By * Dr UME
For some years, the scientists make more and more mention of effects caused by chemical substances of natural and anthropogenic origins, which disrupt the reproductive functions in wild and experience animals (Colborn and al., 1993).
This finding was accompanied by a growing concern felt at all levels of society, that exposure to toxic substances in the environment could have adverse effects on human fertility.
Products acting on the endocrine system have been called "endocrine disruptors", although some prefer, the effect is not necessarily negative, the appellation of "endocrine modulators".
Sources of this pollution. summary
Unwanted exposures
At low doses, exposure to toxins can contaminate our food, our workplace, and even without our knowing, our living environment, housing (indoor pollution).
Everyday, we absorb by
Food
a range of substances - proteins, fats, carbohydrates, water - supplement products (vitamins, minerals, ...), and sometimes medication.
These products, which are considered essential and/or medicines controlled by AMM (authorization to put on the market) are generally accepted as "safe." However, an inappropriate and excessive consumption can have negative effects on health.
Besides these products, necessary for our survival, our food contains, often without our knowledge, a whole series of unwanted contaminants (hormones, antibiotics, pesticides,...)
Also, the indiscriminate use of "natural" therapy products with the deep feeling of absolute efficiency and total absence of danger.
For example, soy isoflavones active "estrogen-like" beneficial for menopausal women [1] and would be protective against breast cancer [2].
Recent studies suggest that exposure to these phytoestrogens in early stages of life could increase the risk, later, of endometriosis and breast cancer [3] In the present case, the phytoestrogens decrease the fertility of birds and sheep [4].
Exposure to tobacco smoke summary
At once intentional from smokers but also undergone by the non-smokers, was studied for its effects on the reproductive system.
- The women who smoke are menopausal two years earlier than nonsmokers[5]
- For men smokers, increased risk of erectile dysfunction and reduced sperm quality [6]
- It is also shown that the transport of the fertilized ovum along the fallopian tube is disturbed with the risk of ectopic pregnancy, abortions.
These endocrine toxicant include...
- Solvents
- Polyhalogenated aromatic hydrocarbons «PHAHs» (combustion du fuel, barbecue,...)
- Pesticides
- Plasticizers, phtalates
- Heavy metals
The effects of vehicle pollution summary
The effects on humans have been known through a study of a population working on a toll highway.
The findings of this study from the University of Naples incriminate exhaust gases for their role in lowering fertility.
The use of lead has been severely restricted to fight against the effects of lead poisoning, of which some birth defects or miscarriages can be direct consequences.
The water quality summary
It can also influence the fertility.
The consumption of a water in the abnormally high concentration in pesticides or in other agricultural and industrial pollutants can cause problems of fertility, even a sterility.
The concentration of estrogen in water could also have consequences, although its effects are not yet clearly identified, at least for humans. Some detergents, birth control pills and other chemicals, contribute to increase the concentration of estrogen in the water.
The introduction of female contraceptive patch still increases this risk. Indeed, at the end of their useful life, these percutaneous vectors still contain a large quantity of active ingredients. A massive release of these patches in the environment could have serious consequences, which implies that the laboratories should inform consumers about the necessity of throwing them in a ecological way. (As Hg for dentists)
The air quality. summary
The significant link is demonstrated, dose-dependent between the levels of NO2, CO2, SO2 and intrauterine mortality
It has been suggested that atmospheric nitrogen oxides could increase the rate of methemoglobin in the blood, thus reducing the carrying capacity of oxygen of the hemoglobin.
Previous studies have shown the existence of adverse effects of exposure to air pollution on health. These effects concern the mortality and cardiovascular and respiratory disorders, but also the reproduction : miscarriages, delayed intrauterine growth, premature birth and infant mortality. Furthermore, studies led to animals suggest that air pollutants may be responsible for genetic mutations transmitted to offspring, and in particular DNA mutations of the fetus due to an exposure to air pollution during pregnancy.
Through this research conducted on the subject for many years, the effects of certain environmental pollution begin to be scientifically identified. (Epidemiological studies in the workplace)
The impact is not negligible... summary
- Adverse outcomes of pregnancy (abortion, stillbirth, change ratio male / female)
- Congenital male abnormalities (cryptorchidism, hypospadias)
- Decrease of the numeration and the quality of sperm cells
- Adults testicular cancer
- Menarche and early puberty, polycystic ovary syndrome associated with chronic anovulation
- Shortened lactation
- Endometriosis
- Neurobehavioral effects (due to the disturbance of H. thyroid in utero)
- Mediated endocrine immunotoxicity
- Promotion of cancers with internal secretion (bosoms, endometrium, testis, prostate, thyroid) by oestrogens (pre-or perinatal exposures, infantile)
In front of the multitude of causes of infertility, it is evident that there is no standard treatment.
If cases of infertility of mechanical causes, inflammatory, serious hormonal are the domain of the classic therapy -subsitutif, surgical, IVF,...- the more functional cases, in particular due to chronic exposure, to low doses, to endocrine disruptive agents, of our daily environment, can often be resolved by a complementary biotherapy, less aggressive.
The action strategy will be based on the SIMULTANEOUS action of clean up of the body
and of correction of the deficiencies in trace elements in particular the Zinc, Chromium, Copper and in vitamins (B group, vitamin E.), of specific hormonal rebalancing at every stage of the life, the stimulation of the sexual appetite, the libido, the fight against the stress and the depressive states (sometimes grave owed more particularly to the notion of taboos with which is confronted the couple or one of its members towards the problems relative to its sexuality and to the difficulty of the reproduction), of increase of the quality and the mobility of sperm cells, correction of erectile disorders and stimulation of the ovulation
summary
Back to our natural solutions
[1]Hale and al 1999
[2]Lamartiniere et al. 1998
[3]Yang et al. 2000 ; Allred et al. 2001
[4]Millam et al. 2001
[5]Harlow and Signorello 2000
[6]Kunzle et al. 2003
Studies to confirm summary
These last years, animal experiments have shown that chemicals substances that contains or contaminates our food may
- act as steroid hormones «hormone like» [1]
- increase the production or the metabolism of these hormones [2]
- block the hormonal signal in the receptors of the target tissue.[3]
However, to what extent can we extrapolate from animal experiments to humans ?
Although experimental animals and humans have the same endocrine system, hormones and cellular functions which they control are not exactly alike.
The different approaches used to reduce this uncertainty are :
- research on tissue cultures
- epidemiological studies, particularly in cases of professional exposure
- quantitative measurements of chemical substances in food, air, water and body fluids
- determination of new early markers
- development of qualitative tests of the body's response to the action of these substances (oxidative stress, comet assay,...)
Human reproduction includes all stages from gametogenesis, conception, intra-uterine development until the birth of the child. Its study covers all ages: infants, adolescents in whom pubertal development can be studied, adults of reproductive age...
The study of the probability of pregnancy for couples, a marker of their fertility can be done by measuring the time required to conceive, which depends both on the smooth functioning of the male and female gametogenesis and the success of the implementation of the embryo, and as well of its survival in the first few weeks of pregnancy.
The cycle of the reproductive function[4] starts again with the new generation.
An entire section of the current problem of studying the effects of environment on the reproductive health, concerns the transgenerational effects, that is to say, the reproductive effects of exposures experienced before the conception, thus by one or several previous generations.
For example, the case of the descent of pregnant women, in threat of miscarriages, and exposed in the 1965s to 75 to diethylstilbestrol, estrogen synthesis supposed to be protecting. The danger of this treatment was recognized in 1971 by a gynecologist Herbst who made the link between the use of DES during pregnancy and vaginal adenocarcinoma in daughters of these women. In France, 160,000 children were born of these pregnancies. It is estimated that the impact on fertility will be felt until 2010. A recent Dutch study shows, that the grandsons of women exposed during pregnancy, have abnormalities of the reproductive system up to 20 times of the standard (cryptorchidism, hypospadias ,...), causes of poor sperm quality.
The semen characteristics studied are not only the "classic" parameters of concentration, morphology or mobility, which are associated with the likelihood of pregnancy, but also the characteristics of the sperm nucleus such as the integrity of sperm DNA or the rate of sperm aneuploidy.
Until now, humans - men, women and especially children - few documented studies have explored the link between exposure to potentially toxic substances and the emergence of health problems.
Effectively, several studies showed that there was a catastrophic decrease of sperm quality.
The infertility of couples, in many cases, comes from the man in contrast to old beliefs and taboos.
Approximately one in seven couples is unable to satisfy its desire to have children.
However, we speak generally only about the infertility of the women. «This is probably because until now few research has been conducted on the reasons of the infertility in men» [5].
95% of research budgets are allocated to the studies for substances with estrogenic effects.
5% of the credit for substances with androgenic effects
But also preoccupying.
The most common disorder of male fertility is the insufficient production of normal sperm, with good mobility in the seminiferous tubules.
Normal male sperm: number of sperm cells upper to 20 millions / ml of sperm. At least 15 % of these must be normally formed and 50 % of them has to have a good mobility. If these values are not reached, the ability of man to procreate is reduced.
The proper maturation of sperm cells is the key of the fertility.
Besides the environmental pollution, the causes of abnormalities of the sperm cells maturation are multiple :
- consequence of mumps contracted during puberty
- presence of varicose veins in the scrotum (varicocele)
- hormonal disorders
- testes located high (cryptorchidism), operated tumors, stress
- hereditary predisposition may also be involved.
«Owing to the progress realized in the genetic research during these last years, we have the opportunity to better understand the maturation of sperm cells». For a part of the men suffering from a production strongly reduced of sperm, we noticed the absence of a gene on the male Y chromosome. This gene is called «DAZ gene». The protein encoded by the DAZ gene plays an important role in several stages of maturation of normal sperm cells. [6] This headway would explain the hesitations of many practitioners of assisted reproduction centers, to the technique of intracytoplasmic microinjection (ICSI). This practice would eliminate all stages of sperm cell maturation during its rise in the genital tract of women, with potential consequences in time, quite unpredictable.
A study led by a team of the University of Copenhagen (Denmark) has concluded to a significant decrease in seminal quality in men between 1938 and 1991.
It has established in particular, a decrease of the two thirds of the spermatic account as well as 28 % increase between the 60s and 90 of the number of men who had a hypospermia (deficiency).
By cons, other studies showed no change, but it is possible that studies based on a large populations may mask regional differences.
We find, in any case, the general perception that the prevalence of infertile couples has increased and that environmental contaminants may play an important role.
Professor Franck Comhaire[7], a specialist in endocrinology and andrology at the University of Ghent, was particularly interested in male infertility assessed from the examination of sperm cells (motility and morphological quality) of sperm donors.
Following this analysis, it showed that the percentage of young men from Flanders having risk to have difficulties in childbearing, has been increasing steadily since the end of 70's, from 1.6 % to 9 % in twenty five years. He also put in evidence a difference of morphological quality of sperm cells, according to the housing environment. Surprising, that of the young men living in the campaign, was less good and their rate of testosterone was also more lower than that of young city-dwellers of Antwerp. The concentration of DDT, illegal pesticide since the 70s, used in kitchen gardens in the campaign and whose the persistence in the environment is very long, could explain this situation.
The DDE pesticides, were banned after the consequences of some accidents, but often replaced by other, often so dangerous and put on the market without toxicological studies difficult to perform in humans. We must therefore extrapolate from the animal world and apply the "precautionary principle".
An example : the population of Lake Apopka alligators in Florida has decreased by 90% in early 1980 following a pollution by Dicofol pesticides. But again, this pollution has had a significant and lasting impact even on the remaining populations.
We notice henceforth a decrease of the rate of hatching, a predominance of females and abnormally small genitals in males.
According to Jean Bouyer, a researcher: "We already know that couples where the woman smokes put twice more time than others to achieve pregnancy. The harmfulness of pesticides on male fertility, in particular that of farmers, has also been demonstrated. But other water and air pollutants could be involved."
As usual, Greenpeace[8] brings us back to the mainland, and advanced invisible problems related to pollution, which have very visible effects on our health, here our ability to make babies. It becomes alarming: for example, in fifty years, the semen analysis shows that the number of active sperm cells is reduced by half. But the report points other facts :
- 1. the number of testicular cancer has increased dramatically
- 2. infertility can affect up nearly 20% of couples in industrialized countries (less than 10% in the 60s)
the number of male births is lower than that of girls in some areas (sex-ratio "normal" is for boys O.55)
summary
Back to our natural solutions
[1]Markey and al. 2001
[2]Chedrese and Feyles 2001
[3]Kelse and al. 1994, 1995, 1997
[4]Pollution atmosphérique n° 189 Extrapol n° 28 - Juin 2006
[5]Sigrid von Eckardstein, specialist in male fertility University Hospital of Zurich
[6]Sigrid von Eckardstein, specialist in male fertility University Hospital of Zurich
[7]Dr Franck COMHAIRE Department of Internal Medecine, University Hospital of Ghent (Belgium)
[8]Toxiques en héritage L'enfance en danger : Renforcer le programme Européen REACH, plutôt que l'affaiblir
By the Pr. Dominique Belpomme University of Paris V, Georges Pompidou European Hospital, President of ARTAC
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