Cardiovascular disease (CVD) is the leading cause of death worldwide 1. Because of its prevalence and life-threatening nature, and because it appears that a keto diet is likely to reverse it, we consider it one of the most important conditions to discuss here.
In our last post, we argued that CVD, being a disease strongly associated with metabolic syndrome, is likely to be best treated with a ketogenic diet. In this post we will present more evidence that ketogenic diets do improve heart disease risk factors.
Unfortunately, there is much confusion and misinformation about the impact of nutrition on CVD among scientists and non-scientists alike. Not only does a high fat, keto diet not worsen heart disease risk — as would commonly be assumed — it actually improves it. This confusion about dietary fat is probably the reason that we do not yet have clinical trials directly testing the effects of ketogenic diets on CVD outcomes.
However, we already have many trials of ketogenic diets that measured known CVD risk factors, especially cholesterol profiles. It turns out that these trials show a powerful heart disease risk reduction in those following a ketogenic diet. It is powerful both in absolute terms, and in comparison with low-fat diets, which tend to improve some weakly predictive factors while worsening stronger predictors.
As such, a high-fat ketogenic diet is currently the best known non-drug intervention for heart disease, as defined by mainstream measures of risk. It is arguably better than drug interventions, too.
- Total cholesterol and LDL cholesterol are only weak predictors of CVD.
- Triglycerides, HDL, LDL particle size, and the HDL-to-triglyceride ratio are much stronger predictors of CVD.
- Keto diets improve triglyceride levels, HDL, and LDL particle size — precisely those measures that strongly indicate risk.
Total cholesterol and LDL cholesterol are only weakly associated with CVD
The connection between blood cholesterol levels and the development of heart disease began to be explored in the last century. Over the last several decades, our understanding of the predictive power of various blood lipids has gone through many refinements as our ability to measure finer and finer detail has advanced.
In the early years, it appeared that high levels of total cholesterol carried some risk of heart disease in many cases. However, it is now well established that total cholesterol by itself is a weak predictor 2, 3, 4.
The reason is quite simple. The different subtypes of cholesterol work together in an intricately balanced system. There is a wide range of total cholesterol levels that are perfectly healthy, so long as the proportions of the subtypes are healthy ones. By the same token, a given level of total cholesterol, even if it is perfectly normal, could be pathological when examined by subtype. Strong evidence from recent decades suggests that the best known blood lipid measures for predicting future risk of CVD are HDL, triglycerides, and related ratios (see below).
One reason for this is that like total cholesterol, LDL is not uniform. Just as we distinguish between HDL and LDL, the so-called “good” and “bad” cholesterol, LDL itself is now known to have two important subtypes with opposite risk implications. Having more large, light LDL particles (also called Pattern A), does not indicate high CVD risk, but having more small, dense particles (Pattern B) does 9, 10, 11, 12, 13. Therefore high LDL by itself is not necessarily indicative of CVD.
Low HDL cholesterol is strongly associated with CVD
Having high blood levels of HDL is now widely recognized as predicting lower levels of heart disease. The proportion of total cholesterol that is HDL cholesterol is a particularly strong predictor. In 2007, a meta-analysis was published in the Lancet that examined information from 61 prospective observational studies, consisting of almost 900,000 adults. Information about HDL was available for about 150,000 of them, among whom there were 5000 vascular deaths. According to the authors, "the ratio of total to HDL choleste