AddThis Feed Button "Frequently Copied, Never Duplicated"

Tuesday, July 22, 2008

Organochlorine Exposure Alters Thyroid Function

Organochlorine compounds, also called chlorinated hydrocarbons, include DDT. This same group of chemicals includes sucralose, otherwise known as Splenda.

Chemically speaking sucralose is made from sucrose by substituting three chlorine atoms for three hydroxyl groups to yield 1,6-dichloro-1,6-dideoxy-BETA-D-fructofuranosyl-4-chloro-4-deoxy-alpha-D-galactopyranoside. It was originally developed as an insecticide.

Especially risky to people with diabetes, an endocrine disorder linked to thyroid and other endoctine imbalances. Few human studies of safety have been published on sucralose. One study of diabetic patients using the sweetener showed a statistically significant increase in glycosylated hemoglobin (Hba1C), which is a marker of long-term blood glucose levels and is used to assess glycemic control in diabetic patients. According to the FDA, "increases in glycosolation in hemoglobin imply lessening of control of diabetes.

Research in animals has shown that sucralose can cause many problems in rats, mice, and rabbits, such as:

Shrunken thymus glands (up to 40% shrinkage)
Enlarged liver and kidneys.
Atrophy of lymph follicles in the spleen and thymus
Increased cecal weight
Reduced growth rate
Decreased red blood cell count
Hyperplasia of the pelvis
Extension of the pregnancy period
Aborted pregnancy
Decreased fetal body weights and placental weights
Presence of mutagenic cells related to lymphoma

The FDA acknowledges contaminants are present and that sucralose "is produced at an approximate purity of 98%". While that may sound pure, it turns out that the final sucralose product contains small amounts of potentially dangerous substances such as:

Heavy Metals (e.g., Lead and Arsenic )
Triphenilphosphine Oxide
Chlorinated Disaccharides
Chlorinated Monosaccharide

Some reasons to avoid sucralose:

Pre-approval tests indicated potential toxicity of sucralose.
There are no *independent* controlled human studies on sucralose (similar to 15 years ago for aspartame).

There are no long-term (12-24 months) human studies of sucralose's effects.

There is no monitoring of health effects. It took government agencies decades to agree that there were countless thousands of deaths from tobacco. Why? Simply because there had been no monitoring or epidemiological studies. Without such monitoring and studies, huge effects can easily go unnoticed.

Eventually the metabolites of these compounds enter the waste water and the water supply. The environmental impact is unknown.
NEW YORK (Reuters Health) Jul 21 - Environmental exposure to organochlorine compounds affects thyroid function in preschool children, according to a report from Spain in the July issue of Occupational and Environmental Medicine.

In 259 four-year-olds from a general population birth cohort, Dr. Mar Alvarez-Pedrerol from the Centre for Research in Environmental Epidemiology-IMIM in Barcelona and colleagues measured blood levels of thyroid hormones and organochlorines, including polychlorinated biphenyls (PCBs) and dichlorodiphenyl trichloroethane, the pesticide commonly known as DDT.

In multivariate models, most organochlorine compounds were negatively associated with free T3 levels, the authors report.

Continuous exposures to PCB-118 and beta-hexachlorocyclohexane (HCH) were associated with lower free T4 levels, the report indicates, although the association with beta-HCH was not statistically significant.

There was no association between continuous organochlorine exposure and TSH levels, the investigators say.

The effects were generally greater among boys than among girls, the researchers note.

"The mechanisms involved in the alteration of thyroid hormone homeostasis are still not fully understood," the authors write. "Because of the structural similarity between some organochlorines and thyroid hormones, organochlorines are suspected to either decrease or mimic the biological action of thyroid hormones."

In a related editorial, Dr. Leda Chatzi from University of Crete, Greece points out, "As neurological development occurs in discrete developmental windows, even transient disorders in thyroid hormone availability can have profound effects on brain development."

Dr. Chatzi adds that most studies of organochlorine effects on children have focused on prenatal exposure. "There is increasing need for longitudinal studies measuring the effect of postnatal exposure...and possible causal relationships between organochlorines, thyroid function, and neurodevelopment during childhood," Dr. Chatzi concludes.

Occup Environ Med 2008;65:437,452-457.
Reuters Health Information 2008.

No comments: