Informatics Publishing Limited

Rebecca Kuriyan ¹, P. Parvathi Easwaran ², Anura V. Kurpad ¹

Affiliations
1 Division of Nutrition, Institute of Population Health and Clinical Research, St. John's National Academy of Health Sciences, Sarjapur Road, Bangalore - 560034, IN
2 Department of Food Service Management and Dietetics, Avinashilingam University, Coimbatore - 641 043, IN

Abstract

The FAO/WHO/UNU Expert Consultation on Energy and Protein Requirements adopted the Basal Metabolic Rate (BMR) as the basis of expressing energy requirements. The BMR is the amount of energy used for a series of functions that are essential for life. It is measured under standard conditions that include being awake in the supine position after 10 to 12 hours of fasting and eight hours of physical rest, and being in a state of mental relaxation in an ambient environmental temperature that does not elicit heat-generating or heat-dissipating processes.

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Sulagna Bandyopadhyay ¹, Rebecca Kuriyan ¹, Anura V. Kurpad ¹

Affiliations
1 Division of Nutrition, St. John’s Research Institute, St. John’s Academy of Health Sciences, A Recognized Research Centre of University of Mysore, Bengaluru, IN

Abstract

The recent Food and Agricultural Organization / World Health Organization United Nations University expert consultations on protein quality have emphasized the need for protein digestibility measurements in humans. The standard in vivo oro-ileal protein digestibility measurements are invasive, expensive, time-consuming and burdensome on participants. The in vitro multi-enzyme based assays have been a promising tool for rapid, non-invasive and cost-effective protein digestibility measurements in foods. The digestibility estimates obtained from these methods have not been compared with true ileal digestibility measurements in humans. This study measured in vitro protein digestibility in selected commonly consumed plant and animal proteins, assessed the effect of heat-treatment on protein digestibility and compared the digestibility estimates with previously published human true ileal protein digestibility values. The in vitro protein digestibility in the raw plant proteins ranged from 35% in pigeon pea to 72% in rice. Cooking improved digestibility by 8% in potato to 26% in pigeon pea. The in vitro protein digestibility in freeze dried and spray dried milk powder were €85% which reduced to 73% after heat-treatment at 120°C for 40 minutes. The mean difference between the in vitro protein digestibility coefficients and the true ileal protein digestibility estimates was 4.3% (95% CI:-1.05, 9.74%). Although, the in vitro assays can be used as useful tools to predict ileal digestibility in humans, and to rank food proteins according to their digestibility, further studies are warranted for inter-laboratory validation of assays with appropriate evaluation on same protein sources against true ileal digestibility measured in humans.

Keywords

In vitro Protein Digestibility, Protein Quality, Plant Protein, Legume, Rice, Milk, Heat-Treatment, True Ileal Protein Digestibility.

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Srishti Sinha ¹, Rebecca Kuriyan ¹

Affiliations
1 Division of Nutrition, St. John's Research Institute, Bengaluru, Karnataka - 560 034, IN

Abstract

Indian adults tend to inappropriately accumulate body fat even at low Body Mass Index (BMI). Usually, fat that is stored in the fed state is mobilized for energy during nocturnal fasting, thus achieving daily fat balance. This is called metabolic flexibility, which may be lost in some individuals leading to body fat accumulation. Measuring fat balance requires 24h measurement of fat oxidation, but nocturnal fat oxidation could be a reasonable surrogate. The variability of nocturnal fat oxidation is also unknown. A retrospective analysis on 24h fat oxidation in adult men (n=18) was carried out to test the former hypothesis, while the variability of nocturnal fat oxidation was measured prospectively in 5 adult men, who were fed the same diet for 2 days prior to the measurement. Whole-body indirect calorimetry was used for measuring Respiratory Quotient (RQ), energy expenditure and fat oxidation. In 24h analyses, nocturnal (0.44 ± 0.21 g/kg) was significantly higher than diurnal fat oxidation (0.24 ± 0.21 g/kg) and was 64.5% of the total 24h value. Nocturnal fat oxidation was positively correlated with 24h fat oxidation (r = 0.937; p<0.01) and inversely correlated with 24h fat balance (r = -0.850; p<0.01). Metabolic flexibility, measured as the Fed: Fasted RQ ratio, was negatively correlated with BMI (r = -0.226; p=0.366). The intra- and inter-individual variability of 12h nocturnal fat oxidation was low, at 4.7% and 7.2%, respectively. Nocturnal fat oxidation has a low variability when prior diets over 2 days are constant and the Fed: Fasted RQ ratio is an index of metabolic flexibility, which relates to BMI in young adults.

Keywords

Nocturnal fat oxidation, metabolic flexibility, indirect calorimetry, Indian adults

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