Nutrition Module 3: Nutritional value of the weaning diet

23 September 2018

Which nutrients are important to support an infant’s optimal growth?

Carrie Ruxton PhD, registered dietician

Supported by Petit Filous

A child’s early years are a time of rapid growth and development. An infant’s brain is one-third of the size of an adult's at birth, but grows to half the size of an adult's within three months.[1] As growth charts show[2], most infants will double their birthweight by the age of six months and increase it by 2.5 to 3 times by 12 months.

During this time, an infant’s body will require sufficient energy, protein, vitamins, minerals and fatty acids to support optimal growth; it is therefore clear that the nutritional composition of the weaning diet is of huge importance. Which dietary nutrients do you think are important to growth and development? See Table 1 – are you correct?

Table 1: Key nutrients for weaning

Role in the body is based on European Health Claims authorised either for children or adults. They can be considered as important nutrients for infants as well. 

Nutrient Role in the body Dietary sources Practical advice
Protein Normal growth and development of bone in children[3] Meat, fish, dairy foods, poultry, eggs, beans, pulses  There’s no need to delay introduction of these foods if weaning starts at around six months.[4] Do not offer raw shellfish or fish with high mercury levels such as swordfish[5]
Fibre Increased faecal bulk and acceleration of intestinal transit[3] Fruit, vegetables, wholegrain cereals Fibre targets were only set for age two years (15g/day)[6] but some fibre can be provided earlier from fruit and vegetables
Fats Provide energy; essential fatty acids are needed for normal growth and development of children[3] Meat, oily fish, dairy foods, cooking oil A mix of fats should be offered with no restrictions on amounts until two years of age[7]
Calcium Normal growth and development of bone in children[3] Dairy foods, green leafy vegetables 90% of our lifetime bone mass is set by the age of 18 for females and 20 for males[8], so it’s important to ensure that children consume the recommended amount of calcium each day. One to two portions of dairy foods can be offered daily plus usual drink (breast or breastmilk substitute). Cow’s milk is not suitable as a drink until 12 months as it is too low in iron[9]
Iron An important factor in making red blood cells, which carry oxygen around the body[10] Red meat, fortified cereals, green leafy vegetables, beans and pulses 10% of Caucasian, and around 30% of black and Asian children consume too little iron[8] and should be encouraged to obtain more iron in the diet
Zinc Helps the maintenance of normal bones[11] Fish, poultry, meat, cheese, beans Zinc absorption is lower from plant foods compared with meat and fish[12] so the latter are better dietary sources
Magnesium  Maintains bone health[3] Dark green leafy vegetables, fish, beans, whole grains, bananas Around 10% of young children consume too little magnesium[19] so dietary sources should be encouraged
Vitamin A Helps immune system work properly, helps vision and keeps skin healthy[3] Cheese, yellow and orange vegetables Children under the age of five years should take a daily supplement of vitamins A, C and D[13] 
Vitamin C Maintains healthy skin and bones[3] Fruit (especially citrus) and vegetables Children under the age of five years should take a daily supplement of vitamins A, C and D[10]
Vitamin D Important for normal development of bones, teeth and muscles, and is proven to support normal immune function[3] Oily fish, eggs Children under the age of five years should take a daily supplement of vitamins A, C and D[10]


Fruit and vegetables

As well as these nutrients, it is important to promote regular consumption of fruit and vegetables.

Only 36% of UK parents wean predominantly with vegetables during the first two weeks[14] but research suggests that repeated exposure to vegetables, offering a wide variety of vegetables and introducing vegetables as first foods during complementary breastfeeding can increase acceptance of a vegetable-rich diet in early life and in later childhood.[15] This in turn may shape children’s long-term food preferences as adults.

While the five-a-day target does not apply to very young children, fruit and vegetables can be offered with every meal and as a snack. Portion sizes should be adapted so that they represent the size of the child’s fist rather than the 80g standard size for older children.

Getting portion sizes right

Parents may be concerned that their infants are not taking in enough nutrition, while health professionals are mindful that overfeeding could lead to obesity. Indeed, around a quarter of children are overweight or obese by the time they attend school.[16] Studies show that infants and young children are able to self-regulate their food intake better than adults[17] so caregivers should respond to hunger and satiety cues and portion sizes should reflect what infants and toddlers are willing to eat rather than what parents expect. In addition, there is no need to encourage very young children to clear the plate.

Offering a variety of foods ensures that protein, vitamin and mineral needs are met.

What do infants and young children really eat?

In 2013, the Department of Health and the Food Standards Agency published a nationally representative survey of 2683 children aged four to 18 months, called the Diet and Nutrition Survey of Infants and Young Children (DNSIYC).[18] Key points were:

  • Supplement use was very low despite official advice to supplement all children under the age of five years with vitamins A, C and D.[10] Only 10% of infants aged 12 to 18 months were given a supplement, mostly multivitamins.
  • Energy (calorie) intakes were around 75% of recommendations but growth rates were generally normal.
  • Most infants and toddlers met targets for vitamins and minerals in the diet with around 8% having intakes below the Lower Reference Nutrient Intake (LRNI), which indicates a risk of deficiency. However, this figure was higher for iron (10% to 14% below LRNI) and magnesium (10% below). Infants from lower socioeconomic groups were more likely to have iron intakes below LRNI compared with infants from higher socioeconomic groups (17% versus 8%).
  • Blood sampling showed that 3% of infants and young children were anaemic while a third had low iron stores. Vitamin D status was normal for around 90% of infants and toddlers but this was heavily dependent on fortified milks as surveys in one to three year olds[19] show that average vitamin D intakes are just 2mcg daily. The new recommendation is 10mcg.[20]

Nutrients of concern

As the DNSIYC shows, infants may not be achieving optimal intakes for vitamin D, magnesium and iron.

Vitamin D is an important nutrient to be considered for infants and children. There are two authorised health claims for children specifically on vitamin D (and calcium) in relation to bone health and normal growth and development and another one in relation to the normal function of the immune system.[21],[22]. Vitamin D is particularly important for children as they are growing and developing. Public Health England (PHE) has advised that during the summer months (April to September) skin synthesis and a healthy balanced diet will ensure enough vitamin D for most people; however, dietary sources are particularly important when the amount of sunlight is reduced e.g. autumn/ winter months, or when sunlight containing UVB light is restricted because of lack of time spent outdoors, for example, or little skin exposure.[23]

While the best natural source of vitamin D is oily fish, few infants and children eat this, resulting in a greater role for fortified foods such as fromage frais and yogurt. From six months, infants and young children can be offered a mild oily fish, such as salmon, once a week. Eggs, another natural source, can be given several times a week while fortified dairy foods can be given once or twice daily. In addition, children under five years should receive a daily vitamin D supplement of 8.5mcg to 10mcg as long as they are consuming less than 500ml of breastmilk substitute a day. Click here to learn more about why the vitamin D status of young children needs to be improved.

Magnesium is another important nutrient for infants. Boost infant and young children’s intakes of dark green leafy vegetables, such as cabbage, kale or spinach, provide fish twice a week, offer beans on toast as a light supper and provide snacks such as slices of avocado or dried fruit. Infants aged seven to 12 months need 75mg to 80mg of magnesium daily, while children aged one to three years need 85mg[8]. 

Iron is an essential component of haemoglobin and contributes to normal cognitive development of children[24]. Iron deficiency is also the most common single nutrient disorder in the world[25]. The type of iron found in red meat – haem iron – is most easily absorbed by the body, while the non-haem iron found in plant foods and iron supplements is less well absorbed[26]. Red meat includes pork, beef, lamb and game. A small portion (around 30g to 50g) can be offered several times a week with plenty of vegetables. For vegetarian families, iron can be found in beans, lentils, green vegetables, dried fruit and fortified foods, for example breakfast cereals. Infants aged seven to 12 months need 7.8mg iron daily, while children aged one to three years need 6.9mg.[8]


Infants and young children should be offered a nutrient-rich diet to support optimal growth and development. The weaning period is a crucial time when nutrient-rich breast or breastmilk substitute is replaced by a wide variety of foods. In addition, foods that children are exposed to in this period can set their long-term preferences for a healthy adult diet. Parents need to ensure that young children can access a range of healthy options, rich in protein, vitamins and minerals, and avoid sugary, salty ‘treat’ food and drink such as biscuits, cakes, crisps, fizzy drinks and confectionery. Care should be taken to promote vitamin D, iron and magnesium as these may be lacking in the diets of some infants.

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1. Holland D et al. (2014) Structural growth trajectories and rates of change in the first three months of infant brain development. JAMA Neurol 71:1266-74.

2. Royal College of Paediatrics and Child Health. (2016) Early years – UK-WHO growth charts and resources. See: (accessed 9 August 2017).

3. European Commission (2016) EU Register of Health Claims  

4. NHS Choices. (2015) Your baby’s first solid foods. See: (accessed 9 August 2017).

5. NHS Choices. (2017) Foods to avoid giving your baby. See: (accessed 9 August 2017).

6. Scientific Advisory Committee on Nutrition. (2015) Carbohydrates and health. (accessed 9 August 2017).

7. Committee on Medical Aspects of Food Policy. (1991) Dietary reference values. HMSO: London.

8. National Institute of Arthritis and Musculoskeletal and Skin Diseases. (2015) Kids and their bones: a guide for parents. See: (accessed 9 August 2017).

9. NHS Choices. (2017) Milk and dairy in your diet. See: (accessed 9 August 2017).

10. UCSF Medical Centre. Hemoglobin and Functions of Iron. See:

11. Lansdown AB (2007). Zinc in wound healing: theoretical, experimental, and clinical aspects. Wound Repair Regen. 2007 Jan-Feb;15(1):2-16.

12. Hunt JR. (2003) Bioavailability of iron, zinc, and other trace minerals from vegetarian diets. Am J Clin Nutr 78: 633S-9  

13. NHS Choices. (2015) Vitamins for children. See: (accessed 9 August 2017).

14. YouGov Results/‘Veg for Victory’, 28 April 2016  

15. Harris G, Coulthard C. (2016) Early eating behaviours and food acceptance revisited: breastfeeding and introduction of complementary foods as predictive of food acceptance. Curr Obes Rep 5: 113-20.  

16. Baker C, Bate A. (2016) Obesity statistics, briefing number 3336. House of Commons Library: London  

17. Savage JS, Fisher JO, Birch LL. (2007) Parental influences on eating behavior: conception to adolescence. J Law Med Ethics 35(1): 22-34.

18. Lennox A, Somerville J, Ong K, Henderson H, Allen R (Eds.). (2013) Diet and nutrition survey of infants and young children, 2011. See: (accessed 9 August 2017).

19. Bates B, Lennox A, Prentice A, Bates C, Page P, Nicholson S, Swan G (Eds.). (2014) National diet and nutrition survey, rolling programme years 1-4. See: (accessed 9 August 2017).

20. Scientific Advisory Committee on Nutrition (2016). Vitamin D and health. See: (accessed 9 August 2017).

21. Vitamin D is needed for normal growth and development of bone in children. Commission Regulation (EC) 983/2009 of 21/10/2009

22. Vitamin D contributes to the normal function of the immune system in children. Commission Regulation (EU) 2016/1389 of 17/08/2016  

23. Public Health England. PHE publishes new advice on vitamin D. 2016.  

24. the authorisation and refusal of authorisation of certain health claims made on foods and referring to the reduction of disease risk and to children’s development and health. Commission regulation (EU) no 957/2010 of 22 October 2010

25. Lozoff B, Beard J, Connor J, Felt B, Georgieff M, Schallert T. (2006) Long-lasting neural and behavioral effects of iron deficiency in infancy. Nutr Rev 64(5): S34-91.  

26. Scientific Advisory Committee on Nutrition. (2010) Iron and health. See: (accessed 9 August 2017).