Navita Bansal1, Prachi Tyagi1, Vinutha T.1, Ramesh S.V 2*, Shelly Praveen1*
1. Division of Biochemistry, ICAR-Indian Agricultural Research Institute, New Delhi 110012
2. Division of Physiology, Biochemistry and PHT, ICAR-Central Plantation Crops
Research Institute, Kasaragod, Kerala 671 124
*(Author for correspondence: shellypraveen@hotmail.com)
Summary
Nutrition is a vital determinant of the metabolism which in turn influences the life-span of an individual. In this article we summarize and discuss the effects of nutrition on metabolic age and its repercussions on various aspects such as early puberty, mid-life crisis and late-life hurdles.
Various ages of human
Every individual has three different ages: (a) Chronological age, which is a commonly known measure of an individual’s age based on the calendar date of birth but virtually has little information about the status of individual’s health. (b) Phenotypic or biological age is the age at which your body functions and is quite distinct from the chronological age because it is based on how old a body is according to different biomarkers (1). (c) Metabolic age which has direct relation to the phenotypic age and focuses on the physical health of an individual, and is estimated on the basis of basal metabolic rate (BMR). In medical parlance, the term metabolic age is preferred as it aptly describes the health of an individual and the underlying reasons for any ill-health. Ideally an individual should have same or lower metabolic age compared to his/her chronological age. Aging is an inevitable process which occurs at different levels, either cellular, biochemical or at organelle level. Aging affects DNA, proteins, chromosomes, cells and ultimately it is manifested as an end of an individual’s life. Several factors such as stem cell exhaustion, altered cellular communication, cell senescence, genome instability, telomere degradation, etc. are known to be involved in this continuous process (Fig. 1). Interestingly, nutrition is an important aspect that affects the age of an individual as it drives all the metabolic pathways.
Metabolic rate
Basal metabolic rate (BMR) is the amount of energy consumed in Kilojoules that is required for the normal functioning of the body while resting and it constitutes the major portion of daily total energy (50-80%) requirement of our body. BMR depends on the fat-free mass, fat mass, age, and circulating thyroxine (Johnstone et al., 2005) (2) while metabolic rate (MR) represents the number of calories needed to fuel ventilation, blood circulation, and temperature regulation. The decrease in MR with age is due to the enormous fall in energy expenditure over years and loss of muscles. Metabolic rate is affected by a number of factors including the age, gender, muscle-to-fat ratio, physical activity and hormonal function. Considering the science behind the fat mass and obesity and its impact on health one can focus on the pattern of nutrition to improve the metabolic age. Nonetheless, to account for modern life style pattern, Mifflin and St Jeor in 1990 formulated a new equation to calculate BMR.
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