Uptake from Food

Resorption of the required mineral substances from food usually depends on the body s requirements, and in several cases also on the composition of the diet. One example of dietary influence is calcium (see p. 342). Its resorption as Ca is promoted by lactate and citrate, but phosphate, oxalic acid, and phytol inhibit calcium uptake from food due to complex formation and the production of insoluble salts. 

These conclusions are in agreement with other literature. Opperhuizen [19c] found that the feeding rate of fish [0.02 g/(g d)j compared to the ventilation rate [2000 ml water/(g d)j is very low. Thus uptake from food contributes significantly if the concentration of the chemical in food is 100,000 times higher than the concentration of the chemical in water. 

Figure 1, (a) Alternative vectors for trace metal uptake. Uptake from food components... 

Biota excretion ty, = 235 h following uptake from water, excretion ty, = 15 d following uptake from food for Juvenile salmon (Zitko Carson 1977) ... 

Biota excretion t,/, = 370 d following uptake from water ty, = 55 d following uptake from food in juvenile Atlantic salmon (Zitko Carson 1976) ... 

Calcium is essential for the normal growth and development of the body, especially (in the form of calcium phosphate) of the bones and teeth. Its level in the blood is regulated by the opposing actions of the thyroid hormone calcitonin, and the parathyroid hormone parathormone. Its uptake from food is enhanced by vitamin D (calciferol). Forms of calcium used therapeutically include the folinic acid supplement calcium foiinate, and the mineral supplements calcium bicarbonate, calcium carbonate, calcium gluconate and calcium lactate. 

Analogously, when Eqs. (4), (6) and (18) are combined, ecotoxicological effects can be related to uptake from food ... 

More copper is found in the brain and heart than in any other tissue except for liver, where it is stored as copper thionein and released as ceruloplasmin or in the form of a complex with serum albumin. The high metabolic rate of the heart and brain requires relatively large amounts of copper metalloenzymes including tyrosinase, cytochrome c oxidase, dopamine-/3-hydroxylase, pyridoxal-requiring monamine oxidases, and Cu-Zn superoxide dismutase. Copper deficiency, which can occur for reasons analogous to those discussed above for Fe and Zn, leads to brain disease in infants, anemia (since cytochrome oxidase is required for blood formation), and heart disease. Few details are known about the molecular basis for copper uptake from foods. 

Some of the more important aspects in the study of the biological cycling of hydrocarbons in the marine environment are hydrocarbon uptake from food and water and selective accumulation, stors e and release emd transfer through the oceanic food web. Stegeman and Teal (1973) have suggested that the concentration and the composition of non-biogenic hydrocarbons in oysters reflect both the complete exposure history and the current exposure level, result from the interplay between uptake, release, retention, route of entry and the possible residence of hydrocarbons in multiple lipid compartments. 

A simple compartment model has been used to describe the transfer of technetium through the food-chain lichen-reindeer, as the uptake from food is much more important than from inhalation. The mean residence time for bone, livei and flesh was 55, 11, and 5 days, respectively, giving a dose to the liver of 0.02 pGy yearto the bone 0.06 pGy year... 

The complete picture of uptake from food is unclear. Fixation by acidic soils appears to be a major factor [47], while the amount of Se in plants does not predict its uptake and absorption by humans [10]. However, on the basis of the large volume of research performed, the Food and Nutrition Board (United States) proposed a safe range of50-200 p.g/day Se intake for adults [48]. In countries where soils are Se-deficient, supplementation of the soil or animal feedstuOls is employed. 

Mr. Chairman, there a number of years ago. I think in 1977 or 1976, there was a meeting of the WHO in London, where this question was discussed. I remember one of the elements which came out, which was quite important, and which has probably contributed to the change of the 100 to 50 in our thinking, was in fact the uptake from food when cooked in water in the presence of lead. This is most probably an element which also has to be taken into account, maybe not for infant food, but certainly for junior foods. Dr. Sherlock told me that they have repeated some of these studies, and that they confirmed many of the points which we made at that meeting. It is certainly an additional fact to be taken into account in these calculation. One additional thing that I wanted to mention was about information for women. 

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