Human dietary intake

The capacity of the human body to excrete iron is severely limited as compared with most other mammals (Finch et al.f 1978). Iron loss in human beings (per kg body weight) is only one-tenth that of other mammals (Dubach et ah, 1955 Green et ah, 1968 Finch et ah, 1978) and human dietary intake only one-fiftieth to one-hundredth that of other mammals. It follows, as was originally suggested by McCance and... 

Exposure Levels in Environmental Media. Because of the paucity of data on the levels of thorium in air, water, and food, there are conflicting reports on the importance of each medium to the total human dietary intake of this substance. Data on the levels of thorium in foods grown in contaminated areas, particularly in the vicinity of hazardous waste sites, are limited, and further development of these data will be useful. There is also a lack of air monitoring data around hazardous waste sites. 

R. M. Parr, Human dietary intakes of trace elements a global literature survey mainly for the period 1970-1991 data listings and references, Report IAEA-NAHRES-12, Vienna, International Atomic Energy Agency, 1992. 

The environmental effects of lead had been almost all from auto exhaust, but these effects have decreased considerably since 1973, when unleaded gasoline became available. Gasoline in the United States now has almost no lead in it, but on a global scale, about 105 t/year of lead enters the atmosphere, mostly from the use of leaded gasoline. The lead concentrations in the atmosphere are now about 0.1 pg/m3 in rural areas and up to about 0.6 pg/m3 in urban areas. The human dietary intake is now about 0.2 mg/day in the United States, which is not a problem. 

Metz R and Fanck AE (1978) Antlitz edler Steine, Mineralien-Kristalle. Chr Belser Verlag Stuttgart. Nielsen FH (1986) Rubidium. In Mertz W, ed. Trace Elements in Human and Animal Nutrition, pp. 431-434. Academy Press, Inc Orlando. Parr RM, Crawley H, Abdulla M, Iyengar GV and Kumpulainen J (1992) Human Dietary Intakes of Trace Elements A Global Literature Survey Mainly for the Period 1970-1991. International Atomic Energy Agency 12. 

Human dietary intake of bromine is large and variable. Duggan and Lipscomb (1971) obtained an average intake over 2 years from U S diets of 24 mg Br per day, while Greve (1983) calculated from the results of bromide determination in 100 Dutch duplicate meals a mean bromide intake of 7.8 and 7.6 mg per person per day, respectively, with a range from 1.8 to 17.2 mg. 

International Atomic Energy Commission (1992). Human Dietary Intakes of Trace Elements A Global Literature Survey Mainly for the Period of1970—1991. IAEA, Vienna, Austria. 

Isoflavonoids also have been reported to have physiological activity in animal and human studies. Besides acting as an estro n mimic, it was reported that the isoflavones found in soybean seeds possess antihemolytic, antifungal, tumorsuppressing, and serum cholesterol-lowering effects. In addition, both epidemiological and dietary-intervention studies indicate that when isoflavones in soybean seeds and in subsequent protein products prepared from the seeds are part of the human dietary intake, those products provide many significant health benefits. - ... 

Thus the ADI in mg per kg per day is an estimate of the daily pesticide dietary intake that appears to be without risk over the entire human lifetime. ADI values are estabHshed and periodically reviewed by joint committees of the Eood and Agricultural Organization (EAO) and WHO of the United Nations. 

Manganese. The adult human body contains ca 10—20 mg of manganese (124,125), widely distributed throughout the body. The largest Mg " concentration is in the mitochondria of the soft tissues, especially in the Hver, pancreas, and kidneys (124,126). Manganese concentration in bone varies widely with dietary intake (126) (see Table 10). 

Finally, the presence in human post-mortem brain tissue of the active metabolite of diazepam, desmethyldiazepam, raised some curiosity and frank alarm (Sangameswaran et al. 1986). At the time of its discovery in the brain it was thought that there was no enzyme system capable of producing such halogenated compounds and that its presence in the brain reflected dietary intake from an environment contaminated by overuse of its parent compound. However, its discovery in stored brain tissue which had been obtained before the synthesis of the benzodiazepines allayed these fears. It is now thought possible that some benzodiazepines, including desmethyldiazepam, occur naturally and that they are taken in as part of a normal diet (Table 19.5). 

Limited studies have focused on dietary intake of astaxanthin by humans. In a study reported by Miki, an astaxanthin-containing drink was used to protect low-density lipoprotein from oxidation (astaxanthin was administered at doses of 3.6 to 14.4 mg/day over a 2-week period). Progressive slowing of LDL oxidation with increasing doses of astaxanthin was observed and no ill effects were reported. 

In a 20-week multicenter intervention trial with lutein in healthy human subjects, no changes were noted in hematological or biochemical parameters after continuous daily lutein doses of 15 mg (0.25 mg/kg body weight, assuming a body weight of 60 kg). A relatively large number of human studies have examined correlations between macular degeneration and dietary intake of lutein or zeaxanthin, intakes via dietary supplements, and serum concentrations. 

At least some of the antioxidant nutrients are essential to human health, and others (such as carotenoids) may be highly beneficial, particularly in preventing cancer (e.g. Block et /., 1992). However, we do not yet know what dietary intakes are optimal. In principle, this could be investigated by varying the dietary intake of antioxidants and measuring free-radical damage in the human body. This is one of our current research directions. 

The question of acceptable soil levels in waterway sediments was resolved by linking such levels to the human exposure route of fish ingestion. The fishermen involved do not require the fish they catch to provide a major portion of their diet. Thus, a safe-sided estimate of their fish dietary intake was set... 

For many decades, the standard technique for measuring carotenoids has been high-pressure liquid chromatography (HPLC). This time consuming and expensive chemical method works well for the measurement of carotenoids in serum, but it is difficult to perform in human tissue since it requires biopsies of relatively large tissue volumes. Additionally, serum antioxidant measurements are more indicative of short-term dietary intakes of antioxidants rather than steady-state accumulations in body tissues exposed to external oxidative stress factors such as smoking and UV-light exposure. 

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