SACN Dietary Reference Values for Energy
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In 1991, the Committee on the Medical Aspects of Food Policy (COMA) provided estimates of energy requirements for the UK population in their report Dietary Reference Values for Food Energy and Nutrients for the United Kingdom. The dietary reference values (DRVs) for energy were based on estimating the total energy expenditure (TEE) for groups of people. TEE provides a measure of the energy requirement at energy balance i.e. when energy intake matches energy expenditure. In this way, an energy requirement can be predicted as the rate of TEE plus any additional needs for growth, pregnancy and lactation.
Since the publication of the report in 1991, the methodology to measure TEE – the doubly labelled water (DLW) method – has advanced and as a result, the evidence base on TEE in a wide variety of population groups has expanded considerably. In addition, the Food and Agriculture Organization of the United Nations, World Health Organization, and United Nations University (FAO/WHO/UNU) and Institute of Medicine (IoM) have updated their recommendations on energy requirements. With the high levels of overweight and obesity currently seen in the UK and the wealth of new data now available, it was considered timely for the Scientific Advisory Committee on Nutrition (SACN) to review recommendations for the UK population. The present report details the evidence and approaches SACN have considered in order to update the DRVs for energy.
SACN noted that in populations like the UK, with a high and increasing proportion of overweight and obese individuals, if energy requirements are estimated at current levels of energy expenditure and body weights, many groups in the population would continue to carry excess weight. This is not desirable since excess body weight is associated with long-term poor health and increased mortality. To address this issue SACN chose a prescriptive approach to estimating energy reference values; that is, suitable reference body weight ranges consistent with long-term good health were used to calculate energy reference values. Thus, basal metabolic rate (BMR) values were predicted using healthy reference body weights.
For the purposes of calculation, this equates to the 50th centile of UK-WHO growth standards for infants and pre-school children, the 50th centile of UK 1990 reference for school-aged children and for adults at a Body Mass Index (BMI) of 22.5 kg/m2 at the current height of the UK adult population. Using this approach, if overweight groups consume the amount of energy recommended for healthy weight groups, they are likely to lose weight, whereas underweight sections of the population should gain weight towards the healthy body weight range. This approach represents a significant departure from the method used by COMA.
SACN has derived new energy reference values. For most population groups, except for infants and young children, the values have increased. This change reflects the more accurate methods used to assess energy expenditure; the evidence base available to COMA was more limited and as a result energy requirements were underestimated for some age groups. It is important to note that DRVs should be used to assess the energy requirements for large groups of people and populations, but should not be applied to individuals due to the large variation in physical activity and energy expenditure observed between people. Despite SACN’s best efforts to base their recommendations on the most up to date evidence, it should be noted that there is less DLW data available for infants, younger adults (18-30 years) and those aged 80 years. The Committee hopes that this will be addressed in the future.
Summaries and summary tables
Summaries and summary tables can be found on the following pages of the report:
Energy reference values for infants aged 1-12 months – table 14 on page 83
Energy reference values for children aged 1-18 years – table 15 on page 84
Energy reference values for adults – table 16 on page 85
Energy reference values during pregnancy and lactation – See paragraphs S48-S51 on pages 22-23
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