I know this isn't NECESSARILY a fat-related question, but more so a "I don't trust mainstream health politics" question, but: what do you know about the correlations between cholesterol levels and heart attack / heart health? I've heard some things that recently people are more skeptical of the direct relationship, and also that those with genetically high cholesterol are not able to lower it with any diet changes. Thoughts / a direction to look for answers?
It is well established that fatness is correlated with higher blood lipid levels (cholesterol/triglycerides), and that blood lipid levels is in turn correlated with cardiovascular disease. Based on this correlation, dietary changes and “maintaining a healthy weight” are often recommended to lower the risk of heart disease.
But what does the science tell us?
One meta-analysis concluded that “Increasing soluble fiber can make only a small contribution to dietary therapy to lower cholesterol”.
Another meta-analysis found that: “compliance with current dietary recommendations (30% of energy from fat, < 10% from saturated fat, and < 300 mg cholesterol/d) will reduce plasma total and low-density-lipoprotein-cholesterol concentrations by approximately 5% compared with amounts associated with the average American diet.”
Regarding the potential benefits of weight loss, a recent meta-analysis of weight-loss experiments that included long-term follow-up of participants found that diet/exercise/weight loss did not lower blood lipid levels in any meaningful way (i.e., less than 0.25 mmol/L change), these small observed changes were not correlated with weight loss, and weight-loss did not predict a decreased incidence of cardiovascular disease.
Furthermore: “A meta-analysis of prospective epidemiologic studies showed that there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD or CVD.”
Based on these results, it seems like changes in diet, exercise, and weight-loss have negligible effects on blood lipid levels, and similar (non) effects on incidence of cardiovascular disease. I’m not sure what to make of these results, but as with all things fat and health related, it seems that the literature poses more questions than answers.
- Mod D