Between Saturdays
This week: how sleep impacts cancer, what melatonin really does, why women face more autoimmunity, and how your brain predicts lifespan.
Science rarely screams. It nudges, accumulates, surprises. A hormone we dismiss as “just for sleep” turns out to have anti-cancer properties. A molecule long overlooked may explain why women suffer autoimmune diseases more. And your brain—its biological age, not just your memory—might be an indicator of how long you’ll live.
Let’s get into it.
Caught My Eye…
• The link between sleep and cancer is stronger than we thought
Sleep isn’t just about rest. New data shows it might be a serious player in cancer risk. A sweeping case-control study published by Cancerworld Magazine examined how sleep disorders like insomnia and sleep apnea are linked to significantly higher odds of developing cancers—especially colorectal, breast, and prostate.
In people with sleep apnea, the risk of colorectal cancer jumped by 76%. Even those with just occasional insomnia had a 54% increased risk. But what’s even more compelling is the effect of disrupted circadian rhythms—the body’s internal clock that governs everything from hormone cycles to DNA repair. When that clock is off (think shift work, irregular bedtimes, long-haul travel), the body’s regulatory systems go haywire. DNA damage accumulates. Hormone levels fluctuate. And cancer cells find an opening.
Interestingly, both too little and too much sleep were associated with higher cancer risk—suggesting that quality and timing matter as much as quantity.
This makes sleep not just a lifestyle issue but a legitimate target in cancer prevention strategies.
• Melatonin: small hormone, big defender
We know melatonin as the hormone that lulls us into sleep. But its job description is much longer.
The HighWire outlines research showing melatonin as a potent antioxidant and anti-inflammatory agent. It scavenges free radicals, dampens chronic inflammation, and even protects brain tissue from neurodegeneration in diseases like Alzheimer’s and Parkinson’s.
Its role in cancer is especially striking. Melatonin helps slow cancer cell growth, reduce metastasis, and even boost the effectiveness of chemotherapy. It’s also deeply tied to the immune system, balancing cytokine levels and strengthening immune surveillance—all while syncing the circadian rhythm that regulates so many of these body systems.
This doesn’t mean melatonin supplements are a cure-all. But it does mean that supporting your body’s natural production—through light exposure during the day, darkness at night, and consistent sleep habits—could have far-reaching benefits.
• A molecular reason women get more autoimmune diseases
Here’s a mystery that’s puzzled scientists for decades: Why are women far more likely than men to develop autoimmune diseases like lupus, MS, or rheumatoid arthritis?
A Stanford-led study published in Cell in February sheds light on a possible culprit—Xist, a long non-coding RNA molecule involved in X chromosome inactivation. In women, one of the two X chromosomes in every cell is silenced to maintain gene balance. But the process of that inactivation leaves behind molecular complexes that, in some cases, resemble foreign invaders.
These structures may accidentally trigger the immune system to attack the body’s own tissues. When researchers engineered male mice to express Xist artificially, those mice began to develop lupus-like symptoms—strong evidence that this mechanism could underlie the gender disparity in autoimmune conditions.
This discovery not only adds a new layer to our understanding of autoimmunity—it may pave the way for earlier diagnostics or targeted therapies, particularly for women.
• Your brain’s biological age might predict how long you live
It’s not the number of candles on your birthday cake that matters most—it’s how your brain is aging.
In a groundbreaking study published in Nature Medicine earlier this month, Stanford scientists analyzed protein profiles across 11 organ systems in 45,000 people. They found that while all organs age differently, the brain’s biological age had the strongest connection to overall mortality.
Participants with “younger” brain signatures—meaning their brain’s protein profile matched or exceeded what’s typical for their chronological age—had significantly lower risks of dying from age-related illnesses. Those with older brains had higher mortality risk, even when other organs were healthy.
This suggests that the brain isn’t just a passive passenger in aging—it may be the captain. And it gives new urgency to protecting cognitive health not just through mental exercises, but through metabolic, emotional, and sleep-related habits that support the entire neurovascular system.
Until next Saturday,
Summaya
Detailed Readings
Sleep & Cancer: Why Rest Matters More Than You Think?
Melatonin is crucial for proper sleep and disease management, including cancer
Study shows why women are at greater risk of autoimmune disease
People with ‘young brains’ outlive ‘old-brained’ peers, Stanford Medicine scientists find