.

Strawberries, spinach and peppers, tend to consistently make into the list of ‘dirty dozen’, a list of 12 most contaminated fruits and vegetables, while others, like peas and avocados, rank lower.

Jorge Chavarro, associate professor of nutrition and epidemiology at Harvard Chan School and senior author of the study, said that women trying to conceive may want to limit their intake of high-pesticide fruits and vegetables or eat organic versions, or choose low-pesticide produce such as avocados, onions, or oranges. “I am now more willing to buy organic apples than I was a few months ago,” he told TIME.

When the researchers modeled the effect of swapping one high-pesticide fruit or vegetable a day for a low-pesticide one, they found 79% higher odds of pregnancy and 88% higher odds of a live birth.

Dr. Yu-Han Chiu, a research fellow in the department of nutrition at the Harvard T.H. Chan School of Public Health and first author of the study told CNN "Although we did find that intake of high-pesticide-residue fruits and vegetables were associated to lower reproductive success, intake of low-pesticide-residue fruits and vegetables had the opposite association."

The researchers agree that the study just show an ‘association’ and more work is needed before a direct ‘causation’ can be established. Also, the results pertain to certain subset of women who already had reproductive issues and were seeking fertility treatment.

The study is accompanied by a commentary by Philip J. Landrigan titled

Pesticides and Human Reproduction

Which fruits you should buy organic

It's not always possible or affordable to buy completely organic produce. Nutritionist Lisa Drayer shows us which fruits to look for in the organic section.

Source: CNN

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Soy intake may insulate against the harmful effect of endocrine disruptors on infertility

soybeans 

soy-products

Bis-phenol A, or BPA, is a chemical used to make a hard clear plastic called polycarbonate, 

BPA enters our bodies mainly through  plastic water bottles, food and beverages containers and  Canned foods, because most metal cans are lined with a sealant containing BPA.

Human exposure to BPA is widespread, a survey of the U.S. population found BPA in 93 percent of urine samples from people age 6 and older.

Epidemiological and observational studies have linked BPA to various disorders including male and female infertility.

Animal data have shown that soy intake may modify the harmful effect of BPA exposure; no such human studies have been yet documented. 

According to a study published by Chavarro JE et al in The Journal of Clinical Endocrinology & Metabolism the effects of environmental toxins can be mitigated by lifestyle factors such as diet and nutrition.

This is a pilot study in humans showing interaction between soy intake and levels of BPA in urine among women undergoing ART. Experimental studies in rodents have already documented a protective effect of soy against adverse reproductive health effect of Bisphenol-A (BPA). 

These study participants were a part of an ongoing prospective cohort of women enrolled in the year 2004 to evaluate the role of environmental and nutritional determinants of fertility called as the Environment and Reproductive Health (EARTH) Study. The objective was to examine the hypothesis that soy intake modifies the association between BPA and fertility in women undergoing assisted reproduction.

The study participants consisted of 239 women, 18 to 45 years of age, and who have undergone at least one IVF cycle between  2007- 2012 at the Massachusetts General Hospital (MGH) Fertility Center, provided at least 1 urine sample for the measurement of BPA per IVF cycle, and had data on pretreatment soy food intake.

Of the women, 176 (74%) consumed soy foods. The mean isoflavone intake among soy food consumers was 3.4 mg/d.

The authors found suggestive evidence that increasing BPA levels might be the cause of lower rate of implantation (P=.02), clinical pregnancy (P=.03), and live birth rates (P=.03) only among women who did not consume soy food. Women who consumed soy food increasing BPA levels did not lead to less successful outcome in IVF.

Similarly, women who did not eat soy had the highest level of urinary BPA levels, with live pregnancy rate of  17% in contrast women with the highest level of BPA and ate soy had a pregnancy rate of 49%.

The protective effect of soy was also observed in other parameters such as markers of

oocyte and embryo quality to live birth rates.

The study results have wider ramification beyond infertility, BPA and soy. It implies that the effect of environmental chemicals and toxins can be modified by diet and nutrition.

The study did not look at how the protective effect of soy is executed, but in animal studies it was seen that BPA increases the risk of abnormal chromosomes, or can switch on and off certain gene expression and soy prevented all these actions.

The Limitations of the study are:

As the study subjects are all undergoing IVF, it is not possible to know whether the study findings can be generalized to women trying to conceive naturally.

As the intake of soy was based on study questionnaires answered by the participants it may suffer from recall and information bias.

It is important that these findings be evaluated further in larger populations, in larger studies before any recommendations can be made.

The study author also caution against a mad rush to eat soy, the study participants were consuming soy in moderation and soy itself is estrogenic and can act as endocrine disruptor itself .

References:

http://press.endocrine.org/doi/pdf/10.1210/jc.2015-3473

http://www.sciencedaily.com/releases/2015/04/150415125817.htm

http://www.hazwastehelp.org/chemtoxpesticides/bisphenola.aspx