Milk-and-Dairy-Products-in-Human-Nutrition-FAO

Chapter 4 – Milk and dairy products as part of the diet 111
Milk can make a significant contribution to the required nutrient intakes for
calcium, magnesium, selenium, riboflavin, vitamin B 12 and pantothenic acid (see
Table 4.1). Food of animal origin, including milk and dairy products, can be an
important source of zinc and vitamin B 12 in children at risk for micronutrient
deficiencies (Neumann, Harris and Rogers, 2002). Milk is low in sodium. Bioavailability
of some nutrients in milk, for example calcium, is high compared with that
in other foods in the diet (Weaver, Proulx and Heaney, 1999). Milk does not contain
substances that inhibit mineral bioavailability, such as phytates and oxalates. When
milk is consumed together with foods containing inhibitors, calcium absorption is
decreased slightly by oxalates but little affected by phytates (Weaver, Proulx and
Heaney, 1999). In addition, milk is thought to contain constituents that enhance
mineral absorption, such as lactose and certain amino acids, but absorption of minerals
from cow milk has not been demonstrated to be greater than that from mineral
salts (Weaver and Heaney, 2006).
Cow milk does not contain appreciable amounts of iron (Dror and Allen, 2011).
Consumption of fresh, unheated cow milk by infants prior to 12 months of age is
associated with faecal blood loss and lower iron status (Ziegler et al., 1990; Griffin
and Abrams, 2001). There is evidence that high intakes of calcium interferes with
iron absorption, although inhibition of iron has been reported only in single-meal
studies (Dror and Allen, 2011); over longer periods of time adaptive mechanisms
may negate the single-meal effect (Minihane and Fairweather-Tate, 1998). Compared
with breast milk, cow milk also presents a high renal solute load to infants,
owing to its higher contents of minerals and protein. International guidelines and
most national policies recommend exclusive breastfeeding up to six months of age:
according to WHO guidelines, no undiluted cow milk should be given to infants
up to 12 months of age unless accompanied by iron supplements or iron-fortified
foods, although dairy products such as cheese and yoghurt may be fed to infants
more than six months old (WHO, 2003; WHO, 2004).
Constituents in milk that are not identified as essential nutrients but that are now
being studied for their health-promoting properties are discussed in Chapter 5.
4.3 Dietary dairy in growth and development
Nutrition and health in the first two to three years of life are important for growth
and development of children, with most growth faltering occurring during this
time (Grillenberger et al., 2006). However, “catch-up growth” remains possible
in school-aged children and even adolescents when factors that impair growth are
eliminated (Grillenberger et al., 2006). Stunting is associated with increased child
morbidity and impaired cognitive development (Hoppe, Mølgaard and Michaelsen,
2006). Stunting, along with low birth weight, is also a risk factor for chronic disease
in adulthood (Popkin, Horton and Kim, 2001). Therefore, greater growth is associated
with better child health and development. Taller adult stature has been associated
with reduced risk of cardiovascular disease (Hoppe, Mølgaard and Michaelsen,
2006). However, taller adult stature is not always associated with better health.
For example, the WCRF panel concluded that there is convincing evidence that
the factors that lead to greater adult attained height, or its consequences, increase
the risk of cancers of the colorectum and breast (postmenopause), and probably
also increase the risk of cancers of the pancreas, breast (premenopause) and ovary