Audit a URL →

Sign in Sign up free

Loading…

Weekly · Sunday Morning

Five longevity claims.
Worth your time.
Every Sunday.

Last Sunday

Rapamycin extends mouse lifespan 9–14%
NAD+ precursors reverse aging in humans
Blue-light glasses improve sleep quality
Walking 10 min after meals blunts glucose
Verdict change — caffeine half-life downgraded

5 audits·1 verdict change·0 affiliate links·Every Sunday

Joining 1,247 readers — founders, MDs, and longevity-obsessed people who fact-check their own health decisions.

Browse

Decisions Claims Content Creators

Product

Audit a URL Sunday roundup API (soon)Pricing

About

FAQ Methodology Editorial Standards Corrections Press & brand RSS feed

Legal

Terms of Service Privacy Policy DMCA

Finally, something serious in this space.
Because we actually read the papers.

© 2026 Whalespan. Independent, evidence-graded longevity.

The Biology of Breast Milk — Whalespan

Content›Video›The Biology of Breast Milk…

The Biology of Breast Milk

Rhonda Patrick34m · 2020-08-25

Claims Made

97

Claims Supported

85

Support Rate

88%

Support rate

85 of 97 claims supported

85 supported12 partial / not

Claims from this content

80

✓Well SupportedHuman milk oligosaccharides (HMOs) establish and select for a strong population of beneficial bacteria in the infant gut.✓Well SupportedBreast milk contains stem cells that can enter infant circulation and differentiate into brain, liver, and kidney cells.✓Well SupportedPreterm infants fed breast milk show improved microstructural organization of white matter in their brains compared to formula-fed preterm infants.✓Well SupportedThe structural configuration of fats in breast milk enhances their absorption in the infant's gut.Partially Supported

More from Rhonda Patrick

Rhonda Patrick on Sauna Use

Discussion

Native comments, Twitter mentions, and Reddit threads about this content — surfaced together so the conversation isn't fragmented across platforms.

M

Share your read of this content…

Posting publicly as you · linked to your social profiles

Sort by:

AV

A. Volkovreader

4h

Bookmarking — the dossier-vs-overview split is the right call. Most of the time I want overview; sometimes I want receipts.

NP

N. Park

2d

Would love a "what would change this verdict" RSS feed. Sign me up if it exists.

◐

The American Academy of Pediatrics recommends exclusive breastfeeding for approximately six months, followed by continued breastfeeding with complementary foods for one year or longer if mutually desired.

✓Well SupportedMaternal intake of omega-3 fatty acids is associated with larger brain volumes in specific regions of the frontal cortex and corpus callosum in breastfed infants.

✓Well SupportedBreastfeeding significantly influences an infant's brain development and intellectual development, with breastfed children scoring higher on intelligence tests.

◐Partially SupportedSubstances consumed by the mother, including food, drink, supplements, and smoke, can transfer into breast milk.

◐Partially SupportedFor every 12 months of breastfeeding, breast cancer risk is reduced by 4.3 percent.

◐Partially SupportedBreast milk contains nutritional and non-nutritional components such as immune cells, stem cells, and human milk oligosaccharides.

✓Well SupportedVitamin K1 is low in breast milk regardless of maternal diet, necessitating a vitamin K1 injection for all newborns to prevent hemorrhaging.

◐Partially SupportedCadmium levels in the transitional milk of women who smoke are approximately four times higher than in non-smoking women.

◐Partially SupportedBreast milk contains anti-inflammatory agents such as interleukin IL-10, lactoferrin, and lysozyme.

◐Partially SupportedInfants exclusively breastfed for over four months are 72% less likely to be hospitalized for lower respiratory tract infections in their first year of life compared to formula-fed infants.

◐Partially SupportedBreastfeeding may mitigate cardiovascular complications associated with preterm birth.

◐Partially SupportedLeukocytes in breast milk can increase up to 94% above baseline if the infant, mother, or both develop an infection.

✕Not SupportedCommon social drugs like alcohol, nicotine, caffeine, and cannabis pose potential risks to infants during breastfeeding.

✓Well SupportedMaternal high-dose vitamin D supplementation (6400 IU/day) can increase breast milk vitamin D concentration to sufficient levels for the infant.

◐Partially SupportedA lower omega-6 to omega-3 fatty acid ratio is desirable for reducing the risk of chronic diseases.

✓Well SupportedCow's milk has higher protein content and different specific proteins compared to human milk.

◐Partially SupportedBreast milk composition and function demonstrate evolutionary adaptations for infant nutrition, immune preparation, and development.

✕Not SupportedInfants of mothers consuming extremely high quantities of caffeine (750mg/day or more) could potentially reach toxic concentrations from breast milk.

✕Not SupportedSmokers' breast milk has lower levels of antioxidant vitamins C and E, potentially leading to a pro-oxidative state in infants.

◐Partially SupportedAlcohol in breast milk can cause negative effects in infants, including altered sleep, reduced intake, and impaired development.

◐Partially SupportedNicotine transfers into breast milk, with concentrations in smokers' milk being three times higher than maternal plasma levels, and infants eliminate nicotine much slower than adults.

◐Partially SupportedFats in breast milk provide about half of its calories, support infant growth, aid in the maturation of the gut and central nervous system, and protect against pathogens.

◐Partially SupportedBovine MFGM and lactoferrin in infant formula improved infant cognitive, language, and motor skills.

◐Partially SupportedHuman breast milk contains approximately 415 different proteins that provide nutrition, aid digestion, and offer antimicrobial and immunological factors.

◐Partially SupportedBreast milk composition changes dynamically during a feeding session, from day to night, and throughout lactation in response to infant needs and circadian rhythms.

✕Not SupportedSmoking cigarettes reduces the uptake of omega-3 fatty acids, especially DHA, into breast milk.

◐Partially SupportedInfants breastfed are less likely to develop childhood inflammatory bowel disease and celiac disease if breastfed at the time of gluten exposure.

◐Partially SupportedBreast milk acts as a compensatory immune system for infants.

◐Partially SupportedInfants have a lower capacity to metabolize drugs than adults, increasing adverse events from maternal drug use.

◐Partially SupportedMost drugs can enter breast milk via passive diffusion, with the amount depending on drug characteristics and maternal/infant metabolism.

◐Partially SupportedWomen requiring certain drugs, such as anti-cancer medications, should discuss breastfeeding safety with a healthcare provider.

✕Not SupportedLow levels of nicotine exposure during pregnancy or early life can increase the risk of Sudden Infant Death Syndrome (SIDS) by inhibiting the neonate's ability to auto-resuscitate.

◐Partially SupportedThe type of fatty acids in breast milk, particularly omega-3s, is influenced by the mother's diet.

◐Partially SupportedMaternal dietary intake of 400mg of DHA increases DHA in breast milk by 123% compared to placebo.

◐Partially SupportedWomen who breastfeed are more likely to return to their pre-pregnancy weight within three to six months postpartum.

◐Partially SupportedBreastfeeding provides benefits to infants, including intellectual and emotional development, and to mothers, including protection against cancer and obesity.

◐Partially SupportedBreast milk is low in iron, and infants may develop iron deficiency anemia by six months, necessitating iron-rich complementary foods.

◐Partially SupportedMicrochimerism is the phenomenon where cells from a mother are found in an infant and remain long-term.

◐Partially SupportedNicotine patches may be a better option than smoking for women trying to quit breastfeeding, as breast milk nicotine levels are approximately 70% lower than from smoking.

◐Partially SupportedCadmium is a carcinogen.

◐Partially SupportedDonor milk can be an option for healthy, full-term infants if a mother's milk is insufficient.

✕Not SupportedMaternal cigarette smoking halves iodine concentration in breast milk, impairing infant brain development and thyroid function.

◐Partially SupportedBreast milk can transfer substances or drugs from mother to infant.

✕Not SupportedInfants of mothers who smoke exhale seven times more ethane than infants of non-smoking mothers.

◐Partially SupportedBreast milk provides protection against respiratory infections and certain childhood cancers, and may contribute to lifelong immunity.

◐Partially SupportedMaternal infection exposure before pregnancy may confer lifelong immunity to offspring via milk transfer of immune cells.

◐Partially SupportedSixty-three percent of breast milk samples from marijuana-using women contained detectable THC levels up to six days after last use.

◐Partially SupportedPreterm infants fed breast milk had larger ventricle size and stroke volume in adulthood compared to those fed formula.

◐Partially SupportedWorking with a lactation consultant can be helpful for new mothers breastfeeding.

◐Partially SupportedSome immune and health benefits acquired during breastfeeding may be lifelong, including long-term protection to the gut.

◐Partially SupportedHMOs bind to pathogenic bacteria and prevent them from attaching to and infecting gut cells.

◐Partially SupportedInfants breastfed for at least three months have a lower risk of developing atopic dermatitis.

◐Partially SupportedLactose is the most abundant carbohydrate in breast milk.

◐Partially SupportedInfants fed immediately after a mother smokes sleep approximately 30 minutes less compared to when fed after the mother abstains from smoking.

◐Partially SupportedExpressed breast milk should ideally be provided at the same time of day it was expressed to maintain the infant's circadian rhythm.

✕Not SupportedDrugs that should not be taken during breastfeeding include anti-cancer drugs, lithium, oral retinoids, high-dose iodine, amiodarone, and gold salts.

◐Partially SupportedDHA is crucial for proper brain development and is associated with improved mental and psychomotor development in infants.

◐Partially SupportedBabies of women who smoke cigarettes are more susceptible to respiratory infections, colic, and exhibit poor respiratory function after breastfeeding.

◐Partially SupportedBreast milk contains bacteria that may contribute to differences in gut microbial populations between breast-fed and formula-fed infants.

◐Partially SupportedNighttime breast milk contains higher levels of melatonin and somnogenic amino acids like tryptophan, potentially aiding infant sleep-wake cycle regulation.

◐Partially SupportedLeukocyte concentrations are highest in colostrum, taper off in transitional milk, and reach a baseline in mature milk, but can increase if infection develops.

◐Partially SupportedBreast milk contains immunomodulatory factors including memory T cells, IL-4, IL-10, IL-12, colony stimulating factor 3, tumor necrosis factor alpha, interferon gamma, and leukocytes.

◐Partially SupportedEarly life choices, including antibiotic use and infant feeding, can set a child on a trajectory for a robust or suboptimal gut microbiota.

◐Partially SupportedInfants breastfed for six months or longer have a lower risk of developing acute lymphocytic and myeloid leukemia.

◐Partially SupportedCaffeine in breast milk is typically low, peaks 1-2 hours after maternal ingestion, and infants metabolize it poorly.

◐Partially SupportedBreast milk micronutrient content varies based on the mother's diet and tissue stores, potentially requiring supplementation.

◐Partially SupportedHMOs can break down bacterial biofilms and may enhance the effectiveness of some antibiotics.

◐Partially SupportedComponents of the milk fat globule membrane (MFGM) confer antibacterial and anti-inflammatory benefits to breast milk.

✕Not SupportedExposure to household secondhand smoke increases the likelihood of women stopping breastfeeding early by 30%.

◐Partially SupportedAlcohol metabolism occurs at a constant rate and cannot be sped up by drinking water or pumping milk.

◐Partially SupportedCadmium in breast milk impairs the metabolism of selenium, zinc, copper, and magnesium for infant development.

◐Partially SupportedNicotine from smoking can impair milk production by altering maternal prolactin levels.

◐Partially SupportedInfants fed formula have a different gut microbiota composition compared to breastfed infants due to the absence of HMOs in formula.

◐Partially SupportedMarijuana exposure via breast milk during the first month of life is associated with decreased infant motor development at 12 months of age.

◐Partially SupportedInfants exclusively fed breast milk had lower diastolic and systolic blood pressure at ages 13-16 years compared to formula-fed infants.

◐Partially SupportedBifidobacteria are promoted by breast milk, while harmful bacteria are discouraged through various mechanisms.