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

Chapter 4 – Milk and dairy products as part of the diet 143
low among adults in most countries, and the scientific evidence for health effects
of these levels of rTFA consumption warrants only limited concern. A total TFA
intake of less than one percent of dietary energy was recommended. A recent
systematic review and meta-analysis of cohort studies (Bendsen et al., 2011) supports
the conclusions regarding iTFA and rTFA and risk of CVD.
Studies that have been published since the expert consultation are generally in
agreement with the conclusions of the panel. For example, a recent review supports
the conclusions relating to total fat and SFAs (Hooper et al., 2011): there was
moderate evidence to suggest that modification of dietary saturated fat content 32
and reduction of saturated fat intake (but not reduction of total fat) may reduce
cardiovascular events overall by 14 percent (RR 0.86, 95 percent CI: 0.77–0.96,
65 508 participants). However, no significant evidence was found for concluding
that dietary saturated fat is associated with an increased risk of CVD in another
recent meta-analysis of prospective cohort studies (Siri-Tarino et al., 2010). The
presumed beneficial effects of diets with reduced saturated fat for CVD risk may
be dependent on a significant increase in polyunsaturated fat in the diet (Siri-Tarino
et al., 2010). A large evidence base suggests that n-6 PUFAs reduce risk of CHD
(Kris-Etherton, Fleming and Harris, 2010) by lowering LDL and total cholesterol
levels. In contrast with these studies, a recent study on patients with type 1 diabetes
mellitus 33 found no statistically significant association between SFA and CVD and
all-cause mortality, nor between all-cause mortality risk and replacing 5 percent of
energy from SFAs with energy from PUFAs, MUFAs or carbohydrates (Schoenaker
et al., 2012). However, the authors say the discrepancy with earlier studies that show
a reduced CVD risk with replacement of SFAs by PUFAs may be explained by a
lack of power in their study.
4.8.2 Studies that support reducing animal products and the argument for
low-fat versus high-fat dairy products
This section considers some of the studies that are often cited in support of the
reduction of animal fat/protein consumption, including dairy.
One of the best known ecological studies of diet and CHD is the Seven Countries
Study, in which baseline surveys were carried out between 1958 and 1964
and a number of individual characteristics measured in 12 763 middle-aged men
belonging to 16 cohorts in Finland, Greece, Italy, Japan, The Netherlands, the
United States and former Yugoslavia (Menotti, Kromhout and Blackburn, 1999). A
25-year follow-up study reported a direct correlation between dietary fat and total
cholesterol levels and between total cholesterol levels and coronary-related mortality.
Significant positive correlations between CHD mortality were reported for
32 A modified fat diet was considered to be one that aimed to include 30 percent or more energy from
total fats, and included higher levels of monounsaturated or polyunsaturated fats than a “usual”
diet. A low-fat diet was considered to be one that aimed to reduce fat intake to less than 30 percent
of energy from fat, and at least partially replace the energy lost with carbohydrates (simple or complex),
protein or fruit and vegetables.
33 Patients with type 1 diabetes mellitus are at a markedly increased risk of CVD, and dietary recommendations
for prevention and treatment of both CVD and diabetes have focused on reducing SFA
intake and increasing fibre intake (Schoenaker et al., 2012).