Welcome to the April 2025 issue of Research Extracts. “The Extracts” is designed to keep busy practitioners and savvy consumers up to date on the latest research on diet, nutrients, botanicals, the microbiome, the environment, and lifestyle approaches to good health and wellness. Our medical team, including NDs, RDs, MS biology, MS chemistry, an LAc, and a Certified Specialist in Sports Dietetics (CSSD), summarizes the essence of several interesting recent studies. 

In this issue, we have two extracts that focus on dietary factors affecting the gut microbiome. Our complete lineup: (1) Movement Moment: energy availability and marathon performance, (2) shilajit for collagen support, (3) the effect of ultra-processed foods on the gut microbiome, and (4) the effect of juicing on the oral and gut microbiomes.

(Think you already know the results of these studies? You might be surprised.)

Movement Moment: Low Energy Availability Decreases Marathon Performance

Relative energy deficiency in sport (REDs) is a syndrome related to problematic low energy availability (LEA), a mismatch between calorie intake and energy expended through exercise. LEA can be caused by intentional restriction of energy intake or unintentional inadequate intake due to low-energy diets, lack of appetite post-exercise, lack of education around sports nutrition, and more. 

The occurrence rate of REDs can vary from 23-80% in women, 15-70% specifically in female athletes, and can be detrimental to overall athletic performance. Negative health outcomes include impaired bone health, gastrointestinal problems, reproductive dysfunction, and negative performance outcomes, including decreased training response, endurance performance, and muscle strength. 

This free-living, non-randomized observational cohort study recruited participants from the 2022 Boston Marathon (n=1,030) and assessed indicators of LEA to determine if there is a relationship between LEA, marathon race performance, and/or intra-event medical encounters. All participants self-reported physical symptoms, eating, training, and injury history, in addition to completing screening for eating disorders and disordered eating, at which time it was determined if they had indicators of LEA. 

A total of 317 athletes (232 women, 85 men) were found to have indicators of LEA. Athletes with indicators of LEA had an increased likelihood of bone or soft-tissue overuse injuries before the race, worse marathon performances, and twice the risk of an intra-event medical encounter for LEA-related physiological systems, including exercise-induced low blood pressure, fluid and electrolyte abnormalities, gastrointestinal issues, and impaired ability to regulate body temperature. 

Overall findings support that low energy availability, associated with REDs, will increase negative performance outcomes and medical risk in the sports setting. Prevention includes promoting appropriate calorie intake for athletes to preserve health, maintain normal training schedules, and decrease medical risk. 

Note: Thorne has numerous products to support marathon training including our comprehensive Training Bundle, Sleep Bundle for Athletes, and Recovery Bundle. 

Contributed by Maura Donovan MS, RD, CSSD

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Shilajit: Potential Benefit for Supporting Collagen Synthesis*

Shilajit is a natural resin-like substance found in mountainous regions of the Himalayas, Afghanistan, India, Nepal, and other parts of Asia. It has been revered in traditional Eastern medicine systems (e.g., Ayurvedic, Chinese, Tibetan) for its powerful health benefits.

Rich in fulvic acid and essential minerals, shilajit is known for its adaptogenic properties, helping to support energy levels and overall vitality.* Research suggests it may improve cognitive function, promote healthy aging, and boost immune function.* And a recent study suggests shilajit may also be beneficial in promoting collagen synthesis for joint and skin health.* 

Type 1 collagen is essential for the health of skin, eyes, bones, ligaments, tendons, and muscles. Previous studies suggested that shilajit increases gene expression of collagen synthesis, but its effect on circulating collagen levels was unclear.

The study investigated the effects of shilajit supplementation on type 1 collagen synthesis by measuring serum pro-c1α1 levels (a supportive biomarker) in recreationally trained men over eight weeks. Participants received shilajit in a low dose (500 mg/day), a high dose (1,000 mg/day), or as a placebo. 

Key takeaways from the study:

  • Significant increase in collagen biomarker: Both low-dose (500 mg) and high-dose (1,000 mg) shilajit groups showed significant increases in serum pro-c1α1 (a biomarker of type 1 collagen synthesis), while the placebo group showed no change.
  • Dose-dependent effects: The high-dose group had the most significant increase in collagen synthesis, with 75% of subjects exceeding the minimal clinically important difference, compared to 30% in the placebo group.
  • Clinical implications: These findings suggest that shilajit supplementation may effectively enhance collagen production, benefiting skin, joint, and connective tissue health.*
  • Conclusion: Eight weeks of shilajit supplementation (both 500 mg and 1,000 mg per day) increased type 1 collagen synthesis, with greater effects observed at higher doses.

Note: Thorne’s Advanced Testosterone Support formula provides 500 mg of shilajit per serving along with key supportive nutrients like ashwagandha, luteolin, and zinc, for healthy testosterone levels to benefit sexual function and overall body composition.*   

Contributed by Mario Roxas, ND

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Gut Check: The Gut Microbiome’s Silent Struggle Against Ultra-Processed Foods

Our gut microbiome thrives in delicate and intricate homeostasis, forming a symbiotic relationship with our bodies. Yet, modern lifestyles and dietary habits are constantly pushing this balance to the limit. Why? Ultra-processed foods (UPFs). Now a major component of industrialized diets, UPFs are defined by their abnormally long shelf life, ready-to-eat convenience, and long ingredient lists packed with unrecognizable names offering little to no nutritional value. Additives like emulsifiers, artificial sweeteners, and preservatives, which are rarely found in home cooking, are common staples. Designed for convenience, taste, and shelf stability, UPFs dominate the average American diet. However, emerging research has started highlighting serious health implications. For example, in the February issue of Research Extracts we provided a study summary of the effect of UPFs on insomnia. This review examines their detrimental impact on gut health.

The diverse communities that make up our gut microbiome play a fundamental role in supporting immune function, metabolic balance, gut barrier integrity, and regulation of the gut-brain axis. Diets rich in ultra-processed foods disrupt this ecosystem, decreasing microbial diversity and promoting the growth of pro-inflammatory microbiota species. Notably, UPF consumption reduces populations of beneficial microbes like Akkermansia muciniphila and Faecalibacterium prausnitzii, both essential for producing short-chain fatty acids (SCFAs). These SCFAs, like butyrate, maintain mucosal health, regulate inflammation, and protect against inflammatory-driven diseases. Repeated consumption of UPFs diminishes SCFA production, compromising the gut barrier and contributing to what is commonly known as “leaky gut”. Both animal and human studies consistently show that regular UPF consumption triggers metabolic dysfunction, increases visceral fat accumulation, and raises cardiovascular risk – all traced back to gut dysbiosis and barrier impairment.

Once the gut barrier breaks down, intestinal permeability increases, allowing inflammatory molecules like lipopolysaccharides to circulate. Over time, this fuels systemic inflammation, which contributes to the development of chronic conditions such as metabolic syndrome, type 2 diabetes, cardiovascular disease, and inflammatory bowel disease. In addition, shifts in the gut microbiome can disrupt the gut-brain axis, influencing cognitive function and mental health. Studies continue to link UPF-heavy diets to a higher risk of depression, anxiety, and even neurodegenerative diseases, driven by both inflammation and changes in microbial signaling pathways.

Fortunately, this research offers several strategies to mitigate some of these effects. Dietary interventions remain the top priority; reducing UPF consumption while increasing prebiotic fiber-rich whole foods and probiotic fermented products will support a healthy microbial ecosystem. Beyond diet, incorporating regular exercise, stress management, and quality sleep supports gut health. Public health initiatives ranging from amending food labels to limiting UPF marketing, can guide consumers toward healthier choices. Together, these preventive measures offer a multifaceted approach to preserving gut integrity and reducing the long-term health risks associated with UPFs.

Note: Thorne offers a variety of products that support a healthy gut barrier and balanced microbiome, including EnteroMend® and FloraMend Prime Probiotic®. Want to go a step further? Take our Gut Health Test to get a detailed analysis of your gut microbiome, along with personalized recommendations that can contribute to meaningful changes in your gut microbiome.

Contributed by: Ashley Huber, MS

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Effects of Juicing on Oral and Gut Microbiomes

Because fruits and vegetables are rich sources of fiber, vitamins, minerals, and antioxidant polyphenols, juicing these nutritious foods has gained the public’s interest. Short-term juice fasts or cleanses have grown in popularity, with perceived benefits of detoxification, weight loss, and improved digestion. 

While fruit and vegetable juices can provide vitamins and minerals such as beta-carotene and vitamin C, extracting the juice removes beneficial fiber and results in a high-carbohydrate beverage. This study explored the impacts of juice consumption on the gut and oral microbiomes.

In this study, a three-week dietary intervention compared two juice-based diets to a plant-based, whole food diet. Participants were 14 healthy adults ages 18-35 who were randomized to either a typical “juice fast” group, a juice plus regular diet group, or a plant-based, whole food diet group. All participants completed a three-day elimination diet consisting of fresh produce, whole grains, and eggs, and eight glasses of water per day. During this time, participants were advised to avoid processed foods, red meat, dairy, gluten, caffeine, and alcohol to prepare for their assigned diet which also lasted for three days. Bacterial diversity, richness, and composition of the gut and oral microbiomes were assessed via fecal, saliva, and cheek samples at baseline, after the elimination diet, immediately after the intervention diet, and again 14 days after the intervention diet.

The results of this study showed that the various diets impacted the oral and gut microbiomes differently, with larger effects and more sensitivity seen in the oral microbiome compared to the gut microbiome. The exclusive juice diet and the juice plus regular diet groups both saw increases in abundance of pro-inflammatory bacterial species that consume and process simple carbohydrates, likely due to the higher sugar content and total carbohydrate content of the juice interventions. These increases demonstrate potential risk factors for dental diseases, gingivitis, and colorectal or cardiovascular conditions. However, at the end of the post-intervention 14-day period, the microbiomes showed a trend toward reestablishing their original composition, indicating that brief juice interventions may not significantly alter the microbiome in the long term.

Note: Check out Thorne’s gut health suite for a range of products from probiotics and digestive enzymes to nutrients and botanicals to help support healthy microbial balance and gastrointestinal function.*

Contributed by Carly Duffy, MPH, RD

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