High-sodium diets have historically been linked to increased risk for hypertension, stroke, and other cardiovascular concerns, but new research shows salt-heavy diets might also elicit more frequent eczema flares.
The study, out of the University of California, San Francisco (UCSF), and the University of California, Berkeley, discovered a significant correlation between high-sodium diets and developing atopic dermatitis, known commonly as eczema. Just one extra daily gram of sodium (1000 milligrams)—about half a teaspoon of salt or the amount in one Big Mac—was linked to an 11% higher risk of developing severe eczema.
“This research is exciting because it has been recently shown that sodium is stored in the skin, which could help to explain the connection with inflammatory pathways in eczema,” senior study author Katrina Abuabara, MD, associate professor of epidemiology at UCSF, said in a news release.
Researchers hope that this new research will further persuade people to follow sodium guidelines more carefully. “Although it hasn’t yet been proven that reducing dietary salt can improve eczema, most Americans eat too much salt and can safely reduce salt intake to recommended levels,” Abuabara added.
Sodium Intake and Eczema Risk, Explained
According to Abuabara, “eczema is a chronic, systemic inflammatory condition characterized by itchy rashes that tend to come and go.” Once thought to primarily affect children, data show it’s now common in adults—around 10% of the U.S. population has eczema.
To understand why eczema might be linked to sodium intake, you first have to understand how sodium is processed by the body. Traditionally, experts understood the kidneys to keep sodium levels in check within the body, but newer research has shown that most of the body’s sodium is actually stored in the skin and that the immune and lymphatic systems there work to regulate the body’s electrolyte balances.
Since sodium is stored in the skin, it may also impact certain autoimmune skin conditions—something researchers wanted to take a look at with the new research.
For the study, researchers examined urine samples taken over a 24-hour period from almost 216,000 adults between the ages of 37 and 73 from the UK Biobank, a large-scale biomedical database and research resource. Nearly 11,000 participants—about 5%—had diagnosed eczema. The average participant’s “urine sodium excretion” was about 3 grams per day; but with every 1-gram increase of sodium excretion, a person’s odds of active or severe eczema increased. According to Abuabara, each additional gram of sodium was associated with “an 11% increase in eczema diagnosis, 16% increase in active eczema flares, and another 11% increase in eczema severity.”
Eating for Eczema Management
While this new research may have you thinking that sodium moderation is another effective eczema treatment option, more research is needed before you throw out your salt shaker.
Though the study shows a correlation between sodium intake and eczema, “it doesn’t necessarily mean that sodium management is a way to actually manage eczema symptoms,” said Abuabara, who added that the next phase of research will be to determine if there’s a more significant cause-and-effect relationship between sodium and eczema flares.
But there are still plenty of evidence-based reasons to watch your salt intake, like preventing or managing high blood pressure, heart disease, kidney disease, and stroke.
“The U.S. Dietary Guidelines suggest keeping salt (or sodium) intake below 2,300 milligrams (mg) per day, and many Americans eat nearly 50% more than this on a regular basis,” Maude Morin, MAN, RD, a registered dietitian at JM Nutrition, a skin health-focused nutrition practice, told Health.
Easy ways to start moderating your sodium intake include focusing on whole foods like fresh fruits, veggies, whole grains, nuts, seeds, legumes, lean meats, and seafood while steering clear of overly processed foods and classic high-sodium culprits like salty snacks, condiments, and deli meats.
“Although nutrition cannot treat eczema,” Morin said, “ensuring that we provide the body with nutrients to support skin health and reduce inflammation (like protein, omega-3 fatty acids, and vitamins A and C) while managing body weight could help with the management of this chronic condition.”
So while the findings of this latest study are groundbreaking in their own right, sit tight as exciting research illuminating the connections between diet and eczema is just getting started.