Red Meat in Human Evolution, Health, and Disease: From A Blessing to A Curse?

The Quarterly Review of Biology · 2026-05-07

Paleoanthropological data, such as butchery tools in the archeological record and cut marks on animal fossils, indicate that access to animal tissues likely predated the emergence of the genus Homo, and that its consumption likely increased during expansion of the human lineage. “Red meat” most commonly refers to muscle tissue from large domestic mammals. The red color reflects its rich content of heme iron associated with myoglobin. Given the high nutritive value of animal-sourced foods—rich in iron, zinc, and B vitamins, and fatty tissues providing essential lipids and calories—these resources are especially important during pregnancy, lactation, weaning, and early childhood. Access to red meat and related foods thus likely shaped the evolution of our species. However, in modern contexts, overreliance on red meat—at the expense of dietary diversity from plant fibers—is associated with chronic diseases such as cancer, atherosclerosis, obesity, and type 2 diabetes. Given that red meat is now sought after in most societies, its increasing large-scale production contributes substantially to environmental degradation and climate change. Here, we examine information spanning approximately 3 million years, discussing how so-called “red meat”—once a valuable resource—has, in modern times, been transformed from a “blessing” to a “curse.”

Social, microbial, and immune factors linking bacterial vaginosis and infectious diseases

Journal of Clinical Investigation · 2025-06-01 · 7 citations

Bacterial vaginosis (BV) is a polymicrobial condition of the vaginal microbiota associated with a variety of sexually transmitted infections, infections of maternal and fetal tissues during pregnancy, and even some infections outside of the reproductive tract, including the urinary tract and mouth. BV has also been associated with conditions in which the body generates prominent inflammatory reactions to microbes, including infections of the cervix and other upper genital tract tissues. For reasons still not understood, BV is a highly recurrent and often difficult-to-treat condition, complicating attempts to prevent these associated infections. An additional layer of complexity arises from the increasing awareness that the presence of BV-associated bacteria in the vagina is not always symptomatic or associated with adverse outcomes. In this concise Review, we summarize and synthesize three groups of factors grounded in the literature that may be fueling the associations between BV and infection: (a) aspects of society and culture; (b) pathogens, virulence factors, and processes of microbial antagonism and synergy; and (c) host factors, such as genetics and immunity. Our goal is to understand what contexts and combinations of microbial, host, and social factors conspire to make BV virulent in some individuals but not others. Disrupting these patterns more systematically may achieve healthier outcomes.

The sialome of the retina, alteration in age-related macular degeneration (AMD) pathology and potential impacts on Complement Factor H

bioRxiv (Cold Spring Harbor Laboratory) · 2025-03-13 · 2 citations

Purpose: Little is known about sialic acids of the human retina, despite their integral role in self/non-self-discrimination by complement factor H (CFH), the alternative complement pathway inhibitor. Methods: A custom sialoglycan microarray was used to characterize the sialic acid-binding specificity of native CFH or recombinant molecules where IgG Fc was fused to CFH domains 16-20 (contains a sialic acid-binding site), domains 6-7 (contains a glycosaminoglycan-binding site) or the CFH-related proteins (CFHRs) 1 and 3. We analyzed macular and peripheral retinal tissue from post-mortem ocular globes for amount, type, and presentation (glycosidic linkage type) of sialic acid in individuals with age-related macular degeneration (AMD) and age-matched controls using fluorescent lectins and antibodies to detect sialic acid and endogenous CFH. Released sialic acids from neural retina, retinal pigmented epithelium (RPE) cells and the Bruch's membrane (BrM) were labelled with 1,2-diamino-4,5-methylenedioxybenzene-2HCl (DMB), separated and quantified by high-performance liquid chromatography (DMB-HPLC). Results: -Actylation of sialic acid and sulfation of GlcNAc did not inhibit binding. Different linkage types of sialic acid were localized at different layers of the retina. The greatest density of α2-3-sialic acid, which is the preferred ligand of CFH, did not colocalize with endogenous CFH. The level of sialic acids at the BrM/choroid interface of macula and peripheral retina of individuals with AMD were significantly reduced. Conclusions: The sialome of the human retina is altered in AMD. This can affect CFH binding and consequently, alternative complement pathway regulation.

Evolution of Human Susceptibility to Alzheimer's Disease: A Review of Hypotheses and Comparative Evidence

Evolutionary Anthropology Issues News and Reviews · 2025-01-13 · 2 citations

Primates rely on memory to navigate both physical and social environments and in humans, loss of memory function leads to devastating consequences. Alzheimer's disease (AD) is a neurodegenerative disease which begins by impacting memory functioning and is ultimately fatal. AD is common across human populations and its prevalence is predicted to rise with increases in the aging population. Despite this, the full AD phenotype has not been observed in any other nonhuman primate species. While a significant amount of research has been devoted to understanding the immediate mechanisms involved in AD pathogenesis in humans, less research has focused on why humans are particularly vulnerable to neurodegenerative diseases like AD. Here we explore hypotheses on the evolution of distinct human susceptibility to AD and place these in the context of findings from comparative neuroanatomical and molecular studies and discuss recent evidence for evolutionary changes protective against AD in the primate lineage.

The Sialome of the Retina, Alteration in Age-Related Macular Degeneration Pathology, and Potential Impacts on Complement Factor H

Investigative Ophthalmology & Visual Science · 2025-06-27 · 2 citations

Purpose: Little is known about sialic acids of the human retina, despite their integral role in self /non-self-discrimination by complement factor H (FH), the alternative complement pathway inhibitor. Methods: A custom sialoglycan microarray was used to characterize the sialic acid-binding specificity of native FH or recombinant molecules where IgG Fc was fused to FH domains 16 to 20 (which contains a sialic acid-binding site), domains 6 and 7 (which contains a glycosaminoglycan-binding site), or the FH-related proteins (FHRs) 1 and 3. We analyzed macular and peripheral retinal tissue from postmortem ocular globes for the amount, type, and presentation (glycosidic linkage type) of sialic acid in individuals with age-related macular degeneration (AMD) and age-matched controls using fluorescent lectins and antibodies to detect sialic acid and endogenous FH. Released sialic acids from neural retina, retinal pigmented epithelium (RPE) cells, and the Bruch's membrane (BrM) were labeled with 1,2-diamino-4,5-methylenedioxybenzene-2HCl (DMB), separated and quantified by high-performance liquid chromatography (HPLC). Results: Both native FH and the recombinant FH domains 16 to 20 recognized Neu5Ac and Neu5Gc that is α2-3-linked to the underlying galactose. 4-O-Actylation of sialic acid and sulfation of GlcNAc did not inhibit binding. Different linkage types of sialic acid were localized at different layers of the retina. The greatest density of α2-3-sialic acid, which is the preferred ligand of FH, did not colocalize with endogenous FH. The level of sialic acids at the BrM/choroid interface of the macula and peripheral retina of individuals with AMD were significantly reduced. Conclusions: The sialome of the human retina is altered in AMD. This may affect FH binding and, consequently, alternative complement pathway regulation.

Comparative physiological anthropogeny: exploring molecular underpinnings of distinctly human phenotypes

Physiological Reviews · 2023-01-05 · 10 citations

Anthropogeny is a classic term encompassing transdisciplinary investigations of the origins of the human species. Comparative anthropogeny is a systematic comparison of humans and other living nonhuman hominids (so-called "great apes"), aiming to identify distinctly human features in health and disease, with the overall goal of explaining human origins. We begin with a historical perspective, briefly describing how the field progressed from the earliest evolutionary insights to the current emphasis on in-depth molecular and genomic investigations of "human-specific" biology and an increased appreciation for cultural impacts on human biology. While many such genetic differences between humans and other hominids have been revealed over the last two decades, this information remains insufficient to explain the most distinctive phenotypic traits distinguishing humans from other living hominids. Here we undertake a complementary approach of "comparative physiological anthropogeny," along the lines of the preclinical medical curriculum, i.e., beginning with anatomy and considering each physiological system and in each case considering genetic and molecular components that are relevant. What is ultimately needed is a systematic comparative approach at all levels from molecular to physiological to sociocultural, building networks of related information, drawing inferences, and generating testable hypotheses. The concluding section will touch on distinctive considerations in the study of human evolution, including the importance of gene-culture interactions.

Evolution of Human-Specific Alleles Protecting Cognitive Function of Grandmothers

Molecular Biology and Evolution · 2022-07-09 · 10 citations

The myelomonocytic receptor CD33 (Siglec-3) inhibits innate immune reactivity by extracellular V-set domain recognition of sialic acid (Sia)-containing "self-associated molecular patterns" (SAMPs). We earlier showed that V-set domain-deficient CD33-variant allele, protective against late-onset Alzheimer's Disease (LOAD), is derived and specific to the hominin lineage. We now report multiple hominin-specific CD33 V-set domain mutations. Due to hominin-specific, fixed loss-of-function mutation in the CMAH gene, humans lack N-glycolylneuraminic acid (Neu5Gc), the preferred Sia-ligand of ancestral CD33. Mutational analysis and molecular dynamics (MD)-simulations indicate that fixed change in amino acid 21 of hominin V-set domain and conformational changes related to His45 corrected for Neu5Gc-loss by switching to N-acetylneuraminic acid (Neu5Ac)-recognition. We show that human-specific pathogens Neisseria gonorrhoeae and Group B Streptococcus selectively bind human CD33 (huCD33) as part of immune-evasive molecular mimicry of host SAMPs and that this binding is significantly impacted by amino acid 21 modification. In addition to LOAD-protective CD33 alleles, humans harbor derived, population-universal, cognition-protective variants at several other loci. Interestingly, 11 of 13 SNPs in these human genes (including CD33) are not shared by genomes of archaic hominins: Neanderthals and Denisovans. We present a plausible evolutionary scenario to compile, correlate, and comprehend existing knowledge about huCD33-evolution and suggest that grandmothering emerged in humans.

Evolution of Human-specific Alleles Protecting Cognitive Function of Grandmothers

bioRxiv (Cold Spring Harbor Laboratory) · 2021-11-26 · 1 citations

Summary Late-onset Alzheimer’s Disease (LOAD) pathology is rare in our closest living evolutionary relatives (chimpanzees), which also express much lower microglial levels of CD33(Siglec-3)–a myelomonocytic receptor inhibiting innate immune reactivity by extracellular V-set domain recognition of sialic acid(Sia)-containing “self-associated molecular patterns” (SAMPs). We earlier showed that V-set domain-deficient CD33 -variant allele, protective against LOAD, is derived and specific to hominin-lineage. We now report that CD33 also harbors multiple hominin-specific V-set domain mutations and explore selection forces that may have favored such genomic changes. N -glycolylneuraminic acid (Neu5Gc), the preferred Sia-ligand of ancestral CD33 is absent in humans, due to hominin-specific, fixed loss-of-function mutation in CMAH, which generates CMP-Neu5Gc from its precursor, CMP- N -acetylneuraminic acid (Neu5Ac). Extensive mutational analysis and MD-simulations indicate that fixed change in amino acid 21 of hominin V-set domain and conformational changes related to His45 corrected for Neu5Gc-loss by switching to Neu5Ac-recognition. Considering immune-evasive “molecular mimicry” of SAMPs by pathogens, we found that human-specific pathogens Neisseria gonorrhoeae and Group B Streptococcus (affecting fertility and fetuses/neonates respectively) selectively bind huCD33 and this binding is significantly impacted by amino acid 21 modification. Alongside LOAD-protective CD33 alleles, humans harbor additional, derived, population-universal, cognition-protective variants absent in “great ape” genomes. Interestingly, 11 of 13 SNPs in these human genes (including CD33 ), that protect the cognitive health of elderly populations, are not shared by genomes of archaic hominins: Neanderthals and Denisovans. Finally, we present a plausible evolutionary scenario to compile, correlate and comprehend existing knowledge about huCD33 evolution and suggest that grandmothering emerged in humans.

Mucin-mimetic glycan arrays integrating machine learning for analyzing receptor pattern recognition by influenza A viruses

bioRxiv (Cold Spring Harbor Laboratory) · 2021-04-17 · 1 citations

ABSTRACT Influenza A viruses (IAVs) exploit host glycans in airway epithelial mucosa to gain entry and initiate infection. Rapid detection of changes in IAV specificity towards host glycan classes can provide early indication of virus transmissibility and infection potential. IAVs use hemagglutinins (HA) to bind sialic acids linked to larger glycan structures and a switch in HA specificity from α2,3-to α2,6-linked sialoglycans is considered a prerequisite for viral transmission from birds to humans. While the changes in HA structure associated with the evolution of binding phenotype have been mapped, the influence of glycan receptor presentation on IAV specificity remains obscured. Here, we describe a glycan array platform which uses synthetic mimetics of mucin glycoproteins to model how receptor presentation in the mucinous glycocalyx, including glycan type and valency of the glycoconjugates and their surface density, impact IAV binding. We found that H1N1 virus produced in embryonated chicken eggs, which recognizes both receptor types, exclusively engaged mucin-mimetics carrying α2,3-linked sialic acids in their soluble form. The virus was able utilize both receptor structures when the probes were immobilized on the array; however, increasing density in the mucin-mimetic brush diminished viral adhesion. Propagation in mammalian cells produced a change in receptor pattern recognition by the virus, without altering its HA affinity, toward improved binding of α2,6-sialylated mucin mimetics and reduced sensitivity to surface crowding of the probes. Application of a support vector machine (SVM) learning algorithm as part of the glycan array binding analysis efficiently characterized this shift in binding preference and may prove useful to study the evolution of viral responses to a new host.

Mucin-Mimetic Glycan Arrays Integrating Machine Learning for Analyzing Receptor Pattern Recognition by Influenza a Viruses

SSRN Electronic Journal · 2021-01-01 · 2 citations