Charles R. Santerre

A comparison of actual versus stated label amounts of EPA and DHA in commercial omega‐3 dietary supplements in the United States

BACKGROUND Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are associated with health benefits throughout life and are obtained primarily through fish and fish oil supplements. Due to the growing popularity of dietary supplements, 47 commercial fish, krill, and algal oil supplements were analyzed for EPA, DHA, and other fatty acids. RESULTS For fish- and krill-based supplements, the range of EPA was 81.8 to 454.6 mg g(-1) oil and DHA was 51.6 to 220.4 mg g(-1) oil. For algal oil supplements, EPA ranged from 7.7 to 151.1 mg g(-1) oil and DHA ranged from 237.8 to 423.5 mg g(-1) oil. The percentage of the stated label amount for EPA and DHA ranged from 66 to 184% and 62 to 184%, respectively. Only 10 supplements (21% of those tested) had at least 100% of the stated label amount of EPA, while 12 supplements (25% of those tested) had at least 100% of the stated amount of DHA. Over 70% of the supplements tested did not contain the stated label amount of EPA or DHA. CONCLUSIONS These results indicate that the quality of fish oil supplements is not being adequately monitored by manufacturers or government agencies and increased testing is needed to ensure regulatory compliance.

Analysis of mercury in sportfish tissue by thermal decomposition, amalgamation/atomic absorption spectrophotometry.

Sportfish samples (n = 133) that originated from Indiana waters were analyzed for total mercury using inductively coupled plasma/mass spectrometry (ICP/MS) and thermal decomposition, amalgamation/atomic absorption spectrophotometry (TDA/ AAS). Total mercury concentrations obtained by the two methods were not significantly different (P > 0.05). The correlation coefficient for total mercury obtained for the two methods was 0.94. The limit of detection using TDA/AAS was 0.1 ppm. TDA/AAS is a preferred technique for the analysis of total mercury in fish tissue because it is rapid (6 min per sample) and easy to use and requires little sample preparation.

Mercury and omega-3 fatty acids in retail fish sandwiches.

Mercury and fatty acids were measured in fish sandwiches from six retail restaurant chains. Average mercury concentrations ranged from 5 to 132 ppb and were well below the Food and Drug Administration action level (1,000 ppb). The average concentrations of eicosapentaenoic acid plus docosahexaenoic acid ranged from 91 to 620 mg per sandwich. Consuming one or two fish sandwiches per week could result in the consumption of 2 to 40% of the reference dose for mercury for a 60-kg individual and would provide 18 to 126% of the adequate intake for eicosapentaenoic acid plus docosahexaenoic acid as recommended for a pregnant or lactating woman.

Divergent perspectives on GM food

To the editor: In his commentary “A different perspective on GM food” in the October issue (Nat. Biotechnol. 20, 969, 2002), David Schubert identifies three hazards arising from the introduction of genes into plants and concludes that “GM food is not a safe option.” According to Schubert, an introduced gene may first, produce different proteins in different cell types; second, produce proteins that will react with other substances in a cell to result in “the biosynthesis of molecules that are toxic, allergenic, or carcinogenic”; or third, result in the formation of a new biochemical pathway giving rise to novel or unexpected products of physiological consequence. The fatal flaw in this argument is that each of these three scenarios raised can and do occur in nature during the course of the random “natural” gene mutations and rearrangements that drive evolution. Nevertheless, Schubert dismisses “the apparently rational notion that genetic engineering is just like traditional plant breeding, only more specific.” He concludes: “As GM crops offer potential benefits, it would be in the industry’s best interest to more thoroughly examine these products before continuing with their introduction into the food supply.” Schubert must be aware that many other scientists have gone before him in considering these same issues. The potential hazards of any new technology must be assessed as Schubert suggests, and that is exactly why the scientific and regulatory establishments in many countries have put in place comprehensive pre-market safety evaluation processes before permitting a new product of biotechnology to enter the marketplace. The process for safety assessment of biotechnology products was established by some of the world’s leading scientists through WHO/FAO/CODEX and has been confirmed repeatedly in published studies and reports by numerous regulatory and scientific authorities globally. First, it should be noted that crops produced through biotechnology are subjected to a highly selective screening process that is unlikely to permit unintended or unexpected variation. To satisfy the farmer, the plant must grow and perform in the field as well as or better than its conventional counterpart; furthermore, the new variety will be subjected to a wide array of compositional and functional tests. Only those plants that meet the most stringent performance and safety criteria will advance to the regulators’ desks where the results of the safety studies will be independently assessed (see http://64.26.172.90/agbios/dbase.php for a summary of assessments). The net result is that safety assessments for biotechnology crops do not rely on a priori predictions, such as those offered by Schubert, but instead focus on careful analyses of plants. The system for ensuring the safety of such crops is “evidence-based” not “predictionbased.” The battery of scientific tests conducted on all biotechnology crops is designed to detect unpredicted effects from all kinds of sources, including alternative splicing of mRNAs and post-translational processing of the target protein, and any other unexpected impacts on plant metabolism that might occur. It is instructive to follow one of Schubert’s arguments to its logical conclusion. He suggests that genes may produce different proteins in different cells. Of course, the gene must express the intended protein in the predicted manner or the plant would not display the desired phenotype or trait and would therefore be discarded from further consideration by the developer. The protein produced in the new host is subjected to extensive biochemical characterization to confirm that the protein produced is the one and only one intended. Additional tests include acute toxicity and allergenicity evaluations, extensive agronomic, performance and yield analyses, molecular and biochemical characterization of the expressed protein to assure specificity, compositional analyses of key metabolites and nutrients, and animal nutrition and feed-performance studies. Schubert mentions the reported depletion in isoflavone content in genetically modified (GM) soybean as a demonstration of unintended changes that might occur. Setting aside the fact that the changes he cites were in fact detected, these variations, measured in different varieties of soybeans produced in different growing seasons, fall precisely within the range of concentrations of isoflavones normally found in soybean varieties1. We are also told that toxic metabolites were created in “GM batches of tryptophan.” This allegation is often found in “anti-GM” publications; however, no peer-reviewed published research points to an association of GM technology with the suspected toxic impurities. Instead, publications demonstrate that the increase in the impurity(s) resulted from a change in the purification process. And, finally, some have attributed toxic effects, such as eosinophilia-myalgia syndrome, to the consumption of unprecedented high doses of L-tryptophan per se2. When Schubert states that “a GM plant making vitamin A might also produce retinoic acid derivatives” that could result “in direct toxicity or abnormal embryonic development,” he ignores the fact that “golden rice” was engineered to produce vitamin A precursors (as opposed to the vitamin itself) and that all green plants synthesize its precursors. Thus, we are offered hypotheses for which there is no confirmatory evidence and evidence that is without merit. The real issue, however, is not one of scant or non-existent evidence, but of not considering the genetic realities that accompany all methods of plant breeding, whether conventional or biotechnological. We do not take issue with Schubert’s basic contention that unintended genetic and metabolic events can take place. The reality is that “unintentional consequences” are much more likely to occur in nature than in biotechnology because nature relies on the unintentional consequences of blind random genetic mutation and rearrangement to produce adaptive phenotypic results, whereas GM technology employs precise, specific, and rationally designed genetic modification toward a specific engineering goal. A recent paper illustrates the point. Fu and Dooner3 report the sequence of approximately 100 kb around the naturally selected bz mutant gene in maize, obtained from two different maize varieties. Alignment shows that one variety possesses four genes that are missing from the other. The authors offered the speculation that hybrid vigor may result when two parents complement each other’s missing genes. In the world of plant breeding, new genes and different alleles are constantly being shuffled and reshuffled in an endless array of combinations. In the end, traditional breeding practices all have the same, if not greater, potential ability as a transgene to produce different proteins in different cell types, or produce proteins that will react with other substances in a cell to result in “the biosynthesis of molecules that are toxic, allergenic, or carcinogenic.” Good scientists go astray when they leave their area of expertise to offer opinion when they have not studied the literature, when they selectively ignore information, or when they let their politics and beliefs interfere with the objectivity of their science. Such opinions do little to encourage an informed debate about GM crops, and it is inevitable that Schubert’s arguments will be cited as having been published in Nature Biotechnology.

The impact of Consumer food biotechnology training on knowledge and attitude

Objective: Consumer education is an important aspect in the adoption of any new technology. The objective of this work was to determine whether consumer’s knowledge and attitudes would be influenced by a face-to-face presentation involving food biotechnology. Materials and Methods: Participants (576) were requested to complete a pre-test prior to receiving a 45–80 minute presentation, which was then followed by a post-test. Participants included members from a community organization, undergraduate and graduate college students and cooperative extension educators (county agents). Results: Following training, 98% to 99% correctly indicated that fruits and vegetables contain chromosomes and that foods from biotech crops were currently sold in grocery stores. Prior to training, only 31% felt that these crops were properly regulated by federal agencies, and only 25% were confident that bioengineering was unlikely to make an existing food allergenic. Following training, 83% felt that these crops were properly regulated, and 63% believed that biotechnology was unlikely to add new allergens to our food supply. In addition, 90% of those trained would eat or serve genetically-modified foods to their family, and 90% believed that they or their family would benefit from genetically-modified foods within the next five years. Conclusions: It is apparent from these results that when provided sound, science-based information, participants are more accepting of this technology and the regulatory process.

Mercury content in commercially available finfish in the United States.

Seventy-seven finfish species (300 composites of three fish) were obtained from commercial vendors in six regions of the United States: Great Lakes, mid-Atlantic, New England, northwest, southeast, and southwest. Total mercury in fish muscle tissue ranged from 1 ppb (channel catfish) to 1,425 ppb (king mackerel). Of the top 10 most commonly consumed seafoods in the United States, all finfish species, including salmon species (13 to 62 ppb), Alaskan pollock (11 ppb), tilapia (16 ppb), channel catfish (1 ppb), Atlantic cod (82 ppb), and pangasius (swai) (2 ppb), had low total mercury concentrations. However, two large predatory species, king mackerel and swordfish (1,107 ppb), contained mercury concentrations above the current U.S. Food and Drug Administration action level of 1,000 ppb, indicating that consumers may be unaware that species that are high in mercury are being sold in the marketplace.

Green Tea Increases the Concentration of Total Mercury in the Blood of Rats following an Oral Fish Tissue Bolus

Fish has many health benefits but is also the most common source of methylmercury. The bioavailability of methylmercury in fish may be affected by other meal components. In this study, the effect of green tea on the bioavailability of methylmercury from an oral bolus of fish muscle tissue was studied in rats and compared to a water treated control group and a group treated with meso-2,3-dimercaptosuccinic acid (DMSA), a compound used medically to chelate mercury. Rats were given a single oral dose of fish tissue via gavage and one of the treatments. Rats were given access to food for 3 h at 12 h intervals. They were dosed with each of the treatments with each meal. Blood samples were collected for 95 hours. Green tea significantly increased the concentration of total mercury in blood relative to the control, whereas DMSA significantly decreased it. In addition, feeding caused a slight increase in blood mercury for several meals following the initial dose.

Changes in dieldrin and p,p'-DDE residues following cooking of channel catfish

The influence of cooking (frying, baking, and smoking) on dieldrin and 1,1-dichloro-2,2-bis[4-chlorophenyl]ethylene (DDE) residues in treated channel catfish ( Ictalarus punctatus ) was determined. Dieldrin and DDE were significantly reduced (P < 0.05) during cooking of catfish by 50 to 65% (dry basis) and 50 to 80%, respectively. Smoking resulted in maximum reduction (82%) of DDE residues, while baking resulted in the least reductions for both dieldrin (50%) and DDE (50%) when compared to the other preparation methods.

Modified Dietary Fiber from Cassava Pulp and Assessment of Mercury Bioaccessibility and Intestinal Uptake Using an In Vitro Digestion/Caco-2 Model System

The ability of modified dietary fiber (MDF) generated from cassava pulp to modulate the bioaccessibility and intestinal absorption of heavy metals may be helpful to mitigate health risk associated with select foods including select fish high in methyl mercury. Using a coupled in vitro digestion/Caco-2 human intestinal cell model, the reduction of fish mercury bioaccessibility and intestinal uptake by MDF was investiaged. MDF was prepared from cassava pulp, a byproduct of tapioca production. The highest yield (79.68%) of MDF was obtained by enzymatic digestion with 0.1% α-amylase (w/v), 0.1% amyloglucosidase (v/v) and 1% neutrase (v/v). MDF and fish tissue were subjected to in vitro digestion and results suggest that MDF may reduce mercury bioaccessibility from fish to 34% to 85% compared to control in a dose-dependent manner. Additionally, accumulation of mercury from digesta containing fish and MDF was only modestly impacted by the presence of MDF. In conclusion, MDF prepared from cassava pulp may be useful as an ingredient to reduce mercury bioavailability from food such as fish specifically by inhibiting mercury transfer to the bioaccessibile fraction during digestion.

Postharvest correlation between swordfish (Xiphius gladius) size and mercury concentration in edible tissues.

Total mercury was measured via thermal decomposition amalgamation atomic absorption spectroscopy in the muscle tissue of 82 swordfish originating in the Pacific Ocean and was found to range from 228 to 2,090 ppb. The relationships between total mercury concentration and the size of the fish (i.e., length and weight) were analyzed. It was found that dressed weight (DW) was a better predictor of mercury concentration than cleithrum-to-caudal keel length in a single variable model, and DW was the only significant predictor of mercury concentration in a multivariable model. Based on these relationships, swordfish with a DW greater than 96.4 kg (213 lb; 95% confidence interval, 88 to 107 kg [195 to 235 lb]) will exceed 1,000 ppb of mercury-the action level in the United States, Canada, and Europe-and should not be sold in commercial markets. Additionally, a logistic regression model was created to illustrate the probability of a swordfish at any DW being unsafe to consume (i.e., containing more than 1,000 ppb of mercury). In this model, the probability of a swordfish being unsafe exceeds the probability of being safe at 94.6 kg (209 lb). Taken together, the models presented in this report give regulators valuable postharvest tools to use for rapid determination of the safety of swordfish intended for sale in commercial markets.