SPAM-LOW: Contaminated herbs

[Guest guest]

It is interesting that long gu has a high load since it is old bones before any

" environmental " human contamination

Alon

 

 

[Guest guest]

>

> Have we decided how many PPM we are comfortable with? Please

don't come

> back with 0. I am really interested in what is a reasonable risk.

>

> Thanks,

> Chris

 

This is an excerpt from a November 2003 article in the Townsend

Letter:

 

" Assuming an average body weight of 60 kg, de Smet has provided a

formula for calculating the theoretical maximally tolerable level in

mg/kg for a crude herb. Note that in this formula PTWI is expressed

as mg/kg, whereas it is in mg/kg in Table 1. The formula is as

follows:

 

Theoretically maximally tolerable level (mg/kg) = PTWI (mg/kg) X 60

X extraction factor/average weekly herb consumption (kg) X100

 

The extraction factor is the fraction of heavy metals which can be

extracted from the crude herb. Therefore, for a finished product

this value should be assumed to be 1. For the preparation of herbal

teas and ethanolic extracts, the extraction factor could be expected

to be less than 1 and in some cases could be quite low.

 

Surveys have found unacceptable levels of heavy metals in some

herbal raw materials and products. A survey of 34 samples of some

common Indian herbs found that the concentrations of Pb and Cd were

beyond the permissible WHO limits for most of the samples studied.

(61) In contrast, an analysis of 21 over-the-counter ginseng (Panax

ginseng) products revealed Cd and Pb levels within acceptable

limits. (62)

 

The Cd and Pb concentrations of some herbs, herbal infusions and

herbal preparations used by children and adults were measured in a

Polish study. (63) Unacceptable levels of Cd and Pb were found in

many of the products. A product containing nettle (Urtica dioica)

was recalled in the US in 2002 because it contained " excessive "

levels of Pb. (64)

 

A survey of heavy metals in crude herbs which included data for over

12,000 samples supplied by a number of herbal supply companies in

Germany concluded that, while cadmium appears to have a propensity

to accumulate in some herbs, contamination with mercury is not a

problem. (65) The authors suggested that limits of 10 mg/kg for lead

and 0.5 mg/kg for cadmium were rational and achievable, with the

notable exception of a few herbs which appear to accumulate these

metals and for which slightly higher limits should apply.

 

Adverse reactions have perhaps erroneously been attributed to the

intake of herbs contaminated with heavy metals. A Croatian case of

drug-induced nephritis in a child was linked to the intake of herbs

contaminated with Cd. (66) The patient had been treated with a home-

made herbal mixture, however the levels of Cd found in these herbs

did not appear to be unacceptably high. The herb bladderwrack (Fucus

vesiculosus) and also other seaweeds naturally accumulate arsenic

(As). However, much of this As is organically bound, as for many sea

foods, and not considered to be toxic. (67) Nonetheless, a case of

nephrotoxicity was attributed to bladderwrack intake on the basis of

its arsenic content. (68) "

 

I'll see if I can find the official FDA guidelines.

 

Jill Likkel