Customization Of Nutritional

Consumption of nutrients within the standard limit is prerequisite for an individual as both over and under-nutrition is associated with a variety of complications (1). Hence, dietary guidelines have been designed to guide people and to ensure nutritional adequacy (1). This article reviews the role of local RDA guidelines and balanced nutrition in maintaining the overall health of an individual.

Nutrition requirements of an individual vary at every stage of life (2). Young children need more nutrients than those by adults (2). While in special physiological conditions such as pregnancy and lactation, women require extra nutrients to suffice the requirements for growth of the fetus in utero and during early post-natal life (2). Owing to the importance of dietary pattern in human life, Recommended Dietary Allowances (RDA) for essential nutrients have been established (3).

CONCEPT OF LOCALIZED/NATIONAL/REGIONAL DIETARY ALLOWANCES

RDA, based on scientific knowledge, represents the level of essential nutrients to be consumed daily to meet the physiological needs of all healthy persons in a specified group (2). It is derived from the variability in nutrition requirement and bioavailability of nutrients from a given diet using different approaches such as repletion-depletion, factorial and nutrition balance (2,4). Nutrition requirements of an individual vary according to age, gender, and body weight (2). Anthropometric measurements such as body weight and height are determinants of nutrition, health status and growth rate of children whereas, in adults, they reflect potential features of normal growth (2). World Health Organization (WHO) has proposed internationally applicable anthropometric reference standards that form the basis while framing RDA for nutrients (2).

On the contrary, due to poverty and dietary constraints in developing countries, majority of the population fail to achieve anthropometric measurements corresponding to international reference standards (2). Therefore, each country must establish its own reference standards since the anthropometric measurements of its population may be genetically determined (2). These local reference standards should be set up based on the body weight and height of the individuals from a local elite population without any nutritional constraints (2).

REQUIREMENT OF LOCAL RDA GUIDELINES

Despite the presence of international guidelines and standards, there is a need for country-specific local RDA guidelines due to the following reasons (4):

• Specific nutrition requirements due to variability in genetic and socio-demographic characteristics of the population (4).
• Insufficient/ imbalanced intake of nutrients that leads to the malnutrition in the population of region (1).
• Nature of the habitual diet and the dietary factors that affect the bioavailability of the nutrients (4). For example, >95% of Indian diet consists of non-heme food sources that leads to the low iron bioavailability as compared to western countries where >75% diet may be from heme source. Moreover, prevalence of iron-deficiency anemia is higher among Indian children and adolescence (2). Hence, for iron, higher RDA is required for Indian population and lower for western population (4).

Table 1: Difference in RDA for iron (mg/day) in countries (Adapted from ICMR 2011, NIH & Association of UK dietitians) (1,5,6).

• Region-specific dietary diversification and culinary practices (4), for example, cereal-pulse-vegetarian diet is a major source of protein (60%) for the Indian population. These proteins have low quality in terms of indispensable amino acids content and Protein digestibility corrected amino acid score (PDCASS) is less than 1 (7,8). Hence, Indians require a higher RDA for protein compared to western population (4).

Table 2: Difference in RDA for protein (g/day) in countries (Adapted from ICMR 2011, Dietary Reference Intakes 2002/2005) (1,9).

• Variability in deficiencies, lifestyle of the population, and prevalence of diseases in the area (4).
• Food habits such as transition from traditional to modern food, excessive intake of processed and junk food, changing cooking practices also have altered the dietary behavior of the people in the country (1).
• Overconsumption of the energy-dense foods due to its abundance and availability, and preferability among individuals may also increase the risk of malnutrition (1).

Though nutritional needs are similar in a broader sense, RDA should be decided based on the country-specific challenges to achieve the goal of good health among its individuals in the long-term without any side effects (4).

ROLE OF BALANCED NUTRITION IN MAINTAINING THE QOL

Dietary intakes above and below the body requirements can lead to overnutrition or undernutrition respectively (1). Long-term malnutrition is associated with chronic energy deficiency, iron deficiency anemia, iodine-related disorder, hypertension, diabetes, coronary heart disease, and cancer (1). Reportedly, these diseases affect the functional status and productivity that resulted in poor quality of life (QoL) of people (10). Hence, consumption of an adequate amount of nutrients may improve overall QoL via providing protection against chronic disorders (1, 11).

Children: In children, protein helps in catch up growth and development with the lean body mass (12). Evidence suggests that dietary fiber helps to maintain the gastrointestinal function and prevents and treats constipation in children (13). Reportedly, the supplementation with 850 mg/day calcium has been shown to be linked with increased bone mineral density (14). Moreover, omega-3 docosahexaenoic acid (DHA) supplementation may improve cognitive behavior in children (15).

Adults: A multicenter trial conducted on 292 adults demonstrated that dietary instruction with a low-fat vegan diet had improved anxiety, depression, emotional well-being, daily functioning and productivity (16).

Pregnant and Lactating women: Women during pregnancy require an additional 350 calories and an appropriate amount of protein (0.5 g in 1st trimester, 6.9 g in 2nd trimester and 22.7 g in 3rd trimester) for proper nourishment of their child and for their own health (1). Moreover, 1200 mg/d calcium, 35 mg/d iron and 0.5 mg/day folic acid etc. are essential for growth and development of offspring during pregnancy and lactation (1).

Older adults: In elderly population, higher protein intake improves muscles mass, strength and function (17). Reportedly, the supplementation with 400 IU vitamin D and 1000 mg/day calcium have been shown to be associated with a reduction in the incidence of hip fracture (18).

Owing to the food habits, lack of availability of nutrient-rich foods and many other factors, diet alone is not enough to meet the nutritional demands of an individual. Hence, supplementation is essential to fill this nutrients gap (1). However, nutrient-intake should be based on individual requirement and within the RDA set by the dietary guidelines (19).

CONCLUSION

Adequate nutrition is essential to maintain good health from the time of conception to older age (1). However, requirements and intake of different nutrients vary among individuals (2). Hence, RDA has been established to address variable dietary needs of the population (2). Although dietary guidelines help to understand adequate nutritional intake, customization of diet is essential to meet an individual’s nutrient requirements (1, 2).

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