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

Chapter 4 – Milk and dairy products as part of the diet 153
introduction to this chapter. In addition, substitution of one type of fat for another
or reducing total fat intake invariably results in a range of food substitutions such
that intake of other macro- and micronutrients is altered (Skeaff and Miller, 2009).
Furthermore, many efforts to modify dietary intake of fat have included efforts
to change one or more other elements of dietary and non-dietary behaviour, e.g.
increasing fibre intake, fruit and vegetable consumption or physical activity, or
reducing meat consumption, body weight, smoking, salt intake or alcohol consumption.
The multifactorial nature of the dietary interventions and accompanying
changes in dietary patterns makes it difficult to disentangle the specific effects of one
nutrient/food from other components of the diet (Skeaff and Miller, 2009). Another
limitation may be that in most within-population studies, those who drink milk are
compared with those who do not but who are still consuming a Western-type diet,
not a healthier diet such as the Mediterranean diet.
Early studies have associated high-fat, high-protein ASF, including milk and
dairy, with increased risk of CVD. However, some of these studies included dairy
only as a component of the diet, and often included other dietary interventions and
lifestyle changes. It is clear that saturated fat intake increases blood cholesterol levels
and the occurrence of CVD. The recent expert consultation on fats and fatty acids
(FAO and WHO, 2010) recommended that SFAs should be replaced with PUFAs to
decrease the risk of CHD. The panel did not find convincing evidence for significant
effects of total dietary fat on CHD (FAO and WHO 2010), but concluded that
industrial trans fatty acids increase CHD risk factors and events, and recommended
a total TFA intake of less than 1 percent of energy in the diet. Replacing SFAs with
largely refined carbohydrates has no benefit on CHD, and may even increase the
risk of CHD.
Although dairy foods contribute to SFA content of the diet, other components in
milk such as calcium and PUFAs may reduce risk factors for CHD. The majority of
meta-analyses of available prospective studies show that low-fat milk and total dairy
product consumption is generally not associated with CVD risk, and may actually
contribute to a reduction of CVD. A recent small prospective study suggests that
this may hold true for full-fat dairy too (Bonthuis et al., 2010), although other
studies have found no association between total dairy, low-fat dairy or high-fat
dairy and CHD or stroke (Dalmeijer et al., 2012) or that high-fat dairy products
were significantly associated with elevated risk of CHD (Bernstein et al., 2010) and
increased risk of CVD mortality (van Aerde et al., 2012). Furthermore, in women,
dairy fat intake has been associated with slightly increased all-cause and IHD mortality
rates (Goldbohm et al., 2011). With regard to dairy consumption and stroke,
two recent large prospective cohort studies have found that intake of low-fat dairy
foods was inversely associated with risk of stroke and cerebral infarction, and that
replacing a serving of red meat in the diet with a serving of low-fat or high-fat dairy
was associated with a lower risk of stroke.
Much of the available data concern milk; information on other dairy products and
CVD is scarce, although preliminary data suggest that fermented milk may have a
beneficial role in hypertension, a risk factor for CVD. In observational studies, specific
dietary patterns have been identified that are associated with decreased risk of CVD.
These include the DASH-style diet and the Mediterranean diet. Both these diets include
milk/dairy in moderate amounts, with low-fat dairy specified in the DASH-diet.