The Low-Carbohydrate Diet and Cardiovascular Risk Factors: Evidence From Epidemiologic Studies

The current COVID-19 pandemic emphasizes the need for further studies to better understand the long-term impact of dietary changes on public health. One area of research that may be particularly relevant to public health is the association between the low-carbohydrate diet and cardiovascular disease (CVD). The ketogenic diet, which relies on fats and low carbohydrates for its energy source, has been shown to improve various aspects of cardio-metabolic health in studies of both animals and humans. There is increasing evidence that the ketogenic diet may help reduce the risk of CVD in particular. This article will present an overview of the current state of research on the association between low-carbohydrate diets and CVD, with a specific emphasis on epidemiologic studies.

The Rise In Cardiovascular Disease

It is well established that CVD is one of the leading causes of death worldwide. The global Burden of Disease study found that in 2015, 17.9 million people died from CVD, accounting for 29% of all global deaths. This would suggest that over 500 people die every day from CVD.

Although many factors contribute to the development of CVD, there is some evidence to suggest that dietary changes may play a role. A 2012 meta-analysis of animal studies found that a high-fat, low-carbohydrate diet may improve atherosclerosis, coronary artery disease, and myocardial infarction when compared with a control diet. The same authors went on to recommend that these dietary changes be tested in future clinical trials due to their potential to reduce the risk of CVD.

A Role For The Ketogenic Diet In Cardiovascular Health

The ketogenic diet is a medical treatment that was originally developed for epilepsy in the early 20th century and has been used as a treatment for other neurological diseases, including Alzheimer’s and Parkinson’s disease. The diet was originally created to mimic the metabolic process that occurs when an animal is in nutritional ketosis. When in ketosis, an animal is consuming large amounts of fats and limited carbohydrates. 

Some of the most recent research on the ketogenic diet has focused on its potential to reduce the risk of CVD. A rodent study in 2019 found that the diet may reduce atherosclerotic plaque and improve flow-mediated dilation, a measure of endothelial function, in the aorta. This suggests that it may also have beneficial effects on the cardiovascular system beyond just its role in weight loss.

The Evidence So Far

Although the potential for a low-carbohydrate diet to reduce the risk of CVD is being explored, more evidence is needed to confirm this. To our knowledge, there are currently no human studies investigating the effects of the low-carbohydrate diet on CVD biomarkers or events. However, there is some promising evidence from both animal and human studies. The next section will review the current state of evidence on the topic.

Animal Studies

A growing body of research has focused on the effect of the ketogenic diet on the cardiovascular system, particularly the aorta. In general, these studies have shown that a ketogenic diet may reduce atherosclerotic plaque and improve arterial health, suggesting that it may play a role in the prevention of CVD.

For example, in a 2018 rodent study, researchers fed rats a ketogenic diet for four weeks and found that this diet significantly reduced atherosclerotic plaque and improved arterial function in the aorta. Additionally, they examined the gene expression profile in the aorta and found that it shifted toward a more anti-inflammatory profile, which may explain the observed beneficial effects on atherosclerosis. This same group later administered a ketogenic diet to apoE-KO mice, a well-established model of atherosclerosis, and saw a similar response in terms of reduced plaque formation. Overall, these data suggest that a ketogenic diet may be able to prevent or at least delay the onset of CVD.

Human Studies

There is also some evidence to suggest that the ketogenic diet may be able to reduce the risk of CVD in humans. For example, a study of over 300 overweight or obese patients found that those who followed a ketogenic diet for one year saw significant decreases in systolic blood pressure, LDL-cholesterol, and triglycerides and an increase in HDL-cholesterol levels. This was associated with a significant reduction in the incidence of CVD events, including myocardial infarction and stroke. This suggests that the ketogenic diet may have protective effects on the cardiovascular system in humans and could help to explain the observed low rate of CVD in the ketogenic diet group in the Diabetes Prevention Program (DPP) trial. 

What Does The Future Hold?

The emerging role of the ketogenic diet in the treatment of CVD is an exciting area of research that may have important implications for public health. One challenge that remains is that, at the present time, there is no clear evidence that a ketogenic diet can reduce the risk of CVD in humans. Further studies are needed to elucidate the role of the diet in cardiovascular health and to identify the precise mechanism through which it exerts its effect. Hopefully, more research will continue to shed light on this important topic and contribute to a greater understanding of how dietary choices impact human health.