Health benefits of milk for children and young adults

The Eatwell Guide1 is a pictorial representation of the UK’s guidelines for a healthy diet, showing the proportions of different types of food required to make up a balanced diet, eaten over a day or week, for those aged 5 years and over. The Eatwell Guide does not apply to children under 2 years, and recommends that children should move towards the proportions of food types shown on The Guide, between the ages of 2-5 years.

Various fresh dairy products on wooden background

The Eatwell Guide1 is divided into four main sections, or food groups: starchy foods, fruit and vegetables, protein foods and dairy/dairy alternatives. There is a small fifth section for fats: oils and spreads. The food groups bring together foods with a similar nutrient profile. Milk is found within the ‘Dairy and Alternatives’ section, which makes up about 8% of the food guide2. Butter and cream do not sit in the dairy section and are found in ‘Fats and Oils’. The guide also contains advice on hydration, with low fat milk being a suggested drink, along with water, tea, coffee and sugar-free drinks.

It is therefore important to be aware that the UK dietary recommendations include dairy foods as part of a balanced diet, with alternatives required if dairy is not eaten.

Main nutrients in milk and dairy foods

NHS Choices3 describes milk and dairy foods as good sources of calcium and protein, a source of vitamin B12 and B2, and the fat in milk provides energy for children, although adults are advised to use lower fat options. If a food group is removed from the diet, the nutrients from that food group need to be replaced from elsewhere. An adequate calcium intake is extremely important in childhood for the formation of healthy bones and teeth and calcium requirements are looked at more closely below.

Calcium

Milk and dairy foods are best known for supplying us with calcium. Calcium is required for healthy teeth and bones, blood clotting and muscle contraction, including the heart muscle. It is important to remember that we build our bone mass through childhood to early adulthood, from mid adulthood we begin to lose bone mass4. Therefore, good calcium (and vitamin D, see below) intake in childhood, along with weight bearing exercise, is essential for life long bone health.

Calcium requirements in childhood

Children (male & female) aged 1-3 years have a requirement for 350mg calcium per day.
4-6 year olds (M & F) require 450mg calcium/day. 7-10 year olds (M & F) require 550mg/day. 11-18 years olds require 800mg/day for females and 1000mg/day for males5. Teenagers have a high requirement due to the rapid growth period experienced at this time.

Are children getting enough calcium?

The National Diet and Nutrition Survey (NDNS)6 state that 12% of boys and 19% of girls, aged 11-18years had calcium intakes below the Lower Reference Nutrient Intake* (LRNI). That is the amount of a nutrient that would be sufficient for only 2.5% of the population, in contrast to the RNI which is sufficient for 97.5%.

No children, aged 1.5-3years had a calcium intake below the (LRNI)6. The nutritional quality of the diet of the adolescent age group is known to be poorer than at any other time in childhood7.

Helping children be calcium sufficient

The 350mg of calcium per day requirement for children aged 1-3years, can be found in around 300ml of milk3. A 200ml glass of milk would supply about 240mgs calcium and would supply just under a quarter of a teenage boys requirement. Concerns about excess milk drinking, generally seen in the preschool age group, are discussed later.

For a balanced diet, calcium should come from a variety of food sources, which will also supply other nutrients to support bone and general health. Calcium is of course, found in other dairy foods such as cheese or yogurt, other food types, particularly: tinned fish with bones or whitebait, dark green vegetables, or fortified foods such as calcium fortified cereals or some milk alternatives4.

The amount of calcium in a food is not equal to the amount that will be available to the body to absorb. Theobald4 discusses the issue of bioavailability, for example a 240gm serving of milk or yogurt and a 42gm serving of cheddar cheese would each supply 300mg calcium with an absorbable amount of 96/97mg of calcium. This would be equivalent to a 320gm serving of broccoli, 151gm serving of calcium fortified tahini or a 1386gm serving of spinach4.

The National Osteoporosis Society (NOS) launched a campaign in April of this year called ‘A message to my younger self’, designed to raise awareness of what we could do to promote bone health in the young. The nutritional part of that campaign included the importance of having a calcium rich diet from dairy and other sources, and cautioned against removing dairy from the diet without a plan to replace the calcium and nutrients from elsewhere8 The NOS has freely accessible, evidence based information on bone health and diet and examples of sources of dietary calcium9, see www.nos.org.uk .

Too much milk?

High intakes of calcium have been associated with the inhibition of absorption of other minerals such as magnesium, copper, zinc and haem and non-haem iron4. The Scientific Advisory Committee on Nutrition10 states that the mechanism for this effect is unknown, but maybe due to iron and calcium sharing an absorption pathway. Theobald4 discusses that whilst in single meal studies, calcium inhibits haem and non-haem iron uptake by 50-60%, iron absorption does not appear to be impaired in the longer term. SACN (2000) reviewed various studies looking at the inhibitory effect of calcium (dietary and supplemental) on iron absorption and interested readers should refer to that document for a critique of current evidence. SACN (2000) recommendations (for iron) includes that public health advice should focus on the importance of a balanced diet, including a variety of foods which contain iron, rather than trying to focus on particular enhancers or inhibitors.

However, the association between increased milk consumption and anaemia in pre school children cannot be ignored. For example, in a Canadian child feeding practices study by Parkin et al (2016)11 two samples of children, aged 12-36months, were compared, one group with severe anaemia (hb<80g/l) and one group with iron sufficiency (mean Hb 122.4g/l). The anaemic group were found to be subjected to three feeding practices, associated with their iron deficiency anaemia, these were: cow’s milk consumption greater than 500ml/d, daytime bottle use beyond 12 months of age and bottle use in bed.

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