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

Chapter 4 – Milk and dairy products as part of the diet 141
suggest that consumption of dairy products reduces the risk of having MetS, but
conclude that methodological differences, possible biases and other limitations in
the studies prevent conclusions being drawn. Thus, overall, although more research
is needed, there is emerging evidence that dairy product consumption may decrease
risk of MetS and T2DM.
The mechanisms by which dairy products may affect T2DM and MetS are not yet
clear. The effect of dairy consumption on T2DM may be mediated through calcium
and vitamin D (Pittas et al., 2007). Calcium intake may increase fat oxidation and
suppress adipose tissue oxidative and inflammatory stress, while vitamin D may
enhance the thermic effect of a meal and hence increase fat oxidation (see Tong et al.,
2011 and references therein). Other components in dairy products may also have a
role in lowering the risk of T2DM (see Tong et al., 2011 and references therein). For
example, dairy protein may reduce the risk of overweight and high blood pressure,
major risk factors for T2DM. Dairy proteins may increase satiety, which may reduce
energy intake. Additionally the proteins are precursors of peptides that inhibit
angiotensin-I-converting enzyme, which may reduce blood pressure. However these
effects have been inconsistently reported in human studies (van Meijl, Vrolix and
Mensink, 2008). Furthermore, the fatty acid trans-palmitoleate, which is obtained
primarily from whole-fat dairy, has been associated with a lower incidence of diabetes
(Mozaffarian et al., 2010). More research is needed to better understand the
mechanisms involved and the relationship between dairy consumption and MetS and
the risk of T2DM (Van Loan, 2009; Crichton et al., 2011).
4.8 Dairy intake and cardiovascular disease
Cardiovascular diseases (CVDs) are a group of disorders of the heart and blood
vessels and include CHD (disease of the blood vessels supplying the heart muscle);
cerebrovascular disease (disease of the blood vessels supplying the brain); peripheral
arterial disease (disease of blood vessels supplying the arms and legs); rheumatic
heart disease (damage to the heart muscle and heart valves from rheumatic fever,
caused by streptococcal bacteria); congenital heart disease (malformations of heart
structure existing at birth); deep vein thrombosis and pulmonary embolism (blood
clots in the leg veins, which can dislodge and move to the heart and lungs); and heart
attacks and strokes (mainly caused by a blockage that prevents blood from flowing
to the heart or brain) (WHO, 2012a). CVD kills 17 million people worldwide each
year and is the world’s number one cause of death (WHO, 2008). Many risk factors
for CVD can be controlled; these include cigarette smoking, physical inactivity, high
blood pressure (hypertension), elevated total and LDL blood cholesterol, reduced
HDL cholesterol, elevated triglycerides and overweight/obesity (Krauss et al., 2000;
Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol
in Adults, 2001, Thom et al., 2006). Worldwide, raised blood pressure is estimated
to cause 7.5 million deaths annually; raised blood pressure is a major risk factor for
CHD and ischaemic and haemorrhagic stroke (WHO, 2012b).
Milk and dairy foods are most often linked to CVD risk/events on account of the
milk fat, particularly the high content of SFA. Other nutrients in milk have also been
implicated with CVD risk, such as protein (Bernstein et al., 2010), lactose (Segall,
1994; Moss and Freed, 2003) and the high calcium-to-magnesium ratio (Moss and
Freed, 2003). As milk fat and protein contents are genetically correlated (if the fat