Absorption from milk

Calcium absorption is increased in the presence of food. Oral bioavailability in adults ranges from 25% to 35% when given with a standardized breakfast. Absorption from milk was approximately 29% under the same conditions. 

Kocian, J., Skala, I, and Bakos, K. 1973. Calcium absorption from milk and lactose-free milk in healthy subjects and patients with lactose intolerance. Digestion 9, 317— 324. 

No studies evaluating the excretion of rifaximin into breast milk and its bioavailability to the infant have been performed. However, due to its very limited, if any, absorption from the GI tract and its physicochemical characteristics any milk excretion of the drug is unlikely... 

Janghorbani et al. (58) fed isonitrogenous diets to 10 subjects for 12 days. Both an intrinsic label (chicken) and extrinsic labels were used. Zinc absorptions from an all-chicken diet and from a 50% chicken-50% soy isolate diet were equivalent. Solomons et al. (59) fed 5 or 10 subjects diets in which milk, soy isolate, and beef (or mixtures of these) were protein sources for the milk and/or soy diets, absorptions were similar "fractional" absorptions from beef bologna may have been higher than from soy bologna (Table IV). 

Absorption occurs through the respiratory tract, orai membranes, and skin (Taylor 1996). Absorption from the stomach is iimited, uniess the acidity is reduced, because nicotine is a strong base. Between 80 and 90% of nicotine is metabolized, mainly in the liver but also the kidneys and lungs. Cotinine is the primary metabolite of nicotine, and the half-life of nicotine is about 2 hours. Elimination occurs by the kidneys, but it is also present in the breast milk of lactating women. 

Andon (2003) compared five different CCM formulations covering a threefold range of Ca citrate malate molar ratios from 154 previous studies in humans. Intrinsically labeled tablets or juices comprising 250 mg Ca as CCM were tested in adolescents and groups of women 20 to 30-years and 40 to 77-years old. A comparison of mean values for age groups, molar ratios, and vehicles revealed no differences. Comparison with reported values in the literature, after adjustment to equalize Ca doses and indexing versus a standard (i.e., milk = 100), revealed Ca absorption from CCM consistently exceeded absorption from other sources including milk, various dairy products, fortified foods, and Ca supplements. 

In animals, as is the case with humans, absorption and bioavailability is influenced by age. Smith s result of Ca retention equivalence between CCM and CaCOa in older rats is different to how younger rodents responded (Smith et al., 1987). CCM in OJ was determined to be relatively better absorbed and retained than the Ca in 2% fat milk (mean SFM retention rates 51.1 1.7 vs 42.2 1.8% p <. 001), respectively. This result was reproduced when, based on extrinsic labeling, the Ca from CCM in both AJ and OJ was reported to be better absorbed in juvenile rats than was the Ca from milk (p <. 05) (Andon et al., 1996b). 

Abrams, S. A., Griffin, I. J., Davila, P. M., and Hawthorne, K. M. (2003). Calcium absorption is similar from milk and two types of fortified orange juice at high intake levels. JBMR 18, Abst. S104. 

As a rule, when quinolones are administered orally, their absorption from the gastrointestinal tract is rapid and almost complete, but food in the stomach delays their absorption. In unweaned calves, fluoroquinolones are often given in the milk replacer, but oral bioavailability is slightly reduced compared with the oral drench (139). On tire other hand, fermentation in the rumen of mature ruminants precludes the oral use of fluoroquinolones. Injectable solutions are also available for systemic therapy of large animals and turkeys. 

Sandstrom, B., Cederblad, A. and Lonnerdal, B. 1983. Zinc absorption from human milk, cow s milk and infant formulas. Am. J. Dis. Child. 137, 726-729. 

Chloramphenicol, FLO, and TAP have strong UV absorption, and they could be determined directly by HPLC (9). Unlike many of the more polar antibiotics, these three compounds could be extracted with an organic solvent. A single shake-out with ethyl acetate was sufficient for the quantitative extraction of CAP and FLO from milk (5). The extract was cleaned up using C18 and Florisil SPE cartridges. A review of methods for the determination of three amphenicol residues in food, including eight GC methods and six LC methods for CAP in milk, has also been reported (9). 

There are few data in the literature concerning zinc absorption from meals. However, King, et al. (18), also using stable tracers, reported 46% absorption of zinc from a formula meal by adult women who did not use oral contraceptives. Using 65Zn tracers, Sandstrom, et al. (19) reported 15.7% absorption from a meal containing white bread, milk, and cheese. 

Tsuchita, H., Suzuki, T., and Kuwata, T. 2001. The effect of casein phosphopeptides on calcium absorption from calcium-fortified milk in growing rats. Br. J. Nutr. 85, 5-10. 

Protein Precipitation Procedures involving protein precipitation with trichloroacetic acid for Cu, Fe, and Zn have been developed for flame atomic absorption spectrometry (FAAS) determinations in body fluids [20, 21]. The physical separation of caseins and fat from milk whey can also be achieved using centrifugation at 30,000g. 

In the absence of inadequate endogenous synthesis, vitamin D must be obtained from dietary sources or from supplements. Few foods contain vitamin D except for the flesh of fatty fish (salmon, mackerel, sardines), fish liver oils, and eggs from hens fed feed enriched with vitamin D. In the United States, all commercially produced milk is fortified with vitamin D2 at a level of 400 IU/L (1 IU = 0.025 fig of vitamin D3). Therefore, in the United States (and other economically advanced countries) most dietary vitamin D is obtained from milk and other vitamin D2-fortified foods. Both vitamin D2 and vitamin D3 are converted at the same rate to 25-hydroxyvitamin D by a hydroxylase in the liver and are equally active as a prohormone. Because dietary uptake of vitamin D is dependent on normal fat absorption, conditions in which fat malabsorption is present can result in vitamin D deficiency. Because breast milk contains little vitamin D, vitamin D deficiency can occur in infants who are solely breastfed, are not exposed to adequate sunlight, and are not receiving vitamin D supplements. The adequate intake of vitamin D for children is 5 pg/day (200 IU/day) (Table 30-2). 

It is obvious that x-ray cyrstallographic methods will be the final arbiter of the structural features of molybdoproteins, but until such structures are obtained, and even afterwards as far as dynamic features are concerned, spectroscopic methods must be used to gain insight into the nature of these catalysts. Electronic spectroscopy so far has been of little use here since molybdenum complexes in general appear to exhibit broad weak absorptions. In proteins these are always buried under absorptions from hemes, flavins, and iron-sulfur centers. Massey et al., (15) discovered that pyrazolo [3,4-d] pyrimidines will bind Mo (IV) in milk xanthine oxidase that had been reduced with xanthine... 

Summarizing, it may be concluded that the mechanisms regulating iron-manganese interaction become operative in the third week of the rat s life, i.e., at the same time when the regulation of iron absorption is fully activated. Experimental evidence suggests that the onset of this regulation is not provoked by a change from milk to solid food. 

Absorption Studies of Manganese from Milk Diets in Suckling Rats... 

The pronounced effect of age on the ability of the suckling rats to retain dietary Mn observed in the present study has also been reported by others (20,24-26). This developmental change in the absorption of Mn from milk could be related to the change in the absorption mechanism in response to lactational change in the constituents of milk or because of intestinal maturation. Naturally, change in intestinal resecretion of absorbed Mn could also be a factor (Weigand, E. Kirchgessner, M. Proc. 5th Int. Symp. Trace Element... 

Comparative effects of calcium lactate and milk on apparent manganese utilization by humans are shown on Table II (7). In this study, 10 adult human subjects were fed 900 mg calcium from milk or 916 mg of calcium from calcium lactate/subject/day. Calcium provided by the basal diet was maintained constant. The increase in fecal manganese excretion with the calcium lactate supplemented diet in comparison to values when milk was the supplemental manganese source suggests that calcium supplied by milk had a lesser adverse effect on manganese absorption than did that from calcium lactate (Table II). 

Studies on the effect of oxalic acid in spinach on calcium balance in humans have shown a small decrease or no effect on calcium balance (12). However, when subjects were given test meals of either Swiss chard (13) or amaranth (, 1, which are rich in oxalic acid, urinary excretion of calcium indicated that the absorption of calcium from these sources was less than that of an equal amount of calcium from milk. Absorption of calcium from milk was also reduced when given along with amaranth (14). 

Occasionally, protein hinding of a vitamin on foods increases its absorption and hence its biological availability. For example, folate from milk is considerably better absorbed than that from either mixed food folates or free folic acid (Section 10.2.1). Folate bound to a specific binding protein in milk is absorbed in the Ueum, whereas free folate monoglutamate is absorbed in the (smaller) jejunum... 

---