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At least 271 records · Page 15Linked to original sources
PubMed1990

[Cesium transfer in short food chains].

An investigation of 25,000 samples of foodstuffs and feedstuffs in Czechoslovakia, contaminated by fall-out cesium after the accident in the Chernobyl nuclear power plant, performed from May 5, 1986 to March 31, 1988, revealed that both the values of cesium transfer-factors in food--animal tissues--milk transitions and the values of biological half-life of cesium are functions of internal and external conditions of contamination. Organism individuality as the main internal condition causes the variance of about +/- 50% of the mean value of the respective transfer-factor. Through the external conditions, mainly the environmental contamination level, type of ingested food and time of ingestion, the mean values of transfer-factors are influenced up to 500%, e.g. to the value of 0.5. But this value converges with growing up contamination of food and environment to the limit of 0.3. The first two to three biological half-lives after the last ingestion of contaminated food are up to ten-times shorter than those at stabilized state.

Accidents↗
PubMed1990

Prevention of formation of important mutagens/carcinogens in the human food chain.

Etiological factors for gastric cancer, among others, involve consumption of smoked, salted, and pickled fish of certain types. Their chemical nature is not yet fully established but probably involves diazo phenols, and their formation can be prevented either by omitting the salting and pickling process, or by using vitamins C and E on the food prior to salting, pickling, or smoking. Both preventive approaches would limit the formation of mutagenic and carcinogenic diazo phenols. Sugimura and associates discovered new types of mutagens as heterocyclic amines that are formed during frying or broiling of meats and fish. In rats, these amines induce cancer specifically in organs such as breast, colon, or pancreas, associated with Western-type nutrition where promotional elements such as dietary fat play an enhancing role. Thus, inhibition of the formation of these new carcinogens during cooking would remove the genotoxic components from the diet. Mixing 10% soy protein with ground meat prior to frying prevents the formation of these mutagens presumably by affording a lower surface temperature. More effective is the addition of tryptophan, proline, or mixtures thereof, which specifically blocks the formation of these mutagens/carcinogens, probably by competing for reactive intermediary aldehydes, so that these cannot interact with the normal essential target, creatinine. Thus, we have available practical, yet science-based, mechanistically understood procedures to prevent the formation of carcinogens associated with important types of cancer prevalent in many countries.

Animals↗
PubMed1990

[Xenobiotics in the food chain].

The problem of xenobiotics is presented by nitrate, cadmium, DDT and PCBs. Data are given especially for vegetables, supplemented by residue determinations in human breast milk.

Cadmium↗
PubMed2000

Polyunsaturated fatty acids in the food chain in the United States.

In the United States, intake of n-3 fatty acids is approximately 1.6 g/d ( approximately 0.7% of energy), of which 1.4 g is alpha-linolenic acid (ALA; 18:3) and 0.1-0.2 g is eicosapentaenoic acid (EPA; 20:5) and docosahexaenoic acid (DHA; 22:6). The primary sources of ALA are vegetable oils, principally soybean and canola. The predominant sources of EPA and DHA are fish and fish oils. Intake data indicate that the ratio of n-6 to n-3 fatty acids is approximately 9.8:1. Food disappearance data between 1985 and 1994 indicate that the ratio of n-6 to n-3 fatty acids has decreased from 12.4:1 to 10.6:1. This reflects a change in the profile of vegetable oils consumed and, in particular, an approximate 5.5-fold increase in canola oil use. The ratio of n-6 to n-3 fatty acids is still much higher than that recommended (ie, 2.3:1). Lower ratios increase endogenous conversion of ALA to EPA and DHA. Attaining the proposed recommended combined EPA and DHA intake of 0.65 g/d will require an approximately 4-fold increase in fish consumption in the United States. Alternative strategies, such as food enrichment and the use of biotechnology to manipulate the EPA and DHA as well as ALA contents of the food supply, will become increasingly important in increasing n-3 fatty acid intake in the US population.

Adolescent↗
PubMed1989

Transfer of Chernobyl fall-out caesium radioisotopes in the cow food chain.

From February to October 1987 samples of milk, grass and other components of the cow diet were regularly collected and analyzed for their radiocaesium contents in 26 sampling stations in a north-eastern region of Italy (Friuli-Venezia Giulia). In this paper we report the feed-to-milk transfer factors for radiocaesium obtained in 13 farms of this region of Italy.

Accidents↗
PubMedDate not supplied

Endocrine modulators in the food chain and environment.

Recently, considerable attention has been focused on certain environmental contaminants--"endocrine disruptors"--of industrial origin that may mimic the action of sex hormones. Natural compounds and their effects on other types of hormonal activity (eg, on adrenal or thyroid function) have for some reason not provoked similar attention. As exemplified by tributyltin and certain bioaccumulating chlorinated compounds, available evidence indicates that "endocrine disruption" caused by xenobiotics is primarily an ecotoxicologic problem. In mammals, certain phenylmethyl-substituted siloxanes have been found to be by far the most potent endocrine disrupters among various synthetic xenobiotics. On the other hand, it has not been possible to scientifically substantiate either certain alarming reports of powerful synergistic effects between chlorinated pesticides or the alleged adverse effects on the male reproductive tract in rodents (induced by alkylphenols and plasticizers at extremely low exposures). Whereas there is compelling evidence that estrogens in certain foods and herbal medicines can induce hormonal changes in women as well as overt toxicity in men, existing data are insufficient to support a causal relationship between exposure of the general human population to nonpharmaceutical industrial chemicals and adverse effects operating via the endocrine system. Moreover, in terms of magnitude and extent, all such exposures to so-called endocrine disruptors are dwarfed by the extensive use of oral contraceptives and estrogens for treatment of menopausal and postmenopausal disorders. Also, the exposure to hormonally active xenobiotics is virtually insignificant when compared with the intake of the phytoestrogens that are present in food and beverages, and it is even more insignificant when compared with certain herbal potions used in "alternative medicine." Furthermore, while there has been much concern about negligible exposures to xenobiotics with weak hormonelike activities, the potent endocrine disruptor licorice is freely given to children. Long-term exposure to this substance induces severe toxic symptoms of mineral corticoid hormone imbalance. Although exposures to xenobiotics and many natural compounds occur by identical routes of administration and may contribute to the same toxicological end point, they are, regrettably, judged by completely different standards. As is the case with all other chemicals, rational risk assessment and risk management of man-made and natural endocrine modulators must be based on the mode of action and dose-response relationships. Such end points as the induction of reproductive developmental effects, cancer, etc, relating to actual exposures must also be taken into consideration.

Adult↗
PubMed1993

Inuit exposure to organochlorines through the aquatic food chain in arctic québec.

Inuit people (Eskimos) are likely exposed to persistent organochlorine compounds because their traditional diet includes fatty tissues of the arctic marine biota. Here we present the results of organochlorine compound analysis in milk fat samples from arctic Québec Inuit women and in fat tissues from various animal species inhabiting that region. The total concentration of polychlorinated biphenyl congeners in Inuit milk fat was similar to that of the beluga, while the profile of the 10 congeners resembled that of the polar bear. Mean concentrations of various organochlorines in milk-fat samples from Inuit women were between 2 and 10 times greater than those found in samples previously collected from southern Québec women. The Inuit mothers exhibit the greatest body burden known to occur from exposure to organochlorine residues present in the environment by virtue of their location at the highest trophic level of the arctic food web.

Arctic Regions↗
PubMed1987

Heavy metals in small mammals in roadside environments: implications for food chains.

Lead, cadmium, nickel, and zinc were measured in soil, vegetation, earthworms, small rodents, and shrews from the immediate environs of 4 highways of various traffic densities (range less than 1,000 to c.100,000 vehicles per day) and from 2 control areas. Concentrations of all elements in soil, vegetation, and earthworms varied with volume of traffic and with distance from highways. Concentrations in earthworms of all elements were especially high. Shrews had higher concentrations of lead and cadmium than other small rodents from similar areas.

Animals↗
PubMed1981

The incorporation of toxic organic chemicals into food chains.

The influences of toxic chemicals in man and wildlife are traced from the earliest records. A comprehensive description of wildlife whose populations have suffered from suspected toxic chemical causes is provided. The long-term and long-distance transport of ocean and air currents demonstrate that the impacts of certain pollutants can be delayed, and, once initiated, continued for years past the initiating events. Current toxicological and analytical chemistry approaches to describing and predicting impacts from toxic chemicals are not powerful enough to attack and overcome the problems of the future.

Animals↗