Another Caution About Natural Product

Regular readers know I am not globally opposed to the use of various
natural products.  Even so, I do, from time to time, point out why
we need to be cautious about some herbal or alternative medicine
products.  A good case in point was reported recently, pertaining
to breast enlargement in young boys. 

(Not Self-Portrait)

href="http://content.nejm.org/cgi/content/short/356/5/479">Prepubertal
Gynecomastia Linked to Lavender and Tea Tree Oils

Derek V. Henley, Ph.D., Natasha Lipson, M.D., Kenneth S.
Korach, Ph.D., and Clifford A. Bloch, M.D.

NEJM 356:479-485

February 1, 2007

SUMMARY



Most cases of male prepubertal gynecomastia are classified as
idiopathic. We investigated possible causes of gynecomastia in three
prepubertal boys who were otherwise healthy and had normal serum
concentrations of endogenous steroids. In all three boys, gynecomastia
coincided with the topical application of products that contained
lavender and tea tree oils. Gynecomastia resolved in each patient
shortly after the use of products containing these oils was
discontinued. Furthermore, studies in human cell lines indicated that
the two oils had estrogenic and antiandrogenic activities. We conclude
that repeated topical exposure to lavender and tea tree oils probably
caused prepubertal gynecomastia in these boys.

Gynecomastia
refers to any condition in which there is abnormal breat enlargement in
males.  It is not physically dangerous by itself, although it can
be psychologically challenging. 



Here is a snippet of one case:

A boy who was 10 years 1 month old presented with a 5-month
history of gynecomastia. He and his mother reported that the condition
seemed more prominent in the evening and a little less so in the
morning. His medical history and family history were unremarkable...



...On questioning, it was determined that the patient was not currently
using drugs, herbal supplements, or herbal lotions but was applying a
styling gel to his hair and scalp every morning and regularly using a
shampoo. The labels of both the gel and the shampoo listed Lavandula
angustifolia (lavender) oil and Melaleuca alternifolia (tea tree) oil
as ingredients...

The full
journal article (subscription-only) reveals how the authors were
able to determine that the products has both estrogenic and
anti-androgenic effects.  It was not simple, because it would not
be  appropriate to do study on humans for a study like this. 
Instead, they used cell cultures with estrogen and androgen receptors.



The concern here is that a seemingly innocuous product can have
unintended effects.  Moreover, the full consequences are difficult
to
determine.  It appears that use of these products can have
hormonal effects in humans.  No lasting effects were observed in
any of the three cases; there is no particular reason to think there
will be.  On the other hand, if one were to continue using such a
product over a long period of time, it is conceivable that there could
be significant negative consequences.  In general, it is not a
good idea to mess around with hormones unless there is a very good
reason to do so.