Before you get a new tattoo, read this

Hi readers 🐶 If the scientists are telling you to get a dog for Christmas, we should probably listen, right? This weeks top discoveries:

🪡 How tattoos may raise your risk of skin cancer
🐶 Why dogs support your mental health (and not just from pats)
🔴 Are your everyday LEDs damaging your cells? 
(+ the simple way to clean the air you breathe and why it helps)

🪡 Melanoma risk spikes years after tattooing

A new Swedish study found that people with tattoos had a 29% higher risk of melanoma, even after accounting for sun exposure and skin type. Only a third of cancers appeared on the tattoo itself, hinting that ink's chemicals may have body-wide effects, not just local skin damage [the study].

Julija’s Take (DPhil/PhD ABD, MSc, BA(Oxon), Clinical Scientist, Superpower):

It’s not surprising to see these results, which now sit alongside earlier findings linking tattoo ink to lymphoma [the study]. A clear pattern is emerging: the cancers most associated with immune dysregulation are the first to show signals in people with additional chemical burden. The issue isn’t the art - it’s the chemistry.

Tattoo ink began as industrial pigment, loaded with azo dyes, PAHs, and heavy metals [source], and the cultural normalization of tattooing has simply outpaced its toxicology.

The fact that only ~1/3 of melanomas occur on tattooed skin points to something systemic. If this were purely local pigment toxicity, tumors would cluster on the ink. Instead, the evidence suggests chronic, low-grade immune perturbation. Pigments can migrate to lymph nodes, persist for years, and interact with immune cells in ways we still barely understand.

What you can do:
If you have existing tattoos: Protect tattooed skin from UV: sunscreen, no tanning beds, and strict photoprotection around laser removal (UV accelerates pigment breakdown into harmful byproducts). Get yearly full-body skin and blood checks to monitor both tattooed and non-tattooed areas.
If you want to get a tattoo: Ask which ink brands are used and choose studios that can provide Safety Data Sheets (SDS) and use REACH-compliant inks.

🦮 Family dogs may shape mental health via the microbiome

Teens who live with a dog show fewer social problems and carry distinct oral microbes that appear to boost prosocial behavior. When those microbes were transferred into mice, the animals became more social and empathetic, suggesting part of a dog's mental health benefit may flow through the gut–brain axis [the study].

Brittany’s Take (RDN, BS Genetics, Longevity Advisor, Superpower):

I love these studies because they get us one step closer to being able to outline what a "healthy" microbiome looks like:

1. Healthy means diverse, but not maximally diverse! Extreme richness isn't always better. Like in this study, we are finding that healthy people consistently carry a core set of beneficial species (add S. salivarius to the growing list).

2. Healthy means flexible and resilient, not an exact roster. The goal is to build an ecosystem that supports immune balance, gut barrier function, and beneficial signaling to the brain.

3. Lifestyle shapes these healthy patterns! Growing up with dogs seems to nudge the microbiome toward a pattern that is linked to better mood and social behavior across multiple studies.

What you can do: Increase your fiber, exercise regularly, spend time in nature (soil is your friend), try your best to breastfeed your babies, minimize antibiotic use if you can, and -- obviously -- have a dog lick your face as often as possible (or just share your living space if dog spit isn't your thing).

🔴 Does red light boosts cells while LED flicker harms them?

Neuroscientist Dr Glen Jeffery appeared on The Huberman Lab last week, saying that long wavelength red and near infrared light supports mitochondrial health across the body, while short wavelength LED light can damage it. He personally compared the scale of the LED problem (found in homes, offices and schools) to asbestos [the episode].

Andy Bromberg’s take (Co-founder, Lightwork Home Health):

For the past 18 months, we've been testing homes across the world, and these warnings aren't theoretical: we see them everyday in the data. Almost every home uses LEDs, and most of them come with three main issues:

1) Blue light: LEDs (even “warm” ones) often emit significant blue light, disrupting circadian rhythm (82% of lights we’ve tested exceed a recommended guideline of 0.35 Melanoptic Daylight Efficacy Ratio [the science]),

2) Flicker: Most LEDs flicker subperceptibly, which is linked to eyestrain, headaches, and migraines (67% of lights we’ve tested exceed our optimal level of <10% flicker), and;

3) Lack of infrared: Unlike sunlight and incandescent bulbs, LEDs lack the near-infrared wavelengths that support mitochondrial and metabolic function.

What you can do: Replace high flicker LEDs with low flicker, full spectrum bulbs — ideally incandescents/ halogens for evening lighting, or well-tested LEDs from reputable brands like Yuji, Waveform, or Healthy Home Shop for daytime or evening (although, these are still missing infrared). Don't forget to get outside! We're sun maximalists. Natural sunlight gives you the full spectrum, circadian lighting your body evolved with.

🕵 Did Superpower pass Lightwork’s office health test? Come join us as we reveal the results.

Superpowered by You: Air purifiers.

Most of us obsess over clean food and filtered water but ignore the thing we consume the most: indoor air.

Air that looks clean often isn’t. It carries a mix of dust, smoke residue, microplastics and, most notable, PM2.5.

These particles are small enough to slip past your nose and throat. Small enough to reach the deepest parts of your lungs. Small enough to enter your bloodstream. Yet still big enough to carry things like metals and combustion particles.

And the effects show up everywhere. PM2.5 are linked to higher cardiovascular risk, poorer immunity, slower cognition, weight gain and more [health effects].

A good HEPA air purifier can substantially reduce indoor particle levels. Trials show they cut indoor PM2.5 by roughly 60 percent, and lowered blood pressure by reducing the inflammatory load from particle exposure [the studies].

If you only purify one room, make it your bedroom. Run it on high for ten minutes when you enter, then leave it on medium.

Air quality was one of the things Lightwork tested in our office. Join our LinkedIn Live webinar next week to find out whether Superpower HQ passed the test or needs a rethink.

The lab note:

At Superpower, we care about the mechanistic biology beneath your biomarkers and RDW/MCV is one of those quiet, powerful signals.

If you’re feeling unusually fatigued, short of breath on mild exertion, or mentally “off” despite a normal hemoglobin, this ratio can offer early clues that your red blood cells are under stress.

RDW reflects how varied your red cell sizes are; MCV reflects their average size. Together, they reveal what your bone marrow is dealing with:

• Iron deficiency makes cells smaller.

• B12 or folate deficiency makes them larger.

• RDW rises when the marrow is producing a mixed population — often an early sign of nutrient strain or inflammation.

A stable, lower ratio usually means red cells are uniform and nutrient supply is sufficient. A higher ratio, especially with normal hemoglobin, can flag early iron issues, combined nutrient gaps, or slowed red cell production seen in chronic illness - sometimes before ferritin or hemoglobin move.

While it’s not a diagnosis, it is a powerful early signal that your red cell machinery may need attention.

See you at next Wednesdays webinar!