EAT FOR HEALTH Australian Dietary Guidelines

EAT FOR HEALTH – AusTRALiAn diETARy guidELinEs

70

Guideline 3

Cardiovascular disease, type 2 diabetes and excess weight

•   Cardiovascular disease: Of the systematic reviews addressing the risk of cardiovascular disease and

consumption of fats and oils,664,673-681 only one review^664 focused on the proportions of dietary fatty acids in

the overall diet rather than the effects of omega-3 fatty acids on markers of cardiovascular health. This review

confirmed that replacing SFAs with unsaturated fatty acids may reduce the risk of coronary heart disease,

and that replacing trans fats with unsaturated fats improves blood cholesterol levels. From a whole-of-diet

perspective, this review found that reducing the risk of cardiovascular disease by replacing SFAs with

carbohydrate (as is the case in some low fat diets) depends on the effects on body weight.^664

The Joint FAO/WHO Expert consultation on fats and fatty acids in human nutrition 2010^682 reported convincing

evidence that replacing SFAs with PuFAs decreases the risk of coronary heart disease. The Dietary Guidelines

for Americans, 2010 drew similar conclusions, finding:^198

• strong evidence that dietary SFAs are positively associated with increased serum cholesterol and lDl
  cholesterol, with increased risk of cardiovascular disease


• an association between replacing dietary SFAs or trans fats with PuFAs with improved blood lipid profiles
  and reductions in levels of numerous markers of inflammation


• strong evidence that replacing dietary SFAs with MuFAs and/or PuFAs is associated with improved blood
  lipids related to cardiovascular disease


• moderate evidence that 250 mg of omega-3 lCPuFAs delivered from two servings of seafood per week
  is associated with reduced cardiac mortality from coronary heart disease and reduced risk of sudden
  death from cardiovascular disease.

•   Hypertension: The evidence suggests that consumption of fat, irrespective of amount or type, is not

associated with hypertension in the short term (Grade C; Evidence Report, Section 12.4).683-691

•   Type 2 diabetes: While overweight and obesity increase the risk of type 2 diabetes,^88 recent studies of

short-term interventions are inconclusive and may not adequately reflect the nature of the effect of dietary

fat on type 2 diabetes. The evidence suggests that consuming omega-3 lCPuFAs (0.4 –6 g/day) and diets

of varying fat content are not associated with fasting plasma glucose or insulin concentrations (Grade C;

Evidence Report, Section 12.3).674,681,691-701

In the longer term, the review conducted for the Dietary Guidelines for Americans 2010 found strong evidence

that dietary SFAs were positively associated with increased markers of insulin resistance and increased risk of

type 2 diabetes. In addition, it found that decreasing dietary SFAs and replacing them with PuFAs or MuFAs

decreases the risk of type 2 diabetes in healthy adults and improves insulin responsiveness in insulin resistant and

type 2 diabetes subjects. PuFA intake was associated with a significant decrease in the risk of type 2 diabetes.^198

•   Excess weight: Dietary fat provides a substantial amount of energy (kilojoules) per gram but total dietary energy

is the variable that affects weight. Reducing the amount of dietary fat will not necessarily reduce dietary

energy, but it is prudent to choose low fat and low energy-density foods in a total dietary pattern that seeks to

control overall energy intake. Because of this total energy effect, there are difficulties in appraising research

into the effect of dietary fat alone on weight gain^672 (see Chapter 1).

Cancer

•   All-cause: The evidence suggests there is no association between consumption of omega-3 lCPuFAs with

total all-cause cancer incidence or mortality (Grade C; Evidence Report, Section 12.5).677,702

•   Other cancers: Evidence of an association between total fat consumption across a range of intakes and breast

or endometrial cancer is inconclusive (Evidence Report, Sections 12.6 and 12.7). However, the WCRF report

states there is suggestive evidence that total fat consumption increases the risk of post-menopausal breast

cancer (see Appendix F).^43

Other conditions

•   Dementia: The evidence suggests that higher consumption of omega-3 lCPuFAs is associated with a reduced

risk of dementia (Grade C; Evidence Report, Section 12.8).517,529,703-706