Avoiding Specific Foods May Enhance Pulmonary Hypertension Treatment

A dietary intervention may offer a “whole new way” of treating the deadly disease, adding to the existing options of medication and lung transplantation.

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A recent study published in Cell Metabolism found that avoiding foods rich in the amino acids serine and glutamine may boost the effectiveness of current medications for pulmonary hypertension treatment.

The authors noted that dietary intervention halted excess production of collagen in lung blood vessels that produce stiffness and hinder function, leading to heart failure, chronic lung disease, and death.

“For the first time, we have a dietary maneuver that may serve as an effective way of treating the disease,” said study researcher Dr. Stephen Chan, director of the Vascular Medicine Institute and Center for Pulmonary Vascular Biology and Medicine at the University of Pittsburgh School of Medicine, in a press release.

What Is Pulmonary Hypertension?

Pulmonary hypertension is a condition that involves high blood pressure in the arteries going to the lungs. These arteries receive oxygen-depleted blood from the heart that travels to the lungs to be oxygenated. Symptoms include chest pain, shortness of breath during routine activities, and swelling in the ankles and legs. Over time, the condition can result in serious, life-threatening conditions.

A Mystery Unveiled

Prior to the study, researchers knew that blood vessels in the lungs do not act like those in other parts of the body, but the underlying reasons had been a mystery. In pulmonary hypertension, blood vessels stiffen progressively, yet the excessive vascular stiffening is confined to the lungs. The recent findings have now unveiled the mystery.

The study was conducted by Dr. Chan and colleagues at the University of Pittsburg’s Division of Cardiology, who worked with the team of Thomas Bertero at the Université Côte d’Azur in France.

Using rodents and lung tissue of people with pulmonary hypertension, the researchers discovered that lung blood vessels have a voracious appetite for the amino acids serine and glutamine. It turns out that the metabolism of the two substances is the main driver of pulmonary hypertension progression.

Amino acids are the building blocks of proteins, which help make up structures and have multiple biological functions. In pulmonary hypertension, when blood vessels in the lungs metabolize serine and glutamine, they synthesize two new amino acids—glycine and proline. These, in turn, are the main building blocks that comprise collagen protein, which makes up 30 percent of the body’s total protein, noted the press release.

Collagen serves as the structural framework for the skin, connective tissues, bone, and muscles. Like with any other bodily substance, levels that fall outside a normal range impair health.

Because lung blood vessels in pulmonary hypertension have a highly increased appetite for serine and glutamine, it results in overproduction of collagen. This leads to blood vessel stiffening and impaired function—the primary features of the condition.

The study found that drugs limiting the uptake of serine and glutamine in the cells prevented hypertensive blood vessels in the lungs from craving the amino acids. Consequently, the excess production of collagen stopped, which led to an improvement in pulmonary hypertension. They also discovered that restricting serine and glutamine in the diet resulted in the same benefits.

According to the authors, it’s possible that if individuals with pulmonary hypertension avoid foods with these amino acids, it may increase the effectiveness of current medications. “It opens up a new way that we could treat this disease, because now—instead of just relying on medications and transplantation—there are possibly effective lifestyle interventions,” added Chan in the press release.

Highest Food Sources of Glutamine and Serine

Catherine Rall, a registered dietitian nutritionist, told The Epoch Times in an email that glutamine is primarily found in animal-based proteins. “These include beef, pork, poultry, and dairy, although it is also present in smaller amounts in dark, leafy greens like parsley, spinach, and cabbage,” she said. “Serine is most abundant in nuts, seeds, and fish.”

Dietary Changes–How Much Is Enough?

The promising findings lead to questions, such as, “How stringently would a person have to avoid foods containing serine and glutamine?” They also cause one to wonder to what extent the dietary intervention could help. The Epoch Times put these questions to Dr. Chan in an email.

“Our work fully restricted all dietary serine and glutamine from the rodent diets which led to improvement of pulmonary hypertension,” he said. “We view this finding as important proof-of-concept that dietary maneuvers can be effective as therapies in this deadly disease. However, this level of absolute restriction would not be feasible in a normal human diet, and we certainly do not recommend that our patients attempt to do so at this time.”

Further work is needed to determine if lower levels of amino acid restriction have the same therapeutic effect, added Dr. Chan. The study authors are also exploring whether feasible and safer dietary maneuvers could synergize with current medications that treat pulmonary hypertension to improve disease.

Is There a Downside?

If clinical trials indicate dietary intervention may help people with pulmonary hypertension, doctors would need to weigh the benefits against any possible downsides. The fact remains that these amino acids are necessary for many functions.

Serine plays an essential role in a broad scope of cellular functions, such as neurotransmission and protein synthesis. Deficiency of serine is associated with reduced nervous system function.

Glutamine is vitally needed for several immune system functions, so much so, that it is part of nutritional supplements for people with weakened immunity. Glutamine deficiency stimulates cell apoptosis—programmed cell death—which may lead to sarcopenia, a loss of muscle tissue stemming from aging leading to low-level inflammation.

More Questions

The study brings up more noteworthy questions. Do the physiological factors that underlie pulmonary hypertension also underlie atherosclerosis and other cardiovascular disorders? If so, might restricting the two amino acids help these disorders as well?

Dr. Chan answered that the possibility is somewhat complicated, but the researchers are exploring and addressing the notions.

“Ultimately, we believe that the same fundamental process of accelerated serine/glutamine metabolism and excess collagen deposition can and should occur in blood vessels outside of the lungs,” he said. “This is on the condition that those blood vessels are exposed to the same fundamental disease triggers as in pulmonary hypertension.”

However, triggers of pulmonary hypertension, such as low oxygen and focused inflammation that lead to accelerated glutamine and serine metabolism, frequently occur only in the lungs, explained Dr. Chan. Researchers call this process, which results in excess collagen deposition exclusively in the lungs, a “feeding frenzy.”

“On the other hand, low oxygen and inflammation can be induced in other blood vessels outside of the lungs,” Dr. Chan continued. “When that occurs, we believe the same process of excess collagen production will be induced, which will drive diseases of blood vessels outside of the lungs, including arteriosclerosis, peripheral vascular disease, stroke, and heart attack. We are working on those aspects of this story now and are trying to determine whether similar dietary maneuvers could work in these other vascular diseases as well.”