Dr. Buck Levin is Adjunct Associate Professor of Nutrition at Bastyr University in Kenmore, Washington where he has been teaching since 1990. Bastyr is nationally recognized for its degree programs in naturopathic medicine and natural health sciences, and Dr. Levin's teaching responsibilities there include an annual course entitled “Ecological Aspects of Nutrition.”
Dr. Levin has extensive experience in private practice as a registered dietitian, and has published broadly, including contributions to the Textbook of Complementary and Alternative Medicine, the Textbook of Natural Medicine, The Encyclopedia of Alternative Medicine, and Alternative Medicine—The Definitive Guide. Dr. Levin has also published professionally in Advances: Mind-Body Journal, Journal of the Ecological Design Association, Society for Nutrition Education, and Quarterly Review of Natural Medicine, where he served as nutrition editor. He currently serves as Associate Editor for Integrative Medicine - A Clinician's Journal and sits on the editorial board of Nutrition Science News. Dr. Levin received his bachelor's degree Magna Cum Laude, Phi Beta Kappa, Distinction in Psychology from Yale University. He earned his master's degree in phenomenological psychology from Duquesne University, and his doctorate in food and nutrition from the University of North Carolina at Greensboro where he was selected first annual Alumni Fellow. While there, he also became licensed as a registered dietitian. He is currently working together with primary author Dr. Elson Haas, MD on a revised edition of the 1,100-page nutrition, Staying Healthy with Nutrition for Ten Speed Press.
Please use the link on our "Contact Us" page to e-mail questions to us regarding nutrition and the environment. Dr. Levin will attempt to answer all relevant questions within two weeks. He will reply directly to the e-mail address from which your question was sent. Select questions and answers will also be posted in the Forum's FAQ. Before submitting your question please check the current FAQ posts below to see if your question has already been addressed.
TOPIC: MICROWAVING Q: I often use a microwave to heat food for my children. How safe is microwaved food? A: Microwave ovens have been a source of health controversy for two very different reasons. Since one of these reasons is unrelated to food, I’ll mention it first, but only briefly.
Exposure to radiation leaked out of microwave ovens during use has been a first area of health controversy. The U.S. Food and Drug Administration (FDA) currently permits leakage at a rate of 1mW/sq cm (one milliwatt per square centimeter). The appropriateness of this regulatory standard continues to be debated, with opponents arguing that leakage as low as 0.5mW/sq cm can cause health damage. (An excellent review of microwave radiation and its regulatory status appears in Electromagnetic Fields: A Consumer’s Guide to the Issues and How to Protect Ourselvesby Blake Levitt, Harcourt Brace and Company, 1995, ISBN 0-15-628100-7). If you want to measure leakage from your own microwave oven you’ll need a microwave meter or a service person with one.
Microwave ovens emit two kinds of radiation. The microwaves that actually cook the food are classified as short wavelength, super high frequency (SHF) or extremely high frequency (EHF) radiation. Microwave radiation is non-ionizing, which means that it does not create ions (electrically-charged atoms and molecules) by knocking electrons out of their orbits in atoms and molecules subjected to radiation. The non-ionizing status of microwave radiation does not make it safe, but it does make it less likely to cause direct cellular damage through free radical formation, genetic alteration and other means. Although I have seen articles in the Journal of Microwave Powerand Earthletterstating that microwave leakage can damage human tissue and alter body concentrations of vitamin C and glutathione, and I have no reason to doubt these possibilities, I have not seen research studies in indexed journals that demonstrate these effects.
Like many household appliances including hair dryers, televisions, and computer monitors, microwave ovens also emit radiation in the extremely low frequency (ELF) range near 60 hertz. (In the U.S., ordinary household electrical current, called ac current, operates at 60 hertz, or 60 cycles per second). Keeping 5-10 feet away from an operating microwave oven can lower your ELF exposure. Safe Technologies Corporation in Miami, Florida (1-800-638-9121) is a good option for obtaining further information about radiation exposure at no cost.
A second area of health controversy involves the effect of microwave radiation on food. Here the research findings are mixed. In terms of overall nutrient loss from food, microwave cooking appears to as good a method of preparing food as conventional stovetop cooking. In some cases microwave cooking appears to be a superior way of preserving nutrients (Journal of the American Dietetic Association,1985, Volume 85, Issue 8, pages 922-926, including a review of 30 studies). At the same time, however, microwave cooking of garlic has been recently shown by researchers at the University of Pennsylvania to compromise the therapeutic effectiveness of this food (Journal of Nutrition,1999, Volume 129, Issue 3, pages 657-661). This compromised effectiveness may not be specific to microwave cooking, however, since other methods of cooking garlic have also been shown to alter its composition, and in particular, its pattern of sulfur-containing compounds (Phytomedicine,1995, Volume 4, pages 323-339).
What is not a matter of debate in microwave research is the ability of plastic packaging to migrate into food during the process of microwave cooking. The most extensively researched of the plastic packaging migrants is polyethylene terephthalate (PET). PET is commonly used to make microwave food trays, and “PET trimmer“ is also often found in the packaging of microwave products requiring extra crisping or browning, for example, microwave pizza. (All plastic packaging with PET, whether microwavable or not, is marked with a Number 1 recycling symbol). For a typical example of research showing migration of PET into microwaved foods, see Food Additives and Contaminants, 1990, Volume 7, Issue 6, pages 797-803.
Most plastics, including film food wrap (LDPE, or low density polyethylene, displaying a Number 4 recycling symbol) and styrofoam containers (PS, or polystyrene, displaying a Number 6 recycling symbol) have been shown to migrate from plastic packaging into microwaved foods. Also demonstrated in food science research is migration of benzene from microwave susceptors into foods (Journal of the Association of Official Analytical Chemists International,or J AOAC International,1993, Volume 76, Issue 4, pages 760-764).
While no one questions the migration of plastic packaging into microwaved foods, researchers disagree on the health consequences of this migration. Researchers who look at diagnosed diseases and overt physical symptoms seldom find reason to be concerned about residues of plastic packaging in microwaved food. In contrast, researchers who look not at clear-cut diseases but at changes inside human cells, including metabolic patterns and nutrient ratios, often find reason for broad-based concern.
TOPIC: FOOD IRRADIATION Q: How can I be certain that foods I eat have not been irradiated? A: At present, unless you’re eating 100% organic, you can’t. While the United States Food and Drug Association (FDA) currently requires a small (ingredient list-sized) radiation symbol called a radura on irradiated meats and produce, multi-ingredient foods containing irradiated components (like spaghetti sauces containing irradiated spices) are not required to display the symbol. Beginning in 1963 with wheat and wheat powder, the FDA has approved a wide variety of foods for irradiation treatment. These foods include white potatoes (1965), spices and seasonings (1983), dehydrated enzymes (1985), pork (1985), fresh fruit (1986), dry vegetable substances (1986), poultry (1990), and most recently beef and lamb (1997). The approval of irradiated beef in 1997 followed the well-publicized Hudson Foods Recall. On August 12, 1997, the Hudson Foods Company based in Rogers, Arkansas voluntarily recalled 20,00 pounds of beef after receiving reports from the Colorado Department of Public Health linking E. coli 0157:H7 poisoning to Hudson meats packed at their Columbus, Nebraska facility. On December 3, 1997 in response to a petition from Hudson Foods the FDA announced its decision to allow irradiation of beef at a level of 4.5-7.0 kilogray.
Most objections to irradiated food fall into two basic categories. A first type of objection involves the purpose of irradiation. While authorized by the FDA to promote food safety, many opponents of irradiation believe that food manufacturers use irradiation as a means to salvage low-quality foods and extend the shelf-life of products that should instead be removed from the marketplace. These opponents believe that irradiation of E.coli-susceptible meat only postpones real solutions to underlying problems in beef production, which include: the failure of cattlemen to wash manure off cattle before sending them to market; the feeding of cattle up until hours before slaughter, thereby increasing the risk of intestinal bursting; the re-working of broken and poorly-formed meat patties into subsequent products two and three days after the initial processing of the meat; the failure of fast food restaurants to cook ground beef at 160 degree Fahrenheit; the failure of beef producers to conduct E. coli testing at various stages of the production process; and failed governmental enforcement of existing regulations.
A second type of objection to food irradiation involves the health risk associated with consumption of irradiated foods. Here the research debate remains ongoing and centers around the issue of polyploidy. Polyploidy refers to a condition in which two or more sets of chromosomes are created within the cells of an organism. Human cells usually contain a single set of 46 chromosomes. A polyploid human cell may contain two sets (92 chromosomes), three sets (138 chromosomes), or even more sets of chromosomes. While polyploidy occurs frequently in plants, in humans it is relatively rare.
The controversy over food irradiation and polyploidy began in the mid-1970s when studies on animals and humans showed increased polyploidy after consumption of irradiated wheat. In all studies, however, questions were raised about the true relationship between polyploidy and irradiated food since polyploidy did not increase as expected when doses of radiation applied to wheat were increased. In addition, the link between polyploidy and irradiation was also questions since chromosomal breaks and deletions were also observed to occur in association with other dietary parameters like protein deficiency and overall malnourishment. Follow-up studies in 1975, 1983 and 1993 left most of these questions unanswered.
Consumers wanting to avoid all irradiated foods can do so by eating organically certified products. At present, irradiation is still prohibited on the use of all foods certified as organic. To stay informed about irradiation and its relationship to organically grown foods, visit the Organic Consumers Association website at http://www.organicconsumers.org.
TOPIC: TOXINS IN FRUIT Q: I have always been told to have fresh fruit for snacks, but someone recently told me that fruits have lots of toxins. Is that true? A: It depends what you mean by “lots.“ Pesticides and metals are the most common toxins found in non-organically grown fruit, and they are often present at levels between 10 parts per billion (ppb) and 100 parts per million (ppm). Non-organically grown infant juices typically contain lead at the ppb level, and fruits like grapes and strawberries often have ppb levels of the pesticides folpet and captan. Skins of fruits generally contain higher levels of toxins than the inner pulp and in the case of some fruits like oranges, dyes derived from coal tar may be injected for cosmetic reasons. The government currently allows 2 ppm of Citrus Red Number 2 to be injected into the skins of oranges for uniform color, and cherries are typically injected with Red Number 3 (erythrosine) for this same reason.
Many fruits are aseptically packaged in containers that include aluminum foil liners. Because of the relatively high acidity, fruits can leach this aluminum from the liners. In the case of some highly acidic fruits, aluminum contamination from packaging can reach the 150 ppm level.
Two additional types of contaminants are important to mention in the case of fruit. Many fruits are waxed in petroleum-based waxes that contain residues of petroleum solvents like o-benzyl-p-chlorophenol. Solvents like ethyl alcohol may be added to fruit waxes to promote consistency, and film formers like milk casein (a protein derived from cow’s milk and frequently implicated in milk allergy) may also be added for this reason. Beeswax, secreted from the glands on the underside of a bee’s abdomen; shellac, obtained from the lacca secretion of the lac beetle native to Pakistan and India; carnauba wax, obtained from the carnauba palm tree; and other wood rosins are also used as sources of fruit wax.
Sulfites are a final type of contaminant commonly found in fruit. Sulfites are often used to preserve dried fruit including raisins, dates, figs and cranberries. They are also used to preserve dried, shredded coconut and to preserve fresh lettuce and other vegetables in salad bars.
TOPIC: OTHER ONLINE INFORMATION Q: Where can I go online to find out more information in the area of nutrition and the environment? A: If you are looking for newsletter-type information and weekly updates about key events in the area of health, food, and the environment, I highly recommend Rachel’s Environment and Health Weekly. The online version of this outstanding newsletter, founded in 1986, is available at no charge through http://www.rachel.org. You can subscribe by e-mailing the words “SUBSCRIBE RACHEL-WEEKLY YOUR NAME“ (Replace the words “your name“ with your name and don’t include the quotation marks) to: listserv@rachel.org. Another excellent online newsletter is published by the Pesticide Action Network of North American (PANNA) headquartered in San Francisco. You can visit the PANNA website at http://www.panna.org, and can subscribe to their free online newsletter by e-mail the words: “subscribe panups“ (don’t include the quotation marks) to majordomo@igc.org. Although the PANUPS (Pesticide Action Network Updates Service) newsletter focuses on pesticide-related issues, many other food-related concerns are frequently addressed.
I use the National Library of Medicine’s TOXLINE database more than any other resource for obtaining abstracts of journal articles related to food contaminants and qualitative aspects of the U.S. food supply. My favorite way of accessing TOXLINE is through TOXNET, the incredibly comprehensive toxicology search tool provided free of charge by the National Library of Medicine. The website address for TOXNET is http://toxnet.nlm.nih.gov. When using TOXLINE, it is possible to simply type in the name of a food, for example, “broccoli“ to get back a list of research references related to toxins found in broccoli, since all entries in the TOXLINE database are focused on toxic substances and their appearance in the environment, in food, and in human tissue or body fluids.
Two additional sites that I have found extremely helpful are those of the Environmental Working Group (EWG) at http://www.ewg.org, and the University of California Sustainable Agriculture Research and Education Program (SAREP) at http://www.sarep.ucdavis.edu. Both sites offer a wide variety of resources and keep current with important events occurring in the field.
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