Short Wave — “Never had the flu? Scientists may know why”
Date: April 3, 2026
Hosts: Emily Kwong & Regina Barber
Guest: Juana Summers (Host, All Things Considered)
Length (content): ~00:16–10:25
Episode Overview
This episode of Short Wave is a biweekly health science news roundup, where hosts Emily Kwong and Regina Barber, joined by Juana Summers, dive into three big topics: why some people never get the flu, how little vigorous exercise might go a long way, and the global impact of fortifying everyday foods. The conversation is lively, accessible, and packed with new science findings to make you rethink your daily routines.
Key Discussion Points & Insights
1. Why Do Some People Never Get the Flu? (02:44–05:38)
- Introducing the Mystery
The team discusses people who, despite frequent exposure, have never contracted the flu—like Juana Summers herself. - The Science
- Scientists identified higher levels of a protein called dermcidin in the nose and mouth of individuals who never get flu symptoms, even with no history of flu vaccination (03:17).
- The study, published in PNAS, focused on 19 healthcare workers with high patient contact but no flu.
- Fun fact: The first participant was one of the researchers’ moms, a retired nurse (03:54).
- What is Dermcidin?
- Known previously from sweat as a guard against bacteria and fungus, dermcidin was not known as an antiviral before this research (04:32).
- In these “flu-resistant” people, dermcidin levels were much higher in saliva and nasal passages.
- Why Does This Matter?
- Potential for new methods to identify people at greater flu risk (via dermcidin measurement), and for new preventative treatments—think nasal sprays or eye drops (05:01–05:24).
- Dermcidin also blocks measles, some cold viruses, and flu strains already resistant to antivirals (05:24–05:38).
Notable Quotes
- “I always tell her that she has a superpower.”
— Emily Kwong on the researcher’s mom (03:59) - “Scientists don’t know exactly why some people have different levels of dermcidin…”
— Emily Kwong (05:01)
2. How Much Vigorous Exercise Do You Actually Need? (05:38–08:18)
- The New Data
- Just 15-20 minutes of vigorous exercise a week can significantly reduce risk of severe diseases—including heart and kidney disease, type 2 diabetes, and dementia (05:48).
- Study of 96,000+ people in the UK found intensity mattered more than total weekly exercise time (05:58–07:04).
- What Counts as Vigorous?
- Defined as exercising at 70–85% of your maximum heart rate (06:23–06:29).
- Not just “workouts”: Running up stairs, heavy grocery lifting, short cycling bursts—all can count (06:41).
- Expert Takeaways
- Surprise: Short bursts of intensity are more important than previously believed (07:00–07:07).
- American Heart Association recommends 75 min/week vigorous—or 150 min moderate—but this new evidence hints even less may be enough (07:07–07:26).
- Sports medicine expert Dr. Eli Friedman: Actual high-intensity periods in many workouts are brief, and any exercise is beneficial (07:49–08:16).
Notable Quotes
- “We were struck by how much more important intensity was than total volume.”
— Emily Kwong, paraphrasing lead researcher Ming Cueshen (07:04–07:07) - “During workouts… if you look at the collective time that people are actually engaged in that high intensity, it’s not a lot.”
— Dr. Eli Friedman (07:49–07:56) - “This study… shows pushing yourself a little, even for a few seconds, can go a long way.”
— Regina Barber (08:16)
3. Food Fortification: The Global Health Booster (08:26–10:11)
- What are Fortified Foods?
- Commonplace foods with added vitamins/minerals: iodized salt, bread with folic acid, breakfast cereals with iron (08:34–08:54).
- Billions lack these essential micronutrients worldwide.
- Magnitude of the Impact
- Study in The Lancet Global Health analyzed food fortification programs in 185 countries (09:12).
- Result: Prevents 7 billion “nutrient gaps” globally—meaning fewer people develop deficiencies.
- Even more gaps could be closed with stricter manufacturer compliance and better fortification (09:37–09:51).
- Real-World Example
- California and Alabama now require folic acid fortification in corn masa flour to reduce birth defects (09:51–10:07).
Notable Quotes
- “Based on the best available data, these programs prevent 7 billion nutrient gaps worldwide.”
— Emily Kwong (09:12) - “You probably had iodized salts in a salt shaker—that’s fortified with iodine.”
— Emily Kwong (08:34)
Memorable Moments
- The Superpower Mom: The first study participant in the flu resistance study was the scientist's own mother, a never-sick retired nurse (03:54).
- Instantly Adjusting Habits: Regina sprinted for 30 seconds after learning about the power of even brief vigorous exercise (08:20).
- Science-Driven Humor:
Important Timestamps
- 02:44 — Episode moves into health stories; intro to the “never get the flu” phenomenon.
- 03:17 — Scientists discover dermcidin’s role in flu resistance.
- 04:32 — Dermcidin’s known antibacterial role and its unexpected antiviral power.
- 05:22 — Potential for new flu preventatives: nasal sprays/eye drops.
- 05:48 — New study: small amounts of vigorous exercise make a difference.
- 06:23 — What qualifies as “vigorous” exercise.
- 07:00 — Lead researcher surprised by importance of intensity over duration.
- 07:49 — Athletic trainer reflects on real-world workouts.
- 08:26 — Defining food fortification and its reach.
- 09:12 — Key global impact figures from fortification programs.
- 09:51 — Concrete examples: folic acid in tortillas.
- 10:07 — Lively wrap-up on food, exercise, and healthy habits.
Takeaways
- Flu Resistance may be partly driven by the protein dermcidin; understanding this could lead to new ways to prevent flu and even treat other viral infections.
- Minimum Effort, Big Result: Even brief bursts of vigorous exercise can be far more important for health than the total time spent working out.
- Food Fortification Works: Strategic, widespread addition of micronutrients in food staples prevents massive health issues worldwide—and could do even more with broader implementation.
Listen and learn more science with a side of fun: Search “Short Wave” on your favorite podcast app!