It is now generally accepted that the microbiota of the human gut may influence health and well‐being. Lactic acid bacteria are the most important microorganisms associated with these beneficial effects and the elevated bifidobacterial count may be one of the greatest advantages that breastfed infants have over infants fed with milk formulas. Several studies relative to the selective growth stimulation of bifidobacteria, both in vitro and in vivo, are reported in this review. Over the years, diverse human milk components have been identified as the specific factors able to modulate the growth of bifidobacteria. Even if there is a certain agreement that the bifidogenic activity of human milk may be based not on single growth substances, but on a complex set of interacting factors, the present state of knowledge indicates that the use of non‐digestible but fermentable carbohydrates may be an easy and reliable method to influence the growth of lactic acid bacteria. In this context, some of the characteristics of the major physiological effects of inulin‐type fructans, of galacto‐oligosaccharides, but also of lactoferrin, a milk whey protein fraction with purported bifidogenic activity, are briefly examined.

Milk production is a complex process where nutritional factors interact with structural hormonal and behavioural influences. In recent years important advances have been made in understanding the role of the nutritional status of lactating women on the outcome of breastfeeding. Many questions remain unanswered about the exact requirement of trace elements for lactating mothers. The effect of dietary zinc, copper and iodine supplements on the milk concentration of these micronutrients was studied. The supplementation trial employed a specific balanced nutritional supplement prepared for the nursing mothers. The study was carried out on women living in Ferrara and its surrounding area. The population under study was healthy Italian mothers, of good socioeconomic status, and their normal infants. In total, 32 women were enrolled in the study and 22 completed it. The infants (9F, 13M) were full‐term, healthy singletons and were put to breast within 12 h of birth. All women who finished the study completed a 3 d dietary record. Nutrient analysis revealed the following mean daily dietary trace element intake in the lactating mothers: zinc = 12mg, copper = 1.4 mg and iodine = 145 μg. The zinc and copper dietary intake was in agreement with the daily intake proposed for nursing Italian mothers, while the daily intake of iodine was below the recommended intake of 200 μg. The breastfeeding mothers were placed in 2 groups, with 7 primiparas and 4 multiparas per group: lactating women eating a traditional Italian diet without vitamin and mineral supplements, and lactating women enrolled in the nutrification programme and given a nutritional supplement to their traditional diet. The supplement (PerMamma Abbott) provided 20 mg zinc sulfate, 2 mg copper sulfate and 116 μg potassium iodide. These quantities cover about 60‐90% of the recommended intake for nursing Italian mothers. Samples of 10 ml of milk were collected at 3, 30, 90 d postpartum. Zinc milk concentrations declined significantly over the study period for all lactating subjects, without differences in the rate of decline between the women who started supplementation during lactation and those who did not. Copper did not change during the first month of lactation, then declined at day 90 in supplemented and unsupplemented women, without significant differences between the two groups. An early sharp decline in milk iodine occurred in all lactating subjects, independently of iodine supplementation. After the first month of lactation breast milk iodide levels remained stable in all subjects under study. No significant differences between the two study groups were observed. The lack of correlation between the iodide level in breast milk and maternal dietary intake of iodine is not in agreement with previously published reports. The present results indicate that in healthy, well‐nourished lactating Italian women, whose diet is adequate, the levels of zinc, copper and iodine in milk are not influenced by short‐term supplementary intakes and that the milk levels of the trace elements studied are maintained over different levels of intake. Further research and examination by longitudinal studies are needed to establish the exact relationship between the amount of iodine furnished to the nursing mother and the iodine content of human milk. The role of compensatory homeostatic mechanisms which act during lactation needs further consideration and closer scrutiny.

Low specificity might be due to intrinsic limitations of the standard BHT or to other possible mutations, although no sequence variation was found upon sequencing a 253 bp fragment of the LCT regulatory region in asymptomatic individuals.

No abstract

Adult-type hypolactasia (ATH) is a clinical syndrome of primary lactase deficiency. A lactose-free diet is advisable to avoid the symptoms linked to the condition, but this potentially creates problems for optimal bone mineralization due to reduced calcium intake. To evaluate the effect of the lactose-free diet on the bone mineral status (BMS), we compared the phalangeal BMS of adolescents with ATH to that of peers on a normal diet. Also, we analyzed the correlations between BMS and dietary behavior, physical exercise, and calcium and vitamin D intake. A total of 102 cases and 102 healthy controls filled out a diet record and underwent phalangeal Quantitative Ultrasound (QUS). No difference in BMS was observed. The time spent on lactose-free diet (4.8 ± 3.1 years) was inversely correlated to the BMS. More than 98% of cases consumed lactose-free milk, but calcium and vitamin D intake were significantly lower. Calcium intake was correlated to physical exercise but not to BMS. Our results suggest that a lactose-free diet does not affect the phalangeal BMS of adolescents with primary lactase deficiency when their diet includes lactose-free cow’s milk. However, there is still a significantly lower calcium intake than in the population reference. The inverse correlation observed between the BMS and the time spent on a lactose-free diet suggests that a long-term follow-up is advisable.