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What is metabolism? A biochemist explains how different people convert energy differently − and why that matters for your health

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theconversation.com – Travis Nemkov, Assistant Research Professor of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus – 2024-04-04 07:44:30

If you’ve spent any time scrolling through the health and wellness corners of social media, you’ve likely come across many products claiming to improve your metabolism. But what exactly is your metabolism?

Everything you expose your body to – from lifestyle to an airborne virus – influences your physical characteristics, such as your blood pressure and energy levels. Together, these biological characteristics are referred to as your phenotype. And the biological system that most directly influences your phenotype is your metabolism.

So if you are eating something, take medications, smoke or exercise, your metabolism is responsible for transferring that biological information throughout your body for it to adapt.

Metabolism is energy conversion

Your metabolism consists of a network of tens of thousands of molecules and proteins that convert the food you eat into the energy and building blocks your body uses to move, grow and repair itself. At the chemical level, energy metabolism begins when the three macronutrients – carbohydrates, fats and protein – are broken down atom by atom to release electrons from chemical bonds. These electrons charge components in cells called mitochondria.

Akin to how batteries work, mitochondria harness this electrical potential to create a different form of chemical energy that the rest of the cell can use.

Simply put, a primary role of metabolism is to convert chemical energy into electrical energy and back into chemical energy. How this energy is transferred throughout the body might play a central role in determining whether you’re sick or healthy.

Diagram consisting of dense, interconnected multicolored lines and dots

As illustrated by this simplified diagram of the human metabolome (where lines indicate chemical reactions and dots indicate reactants or products), your metabolic network is incredibly complex.
J3D3/Wikimedia Commons, CC BY-SA

I am a biochemist who studies the various networks of metabolism that are used as your body changes. My team and I have been able to define specific traits of metabolism, such as the presence and amount of certain metabolites – products made from breaking down macronutrients – across a wide range of conditions.

These conditions include diseases such as COVID-19, diabetes, multiple sclerosis and sickle cell anemia, to experiencing unique environments such as radiation exposure, high altitude, aging and sports performance. Each of these settings influences which parts of your metabolic network are used and how they communicate with one another.

Elite athletes define the upper limits

Given the alarming rise in obesity and its associated metabolic syndrome – about 1 in 8 people across the globe were living with obesity in 2022 – defining a healthy or impaired metabolism can help identify what’s gone wrong and how to address it.

Elite athletes offer a prime population to study metabolic function at its best, since their network of molecular and chemical reactions must be finely tuned to compete on the world stage.

Traditionally, lactate threshold has been a critical measure of athletic performance by pinpointing exercise intensity when lactate starts to rise in muscles and blood.

Contrary to common belief, lactate is not merely a waste product but an energy source as well, and it accumulates when it’s produced faster than mitochondria can use it. While a moderately active person might reach their threshold at an exercise intensity of around 2 watts per kilogram, elite cyclists can sustain an intensity up to nearly two to three times higher.

When comparing the lactate thresholds of a group of elite cyclists, we found that the cyclists with higher thresholds had markers of better mitochondrial function. One of these markers was higher production of coenzyme A, a molecule that shuttles carbon around cells and is important for breaking down carbs, amino acids and fat into chemical energy.

Higher-performing cyclists also appeared to burn more fat and burn fat longer during a multistage world tour compared with lower-performing cyclists.

Dysfunctional metabolism in diseases like COVID-19

Your metabolism also changes if you get an acute illness such as COVID-19.

In contrast to elite cyclists, COVID-19 patients have an impaired ability to burn fat that appears to persist with long COVID. The blood of these patients at rest is similar to that of an elite cyclist’s at exhaustion. Considering that exercise intolerance frequently occurs with long COVID, this suggests mitochondrial dysfunction may play a role in COVID-related fatigue.

Person curled up on a couch, half-covered with a blanket

Long COVID patients have metabolic profiles that resemble that of an exhausted elite cyclist.
Maria Korneeva/Moment via Getty Images

Burning fat uses a lot of oxygen. COVID-19 damages the red blood cells that deliver oxygen to organs. Because red blood cells have a limited ability to repair themselves, they might not function as well during the remainder of their roughly 120-day life span. This may partially explain why COVID symptoms last as long as they do in some people.

Blood donors define the middle

Blood transfusions are one of the most common clinical procedures. Over 118 million pints of blood are donated by millions of people worldwide every year. Because blood donors undergo screening to ensure they are healthy enough to donate, they are typically moderately healthy, somewhere between acute illness and elite athletic performance. Blood donors, coming from every walk of life, also have a diverse range of biological traits as a study population.

My team and I looked at blood from over 13,000 blood donors to shed light on their metabolic diversity. We found specific traits that could predict how well a donor’s blood would work in patients, which also has implications for how well that blood works in the donors themselves.

We found that one of these traits is a metabolite called kynurenine, which is produced from the breakdown of the amino acid tryptophan. We found that blood from donors with higher levels of kynurenine was less likely to restore hemoglobin levels in transfusion recipients compared with donors with lower kynurenine levels.

Kynurenine levels are higher in older donors and donors with a higher BMI, and may potentially be tied to higher levels of inflammation. In support, our group also found that kynurenine increases dramatically in runners participating in the 171-kilometer (106 miles) Ultra-Trail du Mont-Blanc. In addition, we also identified that kynurenine is a strong marker of COVID-19 severity.

The relationship between metabolites and health outcomes reinforces the important role metabolism plays in the body. Getting a better understanding of what healthy metabolism looks like can offer unique insights into how it deviates when someone gets sick and may offer new approaches to medical treatments.

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Hundreds of 19th-century skulls collected in the name of medical science tell a story of who mattered and who didn’t

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theconversation.com – Pamela L. Geller, Associate Professor of Anthropology, University of Miami – 2024-11-14 07:23:00

Hundreds of 19th-century skulls collected in the name of medical science tell a story of who mattered and who didn’t

Illustration of just one of almost a thousand skulls Morton and colleagues collected.

Crania Americana by Samuel Morton, CC BY

Pamela L. Geller, University of Miami

When I started my research on the Samuel George Morton Cranial Collection, a librarian leaned over my laptop one day to share some lore. “Legend has it,” she said, “John James Audubon really collected the skulls Morton claimed as his own.” Her voice was lowered so as not to disturb the other scholars in the hushed archive.

As my work progressed, I uncovered no evidence to substantiate her whispered claim. Audubon had collected human skulls, several of which he then passed on to Morton. But birds and ornithology remained Audubon’s passion.

Nevertheless, the librarian’s offhanded comment has proven useful – a touchstone of sorts that continues to remind me of the controversy and confusion long surrounding the Morton Collection.

Morton was a physician and naturalist who lived in Philadelphia from 1799 until the end of his life in 1851. A lecture he delivered to aspiring doctors at the Philadelphia Association for Medical Instruction outlined the reasons for his cranial compulsion:

“I commenced the study of Ethnology in 1830; in which year, having occasion to deliver an introductory lecture on Anatomy, it occurred to me to illustrate the difference in the form of the skull as seen in the five great races of men … When I sought the materials for my proposed lecture, I found to my surprise that they could be neither bought nor borrowed.”

He would go on to acquire almost 1,000 human skulls.

Morton used these skulls to advance an understanding of racial differences as natural, easily categorizable and able to be ranked. Big-brained “Caucasians,” he argued in the 1839 publication “Crania Americana,” were far superior to small-skulled American Indians and even smaller-skulled Black Africans. Many subsequent scholars have since thoroughly debunked his ideas.

Certainly, condemnation of Morton as a scientific racist is warranted. But I find this take represents the man as a caricature, his conclusions as foregone. It provides little insight into his life and the complicated, interesting times in which he lived, as I detail in my book “Becoming Object: The Sociopolitics of the Samuel George Morton Cranial Collection.”

My research demonstrates that studies of skulls and diseases undertaken by Morton and his medical and scientific colleagues contributed to an understanding of U.S. citizenship that valued whiteness, Christianity and heroic masculinity defined by violence. It is an exclusionary idea of what it means to be American that persists today.

Yet, at the same time, the collection is an unintended testament to the diversity of the U.S. population during a tumultuous moment in the nation’s history.

Pen and ink portrait of a 19th century white man

Samuel Morton wasn’t a lone voice on the fringe of medicine.

‘Memoir of the life and scientific labors of Samuel George Morton’ by Henry S. Patterson, CC BY

Men of science and medicine

As a bioarchaeologist who has studied the Morton Collection for many years, I have sought to better understand the social, political and ideological circumstances that led to its creation. From my work – analyzing archival sources including letters, laws, maps and medical treatises, as well as the skulls themselves – I’ve learned that, over a lifetime, Morton fostered a professional network that had far-reaching tentacles.

He had plenty of help amassing the collection of skulls that bears his name.

The physician connected with medical colleagues – many of whom, like him, received degrees from the University of Pennsylvania – gentleman planters, enslavers, naturalists, amateur paleontologists, foreign diplomats and military officers. Occupational differences aside, they were mostly white, Christian men of some financial means.

Their interactions took place during a pivotal moment in American history, the interlude between the nation’s revolutionary consolidation and its violent civil unraveling.

Throughout this stretch of time, Morton and his colleagues catalyzed biomedical interventions and scientific standards to more effectively treat patients. They set in motion public health initiatives during epidemics. They established hospitals and medical schools. And they did so in the service of the nation.

Not all lives were seen as worthy of these men’s care, however. Men of science and medicine may have fostered life for many, but they also let others die. In “Becoming Object,” I track how they represented certain populations as biologically inferior; diseases were tied to nonwhite people, female anatomy was pathologized, and poverty was presumed inherited.

From person to specimen

Such representations made it easier for Morton and his colleagues to regulate these groups’ bodies, rationalize their deaths and collect their skulls with casual cruelty from almshouse dissecting tables, looted cemeteries and body-strewn battlefields. That is, a sizable portion of the skulls in Morton’s collections were not culled from ancient graves but belonged to those of the recently alive.

It is no coincidence that Morton began his scientific research in earnest the same year Andrew Jackson signed the Indian Removal Act of 1830. Men of science and medicine benefited from the expansionist policies, violent martial conflicts and Native displacement that underpinned Manifest Destiny.

line drawing of a skull from three angles, with text beneath about how it was collected from battle

A drawing from Morton’s book of the skull of a Seminole man killed by American troops. A bullet hole is visible on the left side of the man’s head.

‘Crania Americana’ by Samuel George Morton, CC BY

The collection reveals these acts of nation-building as necropolitical strategies – techniques used by sovereign powers to destroy or erase certain, often already vulnerable, populations from the national consciousness. These skulls attest to precarious existences, untimely deaths and trauma experienced from cradle to beyond the grave.

In the specific case of Native Americans, skeletal analysis testifies to the violent effects of U.S. military campaigns and forced removal. Native skulls that Morton labeled “warriors” have evidence of unhealed fractures and gunshot wounds. Children’s skulls bear the marks of compromised health; such pathology and their young ages at death are evidence of long-standing malnutrition, poverty and deprivation or stress.

To effectively transform subjects into objects – human beings into specimens – collected crania were ensconced in the institutional spaces of medical school lecture halls and museum storage cabinets.

There, Morton first numbered them sequentially. These numbers along with information about race, sex, age, “idiocy” or “criminality,” cranial capacity and provenance were inked on skulls and written in catalogs. Very rarely was the person’s name recorded. If used as teaching tools, Morton drilled holes to hang the skulls for display and notated them with the names of skeletal elements and features.

As dehumanizing as this process was, the Morton Collection does contain evidence of resilience and heterogeneous lives. There are traces of people with mixed-race backgrounds such as Black Indians. Several people may have also bent gender to navigate dire conditions or in keeping with social norms, such as native Beloved Women, who were active in warfare and political life.

stone monument in a graveyard

In contrast to those whose skulls ended up in his collection, Samuel Morton’s own grave was memorialized with a monument.

Pamela L. Geller

What these bones mean today

As anthropologists now recognize, it is through the repatriation of the remains of the people in the Morton Collection to their descendants, among other types of reparations, that current practitioners may begin to atone for the sins of intellectual forebears. Indeed, all institutions housing legacy collections must contend with this issue.

There are other, valuable lessons – about diversity and suffering – that the Morton Collection has to impart in today’s interesting times.

The collection demonstrates that the American body politic has always been a diverse one, despite efforts of erasure by men like Morton and his colleagues. Piecing together the stories of past, disenfranchised lives – and acknowledging the silences that have made it difficult to flesh them out – counters past white nationalism and xenophobia and their current resurgence.

The collection, I believe, also urges the repudiation of violence, casual cruelty and opportunism as admirable attributes of masculinity. Valorizing men who embody these qualities has never served America well. Particularly in the mid-1800s, when Morton amassed skulls, it led to a nation divided and hardened to suffering, an unfathomable death count and the increasing fragility of democracy.The Conversation

Pamela L. Geller, Associate Professor of Anthropology, University of Miami

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Weight loss plans are less effective for many Black women − because existing ones often don’t meet their unique needs

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theconversation.com – Loneke Blackman Carr, Assistant Professor of Community and Public Health Nutrition, University of Connecticut – 2024-11-13 07:24:00

People who are obese or overweight are at higher risk of developing several chronic diseases.
andreswd/E+ via Getty Images

Loneke Blackman Carr, University of Connecticut and Jameta Nicole Barlow, George Washington University

The popularity of weight loss drugs such as Ozempic and Mounjaro continue to reflect Americans’ desire to slim down. While these new drugs have offered a solution for people struggling with obesity, many eligible patients – especially Black adults – cannot afford the high price.

These drugs are also not a one-stop solution for better health, as healthy eating and regular exercise are also key to losing weight. But current weight loss interventions based on lifestyle changes largely fail to meet the needs of Black women.

As community health researchers, we wondered why scientists have been unable to craft a lifestyle-based weight loss solution that works for Black women.

So we reviewed 10 years of research on weight loss interventions based on lifestyle changes. We found that only a few studies focused on Black women, and those that did often resulted in only small amounts of weight loss and were inconsistent in how they approached weight loss. Why is that?

Missing the mark for Black women

Obesity increases the risk of developing weight-related conditions such as Type 2 diabetes, heart disease and some types of cancer. Nearly 60% of Black women in the U.S. are obese, placing them at greater risk of developing these conditions.

Lifestyle interventions focusing on healthy diet and increased physical activity are proven to help most people lose weight, typically resulting in a 5% to 10% weight reduction that also reduces the risk of chronic disease. However, these lifestyle interventions usually result in only a 2% to 3% weight loss in Black women.

Our review suggests that lifestyle-based weight loss has been stymied among Black women because they often aren’t included in this research. Because their lived experiences aren’t considered in these studies, these interventions might not meet their specific needs. Of the 138 studies we assessed, Black women made up at least half of the participants in only eight studies.

Research on why lifestyle interventions are often less effective for Black women is lacking. However, some studies highlight the effects of race and gender on their daily lives as potential factors.

Person sitting on couch, pinching skin between eyebrows
The ‘strong’ Black woman is compelled to ignore her physical and emotional needs to take care of others.
PixelsEffect/E+ via Getty Images

The superwoman role

Black women exposed to the persistent stress of navigating everyday racism and sexism face the additional burden of what researchers call the superwoman role. Not only do Black women have to weather their own experiences of race- and gender-based inequalities, they’re also expected to be invulnerable, hyperindependent and suppress their emotions in order to seem strong to their family and community. Many minimize their vulnerabilities and overstress their capabilities in order to fulfill an overwhelming obligation to take care of other people.

Many famous names have spoken about the effects of being the strong superwoman. Actress Taraji P. Henson has pointed to how the need to display strength can lead to ignoring the physical and emotional needs of Black women.

Rapper Megan Thee Stallion spoke about the emotional toll of the superwoman role after being shot by rapper Tory Lanez. “As a Black woman … people expect me to take the punches, take the beating, take the lashings, and handle it with grace. But I’m human.”

The superwoman role levies a heavy tax on Black women, leaving little room to prioritize their health. To cope with the stress, some engage in emotional eating or binge eating. The constant demands of playing multiple caregiver roles can also disrupt physical activity.

Naturally, these challenges make it difficult to adopt healthier eating habits and a consistent exercise routine. Even when working toward weight loss, some Black women continue to gain weight.

Improving weight loss for Black women

Lifestyle interventions that fully integrate the lived experiences of Black women into treatment may be key to improving weight loss. We argue that Black Feminism and Womanism, which focus on the experiences of women of color, can guide researchers to rebuild and reframe weight loss interventions to be more effective for Black women.

Black Feminism and Womanism are approaches guiding Black women and girls to surviving and thriving, specifically by always considering the role that gender and race play in different issues. These frameworks focus on multiple areas of health and wellness, including physical, mental and emotional health, arguing that self-care and wellness practices are acts of social change.

Focusing on the full context of Black women’s lives can lead to better overall health. Obesity, specifically, is influenced by multiple factors, and treating obesity requires a focus on holistic health and well-being. This includes addressing Black women’s economic needs, incorporating faith practices central to Black life, attending to emotional and mental health, and building an environment that makes acquiring healthy food and engaging in daily exercise an easy choice.

Three people walking down a tree-lined trail, smiling at each other
Lifestyle changes are easier to incorporate when they’re tailored to your everyday life.
FG Trade/E+ via Getty Images

Current weight loss interventions vary widely in which elements of Black women’s lives they focus on. For example, some emphasize spirituality, while others concentrate on emotional health. Approaches to weight loss that respond to individual needs and move away from one-size-fits-all will be critical to addressing the various aspects of Black women’s lives that affect their wellness.

If health care providers and researchers begin listening to and working with Black women to redesign weight loss interventions, they will likely find that their efforts at addressing obesity among Black women are more effective.The Conversation

Loneke Blackman Carr, Assistant Professor of Community and Public Health Nutrition, University of Connecticut and Jameta Nicole Barlow, Associate Professor of Writing, Health Policy & Management and Women’s, Gender and Sexuality Studies,, George Washington University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Can AI chatbots boost human creativity?

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theconversation.com – Jaeyeon Chung, Assistant Professor of Business, Rice University – 2024-11-13 07:26:00

AI chatbots can give helpful suggestions.

Carol Yepes/Moment via Getty Images

Jaeyeon Chung, Rice University

Think back to a time when you needed a quick answer, maybe for a recipe or a DIY project. A few years ago, most people’s first instinct was to “Google it.” Today, however, many people are more likely to reach for ChatGPT, OpenAI’s conversational AI, which is changing the way people look for information.

Rather than simply providing lists of websites, ChatGPT gives more direct, conversational responses. But can ChatGPT do more than just answer straightforward questions? Can it actually help people be more creative?

I study new technologies and consumer interaction with social media. My colleague Byung Lee and I set out to explore this question: Can ChatGPT genuinely assist people in creatively solving problems, and does it perform better at this than traditional search engines like Google?

Across a series of experiments in a study published in the journal Nature Human Behavour, we found that ChatGPT does boost creativity, especially in everyday, practical tasks. Here’s what we learned about how this technology is changing the way people solve problems, brainstorm ideas and think creatively.

ChatGPT and creative tasks

Imagine you’re searching for a creative gift idea for a teenage niece. Previously, you might have googled “creative gifts for teens” and then browsed articles until something clicked. Now, if you ask ChatGPT, it generates a direct response based on its analysis of patterns across the web. It might suggest a custom DIY project or a unique experience, crafting the idea in real time.

To explore whether ChatGPT surpasses Google in creative thinking tasks, we conducted five experiments where participants tackled various creative tasks. For example, we randomly assigned participants to either use ChatGPT for assistance, use Google search, or generate ideas on their own. Once the ideas were collected, external judges, unaware of the participants’ assigned conditions, rated each idea for creativity. We averaged the judges’ scores to provide an overall creativity rating.

One task involved brainstorming ways to repurpose everyday items, such as turning an old tennis racket and a garden hose into something new. Another asked participants to design an innovative dining table. The goal was to test whether ChatGPT could help people come up with more creative solutions compared with using a web search engine or just their own imagination.

two adults and two small children play with an arrangement of cardboard boxes in a brightly lit room with hard flooring

ChatGPT did well with the task of suggesting creative ideas for reusing household items.

Simon Ritzmann/DigitalVision via Getty Images

The results were clear: Judges rated ideas generated with ChatGPT’s assistance as more creative than those generated with Google searches or without any assistance. Interestingly, ideas generated with ChatGPT – even without any human modification – scored higher in creativity than those generated with Google.

One notable finding was ChatGPT’s ability to generate incrementally creative ideas: those that improve or build on what already exists. While truly radical ideas might still be challenging for AI, ChatGPT excelled at suggesting practical yet innovative approaches. In the toy-design experiment, for example, participants using ChatGPT came up with imaginative designs, such as turning a leftover fan and a paper bag into a wind-powered craft.

Limits of AI creativity

ChatGPT’s strength lies in its ability to combine unrelated concepts into a cohesive response. Unlike Google, which requires users to sift through links and piece together information, ChatGPT offers an integrated answer that helps users articulate and refine ideas in a polished format. This makes ChatGPT promising as a creativity tool, especially for tasks that connect disparate ideas or generate new concepts.

It’s important to note, however, that ChatGPT doesn’t generate truly novel ideas. It recognizes and combines linguistic patterns from its training data, subsequently generating outputs with the most probable sequences based on its training. If you’re looking for a way to make an existing idea better or adapt it in a new way, ChatGPT can be a helpful resource. For something groundbreaking, though, human ingenuity and imagination are still essential.

Additionally, while ChatGPT can generate creative suggestions, these aren’t always practical or scalable without expert input. Steps such as screening, feasibility checks, fact-checking and market validation require human expertise. Given that ChatGPT’s responses may reflect biases in its training data, people should exercise caution in sensitive contexts such as those involving race or gender.

We also tested whether ChatGPT could assist with tasks often seen as requiring empathy, such as repurposing items cherished by a loved one. Surprisingly, ChatGPT enhanced creativity even in these scenarios, generating ideas that users found relevant and thoughtful. This result challenges the belief that AI cannot assist with emotionally driven tasks.

Future of AI and creativity

As ChatGPT and similar AI tools become more accessible, they open up new possibilities for creative tasks. Whether in the workplace or at home, AI could assist in brainstorming, problem-solving and enhancing creative projects. However, our research also points to the need for caution: While ChatGPT can augment human creativity, it doesn’t replace the unique human capacity for truly radical, out-of-the-box thinking.

This shift from Googling to asking ChatGPT represents more than just a new way to access information. It marks a transformation in how people collaborate with technology to think, create and innovate.The Conversation

Jaeyeon Chung, Assistant Professor of Business, Rice University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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