Gamma-Linolenic Acid Found to Help Relax Constricted Coronary Arteries: A New Insight into Heart Health

A new study by a research group led by Dr. Keisuke Obara, Dr. Kento Yoshioka, and Professor Yoshio Tanaka from the Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, Toho University has revealed that gamma-linolenic acid (GLA), a fatty acid commonly found in plant oils such as evening primrose and borage, can directly relax constricted coronary arteries by blocking a key receptor involved in blood vessel contraction. This discovery offers promising implications for the prevention of coronary spasms and angina.

Coronary artery spasms—sudden narrowing of the arteries supplying the heart—can lead to chest pain (angina) and increase the risk of heart attacks. The underlying cause often involves the activation of prostanoid TP receptors, which trigger vessel contraction in response to chemical signals like thromboxane A₂ and prostaglandin F_2α.

In this study, the Toho University team investigated whether GLA, an omega-6 polyunsaturated fatty acid, could block these contractions in isolated pig coronary arteries. They found that GLA selectively inhibited contractions induced by TP receptor agonists, while having little effect on other contraction triggers. Additional experiments confirmed that GLA acts as a competitive antagonist of the TP receptor—similar to omega-3 fatty acids such as EPA and DHA.

“Surprisingly, GLA—a non-omega-3 fatty acid—showed the same ability as omega-3s to inhibit TP receptor signaling,” said lead researcher Dr. Obara. “This challenges the previous belief that only omega-3 fatty acids have this vascular effect.”

Importantly, the concentrations of GLA used in the experiments correspond to levels achievable through dietary supplementation. GLA is also metabolized into compounds that can suppress inflammation, adding to its potential cardiovascular benefits.

These findings suggest that dietary GLA might help reduce the risk of coronary spasms and related heart conditions by blocking TP receptors in coronary arteries. However, further studies are needed to explore its effects in humans and confirm its long-term safety.