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Lead in Herbs and Herbal Products

Shen Clinic TCM Advice

By Joel Harvey, L.Ac.

California Proposition 65 requires warning when trace amounts of lead are found in plants, food, and water. Should we be alarmed?

Lead has been with us since the beginning of civilization. It is an element found in all the earth's soils, rivers, lakes, and oceans. Lead is also found in the air as a component of dust. Lead levels vary from ½ per million (ppm) to about 10 ppm in soils sampled far from industrial pollution. Lead exists in anything eaten, including all food, beverages, drugs, and supplements.

We all have a right to be warned, and must be warned about health hazards in our environment, but is the trace lead found in plants, animals, food, and water the same hazard as the gross amounts of lead found in gasoline, plumbing, and paint? 

My area of interest is medicinal herbs, which often contain trace amounts of lead. When my patient's hear of this, they are alarmed and wonder, Are these herbs really safe?  I assure them that these herbs have always contained trace lead, and despite this have been used safely for many generations, and that they probably contain less lead now than ever before in the last 100 years.

In fact, these herbs have never been shown to cause any disease associated with lead poisoning. 

However these facts are missing from both government and media sources  which tend to provoke hysteria rather than educate. As a result, many people have become as mistrustful of herbs as they are of pharmaceuticals.

Fanning the flames of mistrust is California Proposition 65 who's warnings are ubiquitous in California and appear on many herbal medicines.

In California, many people have become accustomed to Prop 65 signs, labels, and brochures warning of dangers lurking in their food and household products containing substances that are warned can cause cancer, birth defects or other reproductive harm.

But does the lead found in medicinal herbs (as well as your fruits and vegetables) really cause cancer?  What evidence, exactly, supports such a conclusion. Apparently, very little.

As far as I can tell, the warning that lead causes cancer is based on only a single study showing that high doses of lead might cause cancer in laboratory animals bred to be susceptible to cancer.  I found no study showing that lead, in any quantity, causes cancer in humans.

I did find one small human study of workers who worked in a battery factory and were exposed to high concentrations of lead. But the study showed no increase in the incidence of kidney cancer. 

After surveying all the science available, Kyle Steenland, PhD and Paolo Boffetta, MD, in their article Lead and Cancer in Humans: Where Are We Now (The American Journal of Industrial Medicine, September 2000, vol. 38, issue 3, pages 295 - 299), conclude that the evidence that lead causes cancer in humans is weak.

This doesn't mean that lead is safe for us.  Far from it, lead is toxic to humans because it can replace other metals in our body such as calcium, zinc, and iron, creating abnormal molecules in our enzymes which then fail to carry out normal body functions.

Lead poisoning, also known as painter's colic or plumbism, can result in damage to the kidneys, heart, and nervous system. This is not new information. In ancient Rome, many ills were attributed to lead, which was used in medicine, jewelry, wine, plumbing, and make-up. As early as 250 BC, Nicander of Coloform wrote about lead-induced anemia. His remedy for lead poisoning was mallow or walnut juice with wine.

There is no doubt that some environmental lead comes from industrial pollution. Over 300 million tons of lead, mined in the twentieth century, has returned to our environment via leaded paint, leaded fuels, leaded "tin" cans, and leaded plumbing. However it's incorrect to single out pollution alone for the presence of lead. Even without any human activity, lead would still exist everywhere, as it does in the ancient igneous rocks formed from our planet's natural volcanic activity. Our bodies always contain some lead, normally about .05 ppm. Healthy human bones contain 20-40 ppm of this element.

The typical American diet is said to contain 15 – 25 micrograms or more of lead daily, mainly originating in fruits and vegetables. Other exposures to the air, water, and industry can result in up to 200 millionths of a gram consumed daily. Typical doses of herbal medicine can add 3 to 15 millionths of a gram per day.

Though these figures might sound high, they are actually quite low. The amount of lead in our bodies today is actually the lowest in recorded history. Thirty or more years ago, when lead was in gasoline and paint, we absorbed five to ten times as much as we do today, yet still there is no evidence, despite today's warnings, that our grandparents suffered any ailments whatsoever because of their exposure to lead. If lead really did cause cancer, might not the decline in lead exposure result in a similar decline in cancer rates? On the contrary, while lead exposure has declined precipitously, most cancer rates have risen. Is it possible that fears of lead may have been inflated, and that lead may not be the environmental bogey man we have presumed it to be.

No one doubts that lead is bad for you at toxic levers, but at what levels? Herbal practitioners know that lead can actually be good for you in certain instances. Lead has a long history of cautious use as medicine. The Chinese herbal formula "Lead Special Pill" harnesses the "weight" of lead to settle the lungs in certain cases of asthma. The formula is prescribed at precise doses for periods of no longer than two weeks, and is not given to children or pregnant women. It has been in use safely since the year 1040.

That lead can be medicine is not an apology for lead in the environment. Eight thousand years of observation has shown us that lead is mostly not good for you, so there is absolutely no reason to introduce it into the environment, no excuse for putting lead paint on children's toys.  Laws have solved this problem to a great degree, drastically reducing the lead in our surroundings.

Removing lead from our plants, animals, earth and water is much more difficult.  Eons of volcanoes and chimney smoke have dusted our planet with trace amounts of lead which are now found in the ocean's foam as well as the organic greens you purchased at the health food store.  Did you know that a chocolate bar may contain more lead than ten doses of herbal medicine.

But is chocolate or herbs really a health problem deserving of warning? The fact is that over millennia, a lot of people have eaten a lot of chocolate and taken a lot of herbs without succumbing to any disease.

We know that reduced pollution has already reduced the amount lead in our bodies.  You likely have far less lead in your body than did your parents a generation ago.

Many governments throughout the world have created appropriate standards for lead in herbal medicines. Japan allows 20 parts per million (ppm) for total metals in herbal medicines. The World Health Organization allows 10 ppm for lead. The Australian TGA allows 5 ppm for lead in a product. Germany allows 5 ppm as well. Unfortunately, the US Pharmacopoeia has no standards for herbs, but allows 3 ppm in drugs.

Most Chinese herbal products test at an average of 1-3 ppm, which is considered safe and incidental by all international standards for medicine. However, California's Proposition 65 requires warning at only 1/2 ppm in food, and in California, herbal medicines are considered food rather than drugs. Prop 65 allows the sale of these products, however it requires a warning.

Warnings create fear among consumers; fears that become associated not only with lead, but by association, all of herbal medicine. Fear of herbs, based on misinformation, is bad for everyone except the pharmaceutical industry, which by the way, is allowed six times as much lead in their products - without posting any lead warning.


Shen Clinic TCM Advice