Issue with Case Report on Potential Arsenic Toxicosis and Herbal Kelp Supplement

A statement from Daniel Fabricant, PhD, vice president of the Natural Products Association’s Scientific and Regulatory Affairs Group 

The study appearing in Environmental Health Perspectives, volume 115, number 4, pages 606-608, titled, Case Report: Potential Arsenic Toxicosis Secondary to Herbal Kelp Supplement, is fundamentally flawed, both scientifically and with regards to the regulation of dietary supplements. 
 
The authors claim “to have found detectable levels of arsenic in eight of the nine kelp herbal supplements, ranging from 1.59 parts per million (ppm) to 65.5 ppm by dry weight (1.59, 2.28, 9.55, 9.97, 10.5, 24.1, 34.8, and 65.5 ppm); the median value was 10.23 ppm.” Concentrations are irrelevant in this instance without disclosing the mass of the capsules. This would allow for calculation of the potential exposure to arsenic; any valid scientific argument on toxicity has to be based on exposure levels and daily intake, not concentration.

For example, if we applied a 50-milligram mass as the capsule mass, this would equate to 0.0795, 0.114, 0.478, 0.499, 0.525, 1.21, 1.74, and 3.275 milligrams per capsule respectively, which is obviously well below the normal daily intake, as cited in the paper (“nonoccupationally exposed individuals, with an average total (inorganic and methylated) arsenic intake of 40 milligrams per day. U.S. dietary intake of inorganic arsenic has been estimated to range from 1 to 20 milligrams per day (Schoof et al. 1999)”) with a one capsule a day serving. A 500 milligram capsule, in effect multiplying the daily intake ten-fold, would still result in all the products below the average daily total intake of 40 milligrams as cited in the paper.

The glaring omission of the mass of the capsules and the subsequent presentation of the data as a concentration, allows the authors to provide a provocative story and headline. Once the real world metrics are applied, however, the fog is dispersed and these numbers are obviously well within the numbers the authors cite as daily intake values. These data are no longer provocative, and make it impossible for kelp supplements to be painted as “unsafe” as the authors suggest. 
 
The authors also were not diligent in researching kelp supplements; they overlooked key references with respect to kelp dietary supplements. One important oversight is the European Pharmacopoeia (EP) that contains a monograph on kelp supplements, with guidelines on arsenic concentration in kelp. The European Pharmacopoeia sets a limit at 90 ppm of total arsenic in kelp. (1) Pharmacopoeial monographs are developed over the course of years by experts in the field. The sheer fact this reference was not cited by the authors only further reveals their ignorance on the subject.

The authors’ application of the FDA tolerance level for turkey and eggs in terms of concentration is also not applicable - and frankly unscientific - just on product mass alone. For instance a 4-ounce serving of turkey is converted to 113,398.0924 milligrams. Therefore, a 2 ppm limit is applicable and logical based on the mass of the product. In this instance, 4 ounces of turkey at a 2 ppm concentration would obviously result in exponentially greater exposure to arsenic (approximately 2300 times greater) than a 50 milligram kelp dietary supplement capsule at a 2 ppm concentration. To imply that there is toxicity associated with anything, be it a food, pharmaceutical or dietary supplement, without applying the appropriate metrics is incredibly irresponsible and potentially damaging and confusing to the consumer who may benefit from that product.

In addition to the inappropriate use of metrics, the study did not differentiate between the different species of arsenic present in the kelp samples.  This differentiation is significant since as the authors themselves present, “In most cases the toxic moiety is presumably trivalent arsenic in the form of inorganic arsenious acid (arsenate).”  In fact, the California Clean Drinking Water Act of 1986, commonly referred to as “Proposition 65”, sets limits only on inorganic arsenic compounds (oxides).  This limit is set at 10 milligrams per day.  The California Proposition 65 limit is determined by taking the NOEL limit, which is defined as “the highest level at which a chemical can be administered to an organism without any adverse effect (for example upon health, growth, development, reproductive capacity or lifetime) being observed”, and then dividing by 1000. In addition, the Food Chemicals Codex (FCC) has set a limit of 3 ppm of inorganic arsenic.  There is no limit for total or organic arsenic compounds. The absence of blood arsenic at the time of poisoning from the study is also a relevant and questionable deficiency.

With respect to the authors’ views on the regulation of dietary supplements:

Approximately $23 billion was spent on dietary supplements in 2005,

The $178 billion dollar figure used in the paper is completely incorrect;

Dietary supplements are regulated by the Dietary Supplement Health and Education Act (DSHEA), which was passed in 1994.

Thus, a reference from 1990 the authors cited to describe the state of industry regulation on botanicals is irrelevant and meaningless to the current state of regulation. Unlike foods, dietary supplements have to disclose, in total, all dietary supplement ingredients and the quantity of those ingredients.
For example, two of the major soft drink manufacturers have recently announced they would voluntarily include the amount of caffeine added to the product on the nutritional facts panel on the product label. By comparison, dietary supplements, by law, have always disclosed the total amount of caffeine added to the product in the supplement facts panel on the label;

The assertion that “Given the numerous studies demonstrating unsafe levels of heavy metals in dietary herbal preparations, the growing number of case reports connecting heavy metal toxicities to ingestion of herbal dietary supplements, and the growing popularity of herbal remedies for self-medication in the general public, it is prudent that companies demonstrate safety and efficacy before their products are placed on the market. Concentrations of materials contained in the preparations, as well as expected benefits and potential side-effects, should be studied, standardized, monitored, and accurately labeled” is not based on anything other than opinion. The authors cite seven studies, three of which are dealing with foreign products that are likely not dietary supplements by statutory definition. This is hardly conclusive scientific justification for such condemning statements by the authors.

Currently, more than 180 million Americans take supplements as part of their healthy lifestyle. With regard to the safety of supplements,  The Natural Products Association implores the authors to review the National Poison Control Center Statistics to see that adverse reactions to drugs are 800 percent higher than those attributed to dietary supplements.

It is also important to note that the FDA currently receives over 400,000 adverse event reports on drugs, whereas only 1,214 adverse event reports on dietary supplements were recorded in 2001, the last time that data was made publicly available.  It is also important to add that in December 2006, the bill requiring Adverse Event Reporting for Dietary Supplements and Over-the-Counter (OTC) Drug was singed into law, another clear demonstration that dietary supplements are regulated. Supplements are accurately labeled as mandated by DSHEA and actively monitored by FDA. Regulatory action is taken when and where appropriate. FDA, on a number of occasions, has stated that DSHEA provides all the legislative authority needed to regulate dietary supplements. This comes directly from the testimony of Dr. Robert E. Brackett, Director, Center for Food Safety and Applied Nutrition, Food and Drug Administration, U.S. Department of Health and Human Services before the House of Representatives Committee on Government Reform, March 9, 2006 (http://www.fda.gov/ola/2006.html).

In conclusion, contrary to the authors’ viewpoint, dietary supplements are in fact regulated, have a well-established history of safety and are essential to the health of the nation.

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