Recent research shows how diet and metabolism affect the immune system
There are dozens of new words we’ve learned this year — social distancing, flatten the curve, epidemic vs. pandemic, etc. Many of us may have thought we escaped college-level biology years ago, but the pandemic proved it’s never too late to learn complex scientific terms — including ones like cytokine storm.
The cytokine storm, put simply, is an immune reaction gone haywire. Immune cells begin attacking the lungs when they should be protecting them. Cytokines are a diverse group of small proteins that are secreted by cells for the purpose of intercellular signaling and communication. Basically, our cells can “talk” to each other to respond in real-time to the environment around them.
When these cytokines become too abundant in an effort to build the body’s immune response, they spread beyond the infection and attack healthy tissues. This can lead to blood clots, shock, permanent organ damage, and death. Scientists are in a race to find treatments to either block the storm from starting or calm the storm once it’s begun.
A recent study examines whether ketone-based metabolic therapy (a ketogenic diet or use of exogenous ketones) can blunt the cytokine storm brought on by SARS-CoV-2 (COVID-19).
Ketones and the Cytokine Storm
The study authors hypothesize therapies that increase levels of (R)-beta-hydroxybutyrate (R-BHB), such as the ketogenic diet or consuming exogenous ketones (supplements that induce ketosis while being less strict with diet), should restore altered energy metabolism and redox state (the balance of several important metabolites). R-BHB is a ketone body produced by the liver in the absence of dietary carbohydrates, starvation, or prolonged exercise.
The data suggest that exogenous ketones can increase cell efficiency and metabolic flexibility, allowing the immune system to function properly. The review goes on to describe many of the molecular mechanisms through which an exogenous ketone-based metabolic therapy (using supplements) together with a moderately high-fat diet may stimulate host cell metabolism and defenses as a possible treatment to blunt the cytokine storm associated with severe SARS-CoV-2 infection.
Because there is a lack of published data on the effects of increasing R-BHB in humans, the researchers looked to experiments done with mice. One such study looked at mice who were infected with Influenza A. They found that a short-term ketogenic diet started seven days before exposure protected the mice from infection and death.
Another study published before the COVID-19 crises began, showed patients on a high-fat, low carbohydrate diet in type II respiratory distress spent 40% less time on a ventilator compared to patients on a high-carbohydrate, low-fat diet.
The authors don’t define exactly what they mean by a low or moderate carbohydrate diet. However, a standard ketogenic diet contains 70% fat, 20% protein, and only 10% carbs.
After their review, the authors suggest a ketone-based intervention in COVID-19 patients in three stages.
1. Onset of symptoms
During this stage, they suggest a moderate carbohydrate diet. They say this will allow normal blood glucose levels to boost immune cell function.
Should the patient progress to the point of needing hospitalization, the authors suggest a limited carbohydrate diet would help lower glucose metabolism and its associated pro-inflammatory signaling.
The third stage is after ventilator use ends and difficulty in breathing ensues. They hypothesize a low-carbohydrate diet at this late stage will facilitate beneficial anti-inflammatory processes. They explain that the expected outcomes, no matter when treatment is initiated, are a decrease in the incidence of progression to ARDS, protection of organs from oxidative and inflammatory damage, and increased clearance of the virus to shorten the duration of the infection.
For years, we’ve known a healthy diet can help boost our immune system to fight off infection or to prevent getting sick in the first place. We drink Vitamin C during a cold or consume chicken soup when we have the flu. We know a balanced diet, combined with enough sleep, exercise, and low stress can help fight disease.
Scientists in the past few years are beginning to understand how ketone metabolism decreases the production of reactive oxygen species (free radicals that may cause cell death), known to contribute to inflammation. It’s a natural progression to believe a ketogenic diet could potentially play role in saving the lives of COVID-19 patients.
While current data shows protective benefits in mice, the authors call for clinical trials in humans to begin. Specifically, they’d like to see a randomized trial of COVID-19 patients consuming ketone esters (exogenous ketone supplement) with a moderately high-fat diet. The trial should evaluate the length and severity of the infection and patient death.