Aspartame: a safety evaluation based on current use levels, regulations, and toxicological and epidemiological studies.

Aspartame is a methyl ester of a dipeptide used as a synthetic nonnutritive sweetener in over 90 countries worldwide in over 6000 products. The purpose of this investigation was to review the scientific literature on the absorption and metabolism, the current consumption levels worldwide, the toxicology, and recent epidemiological studies on aspartame. Current use levels of aspartame, even by high users in special subgroups, remains well below the U.S. Food and Drug Administration and European Food Safety Authority established acceptable daily intake levels of 50 and 40 mg/kg bw/day, respectively. Consumption of large doses of aspartame in a single bolus dose will have an effect on some biochemical parameters, including plasma amino acid levels and brain neurotransmitter levels. The rise in plasma levels of phenylalanine and aspartic acid following administration of aspartame at doses less than or equal to 50 mg/kg bw do not exceed those observed postprandially. Acute, subacute and chronic toxicity studies with aspartame, and its decomposition products, conducted in mice, rats, hamsters and dogs have consistently found no adverse effect of aspartame with doses up to at least 4000 mg/kg bw/day. Critical review of all carcinogenicity studies conducted on aspartame found no credible evidence that aspartame is carcinogenic. The data from the extensive investigations into the possibility of neurotoxic effects of aspartame, in general, do not support the hypothesis that aspartame in the human diet will affect nervous system function, learning or behavior. Epidemiological studies on aspartame include several case-control studies and one well-conducted prospective epidemiological study with a large cohort, in which the consumption of aspartame was measured. The studies provide no evidence to support an association between aspartame and cancer in any tissue. The weight of existing evidence is that aspartame is safe at current levels of consumption as a nonnutritive sweetener.

Safety assessment of castoreum extract as a food ingredient.

Castoreum extract (CAS NO. 8023-83-4; FEMA NO. 2261) is a natural product prepared by direct hot-alcohol extraction of castoreum, the dried and macerated castor sac scent glands (and their secretions) from the male or female beaver. It has been used extensively in perfumery and has been added to food as a flavor ingredient for at least 80 years. Both the Flavor and Extract Manufacturers Association (FEMA) and the Food and Drug Administration (FDA) regard castoreum extract as generally recognized as safe (GRAS). Acute toxicity studies in animals indicate that castoreum extract is nontoxic by both oral and dermal routes of administration and is not irritating or phototoxic to skin. Skin sensitization has not been observed in human subject tests. Castoreum extract possesses weak antibacterial activity. A long historical use of castoreum extract as a flavoring and fragrance ingredient has resulted in no reports of human adverse reactions. On the basis of this information, low-level, long-term exposure to castoreum extract does not pose a health risk. The objective of this review is to evaluate the safety-in-use of castoreum extract as a food ingredient.

Risk and safety assessment on the consumption of Licorice root (Glycyrrhiza sp.), its extract and powder as a food ingredient, with emphasis on the pharmacology and toxicology of glycyrrhizin.

Licorice (or 'liquorice') is a plant of ancient origin and steeped in history. Licorice extracts and its principle component, glycyrrhizin, have extensive use in foods, tobacco and in both traditional and herbal medicine. As a result, there is a high level of use of licorice and glycyrrhizin in the US with an estimated consumption of 0.027-3.6 mg glycyrrhizin/kg/day. Both products have been approved for use in foods by most national and supranational regulatory agencies. Biochemical studies indicate that glycyrrhizinates inhibit 11beta-hydroxysteroid dehydrogenase, the enzyme responsible for inactivating cortisol. As a result, the continuous, high level exposure to glycyrrhizin compounds can produce hypermineralocorticoid-like effects in both animals and humans. These effects are reversible upon withdrawal of licorice or glycyrrhizin. Other in vivo and clinical studies have reported beneficial effects of both licorice and glycyrrhizin consumption including anti-ulcer, anti-viral, and hepatoprotective responses. Various genotoxic studies have indicated that glycyrrhizin is neither teratogenic nor mutagenic, and may possess anti-genotoxic properties under certain conditions. The pharmacokinetics of glycyrrhizin have been described and show that its bioavailability is reduced when consumed as licorice; this has hampered attempts to establish clear dose-effect levels in animals and humans. Based on the in vivo and clinical evidence, we propose an acceptable daily intake of 0.015-0.229 mg glycyrrhizin/kg body weight/day.

Safety assessment of aqueous olive pulp extract as an antioxidant or antimicrobial agent in foods.

The olive fruit, its oil and the leaves of the olive tree have a rich history of nutritional, medicinal and ceremonial uses. Olive oil, table olives and olive products are an important part of the Mediterranean diet, the greatest value of which may be due to olive polyphenols that contribute to the modulation of the oxidative balance in vivo. The objective of this review is to examine the available safety/toxicity literature on olive polyphenols, particularly hydroxytyrosol, to determine the safety-in-use of a standardized aqueous olive pulp extract (HIDROX). Among the polyphenols found in the extract, the major constituent of biological significance is hydroxytyrosol (50-70%). In oral bioavailability studies, urinary excretion of hydroxytyrosol and its glucuronide was found to be associated with the intake of hydroxytyrosol. Oral bioavailability of hydroxytyrosol in olive oil and in an aqueous solution was reported as 99% and 75%, respectively. In comparative studies, urinary excretion of hydroxytyrosol was greater in humans than in rats. The LD(50) of the extract and hydroxytyrosol was reported to be greater than 2000 mg/kg. In a subchronic study, the no observed adverse effect level (NOAEL) of the extract in rats was found to be 2000 mg/kg/day. In developmental and reproductive toxicity studies, HIDROX did not cause toxicity at levels up to 2000 mg/kg/day. In an in vivo micronucleus assay, oral exposure of rats to HIDROX at dose levels up to 5000 mg/kg/day for 29 days did not induce increases in polychromatic erythrocytes in bone marrow. Based on the available studies of the extract and polyphenols, and a history of exposure and use of components of the extract through table olives, olive products and olive oil, the consumption of HIDROX is considered safe at levels up to 20 mg/kg/day.

Safety assessment of esters of p-hydroxybenzoic acid (parabens).

Parabens are widely used as preservatives in food, cosmetic and pharmaceutical products. Acute, subchronic, and chronic studies in rodents indicate that parabens are practically non-toxic. Parabens are rapidly absorbed, metabolized, and excreted. In individuals with normal skin, parabens are, for the most part, non-irritating and non-sensitizing. However, application of compounds containing parabens to damaged or broken skin has resulted in sensitization. Genotoxicity testing of parabens in a variety of in vitro and in vivo studies primarily gave negative results. The paraben structure is not indicative of carcinogenic potential, and experimental studies support these observations. Some animal studies have reported adverse reproductive effects of parabens. In an uterotrophic assay, methyl and butyl paraben administered orally to immature rats were inactive, while subcutaneous administration of butyl paraben produced a weak positive response. The ability of parabens to transactivate the estrogen receptor in vitro increases with alkyl group size. The detection of parabens in a small number of breast tumor tissue samples and adverse reproductive effects of parabens in animals has provoked controversy over the continued use of these substances. However, the possible estrogenic hazard of parabens on the basis of the available studies is equivocal, and fails to consider the metabolism and elimination rates of parabens, which are dose, route, and species dependent. In light of the recent controversy over the estrogenic potential of parabens, conduct of a reproductive toxicity study may be warranted.

Safety assessment of (-)-hydroxycitric acid and Super CitriMax, a novel calcium/potassium salt.

(-)-Hydroxycitric acid (HCA) is a principle constituent (10-30%) of the dried fruit rind of Garcinia cambogia, a plant native to Southeastern Asia. The dried rind has been used for centuries throughout Southeast Asia as a food preservative, flavoring agent and carminative. Extensive experimental studies show that HCA inhibits fat synthesis and reduces food intake. The objective of this review is to systematically review the available safety/toxicity literature on HCA to determine its safety in-use. The primary mechanism of action of HCA appears to be related to its ability to act as a competitive inhibitor of the enzyme ATP-citrate lyase, which catalyzes the conversion of citrate and coenzyme A to oxaloacetate and acetyl coenzyme A (acetyl-CoA), primary building blocks of fatty acid and cholesterol synthesis. Super CitriMax, a novel calcium/potassium-HCA extract (HCA-SX), is considerably more soluble and bioavailable than calcium-based HCA ingredients. Acute oral toxicity studies in animals demonstrate that CitriMax (50% HCA as calcium salt) has a low acute oral toxicity. In a subchronic study in rats, the gavage administration of HCA-SX at doses up to 2500 mg/kg/day for a period of 90 days caused a significant decrease in body weight and reduction in feed consumption without any adverse effects. The structure, mechanism of action, long history of use of HCA and other toxicity studies indicate that HCA-SX is unlikely to cause reproductive or developmental effects. HCA-SX was not mutagenic in the presence or absence of metabolic activation in Ames genotoxicity assays in strains TA98 and TA102. HCA-SX-induced increases in number of revertants in other strains (TA100 and TA1535 in the absence of metabolic activation and in strain TA1537 in the presence of metabolic activation) but these were not considered as biologically indicative of a mutagenic effect. In several, placebo-controlled, double-blind trials employing up to 2800 mg/day HCA, no treatment-related adverse effects were reported. There is sufficient qualitative and quantitative scientific evidence, including animal and human data suggesting that intake of HCA at levels up to 2800 mg/day is safe for human consumption.

Evaluation of the health aspects of methyl paraben: a review of the published literature.

Methyl paraben (CAS No. 99-76-3) is a methyl ester of p-hydroxybenzoic acid. It is a stable, non-volatile compound used as an antimicrobial preservative in foods, drugs and cosmetics for over 50 years. Methyl paraben is readily and completely absorbed through the skin and from the gastrointestinal tract. It is hydrolyzed to p-hydroxybenzoic acid, conjugated, and the conjugates are rapidly excreted in the urine. There is no evidence of accumulation. Acute toxicity studies in animals indicate that methyl paraben is practically non-toxic by both oral and parenteral routes. In a population with normal skin, methyl paraben is practically non-irritating and non-sensitizing. In chronic administration studies, no-observed-effect levels (NOEL) as high as 1050 mg/kg have been reported and a no-observed-adverse-effect level (NOAEL) in the rat of 5700 mg/kg is posited. Methyl paraben is not carcinogenic or mutagenic. It is not teratogenic or embryotoxic and is negative in the uterotrophic assay. The mechanism of cytotoxic action of parabens may be linked to mitochondrial failure dependent on induction of membrane permeability transition accompanied by the mitochondrial depolarization and depletion of cellular ATP through uncoupling of oxidative phosphorylation. Parabens are reported to cause contact dermatitis reactions in some individuals on cutaneous exposure. Parabens have been implicated in numerous cases of contact sensitivity associated with cutaneous exposure; however, the mechanism of this sensitivity is unknown. Sensitization has occurred when medications containing parabens have been applied to damaged or broken skin. Allergic reactions to ingested parabens have been reported, although rigorous evidence of the allergenicity of ingested paraben is lacking.

Safety assessment of propyl paraben: a review of the published literature.

Propyl paraben (CAS no. 94-13-3) is a stable, non-volatile compound used as an antimicrobial preservative in foods, drugs and cosmetics for over 50 years. It is an ester of p-hydroxybenzoate. Propyl paraben is readily absorbed via the gastrointestinal tract and dermis. It is hydrolyzed to p-hydroxybenzoic acid, conjugated and the conjugates are rapidly excreted in the urine. There is no evidence of accumulation. Acute toxicity studies in animals indicate that propyl paraben is relatively non-toxic by both oral and parenteral routes, although it is mildly irritating to the skin. Following chronic administration, no-observed-effect levels (NOEL) as high as 1200-4000 mg/kg have been reported and a no-observed-adverse-effect level (NOAEL) in the rat of 5500 mg/kg is posited. Propyl paraben is not carcinogenic, mutagenic or clastogenic. It is not cytogenic in vitro in the absence of carboxyesterase inhibitors. The mechanism of propyl paraben may be linked to mitochondrial failure dependent on induction of membrane permeability transition accompanied by the mitochondrial depolarization and depletion of cellular ATP through uncoupling of oxidative phosphorylation. Sensitization has occurred when medications containing parabens have been applied to damaged or broken skin. Parabens have been implicated in numerous cases of contact sensitivity associated with cutaneous exposure, but high concentrations of 5-15% in patch testing are needed to elicit reaction in susceptible individuals. Allergic reactions to ingested parabens have been reported, although rigorous evidence of the allergenicity of ingested paraben is lacking.

Chronic study of diacylglycerol oil in rats.

The objective of the present study was to evaluate the effects of diacylglycerol oil following long-term administration to rats. Diacylglycerol oil is an edible oil with comparable taste and physicochemical properties of several naturally occurring oils. Diacylglycerol oil can be used as a replacement for any generally used edible oil in the home and has been approved for use in cooking oil in Japan. Male and female Sprague-Dawley rats were divided into four groups and fed low-fat (1.7%) basal diets containing an edible oil composed of rapeseed, corn, high linoleic safflower and high oleic safflower oils at 5.3% (control group 1); an edible oil composed of rapeseed and soybean oils at 5.3% (control group 2); diacylglycerol oil at 2.65% plus edible oil composed of rapeseed, corn, high linoleic safflower and high oleic safflower oils at 2.65% (low-dose group); and diacylglycerol oil at 5.3% (high-dose group) for 2 years. Interim sacrifices were conducted at weeks 30 and 77 and the study was terminated following 105 weeks of feeding. No compound-related effects were noted on clinical signs, body weights, food consumption, cumulative survival rates, hematology, blood chemistry, urinalysis, organ weights or on microscopic non-neoplastic changes. Compared to control group 2, but not control group 1, there was a significant increase in the number of high-dose group females with either benign or malignant epithelial mammary gland neoplasms. These changes were not considered biologically significant, because the tumor incidence was not similar in control group 1 and 2, and the neoplastic findings were not dose related. In summary, the two-year chronic rat study revealed no toxicologically significant or treatment-related effects of diacylglycerol oil consumption at levels of up to 5.3% in the diet.

Safety evaluation of dietary aluminum.

Aluminum is a nonessential metal to which humans are frequently exposed. Aluminum in the food supply comes from natural sources, water used in food preparation, food ingredients, and utensils used during food preparations. The amount of aluminum in the diet is small, compared with the amount of aluminum in antacids and some buffered analgesics. The healthy human body has effective barriers (skin, lungs, gastrointestinal tract) to reduce the systemic absorption of aluminum ingested from water, foods, drugs, and air. The small amount of aluminum (<1%) that is systemically absorbed is excreted principally in the urine and, to a lesser extent, in the feces. No reports of dietary aluminum toxicity to healthy individuals exist in the literature. Aluminum can be neurotoxic, when injected directly into the brains of animals and when accidentally introduced into human brains (by dialysis or shrapnel). A study from Canada reports cognitive and other neurological deficits among groups of workers occupationally exposed to dust containing high levels of aluminum. While the precise pathogenic role of aluminum in Alzheimer's disease (AD) remains to be defined, present data do not support a causative role for aluminum in AD. High intake of aluminum from antacid for gastrointestinal ailments has not been reported to cause any adverse effects and has not been correlated with neurotoxicity or AD. Foods and food ingredients are generally the major dietary sources of aluminum in the United States. Cooking in aluminum utensils often results in statistically significant, but relatively small, increases in aluminum content of food. Common aluminum-containing food ingredients are used mainly as preservatives, coloring agents, leavening agents, anticaking agents, etc. Safety evaluation and approval of these ingredients by the Food and Drug Administration indicate that these aluminum-containing compounds are safe for use in foods.

Evaluation of health aspects of kojic acid in food.

Kojic acid is a fungal metabolite commonly produced by many species of Aspergillus, Acetobacter, and Penicillium. The Aspergillus flavus group has traditionally been used in the production of a number of foods, including miso (soybean paste), shoyu (soy sauce), and sake. Kojic acid is widely used as a food additive for preventing enzymatic browning, and in cosmetic preparations as a skin-lightening or bleaching agent. Because kojic acid is often produced during the fermentation of historically used dietary staples, it has a long history of consumption. Various types of compounds, such as glucose, sucrose, acetate, ethanol, arabinose, and xylose, have been used as carbon sources for kojic acid production. Different Aspergillus species are known to produce variable amounts of kojic acid. The mechanism of action of kojic acid is well defined and it has been shown to act as a competitive and reversible inhibitor of animal and plant polyphenol oxidases, xanthine oxidase, and D- and some L-amino acid oxidases. The structure of kojic acid indicates a relatively simple route of metabolism much like dietary hexoses. Acute or subchronic toxicity resulting from an oral dose has not been reported, but convulsions may occur if kojic acid is injected. Results of mutagenicity studies are mixed, but in the in vivo mammalian dominant lethal assay, kojic acid was proven negative. Continuous administration of high doses of kojic acid in mice resulted in induction of thyroid adenomas in both sexes. Kojic acid reversibly affects thyroid function primarily by inhibiting iodine uptake, leading to decreases in T3 and T4 and increase in TSH. Increased TSH from pituitary gland in turn stimulates thyroid hyperplasia. Several lines of evidence indicate that the proliferative effects of kojic acid on thyroid are not related to a genotoxic pathway. The risk of functional inhibition of iodine uptake and its metabolism (organification) and thyroid tumor induction by kojic acid in humans appears to be extremely low. Based on the literature reviewed and discussed here, consumption of kojic acid at levels normally found in food does not present a concern for safety.

Toxicity and mutagenicity studies of DN-50000((R)) and RP-1((R)) enzymes.

Improved yields of 5'-nucleotides from yeast extract for food flavouring purposes is possible through use of microbial nucleotidases, which will be available to food processors as the flavour enhancer Aromild. The safety of these enzymes, 5'-phosphodiesterase (RP-1) and the 5'-adenylic deaminase (DN-50000) was investigated in male and female rats. Feeding rats a diet admixed with 500, 2000 and 8000 mg/kg body weight of DN-50000 for 35 days resulted in no significant dose-related changes in body weight, water consumption, urinalysis, haematological profiles, blood chemistry or histopathological profiles of either male or female rats from consumption of the enzyme preparation. There was an increase in the absolute and/or relative organ weights of the submaxillary (salivary) glands in both sexes at 8000 mg/kg. The no-observed-effect level (NOEL) for DN-50000 was clearly evident at 2000 mg/kg. Consumption of RP-1 enzyme for 35 days at dietary levels of 500, 2000 and 8000 mg/kg body weight resulted in no significant changes in the above mentioned parameters, which could be directly attributed to a dose-related effect, with the exception of an increase in the absolute and relative weights of submaxillary glands of both male and female rats in the 2000 and 8000 mg/kg groups. The increase in weight of the submaxillary glands was associated with histological evidence of acinar cell hypertrophy. The NOEL for dietary consumption of RP-1 was clearly evident at 500 mg/kg. In a follow-up study in which rats were gavaged with 2000 mg/kg RP-1, submaxillary gland hypertrophy did not occur. These studies suggest that DN-50000 and RP-1 exert an action on submaxillary glands similar to that which has been previously reported for the enzyme pancreatin. Neither DN-50000 nor RP-1 were mutagenic in the Ames assay using Salmonella typhimurium strains TA100, TA1535, TA98, TA1537 or Escherichia coli strain WP2uvrA, in the presence or absence of S9 mix.

Dietary supplements and lessons to be learned from GRAS.

The demand for dietary supplements by the public has transformed this once cottage industry into a 12-billion-dollar-per-year business. Restrictive actions against dietary supplements by the Food and Drug Administration (FDA) prompted Congress to enact new and more permissive amendments governing dietary supplements (Dietary Supplement Health and Education Act, DSHEA) to the Federal Food, Drug and Cosmetic (FFD&C) Act in 1994. A comparison is made between the present status of dietary supplement regulation and the concept of general recognition of safety (GRAS) under conditions of intended use as set forth by the landmark 1958 Food Additive Amendment to the FFD&C Act. An argument is posited for use of applicable principles learned in nearly 40 years of experience with determining the GRAS status for hundreds of substances to problems posed by dietary supplements.

A review of the studies of the safety of polydextrose in food.

Polydextrose (CAS no. 68424-04-4) is a water-soluble polymer of glucose that provides to foods the bulk and texture of sucrose. There are two main forms of polydextrose, an acidic form (PD-A) and a neutralized potassium salt (PD-N). Polydextrose is resistant to mammalian metabolic and microbial degeneration, rendering it both low in caloric value and non-cariogenic. Little polydextrose is absorbed intact although some is metabolized by caecal/colonic bacteria. At high enough levels of ingestion, this bacterial metabolism results in flatus, bloating, loose stools and ultimately a frank diarrhoea. Microbial metabolism also produces some volatile fatty acids that are absorbed by the animal and have calorigenic value. The species and dose threshold for persistent loose stools/watery diarrhoea determines the degree of electrolyte loss by the animal. In the dog, an obligate carnivore, sodium-sparing activity by the kidney and concomitant and obligatory calcium reuptake result in a well-defined aetiology of hypercalcaemia and subsequent nephrocalcinosis, particularly for PD-N. Of the species tested, the dog was the most sensitive to this carbohydrate with a no-effect level of 2000 mg/kg body weight/day. Omnivores, including the rat, mouse and monkey, have a no-effect level ranging from 2500 to 10,000 mg/kg body weight/day. No toxicity has been demonstrated in man, although the dose for laxation (to be distinguished from diarrhoea) is approximately 90 g/day (v. sorbitol at 70 g/day). Polydextrose did not show any reproductive toxicity, teratology, carcinogenesis, mutagenicity or genotoxicity. Polydextrose has been approved for food additive use (21 CFR 172.841) in the US, and an "ADI not specified" by the Joint WHO/FAO Expert Committee on Food Additives (JECFA, 1987). It has been approved in over 50 countries around the world and has been used extensively in the diet for over15 years. Specification monographs are published in the Food Chemicals Codex (FCC) (NAS, 1996) and the FAO Compendium (JECFA, 1995). This review provides an overview of the studies and salient data, not previously reported in the scientific literature, which had been submitted to regulatory agencies in support of these approvals.

Review of the biological properties and toxicity of bee propolis (propolis).

Propolis is a multifunctional material used by bees in the construction and maintenance of their hives. Use of propolis by humans has a long history, predated only by the discovery of honey. Use of products containing propolis have resulted in extensive dermal contact and it is now increasingly being used a dietary supplement. Unlike many 'natural' remedies, there is a substantive database on the biological activity and toxicity of propolis indicating it may have many antibiotic, antifungal, antiviral and antitumour properties, among other attributes. Although reports of allergic reactions are not uncommon, propolis is relatively non-toxic, with a no-effect level (NOEL) in a 90-mouse study of 1400 mg/kg body weight/day.

Safety evaluation of dibenzyl ether.

Dibenzyl ether (FEMA No. 2371, CAS No. 103-50-4) was given in the diet to rats at a rate of 62, 196 or 620 mg/kg/day for 91 consecutive days. Body weights and food consumption were measured weekly; haematological, clinical chemistry and urinalysis values were obtained at wk 6 and 12. Gross and microscopic pathological changes were observed and organ weights recorded. The high-dose females had increased absolute and relative liver weights; this was considered to be related to dose. Other statistically significant events that occurred sporadically within the test groups were unrelated to dose and were considered to be normal adaptive change. No toxicological or pathological effects were noted at any of the dose levels after 91 consecutive days of feeding dibenzyl ether. A no-effect level was achieved at 196 mg/kg/day. In a 60-kg human, this would be equivalent to approximately 11.8 g/day, assuming a direct relationship between dose and body weight across species. Based on the possible average daily intake of 19.2 mg/day, this would confer a safety factor of 600. The safety factor based on the more realistic consumption per capita of 23.6 micrograms/day would be approximately 500,000.

Safety evaluation of benzophenone.

Benzophenone (FEMA No. 2134; CAS No. 119-61-9) was administered in the diet to rats at target dose levels of 20 mg/kg body weight/day for 90 days and 100 or 500 mg/kg/day for 28 days. Body weights and food consumption were measured weekly; haematology, clinical chemistry and urinalysis values were obtained at 4 wk and at the end of the study. Gross and microscopic pathological examinations were conducted and organ weights were recorded. Treatment-related changes occurred in erythrocyte count, haemoglobin, haematocrit, bilirubin, total protein and albumin at the mid- and high-dose levels, although all changes did not occur in both groups in both sexes. There were indications of increased absolute and relative liver and kidney weights in the mid- and high-dose groups, but this was not statistically consistent for absolute kidney weights. Histopathology of the liver in the mid- and high-dose groups showed hepatocellular enlargement with an associated clumping of cytoplasmic basophilic material around the central vein. A no-effect level was demonstrated at 20 mg/kg/day for 90 days of administration. This would be equivalent to an intake of 1200 mg/day for a 60-kg human. On the basis of the calculated Possible Average Daily Intake of 0.33 mg/day, a safety factor of greater than 3600 is demonstrated. The safety factor based on the more realistic per capita consumption of 0.32 microgram/day would be approximately 3.7 million.