Cancer isn’t supposed to happen in your 30s. That’s the assumption most of us carry, and it’s increasingly wrong.
Over the past three decades, cancer incidence in people under 50 has risen by 79%. Adults born around 1990 now have roughly double the risk of colon cancer and four times the risk of rectal cancer compared with those born around 1950. Colorectal cancer is now the leading cause of cancer death in adults under 50. Among women under 50, cancer incidence is 82% higher than in men, up from 51% in 2002.
We don’t have a single, clean explanation for why this is happening, but there are hints…
I’ve stopped thinking about cancer prevention as something that starts at 50. It starts with at conception, and even before that with your biological parent. Certainly by the time we are in our 30s, there’s lot’s that can be done. The exposures you accumulate, your metabolic patterns, your inflammatory tone, your circadian rhythm — these are not neutral. They are writing a long term script.
The good news is that much of it is modifiable.
This is what I focus on with my patients, and what I try to practice myself.
Before we get into that, a reminder: the goal is not perfection. The goal is a life that is well-lived. Love. Connection. Community. Time in nature. With all the mistakes and imperfections along the way.
One of my favorite spots, Lake Ann Trail in Mount Baker Snoqualmie National Forest
Get your metabolic house in order first.
Insulin resistance is one of the most underappreciated cancer risk factors we have. When insulin and IGF-1 are chronically elevated, they activate the PI3K/Akt/mTOR signaling pathway, a core driver of cell proliferation and tumor growth. The epidemiological associations between metabolic syndrome and breast, endometrial, ovarian, colorectal, and prostate cancers are well-established, and Metformin, which works largely by activating AMPK and suppressing mTOR, has earned serious attention in oncology prevention trials on the strength of its anti-cancer signal in observational data. To be clear, I would never reach for a medication before adjusting diet, lifestyle and layering targeted herbs/nutraceuticals.
One of the most important numbers to know in your 30s is your fasting insulin. If it's above 6 µIU/mL, that's worth addressing. The tools are straightforward: reduce refined carbohydrate and ultra-processed food load, eat real food with real protein and high fiber, build muscle, and move your body 30min after eating.
If you are doing all of that and your numbers still are not moving, it is time to look upstream. Genetics, nutrient deficiencies, PCOS and other hormonal imbalances, and gut dysbiosis are common drivers that get missed.
Additional support worth considering at that point includes:
Apple cider vinegar (ACV) 1–2 tbsp before meals
Slows gastric emptying and reduces postprandial glucose excursions. Simple, effectiveDigestive bitters (gentian, dandelion, artichoke blends) 10–20 drops or 1–2 mL before meals
Stimulate cephalic phase digestion, support bile flow, and can modestly improve postprandial glucose handling through improved digestive signaling.Berberine 500 mg 2–3x daily with meals
Improves insulin sensitivity through AMPK activation and reduced hepatic glucose output. One of the most studied nutraceuticals in this category.Chromium (picolinate or polynicotinate) 200–400 mcg daily
Enhances insulin receptor signaling and can modestly improve glucose control, particularly in deficiency states.Gymnema sylvestre 200–400 mg daily (standardized extract)
Reduces intestinal glucose absorption and may support pancreatic beta cell function.Bitter melon (Momordica charantia) 5–6 oz juice or extract BID
Insulin-mimetic effects with evidence for lowering fasting glucose and improving glucose uptake.Targeted probiotics (strain-specific, not generic blends)
Focus on strains with metabolic data such as Lactobacillus reuteri, Lactobacillus plantarum, Lactobacillus rhamnosus, Bifidobacterium lactis, Bifidobacterium longum, and Akkermansia muciniphila. Gut-mediated insulin sensitivity is often overlooked.Psyllium husk 5–10 g before meals
One of the most reliable tools for blunting postprandial glucose and improving insulin response. Start low and slow not to worsen GI symptoms.Myo-inositol 2–4 g daily
Especially effective in insulin resistance with ovarian involvement, but broader metabolic benefits apply.
It takes some humility to question whether you actually know which foods work for your metabolism. I didn’t! Foods labeled “healthy” can spike blood sugar dramatically. Instant oatmeal, granola, smoothies, crackers, noodles, yogurts — intuition fails here regularly. I am a big fan of a month-long trial with a continuous glucose monitor (CGM). One month of data will show you more about your personal metabolic response to food, stress, and sleep than years of general nutrition advice. CGM data also captures something most people don’t expect: stress and poor sleep raise glucose independently of anything you eat.
Seeing that pattern on a graph changes behavior in a way that knowing it intellectually does not. That brings us to the next topic:
Treat sleep like the oncology intervention it is.
The International Agency for Research on Cancer classified shift work involving circadian disruption as a probable human carcinogen, this applies well beyond people working nights. Chronic late nights, variable wake times, and light exposure after dark suppress melatonin, which has anti-proliferative, antioxidant, and immunomodulatory properties beyond regulating sleep. Its suppression raises estrogen bioavailability (relevant in breast and other hormone-sensitive cancers) and reduces natural killer cell activity (immune system defense that fights cancer and virally infected cells).
A 2025 systematic review confirmed associations between circadian disruption and breast, prostate, and colorectal cancer risk. I would protect sleep timing as aggressively as I protect anything else. Consistent wake time, dim light after 9pm, and a cool dark room are the intervention.
Move in a way that mobilizes your immune system.
Exercise reduces tumor incidence by 60% in preclinical models, and the mechanism is increasingly understood. Aerobic exercise drives catecholamine-mediated redistribution of natural killer cells into circulation, enhancing immune surveillance. It also reduces systemic inflammation, lowers insulin, and improves body composition, all independently relevant to cancer risk. Raja Ramaswamy, MD did a fabulous deep-dive on how movement lowers chronic inflammation, and it is worth reading alongside this.
There is also a ventilation component that is often overlooked. During sustained aerobic exercise, your respiratory rate and tidal volume increase, supporting more efficient gas exchange and clearance of volatile compounds through the lungs. This is not detox in the oversimplified sense, but it is a meaningful part of how the body handles metabolic byproducts and environmental exposures.
At a minimum, I would aim for 150 minutes per week of moderate-to-vigorous aerobic activity, with strength training twice weekly to preserve muscle mass and insulin sensitivity.
If you are otherwise healthy, you should be sweating when you are working out. Exercise is not supposed to feel easy. Adaptation requires a signal strong enough for your body to respond.
Reconsider your relationship with alcohol entirely.
There is no safe amount of alcohol for cancer. The IARC rates alcoholic beverages as a Group 1 carcinogen, the same category as tobacco. Acetaldehyde, the primary metabolite of ethanol, is directly genotoxic. Even one drink per day increases breast cancer risk meaningfully in women. About 5 to 6% of cancer cases in US adults are attributable to alcohol.
I am not going to tell you never to drink. What I will say is that alcohol should be a conscious choice with an understood tradeoff. If you drink regularly and want to lower your risk, reducing intake matters. The IARC Handbook (2024) reinforces that risk decreases with reduction, not just complete cessation, particularly for oral and esophageal cancers. The dose-response curve works both directions.
Some practical ways to approach this:
• Replace some drinks with non-alcoholic options. A well-made NA cocktail with bitters can still support digestion and the ritual of drinking.
• If you do drink, have it earlier in the evening. Alcohol close to bedtime disrupts sleep architecture and recovery.
• Something like Anti-Alcohol Complex (Life Extension) or methylene blue likely has modest benefit in supporting alcohol metabolism and reducing some of the downstream oxidative stress.
• If cravings or patterns feel hard to shift, it is worth discussing with your provider. Tools like low-dose naltrexone (LDN) may be appropriate in some cases.
Address your toxic load, especially the estrogenic ones.
PFAS, BPA, and phthalates are in water supplies, food packaging, cookware, personal care products, and receipts. They are found in nearly every human body tested. The Endocrine Society’s evidence review is unambiguous: these chemicals disrupt hormonal signaling, alter puberty timing, and are associated with breast, kidney, testicular, prostate, and thyroid cancers, as well as non-Hodgkin’s lymphoma.
There is also a reproductive biology piece worth naming.
Women today are getting their first period earlier and having children later than previous generations. That means more uninterrupted menstrual cycles and more lifetime estrogen exposure, a direct amplifier of risk for hormone-sensitive cancers. EDCs compound this by adding synthetic estrogenic signals on top of an already higher baseline. The two trends together are more concerning than either alone.
In men, the picture is different but equally concerning. Sperm counts have dropped by more than 50% globally since the 1970s, and phthalates and BPA are directly implicated in that decline through androgen disruption. Lower testosterone and impaired reproductive function are markers of broader hormonal dysregulation, and that same dysregulation carries cancer risk. The reproductive system is a sensitive readout of toxic load, and the signals coming from both sexes right now are worth paying attention to.
Trying to eliminate everything leads to anxiety and not much else. I would be strategic. Filter your drinking water with a reverse osmosis system, which removes PFAS and reduces microplastic load (but make sure you are adding your minerals back). Cook with stainless steel or cast iron and stop storing or heating food in plastic. Clothing is an underappreciated exposure. Most people wear synthetic fabrics for 16 or more hours a day, and microplastics shed from textiles are both absorbed through skin and inhaled. Natural fibers are worth prioritizing, especially for what you sleep in. For personal care, default to unscented everything. Fragrance is a catch-all term that can legally conceal dozens of hormone-disrupting compounds. None of these swaps is dramatic in isolation. The cumulative reduction in daily burden is where it adds up. I wrote a separate post on where to start and what to replace with here.
Build your gut microbiome deliberately.
Every 10 grams of daily dietary fiber reduces colorectal cancer risk by approximately 10%, based on dose-response meta-analyses covering more than 100 prospective studies. The mechanism runs through short-chain fatty acids, particularly butyrate, which act as HDAC (Histone Deacetylase) inhibitors, modulating gene expression in colonic epithelial cells in a way that promotes apoptosis of abnormal cells and reduces proliferation.
I would prioritize 30 or more grams of fiber daily from diverse plant sources. Eat the rainbow, eat seasonally. Diversity matters as much as quantity because different fibers feed different bacterial populations, and microbial diversity is independently associated with reduced cancer risk. The data are strongest for colorectal cancer but extend to breast as well.
My favorite summer meal: one-pan dinners.
Take your stress seriously.
Chronic stress dysregulates the HPA (hypothalamic-pituitary-adrenal) axis, drives sustained cortisol elevation, and impairs immune surveillance through multiple pathways: suppressed NK cell activity, altered T-cell function, and a pro-inflammatory cytokine profile that supports tumor microenvironment development. Stress hormones directly promote tumor progression in preclinical models, including through effects on the p53 tumor suppressor pathway. Chronic physiological stress creates conditions that favor cancer initiation and progression through documented biological pathways.
What most people miss is that stress physiology has three distinct phases, and the right intervention depends entirely on which one you are in. Test your cortisol rhythm with a 4-point salivary cortisol (Labcorp Cortisol, Salivary, 4 Specimens, test code: 004051 or Quest Diagnostics Cortisol, LC/MS/MS, Saliva, 4 Samples, test code: 19806) or a DUTCH test. Do not guess.
Phase 1: Acute / High Cortisol Cortisol is elevated, rhythm is intact but amplified. Symptoms: anxiety, wired-but-tired, difficulty falling asleep.
Nervines to calm the nervous system: Scutellaria, Passiflora, Valerian, Humulus lupulus, Piper methysticum
B-complex vitamins and vitamin C
Melatonin
Magnesium glycinate
Exercise, meditation, deliberate rest and recreation
Reduce caffeine
Phase 2: Chronic Dysregulation The rhythm has flattened or inverted. DHEA begins to drop. Symptoms: fatigue, brain fog, poor recovery, mood instability, early signs of metabolic and connective tissue breakdown.
Phosphatidylserine 400mg to blunt dysregulated cortisol output
L-ornithine 400mg/day for sleep quality and recovery
DHEA as cortisol antagonist, dose guided by testing
Hypericum perforatum and tyrosine if depression is part of the picture
Chromium for glucose regulation
Ascorbates, zinc, glucosamine sulfate for connective tissue support
Calcium, magnesium for bone protection
Omega-3 fatty acids for lipid metabolism and inflammation
Strict sleep and light timing to begin restoring circadian rhythm
Stabilize blood sugar throughout the day
Phase 3: Depletion Cortisol is globally low, DHEA is suppressed, and the system has downregulated output. Contributing factors often include history of steroid use, chronic systemic disease, nutritional deficiencies, inherited conditions such as pyroluria or pernicious anemia, and functional hypoglycemia.
This is the pattern I see in most patients by their 40s and 50s.
Symptoms: profound fatigue, salt cravings, poor immune resilience, hypoglycemia. Rest comes before everything else. Pushing through with stimulants or Phase 1 adaptogens makes this worse.
Botanicals: Glycyrrhiza, Eleutherococcus, Rhodiola, Withania, Astragalus, Crataegus, Rosmarinus, Dioscorea, Schizandra
Nutrients: pantothenic acid, vitamin C, vitamin B12
Sodium chloride to support adrenal output
Anabolic amino acids: arginine, ornithine, lysine
Adrenal glandular support
Graduated moderate exercise, not intense training
Hypoglycemic diet, reduce antigenic load
The foundation across all three phases remains the same: consistent sleep, regular exercise, and structured downregulation. Pick one practice and do it every day.
Check and optimize your vitamin D.
Vitamin D is a hormone with roles in immune regulation, inflammation, and cell signaling, all directly relevant to cancer biology.
The VITAL trial (≈26,000 participants) did not show a reduction in overall cancer incidence with 2,000 IU daily (which is too low of a dose, in my option). But secondary analyses showed a 17% reduction in advanced cancers, and 38% in those with normal BMI. Across meta-analyses, vitamin D has not lowered incidence, but it has shown a modest reduction in cancer mortality, especially with daily dosing.
Observational data is consistent: low vitamin D levels are associated with higher colorectal cancer risk and worse outcomes across multiple cancers.
I do not view vitamin D as a stand-alone prevention strategy, but as a foundational terrain variable. Deficiency is common, especially in the Pacific Northwest. I routinely measure and optimize, targeting 25(OH)D ~40–60 ng/mL. For most adults, 5,000 IU daily is a practical and safe range. And, goes without saying, I prioritize vitamin D from sunlight over supplementation.
The honest version of this list.
40% of cancer cases and nearly half of cancer deaths in US adults are attributable to modifiable risk factors. For someone who has never smoked, maintains a healthy weight, exercises regularly, limits alcohol, uses sun protection, and is vaccinated against HPV and hepatitis B, lifetime cancer risk drops from roughly 40% to approximately 20-25%. The remaining risk is driven by genetics, aging, and random DNA replication errors that no lifestyle intervention fully eliminates. Going from 40% to 20-25% is a meaningful reduction in probability, achieved without a prescription.
I do not believe any of these interventions requires perfection. I believe the compounding effect of several modest changes, sustained over time, is where the protection actually lives. Start with the ones that feel most tractable, build the habits, and let them compound.
That is what I would do.
Ksenia Malarkey, ND is a naturopathic physician specializing in integrative oncology, hormones, and metabolic health.
She provides medical care for Washington residents and offers global health coaching.
To schedule a free 15-minute consult, visit drkseniamalarkey.com
Important article
Excellent article