Are Keto Diets Good for Heart Health?

If you’re at all familiar with the low carbohydrate ketogenic diet space online, you won’t be surprised to hear that the American Heart Association (AHA) does not favor low carbohydrate diets. That’s what is explained in a recently published scientific statement [1]. 

The AHA performed a survey of all the most popular diets and then assigned diets points based on the degree to which each adheres to the recommendations made by the American Heart Association. 

The American Heart Association recommends low fat diets high in whole grains, fruits, and vegetables, and it emphasizes vegetable oils over fruit oils or animal fat. This is all built on the idea that saturated fat causes heart disease by increasing LDL cholesterol. 

Unfortunately, this assertion ignores the substantial amount of evidence suggesting that people who have higher levels of LDL cholesterol levels but lower triglycerides – like what is typical of a person on a low carbohydrate diet – have lower risks of severe infection, lower risk of cancer, lower risk of Alzheimer’s disease, and they tend to live longer [2,3].

In fact, a recent manuscript published by the Journal of the American College of Cardiology stated: “The recommendation to limit dietary saturated fatty acid (SFA) intake has persisted despite mounting evidence to the contrary.” This evidence has been published in numerous studies and directly contradicts the AHA’s assessment [5,6,7].

In other words, the scores the American Heart  Association has given low carb and keto diets don’t match the health outcomes of the diets.

Interestingly, these scores don’t match the heart’s own preferences. 

A recent paper shows that the failing heart, during heart disease, for example, will use ketones as its preferred fuel [8].

Ketones are a byproduct of fat metabolism. When a person eats a diet that consists primarily of healthy fat and protein and limits carbohydrates, this inhibits insulin production in the body. When insulin is low, the liver breaks down fat into small pieces known as ketones [9]. Thus, a diet that avoids insulin-spiking carbohydrates to allow the body to enter a state of ketosis (where it uses its own stored fat for fuel), is called a “ketogenic diet.” 

This preference by the failing heart is significant. When the heart is going through heart failure, among all the options for fuel that it can use, it begins to rely more and more on ketones as a fuel to ensure that it’s working adequately and can keep the body functioning. This is believed to be an adaptation by the heart to decrease the severity of the failure. This same study shows that even providing the body with exogenous ketones (ketones that the body does not produce) through an IV significantly improves the heart function of patients with heart failure. 

The fact that ketones become the preferred fuel of a failing heart is ironic, given the American Heart Association’s aversion to the diets that most readily provide the heart with ketones as a fuel supply. 

Whatever the American Heart Association’s feelings are about keto diets, one thing is clear. 

The heart loves ketones.  

References

1. https://www.ahajournals.org/doi/abs/10.1161/CIR.0000000000001146
2.  Han, R. (2010) Plasma lipoproteins are important components of the immune system. Microbiol Immunol. 54, 246-253
3.  Shor, R., Wainstein, J., Oz, D., Boaz, M., Matas, Z., Fux, A. and Halabe, A. (2007) Low serum LDL cholesterol levels and the risk of fever, sepsis, and malignancy. Ann Clin Lab Sci. 37, 343-348
4.  Astrup, A., Magkos, F., Bier, D. M., Brenna, J. T., de Oliveira Otto, M. C., Hill, J. O., King, J. C., Mente, A., Ordovas, J. M., Volek, J. S., Yusuf, S. and Krauss, R. M. (2020) Saturated Fats and Health: A Reassessment and Proposal for Food-Based Recommendations: JACC State-of-the-Art Review. Journal of the American College of Cardiology. 76, 844-857
5. https://cardiab.biomedcentral.com/articles/10.1186/s12933-018-0698-8
6. https://www.acpjournals.org/doi/10.7326/M14-0180?articleid=1900694
7. https://academic.oup.com/ajcn/article/87/3/567/4633410
8. https://pubmed.ncbi.nlm.nih.gov/32920139/
9.  Laffel, L. (1999) Ketone bodies: a review of physiology, pathophysiology and application of monitoring to diabetes. Diabetes/metabolism research and reviews. 15, 412-426