In summary, there is a strong evidence to say that the risk factors for cardiovascular disease (CVD) include:
- High LDL-cholesterol
- Insulin resistance
- High saturated/unsaturated fat intake ratio and high trans fat intake
- High intake of refined carbohydrates
High LDL-cholesterol and CVD
The Role of Lipids and Lipoproteins in Atherosclerosis (Comprehensive Free Online Endocrinology Book, 2019):
Population studies have demonstrated that elevated levels of LDL
cholesterol and apolipoprotein B (apoB) 100, the main structural
protein of LDL, are directly associated with risk for atherosclerotic
Low-density lipoproteins cause atherosclerotic cardiovascular disease. 1. Evidence from genetic, epidemiologic, and clinical studies. A consensus statement from the European Atherosclerosis Society Consensus Panel (European Heart Journal, 2017):
Consistent evidence from numerous and multiple different types of
clinical and genetic studies unequivocally establishes that LDL causes
atherosclerotic cardiovascular disease.
Insulin resistance and CVD
Association between insulin resistance and the development of cardiovascular disease (Cardiovascular Diabetology, 2018):
Overall, insulin resistance contributes to generate CVD via two
independent pathways: (1) atheroma plaque formation and (2)
ventricular hypertrophy and diastolic abnormality. Both effects lead
to heart failure.
Insulin resistance can also alter systemic lipid metabolism which then
leads to the development of dyslipidemia and the well-known lipid
triad: (1) high levels of plasma triglycerides, (2) low levels of
high-density lipoprotein, and (3) the appearance of small dense
low-density lipoproteins. This triad, along with endothelial
dysfunction, which can also be induced by aberrant insulin signaling,
contribute to atherosclerotic plaque formation.
Dietary fat and CVD
A systematic review of the effect of dietary saturated and polyunsaturated fat on heart disease (NMCD, 2017):
It is not total fat intake or saturated fat intake but high saturated/unsaturated fat intake ratio that is a risk factor for cardiovascular disease.
Reducing saturated fat and replacing it with carbohydrate will not
lower CHD events or CVD mortality although it will reduce total
mortality. Replacing saturated fat with PUFA, MUFA or high-quality
carbohydrate will lower CHD events.
(CHD = coronary heart disease; CVD = cardiovascular disease, PUFA = polyunsaturated fattty acids, MUFA = monounsaturated fatty acids)
Trans Fats and Cardiovascular Health: Dr. Mozaffarian’s Testimony (Harvard.edu, 2006):
In large studies involving over 140,000 participants, trans fat
consumption is consistently associated with increased risk of coronary
Dietary carbohydrates and CVD
Fat, Sugar, Whole Grains and Heart Disease: 50 Years of Confusion (Nutrients, 2018):
It is not high-carbohydrate intake but high intake of refined carbohydrates that can increase the risk of cardiovascular disease.
The evidence linking carbohydrate-rich foods with CHD has been
steadily strengthening. Refined carbohydrates, especially
sugar-sweetened beverages, increase the risk of CHD. Conversely, whole
grains and cereal fiber are protective.
The relatioship between insulin resistance, high LDL and cardiovascular disease (CVD):
- Insulin resistance can increase LDL, which is a risk factor for CVD, but not all individuals with insulin resistance have high LDL levels. On the other hand, high blood glucose alone, in the absence of high LDL can be harmful for arteries.
- High LDL levels can appear in the absence of insulin resistance, for example, due to high saturated/unsaturated fat intake ratio, high trans fat intake, obesity and genetic factors (CDC.gov).
So, it may not be necessary to think, which factor- insulin resistance or high LDL - is a better predictor of CVD - they are both important and may or may not be dependent from each other.