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ABSTRACT: This update focuses on the bioavailability of dietary calcium for humans. Fundamentals of calcium metabolism, intestinal absorption, urinary excretion and balance are recalled. Dietary factors, especially lactose and other milk components, influencing calcium bioavailability at intestinal and renal levels are reviewed. A critical examination of all the methods used for evaluating calcium bioavailability is made. This includes in vitro assays, classical and isotopic balances, urinary excretion, isotope labeling in the urine, plasma and bones, long term evaluation of bone mineralization and the use of biological bone markers. Importance and advantages of animal models are discussed. The state of the art in the comparative bioavailability of calcium in foods is detailed including a comparison of sources of calcium (dairy products and calcium salts) in human studies and in some animal studies, casein phosphopeptides, proteins, lactose and lactase and their relation with calcium bioavailability (in humans and rats). An update on the consumption of dairy products and bone mass is presented. Emphasis on peculiarities and advantages of calcium in milk and dairy products is given.
Journal of the American College of Nutrition 05/2000; 19(2 Suppl):119S-136S. · 2.29 Impact Factor
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L Guéguen
American Journal of Clinical Nutrition 07/1997; 65(6):1898-9. · 6.67 Impact Factor
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ABSTRACT: We have further investigated the "meal effect" on mineral bioavailability in pigs by mineral balance studies and measurements of bone ash contents and bending moment. A group of seven pigs (CAA) was given all its dietary Ca as CaCO3 5 h after the first daily meal for 8 weeks. The control group of seven pigs received CaCO3 in the meal. Both groups were given normal P within the meals. Ca and P absorption and retention were evaluated by a 10-day balance trial. Several bones were collected at slaughter to determine bone ash, Ca, and P contents and bending moment (three-point bending test). Ingesting Ca after the meal did not affect Ca bioavailability or phosphorus absorption, but did reduce P retention, which in turn decreased the bone scores. Osteopenia, indicated by decreased total mineral contents of bones (and decreased ash:bone volume ratio), was associated with elevated plasma osteocalcin in the CAA group. Thus, CaCO3 need not be incorporated into a meal for high Ca absorption, provided that Ca is given after a meal, but simultaneous intakes of Ca and P are required for the best mineral retention.
Bone 11/1995; 17(4):357-62. · 4.02 Impact Factor
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ABSTRACT: The 'meal effect' on mineral bioavailability is evaluated in short-term studies on humans whereas feeding experiments on pigs lasting several weeks allow both mineral balance studies and measurements of bone ash contents or breaking strength. Three groups of 7 pigs were given 3 dietary treatments, differing essentially in the mode of Ca and P distribution, for 7 weeks. Group 1 received Ca and P within the meals, Group 2 was fed Ca separate from meals, and Group 3 was given both Ca and P separate from meals. Ca and P absorption were evaluated by a 10-day balance trial, then several bones were collected to determine mineral contents and breaking strength. Ca was much better absorbed and retained by giving CaCO3 within meals. Simultaneous administration of Ca and P did not influence Ca absorption, but tended to improve Ca and P retention. The best bone scores were obtained when CaCO3 and NaH2PO4 were given simultaneously in meals. The Ca and P balance values and bone parameters were strongly correlated. Thus meal incorporation and simultaneous intake of Ca and P are both required for the best mineral retention, evaluated by balance or bone scores.
Bone and Mineral 05/1993; 21(1):75-81.
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ABSTRACT: The purpose of the present study was to determine the minimum level of endogenous fecal loss of P in sheep receiving a P-deficient and Ca-rich diet composed of natural feedstuffs. The low fecal endogenous loss of P (15 mg/kg/d) was obtained under abnormal physiological conditions and did not correspond to the minimum requirement for maintenance.
Reproduction Nutrition Development 02/1990; Suppl 2:189s-190s. · 1.90 Impact Factor
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ABSTRACT: Casein phosphopeptides are known to influence calcium absorption. A 50-day study was performed in 6-week old pigs fed either a control diet or a 5% casein phosphopeptide-containing diet (PP group). Both diets provided similar amounts of Ca (0.8%), P (0.5%), proteins, energy and vitamins. PP diet provided near 1/2 of total Ca, 1/3 of total P and 1/5 of proteins in the form of casein phosphopeptide. Ca and P excretion, absorption and retention were evaluated during a 10-day balance study. Bones were collected at slaughter to determine density, bending moment and bone mineral content. Calcium absorption and bone parameters (urinary hydroxyproline included) were not influenced by the type of diet. P absorption, but not retention, was slightly higher in the control group. Urinary Ca was higher and urinary P lower in PP pigs than in controls. These changes might result from the different kinds of dietary phosphorus, inorganic versus phosphopeptide, rather than from the difference between dietary proteins.
Reproduction Nutrition Development 02/1989; 29(4):477-86. · 1.90 Impact Factor
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ABSTRACT: Two separate balance experiments of P, Ca, Mg and Zn were carried out on 5 lots of 4 growing pigs each (35-40 kg) adapted for 3 weeks to one of the diets studied. In the first experiment, the control diet was compared with a diet containing 20% of coarse wheat bran, thus richer in minerals, the quantities ingested not being equalized. In the second experiment, three diets were compared: a control diet, a diet with 2.5% of high-methoxylated (HM) apple pectin, and a diet with 2.5% low-methoxylated (LM) apple pectin. The supplement of P and Mg provided by the wheat bran was well absorbed (apparent absorption) and retained by the pigs. On the contrary, in spite of higher intake of Ca and Zn with bran diet, the absorption of these minerals was not improved. The action of wheat bran phytase and the possible absorption of P and Mg (but not of Ca and Zn) in the large intestine could explain these results. Compared to HM pectin that had relatively little effect on mineral utilization, LM pectin drastically diminished the absorption and retention of the minerals studied and resulted in negative Ca, Mg and Zn balances. The degree of pectin esterification would thus be the main factor determining the effect of pectin on mineral availability. In conclusion, wheat bran is a source of available P and Mg for the pig but it might have an unfavorable effect on the utilization of Ca and Zn. LM pectin produces a deleterious influence on mineral balances.
Reproduction Nutrition Development 02/1985; 25(4A):705-16. · 1.90 Impact Factor
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ABSTRACT: Four semi-purified diets with different calcium (Ca) and phosphorus (P) contents were given to adult sheep at a level of 1 kg daily plus 100 g of straw. The phosphorus was supplied as dicalcium phosphate, almost insoluble in rumen fluid. In the preliminary period, all the animals (16) were fed the test diet (NCa-NP) containing 8.4 g of Ca and 3.3. g of P. In the experimental period (table 3) two trials were carried out. In trial 1, two groups of 5 sheep each were given for 5 weeks a diet low in P (1 g/kg) and either low (2 g/kg) (diet BCa-BP) or high (10 g/kg) (diet HtCa-BP) in calcium. In trial 2, which lasted for 19 weeks, the HtCa-BP diet was compared to a high Ca (10 g/kg) normal P (3.3 g/kg) diet (diet HtCa-NP); two groups of 2 sheep each were fed both these diets every 3 hours, and one group (HtCa-BP) was fed twice daily. The concentration of ultrafilterable inorganic Ca (CaiU) in the rumen contents was related to the Ca level of the diet (tables 4, 5). However, individual variations were high and CaiU concentrations were negatively correlated to rumen pH (fig. 7). When diets adequate in P were fed, ruminal concentrations of ultrafilterable P (PiU) were rather high (400-490 mg/l), showing the importance of endogenous P supply in the rumen. With an adequate P supply, a high Ca intake had no effect on either plasma or ruminal PiU. When low P diets were fed, there was a steady decrease in plasma Pi from 6 to 3.5 mg P/100 ml and in ruminal PiU from 500 mg/l to values lower than 300 mg/l up to 5-6 experimental weeks. These decreases were greatest with high Ca intake (HtCa-BP diet) (figs. 2, 3), some animals being markedly affected (ruminal PiU values lower than 20 mg/l). However, the decreases in ruminal PiU were less pronounced with frequent feeding than with feeding twice a day. Considering all the results obtained, ruminal PiU concentrations were positively correlated with plasma Pi concentrations (r = + 0.77; n = 75) (fig. 8). Therefore, high Ca intake can enhance the response to P deficiency and reduce further plasma Pi concentrations and levels of available P in the rumen. Microbial P requirements may not be satisfied in such conditions, which would reduce ruminal microbial digestion in some animals.
Reproduction Nutrition Development 02/1982; 22(5):865-79. · 1.90 Impact Factor
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ABSTRACT: Mineral balances of Ca, P, Mg, K, Na, Zn, Mn, Cu were carried out on 6-week old Fisher rats for 14 consecutive days. Four lots of germfree (GF) and 4 lots of conventional (CV) rats were fed a semi-synthetic diet at weaning containing either 0 or 10 p. 100 of lactose (L). The diet was sterilized either by irradiation (I) or by autoclave (Au). Lactose, when added to the diet, caused very variable modifications of the mineral metabolism, depending on the mineral studied and the mode of sterilization. Thus, retention and apparent absorption of iron were hardly changed by the presence of lactose. On the other hand, those of Mn were strongly enhanced by the lactose. The action of the other minerals was complex; it was modulated either by the mode of diet sterilization, the flora, or by both factors simultaneously. The IL diet increased retention of most of the minerals; in some cases (Na, Zn, P, Ca) it was only evidenced in CV rats; in other cases (Mn, Mg, Cu) its action was visible in both CV and GF animals. Steam-sterilized lactose (AuL) considerably reduced this effect and even reversed it. This change in lactose action under the effect of steam sterilization especially affected absorption, which declined for all the minerals, except Zn and Mn. It was accompanied by a drop in the digestive efficiency ratio which was particularly pronounced in GF rats. The destruction of 1/3 of dietary lactose by steam sterilization could not alone explain the differences between the effects of IL and AuL. Other factors, such as the products of the Maillard reaction formed by steam sterilization of the diet, might be implicated.
Reproduction Nutrition Development 02/1980; 20(1A):119-38. · 1.90 Impact Factor
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ABSTRACT: 3 p. 100 of Maillard's reaction products (MRP), obtained by mild heating of glucose and glycine, were added to a semi-synthetic diet sterilized by irradiation. This resulted in increased dry matter excretion, more marked in axenic than in holoxenic rats, and in reduced apparent absorption of sodium and potassium in holoxenic rats. The addition of these products caused diarrhoea in axenic animals, thus preventing a good estimation of apparent absorption. It led to a significant decrease in the retention of calcium, phosphorus, magnesium and copper only in the axenic rats. It is shown that MRP affect mineral metabolism and that the microflora plays a protective role in the physiology of digestion.
Reproduction Nutrition Development 02/1980; 20(4A):1061-9. · 1.90 Impact Factor
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annales de biologie animale biochimie biophysique 02/1973; 13(3):381-97.
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http://dx.doi.org/10.1051/rnd:19900826.
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ABSTRACT: Dairy products provide abundant, accessible calcium for humans, while some calcium sulfate-rich mineral waters could provide appreciable amounts of calcium. But there is little evidence that this calcium is as available as milk calcium for making bone. The availability of calcium was studied by monitoring bone parameters in 2-month-old pigs fed restricted amounts of calcium (70% RDA) for 2.5 months. The 3 main (> or = 50% Ca intake) Ca sources were either CaCO3 or CaSO4 or skim milk powder (29% of the diet). The bones of the pigs fed the "milk" diet had higher (P < 0.01) ash contents, breaking strength and density (DEXA) than those of the two others groups, in which the bone values were similar. Thus, the calcium provided by a diet containing milk appears to ensure better bone mineralization than do calcium salts included in a non-milk diet. The calcium restriction may have enhanced some milk properties to stimulate calcium absorption in these young, rapidly growing pigs.
Reproduction Nutrition Development 40(1):49-61. · 1.90 Impact Factor
