Replacing animal products with plant-based foods leads to weight loss in people with type 1 diabetes, finds new research

Physicians Committee for Responsible Medicine

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WASHINGTON, D.C.—Replacing animal products with plant-based foods—even those defined as “unhealthy” by the plant-based diet index—is an effective strategy for weight loss in adults with type 1 diabetes, finds a new study by the Physicians Committee for Responsible Medicine published in Frontiers in Nutrition. Participants following a vegan diet lost 11 pounds on average, compared to no significant weight loss for participants following a portion-controlled diet.

“Our research shows that replacing animal products with plant-based foods—even so-called ‘unhealthy’ ones, as defined by the plant-based diet index—benefits people with type 1 diabetes who are looking to lose weight,” says Hana Kahleova, MD, PhD, director of clinical research at the Physicians Committee for Responsible Medicine and lead author of the study. “Whether you have an orange and oatmeal for breakfast or orange juice and toasted white bread, either option is a better choice for weight loss than eggs and cottage cheese.”

The new research is a secondary analysis of a Physicians Committee study, which was the first randomized clinical trial to look at a vegan diet in people with type 1 diabetes. In the 12-week study, 58 adults with type 1 diabetes were randomly assigned to either a low-fat vegan group with no limits on calories or carbohydrates, or a portion-controlled group that reduced daily calorie intake for overweight participants and kept carbohydrate intake stable over time.

In this secondary analysis, participants’ dietary records were used to assess the relationship of a plant-based diet index (PDI), healthful PDI (hPDI), and unhealthful PDI (uPDI) with weight loss in adults with type 1 diabetes. “Healthful” plant-based foods, as defined by the PDI system, include fruits, vegetables, whole grains, nuts, legumes, oils, coffee, and tea. “Unhealthful” plant-based foods include fruit juice, sugar-sweetened beverages, refined grains, potatoes, and sweets. In each of the categories, a higher score indicates greater consumption of the plant-based foods in that category.

In the study, the overall PDI score increased on the vegan diet, and did not change on the portion-controlled diet; the hPDI score increased on both diets, more on the vegan diet; and uPDI increased on the vegan diet, and did not change on the portion-controlled diet.

Participants on the vegan diet increased consumption of “healthful” plant foods including legumes, whole grains, and fruits significantly, while consumption of vegetable oils and nuts significantly decreased; on the portion-controlled diet, participants increased their intake of whole grains. Consumption of “unhealthful” plant foods did not change significantly on either diet, except for reduced consumption of refined grains on the portion-controlled diet.

Participants on the vegan diet lost 5.2 kilograms (about 11 pounds) on average, which was associated with changes in PDI and hPDI scores, while there was no weight change for participants on the portion-controlled diet. Changes in uPDI did not result in changes in weight.

The original study found that a vegan diet also reduced insulin needs, improved insulin sensitivity and glycemic control, and led to improvements in cholesterol levels and kidney function in people with type 1 diabetes.

Founded in 1985, the Physicians Committee for Responsible Medicine is a nonprofit organization that promotes preventive medicine, conducts clinical research, and encourages higher standards for ethics and effectiveness in education and research.

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Journal

Frontiers in Nutrition

DOI

10.3389/fnut.2025.1605769 

Method of Research

Randomized controlled/clinical trial

Subject of Research

People

Article Title

Plant-based dietary index and body weight in people with type 1 diabetes: a secondary analysis of a randomized clinical trial

Article Publication Date

21-May-2025

 

Exercise and eat your veggies: Privileged prescriptions like these don’t always reduce risk of heart disease

A leading cardiovascular disease researcher from Simon Fraser University is ringing the alarm on universal recommendations intended to improve heart health around the globe

Simon Fraser University

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A leading cardiovascular disease researcher from Simon Fraser University is ringing the alarm on universal recommendations intended to improve heart health around the globe.

Cardiovascular disease (CVD) is the leading cause of death worldwide, with 80 per cent of deaths occurring in low- and middle-income countries. However, international heart-health guidelines are primarily based on research from high-income countries and often overlook upstream causes of CVD, says Scott Lear, a health sciences professor at SFU and the Pfizer/Heart & Stroke Foundation Chair in Cardiovascular Prevention Research.

“The world extends beyond high-income countries when we think about universal recommendations like 75 minutes of exercise each week or getting five servings of fruit and vegetables every day,” says Lear, the lead author of a new review examining the impact of social, environmental, and policy factors on cardiovascular disease globally.

“There’s a stark contrast between a daily sidewalk stroll in Vancouver's West End and walking to work in New Delhi, the world’s most polluted city, where many people cannot afford to drive and public transit is lacking,” he says. “We cannot assume that life is the same everywhere. The environments in which people live and the kind of work they do makes a huge difference to their health.”

The review paper examined the causes behind the causes of CVD, using data from the ongoing collaborative Prospective Urban Rural Epidemiology (PURE) study. This study has been collecting data from high-, middle- and low-income countries since 2002, and now includes over 212,000 participants from 28 countries across five continents.

PURE study data is collected every three years and includes a core survey, physical measurements (such as height, weight, blood pressure, waist-hip circumference, and lung capacity), and additional questionnaires targeting specific research interests, including CVD.

In addition to physical activity environments, Lear’s review study identified several other causes behind the causes of CVD worldwide, including nutrition, education, tobacco use, air pollution, climate change, social isolation and access to medication, treatment and health care. 

About 87 per cent of PURE participants live in low- or middle-income countries, uniquely positioning the study to examine individual risk factors related to urbanization, says Lear. Although these review findings are based on global data, they also reflect the microcosms of different regions within a single city, or region.

Privilege shapes exercise 

Lack of exercise is a major risk factor for cardiovascular disease, but the type and context of physical activity people do get also plays a role.

According to Lear's review, self-reported physical activity was highest in high-income countries, despite over 22 per cent of participants sitting for more than eight hours a day. By contrast, only 4.4 per cent of participants in low-income countries reported sitting for more than eight hours a day, yet their overall physical activity levels were lower.

The difference lies in the nature of the activity. In low-income countries, physical activity is often tied to work, transportation, and domestic tasks rather than leisure, explains Lear.

Priced out of produce

A healthy diet containing fruits, vegetables, legumes, nuts, fish and dairy can reduce the risk of cardiovascular disease. Lear reported that regardless of country income, fruits and vegetables were more readily available and more affordable in urban areas. 

But he was also surprised to find that consumption of fruits and vegetables is lower in low-income countries because farmers can’t afford to eat their own produce.

 “This is a real eye opener,” says Lear. “For many of these farmers, getting the recommended minimum of five servings of fruits and vegetables a day would eat up 50 per cent of their household income.”

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Journal

European Heart Journal

DOI

10.1093/eurheartj/ehaf212 

Method of Research

Systematic review

Subject of Research

People

Article Title

Social factors, health policy, and environment: implications for cardiovascular disease across the globe

 

Studies look for potential therapy targets for dogs with Chiari-like malformation

North Carolina State University

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A pair of studies from North Carolina State University looked for biomarkers and genetic markers of a syndrome associated with skull malformations common in Cavalier King Charles spaniels (CKCS) and other toy breeds. The findings could lead to better targeted therapeutics for symptoms as well as potential genetic targets for treatment.

Chiari-like malformation (CM) is a congenital disease characterized by a mismatch in size between the cranial vault of the skull that protects the brain and its contents. The disease is also associated with syringomyelia (SM), a condition where a fluid-filled cavity forms within the spinal cord.

Cavalier King Charles spaniels have a high prevalence of CM and SM, and both conditions can cause neuropathic pain and phantom itching, where the dog scratches at the head and neck without making contact.

“Understanding the source of the clinical signs of CM and SM is complicated given the signs and MRI findings don’t always match,” says Natasha Olby, Dr. Kady M. Gjessing and Rahna M. Davidson Distinguished Chair in Gerontology at NC State. Olby is the corresponding author of both studies.

“We know that humans with neuropathic pain and migraine have elevated levels of a biomarker called Calcitonin Gene-Related Peptide (CGRP), and antagonists to CGRP signaling have provided some effective migraine treatments,” Olby says. “But no one has ever measured the levels of this biomarker in Cavalier King Charles spaniels.”

In the first study, Olby and her team looked at 29 CKCS – using imaging, cerebrospinal fluid samples and pain evaluation – and found that levels of CGRP were elevated in dogs with CM and with painful symptoms, but that CGRP levels were not correlated with the presence of SM.

“In people, SM causes pain, abnormal sensations and weakness in extremities, but in dogs, even when we see the condition there may not necessarily be clinical signs,” Olby says. “Although this was a small study, it points to CGRP as an active pathway in CM, which presents a potential avenue for future therapy.”

In the second study, the team looked for genetic markers associated with the presence of clinical signs of CM and SM.

“The discomfort associated with CMSM is distressing,” Olby says. “Finding genetic markers for the disease would not only give us better insight into the disease itself and treatment pathways, it could also allow CKCS breeders to breed away from the trait entirely.”

The researchers took DNA samples and did MRI imaging on 179 CKCS. Owners also filled out questionnaires regarding their dog’s symptoms and behavior.

The findings were mixed.While no specific regions were associated with the presence of SM alone, the presence of signs of pain and scratch was associated with a region on one chromosome that had previously been associated with skull changes in these dogs.

“We identified a region of interest in a gene also identified by another group using different methods,” Olby says. “This work confirms the area as a region of interest and gives us a place to focus our future work.”

The papers, “Cerebrospinal Fluid Concentrations of Calcitonin Gene Related Peptide in Dogs with Chiari-like Malformation” and “Cerebrospinal Fluid Concentrations of Calcitonin Gene Related Peptide in Dogs with Chiari-like Malformation” appear in the Journal of Veterinary Internal Medicine and BMC Veterinary Research, respectively. Co-authors from NC State are John D. Macri, Courtney Sparks, Zachary Anderson, Michael W Vandewege and Meghan Leber. Jonah N. Cullen and Steven G. Friedenberg of the University of St. Paul co-authored the BMC Veterinary Research paper. The work was supported by the Cavalier King Charles Spaniel USA Health Foundation, the American Cavalier King Charles Spaniel Club Charitable Trust (through the American Kennel Club Canine Health Foundation grant number 02162-MOU), and the National Institutes of Health (grant number F30OD025357).

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Note to editors: Abstracts follow.

“Cerebrospinal Fluid Concentrations of Calcitonin Gene Related Peptide in Dogs with Chiari-like Malformation”

DOI: 10.1111/jvim.70105

Authors: John D. Macri, Courtney Sparks, Zachary Anderson, Natasha Olby, North Carolina State University
Published: May 3, 2025 in the Journal of Veterinary Internal Medicine

Abstract:
Background
The biomarker Calcitonin Gene-Related Peptide (CGRP) is elevated in human conditions associated with neuropathic pain, but has not yet been studied in Cavalier King Charles Spaniels (CKCS) with Chiari-like malformation (CM).
Hypothesis/Objectives
Cavalier King Charles Spaniels with clinical signs of CMSM would have higher CSF concentrations of CGRP than asymptomatic CKCS. Our aim was to measure CSF CGRP concentrations in CKCS with and without clinical signs of CMSM.
Animals
Twenty-nine CKCS drawn from research and clinical cases underwent quantification of pain and scratching, a brain and spinal cord MRI, and lumbar CSF collection.
Methods
This was a prospective study with both normal and clinically affected CKCS recruited. The CSF concentration of CGRP (C-CGRP) was measured using an ELISA assay. Dogs were grouped by the presence of SM, pain, and scratching, and concentrations of C-CGRP were compared between groups using Wilcoxon Rank Sum. The concentration of C-CGRP, pain score, and SM diameter were evaluated using linear regression.
Results
Concentration of C-CGRP was significantly higher in painful dogs (median 116.1, range: 11.6–238.3 pg/mL) as compared to non-painful dogs (median 77.7 pg/mL, range 0–266.2 pg/mL; p = 0.0124). No significant difference in C-CGRP concentration was noted between dogs with (median 99.3, range 0–226.6 pg/mL) and without (median 102.2, range 6.0–266.2 pg/mL) SM (p = 0.305).
Conclusions and Clinical Importance
Cerebrospinal fluid CGRP concentration is elevated in CKCS exhibiting pain regardless of the presence of SM. CGRP might contribute to neuropathic pain in CMSM and could be a target for therapeutic intervention.

“Genomic analyses in Cavalier King Charles spaniels identify loci associated with clinical signs of Chiari-like malformation and Syringomyelia”

DOI: 10.1186/s12917-025-04754-4

Authors: Courtney R. Sparks, Michael W. Vandewege, Meghan Leber & Natasha J. Olby, North Carolina State University; Courtney R. Sparks, Michael W. Vandewege, Meghan Leber, University of Minnesota
Published: May 3, 2025 in BMC Veterinary Research

Abstract:
Background
Chiari-like malformations (CM) and syringomyelia (SM) are common in Cavalier King Charles spaniels (CKCS) leading to variable manifestations of pain and scratch. Inheritance studies suggest a polygenic mode of inheritance and association studies have identified loci associated with the presence of SM on MRI. Given the poor correlation of clinical signs of CMSM with MRI findings, we hypothesized that an association study with clinical signs as the phenotype could reveal new loci of interest. The objectives of this study were to perform genome-wide association studies on CKCS using SM and clinical sign phenotypes of pain and scratch and to use whole genome sequencing (WGS) to identify variants in regions of interest. We collected DNA on 174 CKCS. Owners completed questionnaires to establish the clinical pain and scratch phenotype and magnetic resonance imaging (MRI) was used to identify CM and SM (linear T2 hyperintensity greater than 2 mm in height) in all dogs. Dogs were genotyped using the Axiom K9 HD (710,000 snps) array. GWAS analyses were performed using GEMMA and categorical and quantitative approaches were used to define clinical phenotypes. Whole genome sequencing (WGS) was performed on an Illumina HiSeq 4000 high-throughput sequencing system.
Results
There were no regions associated with SM presence. The presence of signs of pain and scratch was associated with a region on Canis familiaris autosome (CFA) 26 downstream of ZWINT, previously associated with skull changes in CKCS with SM, although genome-wide significance was not reached. Loci were also associated with quantitative pain and scratch scores on CFA 13, 2 and 38. There were 66 variants that segregated with phenotype including 2 missense variants that were predicted to have moderate effects on ZWINT function.
Conclusions
The identification of a locus on CFA26 using the clinical phenotype of pain and scratch that coincided with a locus identified in a morphological study provides strong support for this as a region of interest.

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Journal

Journal of Veterinary Internal Medicine

DOI

10.1111/jvim.70105 

Method of Research

Experimental study

Subject of Research

Animals

Article Title

“Cerebrospinal Fluid Concentrations of Calcitonin Gene Related Peptide in Dogs with Chiari-like Malformation”

Article Publication Date

3-May-2025

COI Statement

Natasha Olby has consulted for TriviumVet on study design to evaluate a questionnaire for owners of dogs with CMSM. There was no link between the studies.

 

The scent of death? Worms experience altered fertility and lifespan when exposed to dead counterparts

Michigan Medicine - University of Michigan

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image: 

Artist's illustration of C. elegans escaping from deceased counterparts.

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Credit: Justine Ross/Michigan Medicine

The mere presence of a dead counterpart elicits strong responses across species.

For example, many insects such as bees and ants will instinctively remove dead members from the hive, seemingly to keep the nest clear of any potential pathogens.

Research from a team at University of Michigan describes a similar aversion for decedents among the roundworm C. elegans.

They’ve discovered that the presence of dead members of their species has profound behavioral and physiological effects, leading the worms to more quickly reproduce and shortening their lifespans.

“We felt this was quite a unique opportunity to start diving into what is happening mechanistically that enables C. elegans to detect a dead conscript and then what drives their reaction,” said Matthias Truttmann, Ph.D., of the Department of Physiology at U-M Medical School, senior author on the paper, published in Cell Reports.

First author was graduate student and Truttmann lab member Mirella Hernandez-Lima.

Truttmann’s lab studies the maintenance of proper protein function with aging. 

C. elegans, due to their relatively short lifespans, is an ideal model for studying life and life extension.

Their recent study sprung from an observation that worms in a dish would move as far away as possible from deceased counterparts.

The team wondered how the worms – who do not have eyes– determined that their plate-mates were dead and whether there could be a universal death signal emitted by corpses.

To test this, they introduced either worm corpses or fluid from the broken-down cells of worm corpses to different feeding areas on a plate.

They observed that C. elegans showed strong avoidance behavior for both.

Furthermore, they found that death perception led to reduced fitness in exposed worms and a short term increase in egg laying.

They then systematically tested the worms’ sensory neurons to determine which were necessary for the perception of death.

They found two neurons that respond to olfactory information, AWB and ASH—essentially the worms could smell death.

Specifically, the team identified two metabolites, AMP and histidine, which are normally found inside of cells, were the death cues for C. elegans.

“The neurons we identified are well known to be involved in behavioral responses to a variety of environmental cues,” said Truttmann.

“We have now found that they also detect a couple of intracellular metabolites that are not typically found in the environment. If they are around, it indicates that a cell has died, popped open, and that something has gone wrong."

The presence of cellular metabolites where they should not be could very well be an evolutionarily maintained signal of death, says Truttmann.

He points to a recent finding in humans that cells undergoing apoptosis (cell death) release metabolites that result in transcriptional changes in neighboring tissue.

How the detection of this signal ultimately translates into altered health and behavior needs further research.

Additional authors: Brian Seo and Nicholas D. Urban.

Paper cited: “Modulation of C. elegans behavior, fitness, and lifespan by AWB/ASH-dependent death perception.” Current Biology. DOI: 10.1016/j.cub.2025.03.071 

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Journal

Current Biology

DOI

10.1016/j.cub.2025.03.071 

Article Title

Modulation of C. elegans behavior, fitness, and lifespan by AWB/ASH-dependent death perception

Extreme weather events linked to HIV vulnerabilities among sex workers and sexually diverse men in Kenya

Researchers find interconnections between climate change-related extreme weather events and HIV vulnerabilities, such as increased transactional sex, reduced condom agency, increased risk of sexual violence, and LGBTQ stigma

University of Toronto

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Toronto, ON – New research published earlier this month in AIDS and Behavior highlights links between extreme weather events, such as drought and flooding, and increased HIV vulnerabilities among sex workers and sexually diverse men in Nairobi, Kenya. 

While there has been growing attention to the impacts of climate change on HIV vulnerabilities, past research has largely overlooked key populations, such as sex workers and gay, bisexual, and other men who have sex with men (gbMSM), comprising a critical knowledge gap.

“Climate shocks and extreme weather events are already known to exacerbate poverty and resource scarcity, which can amplify HIV risk. Sex workers and gbMSM may be particularly vulnerable to these adversities because of the compounding impacts of stigma and social marginalization,” says lead author Carmen Logie, a Professor at the University of Toronto’s Factor-Inwentash Faculty of Social Work (FIFSW) and an Adjunct Professor at the United Nations University Institute for Water, Environment, and Health.

Researchers from the University of Toronto in partnership with Kenyan community-based collaborators conducted a multi-method qualitative study with 21 sex workers and 15 gbMSM to examine their lived experiences navigating climate change, extreme weather events, resource insecurities (such as a lack of food or water), and HIV vulnerabilities. 

Participants described numerous interrelated connections between extreme weather events and HIV vulnerabilities. For example, drought and flooding led to food and water insecurity, which resulted in participants enacting coping strategies that may increase HIV risk, including increased transactional sex where there is often less agency to negotiate condom use. 

Participants also described facing increased risks of sexual violence when having to travel longer distances to access water, another pathway by which resource scarcity can increase HIV vulnerability.

“Our findings align with emerging research on the links between climate change-related resource insecurities and HIV vulnerabilities through numerous pathways, including transactional sex, sexual violence, and reduced condom efficacy,” says co-author Andie MacNeil, a PhD student at FIFSW. “Combined, this research underscores the urgent need to address resource scarcities, particularly among vulnerable populations in climate-affected areas.” 

Participants also shared how LGBTQ stigma contributed to broader issues of economic precarity that were worsened by extreme weather events and resulting resource scarcities. While the impacts of climate change are widespread, the interplay of stigma and social marginalization creates particular challenges for sex workers and gbMSM. 

“Intersecting stigmas related to sex work and LGBTQ status intensify the harmful impacts of extreme weather events,” says co-author Humphres Evelia, Executive Director of the Centre for the Study of Adolescence in Nairobi, Kenya. “The participants in our study described reduced access to care and increased risks of criminalization due to their identities, compounding the effects of extreme weather.” 

The researchers are hopeful that this study can help inform strategies to mitigate HIV risk in the context of climate change. 

“Interventions to reduce resource scarcities are paramount to addressing HIV vulnerability,” says Logie. “There is a need for further development and evaluation of climate-informed HIV interventions, such as long acting PrEP and mobile pharmacies, with particular consideration for reducing stigma and ensuring these services are tailored for sex workers and gbMSM.” 
 

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Journal

AIDS and Behavior

DOI

10.1007/s10461-025-04759-y 

Article Title

Extreme weather events and linkages with HIV vulnerabilities among young sex workers and sexually diverse men in Nairobi, Kenya: Qualitative multi-method insights.

Article Publication Date

22-May-2025

COI Statement

CHL was supported by the Canada Research Chairs Program (CRC in Global Health Equity & Social Justice with Marginalized Populations) and Canada Foundation for Innovation (CFI). LG was supported by a Social Sciences and Research Council of Canada (SSHRC) post-doctoral fellowship.