The Languages We Keep: How Multilingualism Protects Your Brain

Read the companion article on Substack

What if speaking multiple languages is one of the most powerful anti-aging interventions available—and it costs nothing?

Today, we unpack a groundbreaking study from Nature Aging examining 86,149 people across 27 European countries. The findings are remarkable: multilingualism provides a 54% reduction in odds of accelerated aging, while being monolingual more than doubles your risk.

But here's the twist: the number of languages matters, and the effect changes with age in surprising ways. Speaking just one additional language helps—but that protection weakens over time. Speaking two or more additional languages? The protection becomes progressively STRONGER as you age.

In This Episode:

• How researchers measured biological age using "biobehavioral age gaps" (BAGs)
• Why this study succeeded where previous research failed
• The sophisticated controls for wealth, healthcare, environment, and inequality
• Breaking down the numbers: odds ratios and relative risk explained
• The cognitive reserve theory and what "dose" of linguistic complexity you need
• Why language engagement should be reframed as brain maintenance
• Implications for education, public health, and your personal choices

This isn't just about correlation. After controlling for every confounding factor imaginable, the linguistic effect persisted. It's a genuine biological benefit tied to the continuous mental effort of managing multiple language systems.

Your brain is begging you to be difficult. To maintain com

This is Heliox: Where Evidence Meets Empathy

Independent, moderated, timely, deep, gentle, clinical, global, and community conversations about things that matter.  Breathe Easy, we go deep and lightly surface the big ideas.

Thanks for listening today!

Four recurring narratives underlie every episode: boundary dissolution, adaptive complexity, embodied knowledge, and quantum-like uncertainty. These aren’t just philosophical musings but frameworks for understanding our modern world. 

We hope you continue exploring our other podcasts, responding to the content, and checking out our related articles on the Heliox Podcast on Substack. 

Transcript

Speaker 1: 0:25

This is Heliox, where evidence meets empathy. Independent, moderated, timely, deep, gentle, clinical, global, and community conversations about things that matter. Breathe easy. We go deep and lightly surface the big ideas. Welcome to the Deep Dive. We're here to basically break down complex research so you don't have to. And today we're looking at something pretty compelling. The idea of, well, a kind of cheat code against aging faster than you should.

Speaker 2: 1:02

Yeah. Specifically asking, does speaking more than one language actually keep you biologically younger? It's a question people have chased for a long time.

Speaker 1: 1:12

But the research has been a bit messy, hasn't it?

Speaker 2: 1:14

It really has. You know, previous studies often hit roadblocks. They might have used health markers that weren't ideal or maybe the sample sizes were just too small. And crucially, it's really hard to control for all the other things in life that affect aging. The sources call these inadequate confounder control.

Speaker 1: 1:32

Which is exactly why this particular study we're focusing on today is, well, a big deal. It's published in Nature Aging titled Multilingualism Protects Against Accelerated Aging. Our mission here is to unpack the evidence from this huge study. We're talking nearly 90,000 people across 27 countries in Europe. How do they define aging and what are the actual numbers behind this protection?

Speaker 2: 1:53

Okay, yeah, before we even get to the multilingual part, we need to understand how they measured aging itself. Because obviously it's not just counting birthdays.

Speaker 1: 2:01

Right. You need a different kind of ruler, one that measures, like, biological wear and tear, not just years lived. So what did they come up with?

Speaker 2: 2:07

They developed something called biobehavioral age gaps, or BAGS for short.

Speaker 1: 2:13

BAGS.

Speaker 2: 2:14

Yeah. Think of a bag as like a score. It tells you if someone's biological systems seem older or younger than their actual chronological age. It quantifies that gap. This lets them measure delayed or accelerated aging across the board, which is, you know, way more useful than just waiting for someone to get diagnosed with something specific later on.

Speaker 1: 2:34

Makes sense. So what went into this bag score? What factors did they use to sort of define biological age?

Speaker 2: 2:41

Well, they pulled together a bunch of individual level data, clinical stuff, functional stuff. And the model they built was actually pretty good at predicting chronological age, which is sort of the first test for any biological clock measure. They found factors basically fell into two camps. There were things linked to slower or delayed aging.

Speaker 1: 3:01

The good stuff first. Yeah. What helps slow things down?

Speaker 2: 3:04

Right. So things like better functional ability, being able to do daily tasks, easily higher levels of education and generally strong cognitive function. Those were protective.

Speaker 1: 3:13

And the flip side, factors linked to speeding aging up.

Speaker 2: 3:17

That included things like cardiometabolic conditions, think heart issues, diabetes, risk sensory impairments like problems with vision or hearing. And interestingly, female sex also came up as an adverse predictor in the age prediction model itself. Though the implications for aging speed overall need careful interpretation.

Speaker 1: 3:38

Gotcha. So it's a really broad picture of aging function, education, health conditions all rolled together.

Speaker 2: 3:44

Exactly. It's comprehensive.

Speaker 1: 3:45

And doing this with, what was it, 86,149 people? That's huge.

Speaker 2: 3:50

It's massive. The data mostly came from big national surveys, like share the survey of health, aging, and retirement in Europe.

Speaker 1: 3:56

And across 27 different countries.

Speaker 2: 3:58

Which really helps make the findings feel more, you know, generalizable, not just specific to one place.

Speaker 1: 4:03

Okay, now let's get into the controls. Because, you know, you could argue that people in wealthier countries might just be healthier anyway, regardless of language, right? How did they separate the language effect from like the effect of living in a richer place?

Speaker 2: 4:16

Ah, yes. This is where the analysis gets really sophisticated. They called this whole complex web of environmental factors the exposome.

Speaker 1: 4:24

Exposome.

Speaker 2: 4:25

And they were really careful to adjust for it. They wanted to make sure the multilingualism benefit wasn't just, you know, a side effect of having better health care or living in a cleaner environment.

Speaker 1: 4:34

So what kind of factors are we talking about in this exposome? What did they adjust for?

Speaker 2: 4:38

A whole lot. They looked at linguistic factors, obviously, but also physical environment stuff like air quality, social factors like migration rates and socioeconomic inequality using the Gini Index, and even broader things like national GDP and country-level gender inequality indexes. Wow. Yeah, it was deep. And the key thing is the protective effect of multilingualism. It still showed up clearly even after they statistically controlled for all of that.

Speaker 1: 5:06

That's crucial, isn't it? It means the language link isn't just some statistical ghost caused by other factors. It seems to be a real independent effect.

Speaker 2: 5:16

Precisely. It survived a very tough statistical stress test.

Speaker 1: 5:20

Okay. All right. Let's get to the payoff then. The core finding. Did speaking more languages protect against this accelerated aging, these bags?

Speaker 2: 5:28

Yes. Unequivocally. Multilingualism consistently emerged as a significant protective factor.

Speaker 1: 5:34

Let's break down the numbers, starting with the cross-sectional data that's like taking a snapshot of everyone at one point in time. What was the key figure there?

Speaker 2: 5:42

In that analysis, multilingualism had an odds ratio in OR of 0.46.

Speaker 1: 5:47

Okay, hold on. ORR 0.46. Let's translate that for everyone listening. An odds ratio below 1 means protection. How much protection is 0.46?

Speaker 2: 5:55

It's substantial. It means that at that snapshot in time, being multilingual was associated with roughly a 54% reduction in the odds of exhibiting accelerated aging compared to not being multilingual, even after accounting for all those other factors.

Speaker 1: 6:08

54% lower odds. That's a huge effect. Did it hold up when they followed people over time, the longitudinal view?

Speaker 2: 6:15

It did, yes. When they tracked people over several years, multilingualism showed a relative risk RR of 0.70.

Speaker 1: 6:22

So still protective, a 30% reduction in relative risk over time.

Speaker 2: 6:26

Exactly. Shows a consistent, measurable benefit as people age.

Speaker 1: 6:30

Okay, now let's look at the other side. What about monolingualism? Was there a penalty for speaking only one language?

Speaker 2: 6:36

Yes, and the contrast is quite stark. Looking specifically at the monolingual group, their risk of accelerated aging was significantly higher.

Speaker 1: 6:44

Give us the number.

Speaker 2: 6:45

In the cross-sectional snapshot, the odds ratio for accelerated aging among monolinguals was 2.11.

Speaker 1: 6:51

Whoa. Oh, 2.11. So more than double the odds.

Speaker 2: 6:55

That's right. Compared to the non-monolingual group in the study, being monolingual more than double the odds of showing accelerated aging at that point in time.

Speaker 1: 7:02

That really puts the benefit into perspective. And over time, the longitudinal risk for monolinguals.

Speaker 2: 7:08

That remained elevated, too, with a relative risk of 1.43 over the follow-up period.

Speaker 1: 7:13

So a 43% higher relative risk of aging faster over time if you're monolingual.

Speaker 2: 7:19

Correct. It really paints a picture of continuous linguistic engagement as a kind of defense mechanism.

Speaker 1: 7:25

Okay, this is already fascinating. But you mentioned there's a nuance here, right? It's not just if you speak multiple languages, but maybe how many and how it interacts with age.

Speaker 2: 7:34

Exactly. This is where it gets really interesting. When they stratify the results, broke them down by age group, and by the number of languages spoken.

Speaker 1: 7:43

So what's the baseline again? For monolinguals, what happens as they get older?

Speaker 2: 7:46

Pretty much what you'd expect, unfortunately. Their risk of accelerated aging tends to increase steadily with age. That's kind of the default biological trajectory in this model.

Speaker 1: 7:55

Okay. Now, what about people who speak just one additional language? Bilingues, essentially.

Speaker 2: 8:00

They definitely showed a protective effect compared to monolinguals. But here's the twist. For this group, the strength of that protection actually seemed to weaken a bit as they got older.

Speaker 1: 8:11

Weakened. So the benefit faded somewhat later in life.

Speaker 2: 8:15

It seems that way, yes. Still beneficial overall, but less powerfully protective in the oldest age groups compared to when they were younger.

Speaker 1: 8:23

Huh. Okay, that sets us up for the really surprising part then. What about the people who speak two or more additional languages, the deeply multilingual group?

Speaker 2: 8:32

For them, it was the complete opposite pattern. Instead of weakening, the protective effect of speaking two or more extra languages became progressively stronger as they aged.

Speaker 1: 8:43

Stronger.

Speaker 2: 8:44

Yes. The older they got, the more protected they seemed to be against accelerated aging compared to their peers. The gap widened in their favor.

Speaker 1: 8:53

Wow. That's the real kicker, isn't it? It suggests it's not just about knowing another language, but maybe the continuous mental effort of managing multiple language systems.

Speaker 2: 9:03

That's certainly what it points towards. It strongly aligns with this idea of cognitive reserve.

Speaker 1: 9:07

Cognitive reserve, right. The brain's ability to withstand damage or decline.

Speaker 2: 9:11

Exactly. We already have research linking bilingualism to things like delaying Alzheimer's symptoms. This study adds a layer. It suggests that maybe a higher dose of linguistic complexity, managing three or more languages, might be needed to really keep strengthening that reserve deep into old age.

Speaker 1: 9:27

So bringing it all together, what's the big message from this deep dive for global health, for us as individuals?

Speaker 2: 9:36

Well, I think it powerfully confirms that living in and presumably actively using multiple languages acts as a quantifiable shield against accelerated biological aging. And crucially, it's not just because multilingual people tend to live in better places. The effect holds up even when you account for major socioeconomic differences. It seems to be a genuine biological benefit tied to language itself.

Speaker 1: 9:58

So we should really start thinking about language engagement differently, not just as a skill or a hobby, but almost like brain maintenance.

Speaker 2: 10:05

I think so, yeah. Like an essential exposure throughout life that has real measurable effects on how our bodies and brains age.

Speaker 1: 10:11

Okay, so here's a final thought to leave you with. Based on that really interesting nuance about how many languages matter most later in life, if that maximum strengthening protection against accelerated aging really kicks in only when you're juggling two or more additional languages, especially as you get older, what does that tell us about the intensity or maybe the consistency of linguistic engagement needed? Is just learning a second language enough? Or do we need to keep pushing, keep those linguistic muscles actively working throughout our entire lives to get the biggest benefit?

Speaker 2: 10:44

It certainly raises that question, doesn't it? Maybe the goal isn't just ticking the bilingual box, but maintaining a truly active, complex linguistic life for the long haul.

Speaker 1: 10:54

Something to definitely think about, perhaps on your next trip, or maybe when you're deciding whether to pick up that language up again.

Speaker 2: 11:03

Thanks for listening today. Four recurring narratives underlie every episode. Boundary dissolution, adaptive complexity, embodied knowledge, and quantum-like uncertainty. These aren't just philosophical musings, but frameworks for understanding our modern world. We hope you continue exploring our other podcasts, responding to the content, and checking out our related articles at heliocspodcast.substack.com.