A secondary analysis of the UK National Diet and Nutrition Survey, published in Frontiers in Nutrition, highlights a tendency to report micronutrients intakes collectively for adults, with broad age ranges being used. This means that certain sub-population groups such as younger adults are often overlooked.

The current analysis, which looked at these subpopulations, noted that improvements in dietary quality are needed in young adulthood and mid-life. To achieve this, they note, supplementation strategies could help young adults be where they should be at these ages – in their “nutritional prime.”

The analysis found sizeable deficiencies in several important nutrients. For magnesium in both men and women, 19% of young people in their twenties having intakes below the Lowest Recommended Nutrient Intake (LRNI). There were also considerable gender gaps in dietary selenium intakes, with 50% females and 26% of males having total intakes beneath the LRNI.

Furthermore, a quarter of women had both iron and potassium intakes below the LRNI, while among UK males, vitamin A and zinc shortfalls were apparent.

The researchers say that an adequate micronutrient profile for women is not only important for fertility but also to prepare the body for the extensive physiological demands should pregnancy occur. Selenium, for example, has been highlighted as a crucial nutrient for women seeking to become pregnant.

By increasing their risk of preeclampsia, mothers with low selenium levels may also be at increased risk for heart disease, stroke and high blood pressure later in life. The summary calls for higher levels of supplementation of high selenium yeast to combat heart health threats.

Male fertility at risk too

Zinc, of course, is a known antioxidant with research showing that fertile males tend to have higher seminal zinc levels than their infertile men. Zinc also helps to support immunity and avert age-related diseases.

Zinc shortfalls are somewhat surprising to see, the researchers add, especially among males, given that meat and meat products are one of the main providers of zinc. It is possible that younger men in their twenties are eating less meat which could have contributed to lower zinc intakes in this age group, the researchers note. This is an important finding and worthy of consideration in the context of public health given current trends toward plant-based diets, they explain.

In terms of the low vitamin A intake found in males, the researchers found that young men’s mean intakes of fruit and vegetables were slightly lower at 3.9 portions daily compared with 4.1 portions daily among women aged 19 to 64 years. It has also been found that fruit and vegetable variety tends to be lower in men, especially in instances where education and social class is lower.

Why are levels so low?
Adequate nutrition at this stage of life can also help to future-proof health against debilitating and chronic diseases that can occur in later life.

The researchers suggested that when it comes to women’s nutritional shortfalls, societal pressures around body image could be a factor. They cite a recent survey of 1,035 social media tweets typically used by young adults that found that 67% related to body image, eating disorders, fitness, food or dieting. This, in turn, could have wider ramifications impacting on dietary habits and micronutrient profiles of young women.

Emerging food trends and the avoidance of food groups could also be impacting on micronutrient intakes. For example, the consumption of eggs, milk, and dairy correlates strongly against female nutritional iodine status while veganism has also been found to impact on vitamin D, calcium and vitamin B12, iodine and selenium intakes. They further add that UK females having diets lower in red meat (less than 40 g daily) have reduced micronutrient intakes, especially zinc and vitamin D.

“It is imperative to continue raising awareness about the importance of healthy and balanced diets and adequate micronutrient intakes. The implications of ‘cutting back or cutting out’ certain food groups also need to be communicated, especially to younger generations who are strongly influenced by social media which is not subject to peer review or monitoring systems,” says author Dr. Emma Derbyshire, Public Health Nutritionist and an advisor to the Health & Food Supplements Information Service (HSIS).

A daily insurance policy
The current research found that females and young adults are at particular risk of micronutrient shortfalls. In an environment, where the public are being encouraged to reduce their energy intakes, it is important to ensure that younger people get the nutrient they need sand that multivitamin and mineral supplements could help.

Supplement, of course, are no substitute for a healthy diet, but as the nutrient content of our food declines and food fads become more prevalent, they may be an important insurance policy for health. For information on choosing the best supplements see our article What to look for in supplements.

The benefits, which were seen after only 14 weeks of regular consumption, “support a beneficial role for chronic nut consumption in sperm quality” may reflect a need to develop dietary recommendations that are more “male specific”.

The results of the study are presented today at the annual meeting of the European Society of Human Reproduction and Embryology.

According to Dr Albert Salas-Huetos from the Human Nutrition Unit of the Universitat Rovira i Virgil in Reus, Spain, who led the study, the research was performed against a background of general decline in quantity and quality of human sperm, attributed in industrialised countries to “pollution, smoking, and trends toward a western-style diet.”

Significant improvements

The study was a 14-week randomised clinical trial in which 119 healthy young men aged 18-35 were allocated to either their usual western-style diet supplemented with 60 g/day of mixed almonds, hazelnuts and walnuts, or their usual western-style diet without nuts.

Results showed significantly higher levels of sperm count, vitality, motility and morphology (shape) in the men randomised to the 60 g/day nut diet than in those following their usual diets free of nuts.

Improvements in the former group were by around 16% in sperm count, 4% in sperm vitality, 6% in sperm motility, and 1% in morphology (shape). These four parameters, explained Salas-Huetos, are all associated with male fertility.

These improvements were consistent with improvements found in other recent studies with diets rich in omega-3, antioxidants (eg, vitamin C and E, selenium and zinc), and folate. Nuts are dense foods containing many of these nutrients and other phytochemicals.

Benefits at the genetic level

The researchers, however also looked deeper into the DNA of the sperm to try and understand why the nuts might trigger these benefits. At the molecular level it has also been proposed that the genetic integrity of each sperm cell is essential for fertility. If DNA strands in the cell become damaged or fragmented, they will be unable or less likely to fertilise an egg and maintain embryonic development.

It is believed that this DNA fragmentation is caused by oxidative stress as a result of environmental and lifestyle factors.

In this study the men in the nut group also showed a significant reduction in their levels of sperm DNA fragmentation, a parameter closely associated with male infertility. The researchers propose that it is this change, at genetic level that is responsible for all the other benefits seen.

More to learn

The men in this study were generally healthy and exhibited no signs of infertility. The researchers say that a next step would be to look at the effects of regular nut eating on men with fertility problems.

Nevertheless Salas-Huetos concludes that “healthy lifestyle changes such as following a healthy dietary pattern might help conception – and of course, nuts are a key component of a Mediterranean healthy diet.”

Animal studies suggest consumption of pesticide mixtures in early pregnancy may be associated with fewer live births, leading to concerns that levels of pesticide residues permitted in food by the US Environmental Protection Agency (EPA) may still be too high for pregnant women and infants.

To find out more, researchers from Harvard T. H. Chan School of Public Health, Boston studied 325 women who were using assisted reproductive technologies at a fertility centre at a teaching hospital in Boston between 2007 and 2016

The women’s diets were assessed using a standardised food questionnaire.

For this observational study, researchers, led by Jorge E. Chavarro, M.D., Sc.D categorized fruits and vegetables as having high or low pesticide residues using a method based on surveillance data from the US Department of Agriculture (USDA). They then counted the number of confirmed pregnancies and live births per cycle of fertility treatment.

Results of the study indicate that eating more high-pesticide residue fruits and vegetables otherwise considered healthy (for example, strawberries and raw spinach) was associated with a lower probability of pregnancy and live birth following infertility treatment.

Conversely, eating more low-pesticide residue fruits and vegetables was not associated with worse pregnancy and live birth outcomes.

The study, published in JAMA Internal Medicine, was not able to link specific pesticides to adverse effects.

Pesticide regulation is failing us

In a commentary that accompanied the study, epidemiologist and paediatrician Phillip Landrigan, MD, of Mount Sinai warned, “our current laissez-faire attitude toward the regulation of pesticides is failing us”.

The study, he said, “comes at a time when multiple lines of evidence suggest that human fertility is on the decline and that the frequency of reproductive impairment is increasing,”

He noted that trends such as reduced sperm counts and increases in reproductive birth defects and testicular cancer that are “almost certainly” linked to environmental exposures to chemicals – many of which are endocrine disrupters –  and that physicians should respond to these findings by educating patients about pesticides and urging reductions in exposure wherever possible.

Following the publication of the study, in an interview with Time magazine Dr Chavarro noted “I was always skeptical that pesticide residues in foods would have any impact on health whatsoever. I thought we were not going to find anything…I am now more willing to buy organic apples than I was a few months ago.”

Previous research in the US has shown that eating organic produce can substantially reduce pesticide exposure so couples having trouble getting pregnant should consider making the switch.

• For more on this topic see also How to grow a healthy baby

A study of more than 9,000 men with fertility problems found a correlation between the number of different defects in a man’s semen and the likelihood that the man has other health problems.

The study, conducted by investigators at the Stanford University School of Medicine, also links poor semen quality to a higher chance of having various specific health conditions, such as hypertension, and more generally to skin and endocrine disorders.

The findings, published in Fertility and Sterility, may spur more-comprehensive approaches to treating male infertility. They also point to the wisdom of performing complete physical examinations of men experiencing reproductive difficulties.

“About 15% of all couples have fertility issues, and in half of those cases the male partner has semen deficiencies,” said the study’s lead author, Michael Eisenberg, MD, assistant professor of urology and director of male reproductive medicine and surgery at Stanford. “We should be paying more attention to these millions of men. Infertility is a warning: Problems with reproduction may mean problems with overall health.”

A study Eisenberg co-authored a few years ago showed that infertile men had higher rates of overall premature death, as well as death linked to heart problems, in the years following an infertility evaluation. “But here, we’re already spotting signs of trouble in young men in their 30s,” he said.

Making connections

In the new study, Eisenberg and his colleagues analyzed the medical records of 9,387 men, mostly between 30 and 50 years old, who had been evaluated at Stanford Hospital & Clinics (now Stanford Health Care) between 1994 and 2011 to determine the cause of their infertility. The men had routinely provided semen samples, which the researchers assessed for characteristics including volume, concentration and motility.

In about half of all the male infertility cases, the problem was abnormal semen; in the rest, the fault lay elsewhere. So, using the database, the investigators were able to compare the overall health status of men who had semen defects to that of the men who didn’t.

With an average age of 38, this was a fairly young group of men. However, 44% of all the men had some additional health problem besides the fertility problem that brought them to the clinic.

In particular, the investigators found a substantial link between poor semen quality and specific diseases of the circulatory system, notably hypertension, vascular disease and heart disease. “To the best of my knowledge, there’s never been a study showing this association before,” said Eisenberg. “There are a lot of men who have hypertension, so understanding that correlation is of huge interest to us.”

In addition, as the number of different kinds of defects in a man’s semen rose, so did his likelihood of having a skin disease or endocrine disorder. When looking at the severity of all health problems, the scientists observed a statistically significant connection between the number of different ways in which a man’s semen was deficient and the likelihood of his having a substantial health problem.

Semen quality, a health warning

The study wasn’t designed to determine precisely how connections between semen deficiencies and seemingly unrelated disorders, such as cardiovascular or endocrine disease, come about. But, Eisenberg noted, some 15 percent of all genes in the human genome are connected fairly directly to reproduction, and most of these genes also have diverse functions in other bodily systems. He also noted that it may not be a disease itself, but the treatment for the disease, that’s actually responsible for reproductive malfunction.

Eother way he notes that semen qualty can he a kind of health warning.

“A man’s health is strongly correlated with his semen quality,” he said. “Given the high incidence of infertility, we need to take a broader view. As we treat men’s infertility, we should also assess their overall health. That visit to a fertility clinic represents a big opportunity to improve their treatment for other conditions, which we now suspect could actually help resolve the infertility they came in for in the first place.”

The study found no difference in sperm concentration, viability and mobility, but there was an increase in abnormal sperm formation measured 2, 3, and 4 months after this short exposure.

The study, published in the journal Environmental Toxicology and Pharmacology, is the first to measure the delayed effects of exposure to Roundup on sperm in mammals from a short exposure. It was conducted by a team including Prof Gilles-Eric Séralini at the University of Caen, France.

Roundup was found to change gene expression in sperm cells, which could alter the balance of the sex hormones androgen and estrogen. A negative impact on sperm quality was confirmed, raising questions about impaired sperm efficiency. The authors suggested that repeated exposures to Roundup at doses lower than those used in agriculture could damage mammalian reproduction over the long term.

Roundup, the active ingredient of which is glyphosate, is the world’s most widely used herbicide formulation. It’s widespread use is due in part to the fact that many GM crops are engineered to withstand repeated sprayings.

The study’s findings should raise alarm in farm workers, as well as people who spray Roundup for municipal authorities and even home gardeners. People exposed to lower doses repeated over the long term, including consumers who eat food produced with Roundup and people who happen to be exposed to others’ spraying activities, should also be concerned.

Those who want to conceive a child should take special measures to minimise their exposure, including eating organic food and lobbying for a ban on Roundup spraying in their neighbourhoods.

• Thanks to our friends at GM Watch for allowing us to publish this story, which first appeared on their site.

Cholesterol is a waxy, fat-like substance found in all cells of the body. We need cholesterol to make a number of substances, including hormones and vitamin D. While high blood cholesterol levels typically do not cause any signs or symptoms, they can increase the chances for heart disease.

The researchers were investigating the theory that blood cholesterol might be related to fertility as the body uses cholesterol to manufacture sex hormones like testosterone and estrogen.

The study findings were published online in the Journal of Clinical Endocrinology and Metabolism.

For the current analysis, the researchers studied couples who were not being treated for infertility but who were trying to conceive a child. The researchers enrolled 501 couples from four counties in Michigan and 12 counties in Texas from 2005 to 2009.

Study volunteers provided blood samples, which the researchers tested for free cholesterol, that it the total amount of cholesterol in the blood, as opposed to the usual cholesterol subtypes: HDL cholesterol, LDL cholesterol and triglycerides.

Get cholesterol under control if you want to get pregnant

The researchers found that on average, those couples in which the woman did not become pregnant during the study duration had the highest free cholesterol levels.

In general, high free cholesterol levels were correlated with longer times to pregnancy and lower level of fertility. Couples in which the woman had a high cholesterol level and the man did not also took longer to achieve pregnancy when compared to couples in which both partners had cholesterol levels in the acceptable range.

“We’ve long known that high cholesterol levels increase the risk for heart disease,” said the study’s first author, Enrique Schisterman, PhD, chief of the Epidemiology Branch at the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD),

“In addition to safeguarding their health, our results suggest that couples wishing to achieve pregnancy could improve their chances by first ensuring that their cholesterol levels are in an acceptable range.”

In the first, researchers have identified 17 “high-priority” environmental chemicals women should avoid in order to reduce their risk of breast cancer

The study, by Scientists from the Silent Spring Institute in Massachusetts also documents how to test for the presence of these chemicals in women’s bodies.

According to the researchers, their findings, recently published in Environmental Health Perspectives significantly advance breast cancer prevention efforts.

“The study provides a road map for breast cancer prevention by identifying high-priority chemicals that women are most commonly exposed to and demonstrates how to measure exposure,” explains study author Ruthann Rudel, research director of the Silent Spring Institute.

“This information will guide efforts to reduce exposure to chemicals linked to breast cancer, and help researchers study how women are being affected.”

Beyond genetics

Rudel and his team say, only 5-10% of breast cancers are a result of high-risk inherited genes. Furthermore, the researchers note that around 80% of women diagnosed with breast cancer are the first in their family to develop the disease. Such figures, they say, are evidence that breast cancer is caused by additional factors.

These, according to the study published in Environmental Health Perspectives, include chemicals in gasoline, diesel and other vehicle exhaust, flame retardants, stain-resistant textiles, paint removers, and disinfection by-products in drinking water.

More than just alcohol and HRT

It is well documented that exposure to some chemicals, including alcohol, tobacco smoke and those involved in combination hormone replacement therapy, may increase the risk of breast cancer in women.

But say the researchers many other chemicals have been shown to cause mammary tumours in animals. However, only a small number of these chemicals have ever been incorporated in human breast cancer studies, partly because there have been no reliable techniques through which to measure exposure.

Therefore, the team set out to determine what chemicals present the highest risk of breast cancer in women and how exposure to such chemicals can be measured.

The researchers identified 216 chemicals that have been associated with mammary tumours in rodents, before identifying 102 that women were most likely to be exposed to.

The team then reviewed exposure to such chemicals in rodent studies and compared the results with human breast cancer studies. This was to see whether rodent studies could be used to predict human study results.

The researchers assessed studies in which researchers had measured breakdown products (metabolites) of each chemical or the chemical itself in the blood, urine or other samples of humans. This was to determine the best way for researchers to measure exposure to carcinogens.

High risk from gasoline and chemicals formed by combustion

The researchers were able to put the toxic chemicals identified into 17 high-priority groups that may cause breast cancer in women.

The most dangerous of these were gasoline and chemicals created by combustion, such as benzene and butadiene. Such chemicals are present in vehicle fuel, lawn equipment, tobacco smoke and burned or charred food.

Solvents including methylene chloride and other halogenated organic solvents – often found in industrial degreasers, specialty cleaners and spot removers – were found to be other breast cancer-causing chemicals.

Other breast carcinogens include chemicals found in flame retardants, stain-resistant textiles, hormone replacement therapy and drinking water disinfection by-products.

Exposures ‘largely ignored’

The researchers found biomarkers in urine, blood and other samples for 62 of the 102 high-priority breast cancer carcinogens identified that could be used to measure women’s exposure. They discovered that techniques used in rodents could be used to identify a further 11 chemicals in humans.

Study author Julia Brody, PhD, executive director at Silent Spring Institute, says that the association between toxic chemicals and breast cancer has “largely been ignored” so far, adding:

“Reducing chemical exposures could save many, many women’s lives. When you talk to people about breast cancer prevention, chemical exposure often isn’t even on their radar. Studies that address toxic chemical exposure account for just a drop in the bucket of money spent on breast cancer.”

However, this latest research could change this.

Official recognition

The US National Institutes of Health says it will now incorporate the study’s recommendations as it prepares to test samples from around 50,000 women in its closely watched study of sisters to evaluate causes of breast cancer.

“This paper is a thorough review of toxicology data and biomarkers relevant to breast cancer in humans. It’s a terrific  resource for epidemiologists thinking about studying environmental contributors to breast cancer or trying to understand the associations they see in their questionnaire data,” said Dale Sandler, PhD, Chief of Epidemiology at NIH’s National Institute of Environmental Health Sciences (NIEHS).

Reducing your exposure

There are a number of things women can do to reduce their risk of exposure to mammary carcinogens, say the researchers, including:

• Limit exposure to fumes from gasoline, and to exhaust from diesel or other fuel
• combustion, for example from vehicles or generators. Don’t idle your car. Use electric rather than gas powered lawn mowers, leaf blowers and weed whackers.
• Use a ventilation fan when you cook and limit consumption of burned or charred food.
• Don’t buy furniture with polyurethane foam or ask for foam not treated with flame retardants.
• Avoid stain-resistant rugs, furniture and fabrics.
• Find a dry-cleaner who doesn’t use PERC or other solvents; ask for “wet cleaning.”
• Purchase a solid carbon block drinking water filter.
• Reduce exposure to chemicals in house dust by removing shoes at the door, using a vacuum with a HEPA filter, and cleaning with wet rags and mops.

Men at risk too

In a separate study European scientists looked at the direct effects of a number of chemicals, on sperm health.

Endocrine disruptors are present in food, textiles, drugs, household, and personal-care products such as plastic bottles, toys, and cosmetics. Proving the deleterious effects of endocrine disruptors on human beings, however, has been difficult.

As with the US study the researchers are now taking advantage of new methods of testing which rapidly demonstrate these substances’ potential to interfere with human sperm function

In this initial study, about one hundred chemicals were tested. Around one third, including ultraviolet (UV) filters like 4-methylbenzylidene camphor (4-MBC) and octyl methoxycinnamate used in some sunscreens, the anti-bacterial agent triclosan used in toothpaste, showed adverse effects including reducing motility. Some parabens (not used in cosmetics and recently banned by the EU) and phthalates also showed these harmful effects.

“For the first time, we have shown a direct link between exposure to endocrine disrupting chemicals from industrial products and adverse effects on human sperm function,” said Niels E. Skakkebaek, professor and leader of the Danish team.

Studying the effects of fruits and vegetables on ‘motility’ (the ability of sperm to swim towards an egg), researchers concluded that carrots are the food that seems to carry the most health benefits.

For the study, which was published in the journal Fertility and Sterility, researchers used a questionnaire to survey the diets and supplement use of nearly 200 young, college-age men in the Rochester, New York. They also tested the quantity and quality of the men’s sperm.

Comparing data

Each man provided a semen sample which was analysed within half an hour for:

• semen volume
• sperm count
• sperm motility
• sperm morphology

From the food and supplement frequency questionnaire, the researchers were able to estimate the amount of the following micronutrients in the men’s diet:

• vitamin A
• vitamin C
• vitamin E
• carotenoids (alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein and lycopene)

With this data the researchers were able to look for links between the amount of each micronutrient consumed and semen quality.

Beta-carotene benefits

Increased carotenoid intake was associated with sperm that moved 6.5% faster compared with those from men with the lowest carotenoid intake. This association was higher if the intake came from food rather than supplements.

The sperm boosting effect of carrots was attributed to the carotenoids, especially beta-carotene which the body converts into vitamin A, which in turn can support sperm health and neutralise free radicals. The carotenoid lutein was found to have a similar benefit to sperm health.

Higher intake of lycopene, which is found in large amounts in tomatoes, was associated with 1.7% higher numbers of normally-shaped sperm compared with men with the lowest intake.

Interestingly, high intake of vitamin C (from food only) was associated with lower sperm count. The sperm concentrations were 22% lower than in the men with the least intake of vitamin C.

However moderate amounts of vitamin C in the diet produced the highest sperm concentration, count and motility. Vitamin C was not related to any change in sperm shape.

In this study no associations were seen with intake of vitamin A or E, and none of the results were affected by BMI or smoking status. However in an older population, as previous studies have shown, the effects of these things might have been more apparent.

Salad foods means better sperm

Three foods (carrots, lettuce and spinach) accounted for 59% of the beta-carotene intake and two foods (lettuce and spinach) accounted for 56% of the lutein. The majority (98%) of the lycopene was in five foods (tomato soup, tomato juice, salsa, ketchup and fresh tomatoes).

According to the researchers: “In a population of healthy young men, carotenoid intake was associated with higher sperm motility and, in the case of lycopene, better sperm morphology. Our data suggest that dietary carotenoids may have a positive impact on semen quality.”

But clean up your environment, too

Recent studies have indicated that average sperm count has decreased by more than half in western countries. Environmental toxins and physiological changes in the body, weight gain, a sedentary lifestyle, and high alcohol use, cell phones in pockets and estrogen in dairy products or water have all been linked to a decline in sperm health.

Apart from a diverse and antioxidant-rich diet, other ways to improve your sperm quality include:

• Quit smoking
• Try to achieve and/or maintain a healthy weight
• Exercise more
• Drink sensibly
• Keep your testicles cool
• Don’t put your laptop on your lap – or your mobile phone in your pants pocket
• Filter your water
• Eat organic food to avoid hormone disrupting pesticide residues

Polycystic ovarian syndrome (PCOS), a common disorder affecting approximately 6-10% of woman of reproductive age.

Women with the disorder are typically insulin resistant – their bodies produce an overabundance of insulin to deliver glucose from the blood into the muscles. This insulin resistance leads to an increase in male sex hormones (or androgens) such as testosterone, and can also cause menstrual irregularities, hair loss on the scalp though increase in body hair, acne, fertility problems and future diabetes.

Timing counts

The new study, which involved 60 women over a 12-week period, examined whether meal times have an impact on the health of woman with menstrual irregularities due to PCOS. The women, who were between the ages of 25 to 39, were thin with a BMI (body mass index) of less than 23 and suffered from PCOS.

The Israeli researchers divided the women into two groups and allowed them to consume about 1,800 calories a day. The difference between the groups was the timing of their largest meal.

In one group the women had a 980 calorie breakfast, a 640 calorie lunch and a 190 calorie dinner. In the other the women had a 190 calorie breakfast, a 640 calorie lunch and a 980 calorie dinner.

As opposed to looking at nutrient content, the purpose of this fascinating study was to examine whether the timing of calorie intake affects insulin resistance and the increase in androgens among woman suffering from PCOS. The women kept records of exactly what they ate.

Improvements in insulin resistance

The findings, recently published in the journal Clinical Science showed improved results for the group that consumed a high calorie breakfast. Glucose and insulin levels decreased by 7% and 54% respectively, while the ‘dinner’ group showed no changes.

Another finding showed that among the ‘breakfast’ group, testosterone levels decreased by nearly 50%, while in the ‘dinner’ group level stayed neutral.

In addition, there was a much higher rate of ovulating woman amongst those women who had a good breakfast, compared to the ‘dinner’ group, showing that eating a hearty breakfast leads to an increase in the level of fertility among woman with PCOS.

According to lead researchers Prof. Oren Froy, director of the Nutrigenomics and Functional Foods Research Center, at the Hebrew University of Jerusalem, “The research clearly demonstrates that indeed the amount of calories we consume daily is very important, but the timing as to when we consume them is even more important.”

The US study followed the progress of 231 women scheduled for IVF at the Massachusetts General Hospital between 2004 and 2012. Uurine samples were taken at the start of and throughout treatment and analysed for metabolites (breakdown products) of four common phthalates.

The presence of these metabolites was then measured against three markers of response to IVF: the number of eggs produced following ovarian stimulation, embryo development, and implantation failure.

Phthalates were detected in almost all the women, reflecting the widespread level of exposure but beyond that the study also found that:

• The odds of implantation failure increased as phthalate levels rose. For example, for DEHP (used in vinyl plastic products) the odds of implantation failure for women with the highest levels was twice that of those with the lowest.
• The number of egg cells retrieved also fell as levels of DHEP rose.

According to lead author Dr Irene Souter of Massachusetts General Hospital and Harvard Medical School in Boston, the results “support the hypothesis” that phthalates are widespread in the environment and may well have an adverse effect on female fertility, particularly when tested in the model of IVF.

The study was published as an abstract for the recent European Society of Human Reproduction and Embryology conference in London.

Hormone disrupting

Phthalates are a family of synthetic chemicals used in a wide variety of consumer products.

Studies show that they are hormone disrupters and that they have adverse effects on reproductive health and development, particularly in males. As such, they are one of several types of environmental chemicals linked to a general decline in fertility.

Some phthalates such as Di(2-ethylhexyl)phthalate (DEHP) are used in polyvinyl chloride (PVC, vinyl) plastics to soften them. PVC is used in the manufacture of building materials, vinyl household and industrial products, medical tubing, and blood storage bags.Others such as diethyl phthalate (DEP) are used in a wide variety of personal care products, where they are added to maintain scent and colour, while some like dibutyl phthalate (DBP) are used mainly in nail products.

Limiting exposure

In 2012 a survey of US gynaecologists and obstetricians showed that doctors routinely fail to warn pregnant women about the risks of environmental chemicals such as phthalates.

“We are all primarily exposed to phthalates through inhalation and ingestion,” Souter explained. “It is extremely difficult if not impossible to avoid exposure to phthalates, since they are in so many products.”  However, she added, exposure can be reduced by the following:

• Limit the use of personal care products with fragrances in them (including many of the modern baby care products and air fresheners).
• Limit use of plastic food storage containers and plastic wraps (certainly do not heat food in them).
• Read the labels and avoid children’s toys made of plastics (vinyl) that contain phthalates.

Using certified organic personal care products is also a simple way to avoid phthalate contaminants.