Tag Archives: evolution

Dr. M’s SPA Newsletter Volume 15 Issue 28 – Feeding Infants


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Food in Infancy
What do we know?

“Humans are the only mammals who feed our young special complementary foods before weaning and we are the only primates that wean our young before they can forage independently. There appears to be a sensitive period in the first several months of life when infants readily accept a wide variety of tastes and this period overlaps with a critical window for oral tolerance. As a result, infants should be exposed to a wide variety of flavors while mother is pregnant, while mother is nursing and beginning at an early age. There also appears to be a sensitive period between 4 and 9 months when infants are most receptive to different food textures. There remains debate about when it is best to begin introducing solid foods into an infant’s diet however, the available evidence suggests that provided the water and food supply are free of contamination, and the infant is provided adequate nutrition, there are no clear contraindications to feeding infants complementary foods at any age. There is emerging evidence that introduction of solid foods into an infant’s diet by 4 months may increase their willingness to eat a variety of fruits and vegetables later in life, decrease their risk of having feeding problems later in life, and decrease their risk of developing food allergies, and the early introduction of solid foods into an infant’s diet does not appear to increase their risk of obesity later in childhood.” (Borowitz S. 2021)

Food Introductions — What’s the best way to approach it?

As infants begin the shift from exclusive milk feeding to solid foods, a range of opinions inevitably emerge on how to navigate that transition. It’s tempting to get lost in modern guidelines, but an anthropological lens is often more revealing. Long before the age of purées in jars and puffed snacks in canisters, human infants ate what their parents ate. It was delivered in whole-food form and mechanically softened by chewing, cooking, or crushing. These early first foods carried important evolutionary advantages…Plus a piece on Hell Yeh or No by Derek Sivers

Enjoy,
Dr. M

Dr. M’s SPA Newsletter Volume 15 Issue 27 – Immune Aging

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The Evolutionary Tug-of-War – Inflammation’s Double-Edged Sword

“Environmental factors, particularly infections, have fundamentally shaped human evolution by selecting for protective inflammatory response mechanisms that enhance survival. This evolutionary pressure has created a core biological paradox: inflammation is indispensable for host defense, yet its dysregulation significantly heightens disease and mortality risk. This fundamental tension raises three fundamental questions about human aging and immunity: (1) How have selective pressures driven the evolution of mechanisms to balance inflammation’s protective benefits against its harmful consequences? (2) Why does substantial variability in healthspan persist despite historically stable rates of aging? (3) Does evolutionary prioritization of reproductive fitness inherently limit longevity?” (Manoharan et. al. 2025)

Let’s talk about the fire inside us. Inflammation is our body’s 911 system: lightning-fast, life-saving when a bug invades or a thorn rips skin. But leave that alarm blaring 24/7 and the fire torches the house.

Evolution faced this paradox: crank the immune dial high enough to survive infection and childbirth, yet install brakes so we don’t self-destruct by 40. Manoharan’s team just mapped those brakes in 17,500 humans and called it immune resilience (IR) or the ability to fight hard, clean up fast, and stay cool afterward… and linguistic aging associations…

Dr. M

Dr. M’s SPA Newsletter Volume 14 Issue 50

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“Life forms on our planet have evolved under the strong influence of a daily light/dark cycle. Sunlight being the primary source of energy for photosynthesis, the daily production of photosynthetic biomass has a predictable diurnal rhythm. The daily cyclical production of photosynthesized chemical energy is at the base of the food chain. Daily changes in light and darkness result in diurnal rhythms in other environmental parameters such as temperature and humidity. Such a predictable and robust daily rhythm in food availability and environmental factors has led to the evolution of a ~24 h internal timing mechanism or circadian rhythm to enable organisms to anticipate daily changes and to optimize fitness. Fundamental to this 24 h rhythms is the ability to acquire food when it is available and to store a portion of these resources for utilization during the rest of the day (i.e. the fasting period) without compromising fitness and vitality. The fasting period also serves as a time for standby and repair so that the organism is fit and competent to harvest energy when light (for photosynthetic organisms) or food becomes available. While many non-photosynthetic lifeforms with short lifespan (< a few days) may not derive profound benefit from a circadian timing system, they share fundamental biochemical mechanisms for acquiring and storing food when it is available and then utilizing this stored energy during a quiescent period of fasting for repair, stress resistance and vitality.” (Longo et. al. 2016)

This is the crux of the understanding that we, the homo sapiens on Earth, need to realize that biology trumps any desire that we may have to fight against it. We are and have been moving in the wrong direction for quite some time as it relates to what we were meant to do biologically as children and then adults. Not coordinating activity with the sun is a negative recipe for health. Third shift workers are the canary’s in the coal mine for the risks of working and being awake when the sun is down and sleeping when it is up. This population has some very high risks for metabolic disease based on the data. (Biggi et. al. 2008)

Plus a section on filaggrin genes and skin function.

Dr. M

Dr. M’s Women and Children First Podcast #11 – Dr. EA Quinn, Breastfeeding Through History

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Dr. EA Quinn and I had a wide ranging discussion on breastmilk from an evolutionary perspective for podcast episode #11.
Dr. Quinn is a biological anthropologist with a specialty in human biology. Her research is broadly focused on understanding the ways in which human milk is an essential part of human biological variation and how such variation has been selected for by different ecological pressures.
Her primary research project at present is Infancy @Altitude, a longitudinal birth cohort study of ethnic Tibetan mothers and infants living in the Nubri Valley, Nepal. She is investigating the ways in which ecological pressures – in this case the ecological pressures of hypoxia, chronic cold stress, shorter growing seasons, UV radiation, and infectious diseases – create selective pressures on human milk and how this translates into adaptive patterns of child growth.
One of the major findings of this research was elevated milk fat in the high altitude sample compared to other previously studied human populations and lower levels of metabolic hormones than predicted based on maternal body composition.
Breastmilk is a magical human derived food and medicine all wrapped up into one. The magnificence of human milk is on full display during this hour long podcast.
I hope that you enjoy my conversation with Dr. EA Quinn,
Dr. M

Dr. M’s Women and Children First Podcast #8 – Dr. Kjersti Aagaard, A Womb With a View

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Dr. Kjersti Aaagard, is an expert in maternal-fetal medicine holding the distinction as the Henry and Emma Meyer Professor and Chair in Obstetrics and Gynecology at Baylor College of Medicine and Texas Children’s Hospital. She serves as vice chair of research for obstetrics and gynecology and is a professor in the Departments of Molecular and Human Genetics, Molecular and Cellular Biology, and Molecular Physiology and Biophysics. She is an expert in the study of the maternal microbiome and metagenomics Research.

She is a tour de force of knowledge in the evolutionary understanding of the maternal-fetal communications throughout pregnancy and post delivery. We share a fascinating hour discussing the maternal microbiome, breastmilk, diet and much more as they relate to mom and her babe.

I hope that you enjoy this stimulating conversation with Dr. Aagaard,

Dr. M