STUDY: You are what you ate, breathed, drank and more
AUTHORS: Dr. David Fleming
ABSTRACT: Researchers say toxic chemicals make their way into our bodies every day through a range of products from cosmetics and food additives to pesticides and building materials.
Two recent studies cast dramatic light on the extent to which Americans are absorbing toxic chemicals in their bodies as part of everyday life. They present a striking picture of Americans riddled with low levels of chemicals, the vestiges of eating, drinking, breathing and touching the synthetic products of the industrial world. Given how common these chemicals are, can personal actions and better choices reduce one’s level of exposure in a toxic world?
COMMENTARY: C Brody used to think so. For 20 years, she ate organic produce and followed all the usual recommendations to reduce chemical exposure, from using non-toxic household cleaning detergents to avoiding pesticides in her home and garden.
Joking that she washed her bathtub in vinegar so much that her family said it smelled like a salad, she adds, “I’m the one hand-picking individual weeds from my garden rather than using chemical sprays, and going that extra mile to get my organic milk in a glass bottle.”
With more than 70,000 chemicals in use in the United States and 2,000 new compounds being introduced every year, according to government figures, the average American is exposed to a cocktail of chemicals from various sources.
Brody used to think her efforts helped limit her exposure, but after volunteering to take part in a study measuring toxic chemicals in her body, she was shocked to find that she still had some 85 toxic chemicals in her blood and urine.
“I’m proof that a healthy lifestyle doesn’t shield you,” says Brody.
Brody and eight other volunteers were tested for the presence of 210 chemicals, commonly found in consumer products and industrial pollutants, by the Mt. Sinai School of Medicine in New York and two non profit groups, the Environmental Working Group and Commonweal.
The study claims to be “the most comprehensive” survey to date of the multitude of contaminants found in humans.
Tests on blood and urine detected an average of 91 industrial compounds, pollutants and other chemicals in the volunteers, with a total of 167 chemicals found across the entire group. The researchers chose subjects who did not work with chemicals in their jobs or live in industrial areas.
This small Mt. Sinai study and a much more comprehensive survey done by the Centers for Disease Control, also released in January, shed new understanding on the “body burden” of toxic chemicals we all carry inside. The results illustrate a side effect of modern life in which everything from carpets to cosmetics are bathed in toxins.
The CDC tests measured some 116 harmful chemicals, including lead, mercury and other heavy metals, chlorinated solvents, insecticides and other pesticides, PCBs, and plasticizing agents called phthalates, to name but a few.
The agency noted some public health successes, such as a decline in lead levels and in cotinine, the byproduct of tobacco smoke. But the researchers also announced some troubling findings, including:
Children have twice the levels of certain pesticides in their blood as adults Children have higher levels of cotinine than adults
Children have higher levels of certain chemicals used in soft plastic toys Adolescents have high levels of phthalates from personal care products
Mexican-Americans have three times the levels of the banned pesticide DDT in their systems as other Americans.
Rather than be paralyzed by our toxic exposure, we ought to use the results of these studies to promote better policies and product lines.
JOURNAL: Cancer Cytopathol 2002;96:338-343.
AUTHORS: Dr. Raheela Ashfaq
ABSTRACT: The ThinPrep Pap test (Cytyc, Boxborough, Massachusetts) is more sensitive in detecting cervical and endometrial adenocarcinomas than is the conventional Pap smear.
COMMENTARY: Dr. Raheela Ashfaq and colleagues from the University of Texas Southwestern Medical Center, Dallas, evaluated women with atypical glandular cells of undetermined significance (AGCUS) or adenocarcinomas diagnosed between 1998 and 2000 using the ThinPrep method. The control group included women who underwent conventional smears obtained between 1996 to 1998. Histological follow-up was performed for all patients.
Of 112,058 ThinPrep Pap tests, 186 (0.17%) were found to be AGCUS/adenocarcinomas, the researchers report. Of the 83,464 conventional smears, 77 (0.09%) were interpreted as AGCUS/adenocarcinomas.
The overall sensitivity in detecting cervical and endometrial adenocarcinomas was higher with the ThinPrep Pap test (72%) than with the conventional Pap smear (41.5%, p < 0.001).
"We believe that the introduction of the ThinPrep Pap test in our laboratory has resulted in a significant improvement in the detection of glandular lesions," the investigators conclude. "Our findings suggest that this system can facilitate a more directed approach to the evaluation and treatment of cervical and endometrial adenocarcinomas."
STUDY: people should strongly consider taking additional folic acid
JOURNAL: BMJ 2002;325:1202-1206.
AUTHORS: Dr. Wald
ABSTRACT: Increasing folic acid intake to lower concentrations of homocysteine would significantly reduce the risk for ischemic heart disease, deep vein thrombosis and stroke.
COMMENTARY: For quite some time an association between homocysteine and cardiovascular disease has been recognized, but there has been considerable doubt as to whether this association is causal.
To investigate the causal role of homocysteine in cardiovascular disease, Dr. Wald from Southampton General Hospital, UK, and colleagues performed a meta-analysis of 72 studies in which the prevalence of a mutation in the methylenetetrahydrofolate reductase (MTHFR) gene was determined in 16,849 cases and controls.
They also analyzed 20 prospective studies, which included 3820 subjects and measured the relationship between homocysteine and disease risk.
Dr. Wald's team found a significant association between homocysteine and the risk for ischemic heart disease, deep vein thrombosis and stroke. A 5-mol/L increase in homocysteine was associated with an increased risk of ischemic heart disease in both the genetic studies (odds ratio 1.42) and in the prospective studies (odds ratio 1.32).
The same association was seen for deep vein thrombosis with and without pulmonary embolism (odds ratio in genetic studies 1.60; there were no prospective studies), and for stroke (odds ratio 1.65 in the genetic studies and 1.59 in the prospective studies), the researchers report.
Dr. Wald and colleagues conclude that "our results strengthen the evidence that a raised serum homocysteine concentration is a cause of cardiovascular disease."
They base their conclusions on their analysis of both genetic and prospective studies, which while susceptible to different types of error both found similar associations between homocysteine and cardiovascular disease.
They also note that homocystinurias cause high homocysteine levels and a high risk of premature cardiovascular disease, and that "lowering serum homocysteine reduced risk in both a randomized trial in patients with heart disease and in patients with homocystinuria."
They add that "on this basis, lowering homocysteine concentrations by 3 mol/L from current levels (achievable by increasing folic acid intake) would reduce the risk of ischemic heart disease by [an average of] 16%, deep vein thrombosis by 25% and stroke by 24%."
Dr. Wald advises that "people should strongly consider taking additional folic acid to lower their risk of cardiovascular disease." The priority groups are those with existing cardiovascular disease, but all those over 55 years of age should consider taking folic acid to reduce their risk, he added.
STUDY: DHA Good for Brains
JOURNAL: Pediatrics (2003; 111:e39–44)
ABSTRACT: Women who take cod-liver oil during pregnancy and the first three months of breast-feeding are likely to have more intelligent children.
COMMENTARY: This report adds to a growing body of evidence that dietary intake of a specific fatty acid present in fish oils (docosahexaenoic acid [DHA]) is needed to promote optimal brain development.
DHA, which is needed by the body for normal development of the brain and of visual function. This omega-3 fatty acid can be manufactured in the body from a precursor molecule, alpha-linolenic acid, which is present in some vegetable oils and nuts, and in small quantities in certain other foods. However, it is not clear whether infants have the capability to manufacture as much DHA as their rapidly developing nervous systems need.
Moreover, alpha-linolenic acid tends to be in short supply in the typical Western diet, potentially rendering it even more difficult for infants to obtain an adequate supply of DHA.
Therefore, a dietary supply of this fatty acid (through the mother) seems to be important for the growing fetus and infant.
I give my pregnant patients a plant based DHA source that has very little or no Vit A.
AUTHORS: Dr Robert Chen
ABSTRACT: The US Institute of Medicine’s immunisation safety review committee has been investigating whether the influenza vaccine might carry a risk of the demyelinating disorder Guillain-Barré syndrome.
COMMENTARY: A sharp increase in cases of the disorder occurred in 1993-4 after immunisation . There were 74 cases in 1994, compared with only 37 cases in 1993 and 23 in 1991. Although the number of reports of vaccine associated cases of the syndrome has remained low in recent years—between 20 and 40—the sudden increase in 1994 raised concerns about vaccine safety.
In a fact finding session earlier this month, the committee heard reviews of studies since 1976, when the numbers of vaccine associated cases of the syndrome stopped the US immunisation campaign against "swine flu." By then, 45 million people had been vaccinated. Ultimately, 581 cases of Guillain-Barré syndrome were reported that year, said the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia.
Initial studies suggested a causal relation between Guillain-Barré syndrome and the vaccine. Subsequently this was challenged on several grounds, including that the cases had been gathered by public health officers who had not been trained to diagnose the syndrome; reports were not based on medical records; some cases accepted by the CDC failed to meet the criteria for the syndrome; and the publicity over the possible link had biased the reporting of cases.
A later study, in 1991, reviewed all the cases of the syndrome in adults (whether vaccinated or unvaccinated) from two states. Using a standard definition of Guillain-Barré syndrome, it rejected 29% of them, said Dr Robert Chen of the CDC’s immunisation safety branch.
A 1998 study, summarised for the committee, showed that if there was a risk of flu vaccine causing the syndrome, it was extremely small. Dr Tamar Lasky from the University of Maryland School of Medicine put it at between 1 and 2 cases per million vaccinated persons a year.
One possible cause is that flu vaccine contains Campylobacter, said Dr Chen. He said that the vaccine is made in chicken eggs and that 40-50% of chickens are infected with Campylobacter, which is difficult to eradicate.