Phytosterols have an unfavourable effect on bacterial activity and no evident protective effect on colon carcinogenesis.

The effects of physiological dietary phytosterol supplements on intestinal microflora activity and faecal sterols and their capacity to protect rats fed a normal or high saturated fatty-acid diet against tumour development were studied. A group of 80 female Wistar rats were fed an 8% lipid diet for 4 weeks (adaptation period) and then randomly assigned in a factorial experimental design study to diets containing 8% or 24% hydrogenated coconut oil, with or without a 24-mg/day/rat phytosterol supplement. They were instilled intrarectally with saline or methyl-nitroso-urea (MNU). Faecal sterol output was analysed for one week each month. Pathological analysis was done at the end of the 30-week experiment. Animals treated with MNU and given phytosterol supplements had tumour frequencies (8/20) similar to those not fed phytosterols (11/20). The fat-supplemented diet had no significant influence. Colonic glands were found in area of lymphoid follicles in all the groups, but were more frequent in rats on high-fat diets (P < 0.01). The coprostanol and the cholesterol excretion of the phytosterol-supplemented rats was significantly enhanced. Therefore phytosterols have an unfavourable effect on bacterial activity. These data confirm the capacity of phytosterols to decrease cholesterol absorption, but indicate that a large excess of phytosterol must be avoided until further research on its effects on carcinogenesis has been done.

Relationship between plasma retinol and infectious diseases in the elderly. A case-control study.

This study assessed the relationship between plasma retinol deficiency and infectious diseases. The plasma retinol, anthropometric (Body Mass Index, triceps skinfold thickness, mid-arm muscle circumference) and biological indices (proteins, albumin, transferrin, prealbumin, retinol binding protein) of protein-energy malnutrition of 63 patients with infectious diseases (ID) were compared to those of two control groups of similar age: 527 patients with other diseases (C1) and 92 healthy people (C2). Plasma retinol, albumin, transferrin and prealbumin were significantly lower in the ID group than in the C1 group. A lower body mass index was noted in men only. The ID and C1 groups had lower values for all indices (except for mid-arm muscle circumference). The ID group had lower albumin, transferrin, and prealbumin than the C1 group. The percentage of patients with plasma retinol below 300 microg/l was higher in the ID group (48.0% in men, 39% in women) than in the C1 group (25.0 and 21.5%); the odds ratio adjusted on age and sex equaled 2.46, 95% CI (1.39-4.37). It was lower than 2% in the C2 group. The results obtained with multiple regression analysis showed that, in the patients, the association between plasma retinol and infectious diseases remained significant when age, sex, anthropometric and biological indices were taken into account. Consequently, it is useful to check up the food intake habits of the elderly.

Influence of a high-calcium carbonate diet on the incidence of experimental colon cancer in rats.

This study was done to determine whether a high dietary calcium carbonate concentration could protect against colon tumors in rats. Female Wistar rats were randomly assigned to one of four groups and maintained on an 8% lipid diet for an adaptation period of four weeks. All groups were then fed a 24% lipid diet (sunflower oil), with (Groups 2 and 4) or without (Groups 1 and 3) a 1.5% calcium carbonate supplement. They were intrarectally instilled with saline (Groups 1 and 2) or nitrosomethylurea (NMU) (Groups 3 and 4). Fecal sterol output and pH were analyzed for one week each month. Histological analysis was done at the end of the 32-week experiment. No tumors were found in the non-NMU-treated animals. The NMU-treated rats had tumors: 31% in Group 3 and 30% in Group 4. The calcium carbonate supplement had no effect on this incidence. The lipid and cholesterol excretions of the calcium carbonate-supplemented rats were significantly enhanced. The coprostanol output was not altered, although its fecal concentration of the calcium-supplemented rats was decreased. Although neither lipid overload nor NMU treatment altered the fecal pH, it was significantly increased in both calcium carbonate-supplemented groups. These findings suggest that additional calcium as carbonate has no effect on colon tumor incidence, although the fecal composition is altered. The increased pH of the feces due to the carbonate could have the opposite effect to calcium.

Determination of dietary tin intake in an adult French citizen.

The tin contents in fresh food or in food stored in lacquered or unlacquered cans were determined in order to estimate the daily tin intake in a French citizen. Tin levels were 76.6 +/- 36.5 mg/kg in foods preserved in unlacquered cans, 3.2 +/- 2.3 mg/kg in foods stored in lacquered cans, and 0.03 +/- 0.03 mg/kg in fresh foods. Tin intake is essentially dependent on food stored in tin cans (98%), which only represents 5.6% of the total daily consumption of foods by a French citizen. The estimated tin intake (2.7 mg/day whether 0. 04 mg/kg of body weight) remains widely inferior to the daily tolerable dose in humans (2 mg/kg of body weight).

Daily intake of essential minerals and metallic micropollutants from foods in France.

Daily intakes of essential minerals and metallic micro-pollutants are estimated from foods usually eaten in France. These foods are grouped in nine categories. For essential elements, intake estimates are comparable to the values recommended by the WHO. The cadmium value is lower than the tolerable daily dose. The estimated values are: cobalt 29 micrograms/day, chromium 98 microgram/day, copper 1.5 mg/day, manganese 2.5 mg/day, molybdenum 275 micrograms/day, zinc 14 microgram/day, aluminium 4.2 mg/day, boron 1.6 mg/day, cadmium 27 micrograms/day and nickel 231 microgram/day.

Determination of mineral contents in different kinds of milk and estimation of dietary intake in infants.

Concentrations of 11 minerals were determined in six kinds of milk (cow's milk-based formulae, breast-milk, soya milk, bottled milk, dried milk and evaporated milk). The contents of copper, magnesium, molybdenum, aluminium, barium and nickel were higher in soya milk than in any other kinds of milk. Except for nickel in soya milk, the dietary intakes of minerals were below or close to the intake recommended by the FAO/WHO.

Effects of malnutrition and atherosclerosis on the fatty acid composition of plasma phospholipids in the elderly.

The fatty acid profiles of plasma phospholipids have been compared in 53 elderly subjects suffering from malnutrition (group U, 17 subjects) or from atherosclerosis (group A, 15 subjects). A control group was also included in the study (group C, 21 subjects). Main differences were observed in phosphatidylcholine (PC). In group U, the proportion of monounsaturated fatty acids increased in PC, which was reflected by an increase in unsaturated fatty acids without significant modification of essential fatty acids. In group A, no major modification has been observed statistically, although the proportion of saturated fatty acids tended to increase.

Effect of egg consumption in healthy volunteers: influence of yolk, white or whole-egg on gastric emptying and on glycemic and hormonal responses.

The effects of the ingestion of 2 whole eggs (E), 2 egg whites, 2 egg yolks (Y), or no eggs with a standard breakfast on gastric emptying, glycemic and hormonal responses have been studied in 12 healthy young males. E and Y induce a significant delay of gastric emptying, together with reduced blood glucose and insulin peaks (Y). Egg ingestion, whatever the part, increases gastric inhibitory peptide level in blood. Cholecystokinin is enhanced after E or Y ingestion. The results indicate that egg ingestion, especially yolk ingestion, may be of interest in regulating metabolic variables of glucose metabolism.

Dietary calcium salts as protective agents and laminin P1 as a biochemical marker in chemically induced colon carcinogenesis in rats.

To evaluate the protective effect of different calcium forms against colon carcinogenesis, Wistar rats fed a high-fat diet (24%) were supplemented with different chemical forms of dietary calcium and were intrarectally instilled with N-methyl-N-nitrosourea (NMU). Supplemental calcium was administered at 1.5% mineral (w/w of total diet) complexed with either carbonate, gluconate, or lactate in Groups 2, 3, and 4, respectively. The tumor incidence of colon cancer was compared with a control group (Group 1), fed the same diet without supplemental calcium. Colon carcinoma incidence was 31, 33, 13, and 7% in Groups 1, 2, 3, and 4, respectively. Calcium had a significant protective effect against carcinogenesis, and the maximum protective effect was observed with gluconate and lactate forms. Laminin P1 blood level was measured as a tumor marker. Laminin P1 results were compared with the reference group (Group T), fed a standard diet and not NMU instilled. The serum laminin P1 level was significantly higher (p = 0.0001) in NMU-instilled Groups 1, 2, 3, and 4 (0.24 +/- 0.03, 0.93 +/- 1.43, 0.84 +/- 1.33, and 0.41 +/- 0.34 mU/ml respectively) than in the Reference Group T (0.10 +/- 0.05 mU/ml).

A diet moderately enriched in phytosterols lowers plasma cholesterol concentrations in normocholesterolemic humans.

Twelve normolipidic healthy human subjects were fed a diet with or without additional soybean phytosterols for 4 weeks in a crossover design. The order of the treatments was randomized. Phytosterols were added to the diet blended in butter. The dietary ratio cholesterol:phytosterols was 0.7 during the control period (436 mg cholesterol/day and 29 mg phytosterols/day) and 1.88 during the phytosterols period (410 mg cholesterol/day and 740 mg phytosterols/day). Blood cholesterol was 10% lower after subjects consumed the phytosterol-enriched diet than when they consumed the control diet (p < 0.001), which was due to a 15% LDL cholesterol decrease (p < 0.001). The HDL cholesterol:LDL cholesterol ratio was markedly enhanced (+25%) (p < 0.01). These findings suggest that a significant lowering of plasma total and LDL cholesterol can be effected by a modest dietary intake of soybean phytosterols.

Potential teratogenic and neurodevelopmental consequences of coffee and caffeine exposure: a review on human and animal data.

The teratogenic effect of caffeine has been clearly demonstrated in rodents. The sensitivity of different animals species is variable. Malformations have been demonstrated in mice at 50-75 mg/kg of caffeine, whereas the lowest dose usually needed to induce malformations is 80 mg/kg in rats. However, when caffeine is administered in fractioned amounts during the day, 330 mg/kg/day are necessary to reach teratogenicity in rats. In rodents, the most frequently observed malformations are those of the limbs and digits, ectrodactyly, craniofacial malformations (labial and palatal clefts) and delays in ossification of limbs, jaw and sternum. Nevertheless, even in rodents, caffeine can be considered as a weak teratogenic agent, given the quite large quantities of caffeine necessary to induce malformations and the small number of animals affected. In humans, caffeine does not present any teratogenic risk. The increased risk of the most common congenital malformations entailed by moderate consumption of caffeine is very slight. However, caffeine potentiates the teratogenic effect of other substances, such as tobacco, alcohol, and acts synergistically with ergotamine and propranolol to induce materno-fetal vasoconstrictions leading to malformations induced by ischemia. Therefore, even though caffeine does not seem to be harmful to the human fetus when intake is moderate and spread out over the day, some associations, especially with alcohol, tobacco, and vasoconstrictive or anti-migraine medications should be avoided. Maternal consumption of caffeine affects brain composition, especially in case of a low-protein diet and also seems to interfere with zinc fixation in brain. Maternal exposure to caffeine induces also long-term consequences on sleep, locomotion, learning abilities, emotivity, and anxiety in rat offspring, whereas in humans, more studies are needed to ascertain long-term behavioral effects of caffeine ingestion by pregnant mothers.

Caffeine and sports activity: a review.

Potential ergogenic effects of caffeine at the cellular level are mediated by three main mechanisms of action which are: intracellular mobilization of calcium from sarcoplasmic reticulum and increased sensitivity of myofibrilles to calcium; inhibition of phosphodiesterases leading to an increase in cyclic-3',5'-adenosine monophosphate (cAMP) in various tissues including muscle; and the antagonism at the level of adenosine receptors, mainly in the central nervous system. The main mechanism of action of caffeine at the level usually encountered in vivo after the ingestion of a few cups of coffee is undoubtedly linked to the antagonism of caffeine at adenosine receptors. Caffeine also increases production of plasma catecholamines that allow the body to adapt to the stress created by physical exercise. Catecholamine production increases probably, in turn, the availability of free fatty acids as muscle substrates during work, thus allowing glycogen sparing. Caffeine is able to increase muscle contractility, has no ergogenic effect on intense exercise of brief duration, but can improve the time before exhaustion. Caffeine is also able to improve physical performance and endurance during prolonged activity of submaximal intensity. Glycogen sparing resulting from increased rate of lipolysis could contribute to the prolonged time to exhaustion. Finally, tolerance to the methylxanthine should be taken into account when an athlete wants to draw any benefit from caffeine absorption prior to a sports event.

Glycaemic and insulinaemic responses in healthy volunteers upon ingestion of maltitol and hydrogenated glucose syrups.

Glycaemic and insulinaemic index of maltitol and maltitol-containing chocolate have been determined in healthy subjects with reference to glucose and compared with those of sucrose solution and sucrose containing chocolate. All maltitol containing products (solutions and chocolate) show a reduced glycaemic index. Insulinaemic index of maltitol solutions is also low, while that of maltitol chocolate remains high.

Mean daily intake of N-nitrosodimethylamine from foods and beverages in France in 1987-1992.

N-nitrosodimethylamine (NDMA) contamination was determined in 556 food samples and 75 beverages purchased in eastern France in 1987-1992. NDMA was found in 427 samples (68%). Data amassed enabled the first estimation to be made in France of the mean daily intake of NDMA from French foods and beverages in 1987-1992 (0.19 microgram/day). One-third of this daily exposure resulted from the consumption of alcoholic beverages.

Potential genotoxic, mutagenic and antimutagenic effects of coffee: a review.

Coffee and caffeine are mutagenic to bacteria and fungi, and in high concentrations they are also mutagenic to mammalian cells in culture. However, the mutagenic effects of coffee disappear when bacteria or mammalian cells are cultured in the presence of liver extracts which contain detoxifying enzymes. In vivo, coffee and caffeine are devoid of mutagenic effects. Coffee and caffeine are able to interact with many other mutagens and their effects are synergistic with X-rays, ultraviolet light and some chemical agents. Caffeine seems to potentiate rather than to induce chromosomal aberrations and also to transform sublethal damage of mutagenic agents into lethal damage. Conversely, coffee and caffeine are also able to inhibit the mutagenic effects of numerous chemicals. These antimutagenic effects depend on the time of administration of coffee as compared to the acting time of the mutagenic agent. In that case, caffeine seems to be able to restore the normal cycle of mitosis and phosphorylation in irradiated cells. Finally, the potential genotoxic and mutagenic effects of the most important constituents of coffee are reviewed. Mutagenicity of caffeine is mainly attributed to chemically reactive components such as aliphatic dicarbonyls. The latter compounds, formed during the roasting process, are mutagenic to bacteria but less to mammalian cells. Hydrogen peroxide is not very active but seems to considerably enhance mutagenic properties of methylglyoxal. Phenolic compounds are not mutagenic but rather anticarcinogenic. Benzopyrene and mutagens formed during pyrolysis are not mutagenic whereas roasting of coffee beans at high temperature generates mutagenic heterocyclic amines. In conclusion, the mutagenic potential of coffee and caffeine has been demonstrated in lower organisms, but usually at doses several orders of magnitude greater than the estimated lethal dose for caffeine in humans. Therefore, the chances of coffee and caffeine consumption in moderate to normal amounts to induce mutagenic effects in humans are almost nonexistent.

Consequences on the newborn of chronic maternal consumption of coffee during gestation and lactation: a review.

The present review is devoted to effects on the newborn of maternal ingestion of caffeine during gestation and lactation. In rodents, caffeine is able to induce malformations, but usually at high doses never encountered in humans; indeed, when caffeine is administered in fractioned quantities during the day, as it is the case with human caffeine intake, caffeine is no longer a teratogen in rodents. Caffeine ingested during gestation induces a dose-dependent decrease in body weight, but only for large doses (> 7 cups/day of coffee), whereas it has no effect at moderate doses. Maternal caffeine consumption during gestation affects hematologic parameters in both rat and human infants and induces long-term effects on sleep, locomotion, learning abilities, emotivity and anxiety in rodent offspring, whereas in humans, more studies are needed to determine the consequences of early caffeine exposure on behavior. Investigators do not agree on the quantities of the methylxanthine found in breast milk, but caffeine does not change breast milk composition, and rather, stimulates milk production. We conclude in this review that maternal caffeine consumption in moderate amounts during gestation and lactation has no measurable consequences on the fetus and newborn infant. Pregnant mothers, however, should be advised to consume coffee and caffeinated beverages in moderation, especially because of the prolonged half-life of caffeine both during the last trimester of pregnancy and in the newborn infant.

[Effects of coffee and caffeine on fertility, reproduction, lactation, and development. Review of human and animal data]. / Effets du café et de la caféine sur la fertilité, la reproduction, la lactation et le développement. Revue des données humaines et animales.

In the present review, we have examined the effects of coffee ingestion on fertility, reproduction, lactation and development. The potential effects of coffee consumption on fertility, spontaneous abortion and prematurity are not clearly established but appear to be quite limited. In rodents, caffeine can induce malformations but this effect appears in general at doses never encountered in humans. Indeed, as soon as the quantity of caffeine is divided over the day, as is the case for human consumption, the teratogenic effect of caffeine disappears in rodents. Coffee ingested during gestation induces a dose-dependent decrease in birth weight, but usually only when ingested amounts are high (i.e. more than 7 cups/day), whereas coffee has no effect at moderate doses. Caffeine consumption during gestation affects hematologic parameters of the new-born infant or rat. In animals, caffeine induces long-term consequences on sleep, locomotion, learning abilities, emotivity and anxiety, whereas, in children, the effects of early exposure to coffee and caffeine on behavior are not clearly established. The quantities of caffeine found in maternal milk vary with authors, but it appears clearly that caffeine does not change maternal milk composition and has a tendency to stimule milk production. In conclusion to this review, it appears that maternal coffee or caffeine consumption during gestation and/or lactation does not seem to have measurable consequences on the fetus of the newborn, as long as ingested quantities remain moderate. Therefore, pregnant mothers should be advised to limit their coffee and caffeine intake to 300 mg caffeine/day (i.e. 2-3 cups of coffee or 2.5-3 l of coke) especially because of the increase of caffeine half-life during the third trimester of pregnancy and in the neonate.