What is a Dietary Reference Value?
The European Food Safety Authority defines a Dietary Reference Value (DRV) as “an umbrella term for a set of nutrient reference values”. In the UK the reference values that make up DRVs are:
- Reference Nutrient Intakes (RNIs)
- Estimated Average Requirements (EARs)
- Lower Reference Nutrient Intakes (LRNIs)
- Safe Intake (SI)
What is a Reference Nutrient Intake?
The RNI is the amount of a nutrient that is enough to meet the needs of 97.5% of the population and can be calculated by EAR + 2 SD.
What is an Estimated Average Requirement?
The EAR is the average amount of a nutrient or energy required by half of the population, i.e. 50% of people will need more and 50% will need less of the nutrient/energy.
What is a Lower Reference Nutrient Intake?
The LRNI is the amount of a nutrient that meets the needs of 2.5% of the population, i.e. the majority of people will need more and can be calculated by EAR – 2 SD
What is Safe Intake?
The SI is likely to meet the needs of the majority of the population without adverse effects due to excess intake and is used when no EAR, RNI or LRNI exist.
(image taken from British Nutrition Foundation)
What is the purpose of Dietary Reference Values?
The purpose of DRVs is to provide a guide, with scientific basis, on the amount of nutrients needed to maintain health in a healthy population. As such DRVs can be used by nutrition and healthcare professionals when assessing diets, researchers looking at trends in population health, policy makers looking to recommend nutrient intake values for example on food labelling, as well as food manufacturers for product reformulation. However, it’s important to note that DRVs consider health at a population level rather than at the individual level and are intended for healthy people. For individual nutrient recommendations or for those who have a condition/disease, health professionals should provide guidance on specific needs.
Why do we need Dietary Reference Values?
A healthy, balanced diet is achieved by eating a wide variety of foods in appropriate proportions to provide a diet adequate in the nutrients required to maintain health and wellbeing. Each nutrient is required for a particular function in the body and therefore certain amounts of these nutrients are needed to perform these functions adequately. However, the required amounts vary depending on different factors including age, gender, genetics, physical activity and life stage e.g. pregnancy.
What is a Reference Intake on food labels?
Reference Intakes (RIs) are used on food package labelling to help consumers understand how the food item or portion contributes to their daily nutrient intake. However, there is only one set of RIs meaning they do not vary depending on age or gender, instead they are based on an average-sized women, doing an average amount of physical activity. In recent years a traffic light system has been developed for food packaging to help consumers identify high, medium and low sources of some nutrients.
|Energy or nutrient||Reference Intake||Classed as ‘high’||Classed as ‘low’|
|Fat (g)||70||More than 17.5g per 100g||3g or less per 100g|
|of which is saturates (g)||20||More than 5g per 100g||1.5g or less per 100g|
|of which is sugars (g)||90||More than 22.5g per 100g||5g or less per 100g|
|Salt (g)||6||More than 1.5g per 100g||0.3g or less per 100g|
Why nutrient requirements change across the life course
Throughout an individual’s life, their body goes through changes which in turn means their nutritional requirements to perform normal functions for optimal health also change.
At the beginning of a child’s life, there is a period of rapid growth and development. Mothers are encouraged to breastfeed infants for the first 6 months to help protect the baby from infection and disease and to provide the nutrients required by the baby. Requirements for nutrients including protein, magnesium, iodine and zinc increase after 6 months to promote growth and development. For example at 10-12 months, protein is increased to 14.9 g/day from 13.7 g/day.
This is another rapid growth period during the life course, hence energy requirements increase, as do calcium requirements for bone growth and development. Requirements for calcium are at their highest at the ages of 11-18 years at 1000 mg/day for males and 800 mg/day for females.
Iron requirements in adolescent females also increase to 14.8 mg/day as they begin menstruating to reduce the risk of iron deficiency anaemia, this requirement continues until 50 years of age.
Pregnancy and lactation
Pregnancy and lactation are also periods where additional nutrient requirements need to be met. For example, 400µg Folic acid supplementation is advised for women intending to become pregnant to help reduce the risk of neural tube defects. Higher energy requirements (an additional 200 kcal/day) is also required to promote growth in the final trimester and females who are breastfeeding require an additional 550 mg/day of calcium.
Nutrient Reference Values used by myfood24
The myfood24 healthcare system uses nutrient reference values to help both healthcare professionals and their patients understand more about their nutritional intake and to help them make healthier choices. By default, reference values are set according to age and gender based on those defined in Public Health England’s Government Dietary Recommendations. However, healthcare professionals can tailor these values to create personalised nutrient targets depending on clinical need.
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