While animal studies have shown that exposure to chemicals in the early development stages of life can cause or increase vulnerability to cancer later in life, few human studies have approached this topic, according to a recent review.

Most human research in cancer risk from contaminant exposure begins at the time of diagnosis or afterward. However, if a baby is exposed to several endocrine-disrupting compounds in utero, changes may occur that lengthen the period of sensitivity to carcinogens. Therefore, even if the compounds don't cause cancer directly, they may contribute to cancer risk by increasing susceptibility.

An embryo and fetus develop at much faster rate than adults. While this development occurs, cell division and growth is rapid. These rapid changes provide many opportunities for mistakes, whether mutagenic or caused by outside changes, to occur. Since cell division and growth do not occur at this rapid rate in adulthood, the chances of mistakes being made are much more common in an embryo or fetus than in an adult. Additionally, barriers such as the blood-brain barrier are not yet complete in the womb, and mechanisms that help detoxify contaminants do not fully develop until after birth, both of which leave the embryo and fetus more vulnerable still.

The report reviews several human studies that suggest a causal relationship between developmental exposure to contaminants and cancer in children and young adults. Studies reviewed include occupational exposures of parents and brain cancers in children, pesticides, paints, paint thinners and solvents and leukemia, and cigarette smoke and childhood cancer. The authors note that since childhood cancers are so uncommon, prospective studies rarely have a large enough sample to yield conclusive results, and animal studies for developmental exposures and early age or adult cancer are more convincing and extensive than the available epidemiological data.

Animal studies have shown that prenatal and early postnatal exposure to radiation and chemicals causes cancers in the exposed animals later in life.

Researchers have found, however, that developmental exposure to carcinogens can increase sensitivity to carcinogens later in life. For example, one study showed that adults who had been exposed to ethylene thiourea (ETU), an industrial chemical, perinatally developed more cancers when exposed to the chemical in adulthood than those exposed only in adulthood.

The effects of developmental exposure to several specific endocrine-disrupting compounds are also discussed in the report. Diethystilbestrol, a synthetic estrogen, has been linked to vaginal cancer in young adult women and possibly to testicular cancer in young adult men; genistein, a phytoestrogen in soy, has been linked to the development of uterine cancer in mice; polyhalogenated aromatic hydrocarbons, which include polychlorinated biphenyls (PCBs), polybrominated biphenyls (PBBs) and dioxins, have been linked to a variety of cancers; and Atrazine, a weed killer, has been found to prolong the period of sensitivity to carcinogens and alter mammary gland development during puberty.

The authors question why epidemiological studies often measure contaminant exposure in adults after adverse effects have occurred, when it appears that developmental exposure could be critical to disease vulnerability.

OurStolenFuture.org November, 2002

Dr. Mercola's Comments:

Most people don’t have an immediate negative reaction when they are exposed to a pesticide. They may not enjoy the smell, but it is actually the minority who will notice a physical symptom. Most of us take immediate negative reactions to mean that something is dangerous. This is a protective response that is largely related to our food intake. If we eat something that makes us nauseous we are likely to avoid it in the future. The problem with pesticide exposure is that the majority of the negative reactions occur some time in the future. It seems that the literature is quite clear on the association between pesticides and Parkinson’s and new evidence is now suggesting an association to MS. In addition to neurological illnesses, one of the major hidden dangers of pesticide exposure is to that of pregnant women. If you know a woman who is pregnant, reminding her of this important fact would be one of the biggest gifts you could give to her unborn child. From my perspective there are four essential steps to take during pregnancy. If you thought taking a prenatal supplement was one of them, think again. The only reason why prenatal vitamins are consistently recommended is the association of folic acid and neural tube defects. Folic acid clearly works well for this, but our bodies are actually designed to obtain this nutrient from whole fresh vegetables, not from a pill or fortified white flour. There are two vital food items a woman needs while pregnant. The first is plenty of whole, fresh unprocessed vegetables, preferably uncooked. The other vital nutrient is omega-3 fat in the form of pure fish oil. Consuming fish oil/cod liver oil is a safe way to add omega-3s to your diet as the oils are purified of mercury and other toxins. Premature deliveries are a major cause of grief and needless turmoil in this country, not to mention the many billions of dollars wasted. It is a profound tragedy that most of these premature deliveries could be prevented by something as simple as a little fish oil. EPA and DHA deficiency are major contributing factors. Women who consumed the equivalent of more than two fish oil capsules per day were 400 percent more likely to avoid premature births than women who did not. Related Articles: Why Pesticides May Increase the Price You Pay For Food Science, Precaution And Pesticides How You Can Avoid Having a Premature Baby Alternative to Using Pesticides Pesticides Linked to Miscarriage