The presence of certain elements in sea vegetables causes alarm to some consumers. The following information addresses those fears. Critical to evaluating this question are 1) what form are these elements in, 2) the amounts, and 3) the historical or epidemiological evidence. Because sea vegetables are as low on the scientific research priority list as they are on the food chain, we have to infer in part from studies of other food groups, as well as use our native intelligence and intuition.

Sea vegetables contain a wide array of major minerals and trace elements, including lead, cadmium, arsenic, aluminum, zinc, chromium and many more. Small quantities in the right "organic" form are proven or estimated to be essential to human health. In the straight "inorganic" form and in excessive quantity, they can be toxic. Let's look at arsenic as an example.

Arsenic occurs in two basic forms, inorganic and organic. Inorganic arsenic occurs naturally (20th most abundant element in the earth's crust), and is found in pesticides, paint, and a host of manufactured chemical compounds. Inorganic arsenic is known to be toxic, causing skin lesions, organ damage, and promoting tumor growth, and, in acute overdose, is fatal.

Organic arsenic is presumed to be found in all living organisms. Vegetation absorbs the mineral from the soil (or in the case of sea vegetables, from the ocean) and transforms it into one of many forms of organic or colloidal arsenic. When creatures higher on the food chain eat these plants, this organic arsenic is further processed ("methylated") by the liver into further non-toxic forms, most of which is excreted through the urine. It is only when inorganic arsenic enters the body and lodges in organ tissue that toxic symptoms are observed. Though research is on-going, chronic toxicity from organic arsenic is unlikely, even in the instance of high shellfish consumption, where arsenic levels are briefly but dramatically elevated before being excreted.¹

On the other hand, recent studies suggest that low levels of arsenic in human blood serum are correlated with central nervous disorders, vascular disease, and cancer. Animal studies have shown organic arsenic to be essential to heart and skeletal muscle function in goats, and beneficial in small amounts to a variety of laboratory animals. Recent work indicates that arsenic may have a role in methionine metabolism. Therefore, it is plausible to suggest that humans have an essential need for arsenic, at a computed requirement of 12 to 50µg (micrograms) per day.

Scientists looking at Japanese sea vegetables and consumption habits concluded that eating seaweed provided on average about 100 to 150µg arsenosugar (a form of organic arsenic) per day.² Even with this high intake, there are no reports that the Japanese population demonstrates chronic symptoms of arsenic toxicity due to sea vegetables.

Furthermore, the World Health Organization (WHO) Tolerable Weekly Intake for inorganic arsenic (As) is 50µg per kg of adult bodyweight.³ This would mean that someone weighing 150 lbs could tolerate up to 3409µg of inorganic As per week or 487µg per day. So hypothetically, if a seaweed tested at 3µg/g or ppm of inorganic As, one would have to eat 162g or almost 6 oz daily to exceed this WHO limit. Even the Japanese average much less than this. We believe it's a reasonable conclusion that normal seaweed consumption does not pose a risk in terms of arsenic.

The same sort of reasoning applies to the other metals. They occur naturally; they are taken up and transformed by land or sea vegetation, and are utilized or excreted as needed by mammals and other animals. For example, aluminum is a very abundant metallic element, about 12% of the earth's crust and in the organic form is commonly found in vegetation. Beans contain 20-250 ppm, peppers and peanuts contain 50-200 ppm, corn and wheat contain 20-300 ppm. We can eat these without toxic consequences because metallic aluminum has been transformed by the plants' metabolic process into its non-toxic organic, colloidal form. It's even logical to suspect that our bodies, which evolved from the earth's elements, might have a use for this very common element in its organic form. Inorganic aluminum, however, is known to be toxic, and is implicated in Alzheimer's and breast cancer.

In 1989, a conversation with Dr. Ernest Foulkes, heavy metal researcher at the University of McGill in Montreal, focused on whether the bound organic metallic compounds in the human stomach (pH 1) are broken down at all - and, if so, how they may recombine in the small intestine (pH 6) with hundreds of chelating substances (proteins, amino acids, bile salts, complex carbohydrates) and pass harmlessly through the gut - just as studies show how arsenosugars are excreted in the urine after ingestion of arsenic in seafood.⁴

As there's much yet to learn, we recommend that you consult a healthcare professional if you have any questions about your intake of heavy metals. (Dietary deficiencies and genetic variability, for instance, can effect how well an individual's metabolism changes arsenic to more organic forms, with implications for tissue distribution and toxicity.⁵ Furthermore, vocational or environmental exposure may impact one's body load of metals and effect metabolic capacities.)

Please refer to our annual "Statement of Product Testing" at the top of this page, for specific amounts of certain trace metals in our sea vegetables.

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