1) What is lead?
Who is this mysterious fellow, Mr. Lead? He is certainly a heavy fellow. With an atomic weight of 207.2, and a laundry list of possible perturbances of human biochemistry, lead ranks among the truly heavy elements of the periodic table from the perspective of both mass and potential evil. It is a soft, gray, malleable metal that has been pulled from the earth by man, and smelted out of mineral ores containing, most commonly, copper, zinc or silver. The primary mineral ore is called galena (PbS), a lead sulfide that contains 86.6% lead by weight. Other satisfactorily ores abundant in lead are cerussite (PbCO3) and anglesite (PbSO4). Working around the blast furnaces used to extract lead from rock minerals can expose workers to potential contamination by other metals, including arsenic, antimony, bismuth, zinc, copper, silver, and gold.
2) Why is it found in food and plant materials?
Analytical technology has advanced to a level of such precision that it is now possible to find traces of heavy metals, and particularly lead, in virtually all foods and beverages. They, and it, cannot be avoided. Metals will be in foods bought at the market and consumed at home; in foods consumed at restaurants, even in vegetables you grow at home.
Lead is ubiquitous in the world environment. Its widespread presence is believed to be largely but not entirely due to the activity of man over past millennia. Our ancestors began smelting lead about 8500 years BC, over 10,000 years ago. We have had ample time to release lead in its many chemical forms into the environment, amplifying its natural presence.
Lead is naturally occurring in rocks that make up the Earth’s crust, mostly in the form of galena (lead sulfide), anglesite (lead sulfate) and cerussite (lead carbonate) minerals mentioned above. Apart from any smelting that humans may do, volcanic activity does its own, spewing lead oxides, sulfates and silicates into the atmosphere, to eventually settle onto agricultural soils and reservoirs. Rain that must filter down through topsoil and rock on its way to replenish aquifers can also pick up traces of lead along the way, putting the metal into our drinking water. Lead is now found in all plants tested, whether plucked from the land or dredged from the sea. It is found in all animals and in all humans. It is natural and unavoidable, yet our exposure to it had been increased due to lead’s use in man-made chemical compounds that have a number of industrial applications.
The elimination of tetraethyl and tetramethyl lead additives from gasoline beginning in the US in 1973 was the single most significant victory of the nascent environmental movement at the time. Removing lead from gasoline reduced our exposure to lead by 90%.
3) Are the levels found in natural supplements dangerous?
According to the scientific literature, absorption of lead from food ranges downward from 10%. The presumption of a 7.5% common rate of absorption is legitimate based on the literature. Dietary elements may also either enhance or inhibit absorption. For example, a higher intake of vegetables would correlate to a lower absorption of lead due to the alkalinizing effect of vegetables and high fiber component of the diet. Alkalinization would retard lead solubility and absorption, and high fiber would decrease gut transit time, further limiting the opportunity for absorption.
There is some irony to be found here. On the one hand, plant based foods drive up lead content of dietary supplements when used therein, but it is precisely plants content of vitamin C, calcium, iron, zinc and phosphorus (among other nutrients) that help block lead absorption. Vitamin C, folic acid (vitamin B9), thiamin (vitamin B1) and pyridoxine (vitamin B6) additionally hasten the excretion of lead, and are abundant in fresh vegetables.
Extensive testing of our own supplements show that our dietary supplements fabricated 100% from plant materials would nevertheless actually deliver less than one-tenth of a percent to three tenths; of one percent of the amount of lead considered to contribute no observable biological effect. What is that daily intake of lead that is considered to contribute no observable biological effect. It is 500 mcg.
If a safe exposure level of 500 mcg per day seems fearfully high, that fear is tempered by data showing adult daily ingestion of lead to be around 90 mcg per day for a 200 pound adult in the U.S., and by FDA research data that identifies 750 mcg per day as the minimal exposure level that may pose a threat to adult health.
If dietary supplements can contribute 0% (for a few highly purified or synthesized supplements) to 3% of the 500 mcg per day amount considered to contribute no observable biological effect from a 38 gram dose of pure plant-based supplement, then the EXPOSURE from a supplement may range from 0 mcg to 15 mcg.
Returning attention to the amount of lead that can be added to our total exposure by dietary supplements, we see that amounts contributed by them compare favorably against lead levels found in fresh food. The schedule below, for servings of 4 ounces each, was compiled by Michael Mooney from lead analyses of the U.S. food supply published by the FDA.
|Food||Lead in 4 oz (mcg)|
|Italian salad dressing||12.20|
|Mixed nuts, no peanuts, roasted||10.20|
|Liver, beef, fried||9.00|
|Brussels sprouts, fresh, boiled||7.90|
|Sweet potato, fresh, baked||7.20|
|Dry table wine||6.80|
|Raisin bran cereal||4.10|
|Cottage cheese 4% milk fat||3.40|
|Shredded wheat cereal||3.00|
|Whole wheat bread||2.80|
|Onions, mature, raw||2.70|
|Apple, red, raw||2.60|
|Green peas, boiled||2.20|
|Lima beans, boiled||2.20|
|Courtesy Michael Mooney
The World Health Organizations latest comprehensive report on food contaminants reminds us that
Food categories with the highest frequency of detectable lead include meat, especially offal, organ meats and wild game, shellfish (particularly bivalves), cocoa, tea, cereal grains and products, and vegetables.
So let’s make a meal of it. Let’s pretend you have just eaten a meal of shrimp scampi, 4 oz. worth, with Brussels sprouts and green peas as your vegetable (2 ounces each) accompanied by a light salad of spinach, avocado, cucumber, a sliced, hardboiled egg and a little Italian dressing. You chose a healthful dessert of watermelon pieces and sliced strawberries, 2 oz. each. But your major indulgence was a relaxing 4 oz. glass of dry wine with the meal. Your total lead intake from this one dinner would be 49.3 mcg. Keep in mind that food, nutrients and lead passing through the gastrointestinal tract are still outside the body. In the above scenario, the 49.3 mcg of lead represents exposure only until absorption actually takes place. Still, the meal represents more than three times the highest amount of lead contributed by a rather large 38 gram serving of a purely pant based supplement. The meals 49.3 mcg is also less than one-tenth of the daily intake considered to contribute no observable biological effect.
It is reasonable to answer, no, lead levels found in natural supplements do not appear to be dangerous, barring some egregious human error that allows contaminated material to find its way into a product. Put your trust in reputable brands, as you would do with any consumer product.
4) Do organic foods have less lead than non-organic?
Usually they do, but mineral content of the soil is a major influence on ultimate lead content of a food. Each ingredient for use in a dietary supplement must be tested.
5) How can I avoid consuming too much lead?
You cannot avoid consuming lead. But the risk of consuming too much lead in the United States is very slim. Do we need to worry? Not really. Lead levels in foods have declined over time in many developed countries. Elimination of lead additives from most gasoline in the 1970s and from paints is credited with much of the reduction in exposure. The cutback in industrial use has dramatically benefitted the food supply. From 1980 to 2006, lead levels in food dropped 75% in New Zealand, 95% in the United Kingdom, and 50% in France and Canada. In the U.S., lead intake by teenage males declined from 70 mcg per day in 1976 to 3.45 mcg in 2000, another 95% drop. These are nationwide statistics that were, of course, totally uninfluenced by Prop 65.
6) Does Vibrant Health test for lead content in all products?
We certainly do. Every lot number of each product is submitted to an outside, third-party analytical laboratory looking for trace amounts of arsenic, cadmium, lead and mercury. But that is not the only analysis that safeguards consumers.
In the United States, the Dietary Supplement Health Education Act (DSHEA) was enacted in 1993 for multiple reasons, one of which was to put in place a higher level of official regulation of the dietary supplement industry in order to protect consumers. DSHEA has been followed by Good Manufacturing Practices (GMPs) that codify appropriate manufacturing procedures that should preclude contamination of supplements by heavy metals. Every reputable dietary supplement manufacturer in the country, including Vibrant Health, now follows GMPs, and FDA has accelerated their inspection and enforcement of GMPs.
As a result, every raw material that goes into a dietary supplement must be redundantly tested for heavy metals by the raw material supplier, and again by the manufacturer before it is added to any dietary supplement formula. A third test for heavy metals should be conducted on the finished product. At any of these three steps, a raw material or finished product showing excessive levels of any of the heavy metals must be rejected. Vibrant Health adheres to these regulations. Outside testing labs, unaffiliated with the seller of the raw materials or the marketer of the finished product are most often used to do the testing, thereby, injecting a welcome level of impartiality to the process. (Microbiological analyses of ingredients and finished products follow similar procedures.)
Are you a California resident interested in learning more about Proposition 65? Click here to read Vibrant Health formulator, Mark Timon’s response.