ABSTRACT
There has been recent advocacy for food fortification with zinc in India. However, there are three important conditions that should be established before fortifying food with any micronutrient, which requires that there should be i) Established high prevalence of biochemical or sub-clinical deficiency (?20%), ii) Low dietary intakes that increase the risk of deficiency, and iii) Evidence of efficacy of supplementation from clinical trials. For zinc, all three conditions are not satisfied. The prevalence of low serum zinc concentrations in Indian children is well below 20% (~6%), signifying that zinc deficiency is not a public health problem. There is no risk of dietary zinc inadequacy in Indian populations where intake has been measured. Finally, there is no robust evidence that zinc-fortified foods improve functional outcomes, even if the serum zinc concentration is increased. Thus, contemporary evidence does not justify the need for food fortification with zinc in India.
ABSTRACT
Advances in the medical field and healthcare sector during the last few decades have resulted in increased longevity. Increased lifespans have in turn led to a rapid global rise of the elderly population. However, ensuring the health and quality of life, especially in the context of chronic age-related ailments, among the growing geriatric population is a challenge. Ageing is associated with several changes in body composition including a decline in the lean body mass usually accompanied by an increase in body fat content which have a bearing on the nutrient requirements for the elderly. The nutrient requirements currently recommended for Indian adults are primarily computed using a factorial approach, that considers the cumulative loss of nutrients and is adjusted for optimal body weights and bioavailability. It is logical that physiological and metabolic changes associated with ageing influence several of these factors: body weight, lean mass, energy expenditure, nutrient retention and bioavailability and thus alter nutrient requirements compared to the adult population. Acknowledging these age-related changes, some international organizations have suggested nutrient requirements specific to the elderly. Given the contextual differences in physiology, caution needs to be exercised in adopting these guidelines for the Indian elderly. In addition, in the Indian context, there is sparse information on the diet and nutrient intakes vis-à-vis nutritional status and physiology of the elderly. This status paper highlights some of the pertinent issues related to nutritional requirements for the elderly that advocate a need for deriving nutritional requirements for the elderly in India
ABSTRACT
Background & objectives: Oxytocin (OT) injections to milch cattle for milk letdown have become a common practice amongst dairy farmers in India. Although there is no reported evidence, it is widely presumed that long term consumption of such milk leads to adverse health consequences. However, there is no information on the effect of exogenous OT injections on milk OT content and its stability during heating and gastrointestinal digestion. This study was carried out to determine the OT content in milk samples given by buffaloes with and without OT injections and to assess the stability of OT in the milk. Methods: Milk samples from milch buffaloes (Murrah buffalo) were collected from local farmers with (n=121) or without (n=120) exogenous OT injections during 3 to 5 months of lactation period. The OT content of milk samples was estimated by competitive enzyme immunoassay (EIA). The thermal and digestive stability of OT was assessed by in silico and in vitro digestion methods. Results: The OT content of the milk samples was similar regardless of OT injections used. Further, OT was found to be stable to heat treatment and gastric pepsin digestion while it was rapidly digested during the simulated intestinal digestion. reduced OT was digested by pepsin, implying that internal disulphide bridge of OT rendered the peptide resistant to peptic digestion. On the other hand, phenylmethylsulphonyl fluoride (PMSF), a serine protease inhibitor, abrogated the pancreatin induced digestion of OT. Interpretation & conclusions: These findings suggest that exogenous OT injections do not influence its content in milk. Further, OT present in milk is rapidly degraded during intestinal digestion, ruling out its intestinal absorption and associated adverse health consequences, if any.
ABSTRACT
Iron and zinc interact at the enterocyte during absorption, but the mechanism(s) remain elusive. The aim was, therefore, to understand the mechanism of interaction using kinetic analyses of iron and zinc uptake, individually and in combination under normal and altered cellular mineral concentrations in human intestinal Caco-2 cell line. Striking differences in kinetic parameters were observed between iron and zinc uptake. Iron uptake followed a two-component model, while zinc uptake followed a three-component model. Iron uptake had a Km of 3.6 µM and Vmax of 452 pmol/mg protein/min, while zinc uptake had a Km of 42 µM and Vmax of 3.09 pmol/mg protein/min. Zinc dose-dependently inhibited iron uptake through mixed-inhibition but iron marginally increased zinc uptake. Cellular zinc repletion doubled iron uptake and eliminated inhibition, but zinc depletion decreased iron uptake. Iron pre-treatment had no effect on zinc uptake. Based on these results, a two-transporter model of iron uptake, comprising the apical iron uptake transporter divalent metal ion transporter-1 (DMT-1) and an unknown putative transporter was derived. This model for DMT-1 was verified by immunoblotting. These results implied that cellular zinc status profoundly influenced iron uptake and its interactions with zinc during uptake. DMT-1 might not simultaneously transport iron and zinc, providing a mechanistic basis for observed interactions.