FOR IMMEDIATE RELEASE, Saturday, Jan. 8, 1994 (1100 words) Contact: Ken Campbell, MIT News Office, 617 253-2703, 2700 MIT Reviews 4 Fernald Nutrition Studies Using Iron, Calcium Radioactive Tracers Involved Iron Supplements and Led to Osteoporosis Research The Massachusetts Institute of Technology today released details of an internal review this week on the four published nutrition studies involving iron and calcium which were carried out by the late MIT Professor of Nutrition, Robert S. Harris, and others. MIT President Charles M. Vest on Friday commented, "I was sorry to hear that at least some of the young people who participated in this research and their parents apparently were unaware that the study involved radioactive tracers. "People should not unknowingly become the subjects of research studies of this type. We have had in place for more than two decades at MIT numerous safeguards and approval processes that assure informed consent of human subjects of any research. "It is important to recognize that the purpose of these studies was to improve understanding of nutritional processes in order to promote health of young people, and that radiation exposure appears to have been well within even today's limits," Dr. Vest said. Professor of Physics J. David Litster, vice president and dean for research, reviewed the four articles published in professional journals in the 1950s plus a Ph.D. thesis that dealt with the work. The published studies made no mention of the matter of informed consent, and the review was therefore limited to the scientific aspects and the radiation exposures. REVIEW: EXPOSURE LEVELS WERE 30% TO 99% BELOW CURRENT LIMITS The occupational and research limits today for people 18 or under is 500 millirems (mRems) per year, in addition to background radiation of 300 mRems per year plus any medical radiation,. The adult occupational limit and the research limit are 5,000 mRems per year in addition to the 300 mRems of background radiation, plus any medical radiation. For a fetus, the mother's occupational limit is also 500 mRems but it is recommended that exposure to the mother (and fetus) be limited to no more than 50 mRems per month. (In the 1950s, the limit for an adult was 15,000 mRems; for a person 18 or under, it was 1,500 mRems.) Levels of exposure to radioactivity, like alcohol intoxication levels, depend on a person's weight. DIETARY IRON RESEARCH The study (by Professor Harris and three other MIT researchers) showed that iron supplements are more effective when taken between meals, because eating cereals decreases iron absorption. To track the iron absorption, less than a billionth of an ounce of a radioactive iron tracer was mixed with the cereal. The 17 youths, aged 12 to 17, had seven oatmeal or farina breakfasts over a period of 40 weeks. The average exposure in the iron study was 230 mRems, or 54% below the current limit. The exposure of the lightest youth was 330 mRems (34% below)) and the exposure of the heaviest youth was 170 mRems (66% below). DIETARY CALCIUM RESEARCH The calcium research was a pioneering study which laid the foundation for much subsequent research on osteoporosis. The studies gave 45 youths and one adult two exposures totaling 4 to 12 mRems (99% to 97% below the current limit). To interpret these figures, it should be noted that the extra radiation dose for a round trip airplane flight from Boston to California is 12 mRems. Also, 10 mRems is the amount of exposure per year from daily use of salt substitute (potassium chloride). The research was done by F. Bronner, Professor Harris, C.J. Maletskos, all of MIT, and C.E. Benda, who had an appointment at the Harvard Medical School and was Clinical Director at the Fernald School. The first calcium study, published in 1954, involved 19 youths aged 13 to 17 with a low calcium diet. They received two oatmeal or farina breakfasts three weeks apart, each containing in the milk 0.85 microCuries--2/trillionths (2/1,000,000,000,000) of an ounce-- of radioactive calcium45 as a tracer. The second study, published in 1956, involved 17 youths aged 10 to 16 years with a moderate calcium diet; each of them also received two oatmeal or farina breakfasts containing the same amount of radioactive calcium, with a three week interval between them. The two studies showed that if sufficient calcium was present in the diet, phytates (a class of chemical compounds) in food such as oatmeal has no effect on the amount of calcium absorbed by the body. The amount of dietary calcium required was about three times the amount of phytate in the diet; this requirement is met by most American diets (but not, perhaps, by very low calcium diets in other countries). The third calcium study published in 1956) involved nine youths (aged 11 to 15) who had the same breakfast as the youths in the other two studies, plus they received a direct injection of calcium containing as a tracer slightly less than 2/trillionths of an ounce (0.75 microCuries) of radioactive calcium. An adult also received an injection, proportionally higher. The purpose of the third study was to establish a baseline for the metabolism of calcium in the blood, including how much is excreted via the urine and how much is excreted via the feces after the calcium, in a reverse absorption process, passes through the wall of the lower gastrointestinal tract. The third calcium study found that calcium in the body system is excreted mostly through the urine, with only a third being excreted in the feces. It also showed that the body excretes injected calcium very slowly (because the calcium goes to the bones and stays there). Therapeutic LEVELS OF RADIATION MUCH HIGHER In comparison to the radiation exposure levels of radioactive tracers used to track nutrition is minute in comparison with the exposure from therapeutic radiation treatments. These involve much higher doses focused on a small part of the body, such as the thyroid. For example, the hyperthyroid problem such as that experienced by former President George Bush is typically treated with a radioactive iodine drink designed to deliver about 10,000,000 mRems to the thyroid. It would coincidentally deliver a dose to the rest of the body of about 20,000 mRems. CANCER RISKS The normal lifetime risk for someone to contract cancer from all sources--tobacco, chemicals , background radiation, medical radiation etc.)--is 1 in 3. The life time risk for a fatal cancer is 1 in 5. For the iron study, there was an increased lifetime risk of a fatal cancer ranging from about 1 in 2,000 to about 1 in 4, 000. For the calcium study, the increased lifetime risk of a fatal cancer ranges from about 1 in 55,000 to 1 in 160,000.