Factors affecting requirements
e.g. the RNI for vitamin C for a child aged 1 year and under is 25mg/d, and for an adult is 40mg/d
e.g. the RNI for iron in women aged 19-50 years is 14.8mg/d, which is higher than for men (8.7 mg/d) to cover menstrual losses
e.g. adolescents have higher calcium requirements to cover their bone growth
• Pregnancy and Lactation
e.g. The RNI for vitamin D in women that are pregnant or breastfeeding is 10 μg/d, whereas there is no RNI set for women of childbearing age who are not pregnant or breastfeeding.
|Infants||First 4-6 months of life (period of rapid growth and development) breast milk (or infant formula) contains all the nutrients required.
Between 6-12 months – requirements for iron, protein, thiamin, niacin, vitamin B6, vitamin B12, magnesium, zinc, sodium and chloride increase.
Department of Health advice recommends exclusive breastfeeding until 6 months of age with weaning introduced at 6 months.
|1-3 years||Energy requirements increase (children are active and growing rapidly). Protein requirements increase slightly. Vitamins requirements increase (except vitamin D). Mineral requirements decrease for calcium, phosphorus and iron and
increase for the remaining minerals (except for Zinc).
|4-6 years||Requirements for energy, protein, all the vitamins and minerals increase except C and D and iron.|
|7-10 years||Requirements for energy, protein, all vitamins and minerals increase except thiamin, vitamin C and A.|
|11-14 years||Requirements for energy continue to increase and protein requirements increase by approximately 50%.
By the age of 11, the vitamin and mineral requirements for boys and girls start to differ.
Boys: increased requirement for all the vitamins and minerals.
Girls: no change in the requirement for thiamin, niacin, vitamin B6, but there is an increased requirement for all the minerals. Girls have a much higher iron requirement than boys (once menstruation starts).
|15-18 years||Boys: requirements for energy and protein continue to increase as do the requirements for a number of vitamins and minerals (thiamin, riboflavin, niacin, vitamins B6, B12, C and A, magnesium,
potassium, zinc, copper, selenium and iodine). Calcium requirements remain high as skeletal development is rapid.Girls: requirements for energy, protein, thiamin, niacin, vitamins B6, B12 and C, phosphorus, magnesium, potassium, copper, selenium and iodine all increase.Boys and girls have the same requirement for vitamin B12, folate, vitamin C, magnesium, sodium, potassium, chloride and copper. Girls have a higher requirement than boys for iron (due to menstrual losses) but a lower requirement
for zinc and calcium.
|19-50 years||Requirements for energy, calcium and phosphorus are lower for both men and women than adolescents and a reduced requirement in women for magnesium, and in men for iron. The requirements for protein and most of the vitamins and minerals
remain virtually unchanged in comparison to adolescents (except for selenium in men which increases slightly).
|Pregnancy||Increased requirements for some nutrients. Women intending to become pregnant and for the first 12 weeks of pregnancy are advised to take supplements of folic acid. Additional energy and thiamin are required only during the last three
months of pregnancy. Mineral requirements do not increase.
|Lactation||Increased requirement for energy, protein, all the vitamins (except B6), calcium, phosphorus, magnesium, zinc, copper and selenium.|
|50+ years||Energy requirements decrease gradually after the age of 50 in women and age 60 in men as people typically become less active and the basal metabolic rate is reduced. Protein requirements decrease for men but continue to increase
slightly in women. The requirements for vitamins and minerals remain virtually unchanged for both men and women.After the menopause, women’s requirement for iron is reduced to the same level as that for men.After the age of 65 there is a reduction in energy needs but vitamins and minerals requirements remain unchanged. This means that the nutrient density of the diet is even more important.