Soy Supplements: Do They Really Assist in Alleviating Asthma Symptoms?

Key Takeaways:

  • Recent comprehensive research indicates that soy supplements do not lead to any significant improvements in lung function amongst asthma patients, challenging the commonly held belief of soy’s asthma-alleviating properties.
  • The study emphasizes the necessity for rigorous, placebo-controlled studies when drawing connections between specific nutrients and disease outcomes, highlighting the importance of a holistic health management approach.
  • Despite an increase in blood levels of principal soy isoflavone genistein as a result of the soy supplement, the study found no improvement in lung function, asthma symptoms, or inflammation parameters.
  • The investigation breaks down the misconception of the ‘soy shield’ against asthma, a theory based on low asthma rates in countries with high dietary soy intake like China and Japan.
  • The study underscores the complexity of disease processes, suggesting that a single supplement or nutrient is rarely the answer to managing a health condition such as asthma.

Many asthmatics, in search of natural alternatives to pharmaceuticals and their potential side effects, have turned to nutritional supplements. Among these have been soy-based supplements, which have been proposed by some research as a possible aid for improving lung function. However, lately, extensive research findings have questioned these assumptions.

The Unfruitful Search for Relief

A recent comprehensive study, conducted by leading researchers at the Northwestern University Feinberg School of Medicine, found that despite theories, soy supplements do not lead to any significant improvements in lung function amongst asthma patients. “This study underscores the necessity for rigorous, placebo-controlled studies when connections are suggested between particular nutrients and disease results,” said study’s leading author and professor of medicine, Dr. Lewis Smith, further advancing the plea for a holistic approach towards managing the illness.

The Whole Picture of Health

The findings of the study not only debunk the myth of soy improving asthma but also emphasize the need for a more comprehensive approach towards managing it. “A person’s health is a composition of their diet, lifestyle, and entire suite of nutritional consumption, and not just a single food or component,” elaborated Dr. Smith. Hence, supplements should not be the focal point; a broader perspective on health management is necessary.

Shattering the Soy Shield Myth

The study was led by Dr. Smith’s team studying 386 asthma patients aged 12 and older, who were not regular consumers of soy. The study aimed to explore the theory that the consumption of soy could have protective effects against asthma, a hypothesis developed based on low asthma rates in countries like China and Japan with high dietary soy intake.

Participants were divided into two groups for this study. For six months, one group took a soy isoflavone supplement twice daily, while the other group received a placebo. Though it’s been suggested that plant-based compounds like soy isoflavones — found in foods like tofu — may help with menopausal hot flashes, this study discovered otherwise for asthma.

The Hard Truth About Soy and Asthma

Conclusively, the study reported that despite the soy supplement increasing blood levels of the principal soy isoflavone genistein, it failed to improve lung function, asthma symptoms, or inflammation parameters. Experts in asthma care have commended this study, stating that it not only reveals important insights about soy supplements but also highlights how disease is a complex process with myriad components contributing to the healing process.


“It’s rare for a supplement alone to be the answer. In reality, not only does soy not enhance asthma symptoms, but this study also highlights how so many aspects can shape the results of initial studies, leading sometimes to misleading inferences,” stated Dr. Len Horovitz, a pulmonary specialist based in New York City.

Want to know more?

By clicking this link, you can gain further knowledge about asthma treatment and control from the U.S. National Heart, Lung, and Blood Institute.

Emma Caplan

Hola from sunny Costa Rica! I’m Emma Caplan, a California native turned Costa Rican resident. With over a decade of writing experience under my belt, I’ve crafted stories, articles, and narratives on a multitude of subjects. But at heart, health and lifestyle topics resonate the most with me.Not just a writer by profession, I'm an athlete by passion. CrossFit challenges and exhilarates me, shaping both my physical stamina and my perspective on life. I love intertwining my firsthand experiences from the box with my pieces, giving readers a unique blend of authenticity and expertise.Married and fully immersed in the pura vida lifestyle, I've found the perfect balance between my personal and professional life in this tropical paradise. Whether you're here for tips, insights, or stories, I’m committed to delivering content that informs, inspires, and perhaps even pushes you to try that one workout you've been hesitating to start.Join me in my journey as I explore the nexus between physical wellbeing and the art of writing. Let's sweat, learn, and grow together!
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