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Medscape
2 days ago
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Time Your Meals, Tune Your Metabolism
New research from UC San Diego has revealed fascinating insights into how timing our meals might significantly affect our metabolic health by aligning with our body's natural microbial rhythms. Just as our bodies follow circadian rhythms, our gut microbes have their own daily patterns, with certain beneficial activities increasing during our active periods to help with digestion and metabolism. The study found that unrestricted access to high-fat foods disrupted these natural patterns, leading to unusual daytime eating and metabolic dysfunction — similar to what human shift workers experience when their eating cycles don't match their biological clocks. Using cutting-edge metatranscriptomics technology, researchers identified a specific enzyme called bile salt hydrolase that plays a crucial role in metabolic improvements. When engineered into beneficial bacteria, this led to increased lean muscle mass, reduced body fat, and better blood glucose regulation. These findings could potentially lead to new targeted therapies for common metabolic disorders, offering hope for those struggling with obesity and diabetes. This breakthrough not only demonstrates the significant influence of circadian rhythms on microbial function, but it also provides a new method for testing how specific microbial activities affect our metabolism through engineered gut bacteria. This content was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.
Medscape
2 days ago
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Weighted Vests: Are They Effective for Weight Loss?
With the ongoing obesity epidemic, researchers are constantly looking for strategies that optimize weight loss while minimizing associated side effects. One strategy currently gaining interest is the use of weighted vests— form-fitting garments into which weights are sewn or carried in pockets, enabling the wearer to add or remove them as needed. In theory, this offers a nonpharmacologic way to induce weight loss without the side effects of medications or weight-loss surgery, but with potential bone-sparing effects. The latter is important because even modest weight loss can reduce bone density and strength, increasing the risk for fracture. Weight loss — particularly when induced by caloric restriction — is associated with bone loss, especially at the hip. This is a consequence of loss of muscle mass and an unloading of bones from the decrease in body weight. Even modest diet-induced weight loss results in small but significant reductions in hip bone mineral density (BMD), with less consistent changes at the spine or whole body. These skeletal losses may increase fracture risk, particularly in older adults, and are more pronounced when weight loss occurs in the absence of exercise. Resistance training or combined aerobic-resistance exercise mitigate but do not fully prevent this bone loss. How Do Weighted Vests Help? Weighted vests can be used to preserve muscle mass during periods of caloric restriction. This is achieved by increasing gravitational loading and placing mechanical stress on weight-bearing tissues. Local fat mass is theoretically reduced by the work required to wear the weighted vest. Preservation of muscle mass has the dual benefit of preserving bone mass and maintaining resting metabolic rate (RMR). This is important because weight loss typically results in a lower RMR, which makes subsequent weight loss more difficult. Although using weighted vests does not lead to the same degree of weight loss reported with GLP-1 receptor agonists such as semaglutide, or GLP-1/glucose-dependent insulinotropic peptide (GIP) receptor agonists such as tirzepatide, the data demonstrate benefits of this strategy. For example, 5 weeks of high-load vest use (11% of body weight worn 8 hours per day) vs a low-load vest (1% of body weight) reduced fat mass and waist circumference with no significant change in overall body weight. Loss of fat mass and a reduction in waist circumference are not inconsequential outcomes. Fat distribution (particularly an excess of visceral fat with an increased waist circumference) is a major driver of many metabolic morbidities associated with obesity. In fact, newer definitions of preclinical and clinical obesity emphasize body fat distribution and waist circumference, rather than absolute body weight. The impact of weighted vest use on skeletal health is inconclusive at this time. Snow and colleagues reported preservation of hip BMD over a 5-year period in older, postmenopausal women when weighted vest use was combined with jumping exercises. However, a randomized controlled study from Wake Forest University (INVEST in Obesity) involving 150 older adults with obesity did not find a bone-protective effect of weighted vest use or resistance training following intentional weight loss. Further studies are needed to evaluate the impact on BMD of varying durations of vest use and varying weights of the vest. In conclusion, studies thus far have not demonstrated a significant impact of weighted vests for total weight reduction, although reductions in local fat mass and waist circumference may confer some metabolic benefit. These vests may provide mechanical stimuli that support musculoskeletal integrity; however, further research is necessary to prove this point and data available thus far are conflicting.
Medscape
2 days ago
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These Two Simple Interventions May Cut CRC Recurrence Risk
This transcript has been edited for clarity. Hello. I'm Dr David Johnson, professor of medicine and chief of gastroenterology at Eastern Virginia Medical School and Old Dominion University in Norfolk, Virginia. New guidelines have lowered the age to begin screening for colon cancer to 45 years old. Although this change is positive, we're still seeing advanced cancer in younger patients who haven't been screened in time. Once diagnosed, these patients undergo surgery and chemotherapy and often return to us asking, 'What can I do now to help myself?' Two recent studies highlight interventions that are simple, affordable, and actionable today: exercise and aspirin. Let's take a closer look at the results. Exercise's Risk Reduction Potential The idea that exercise reduces cancer recurrence and mortality is supported by observational data. The mechanistic effects behind this have been ascribed to metabolic growth factors, inflammatory changes, immune function changes, and perhaps even positive impact on sleep. A study just published in The New England Journal of Medicine examined structured exercise after adjuvant chemotherapy for colon cancer. The phase 3 randomized CHALLENGE trial, mostly conducted at Canadian and Australian centers, recruited patients with resected stage II or III colon cancer (9.8% and 90.2%, respectively) who had completed adjuvant chemotherapy. Patients with recurrences within a year of diagnosis were excluded, as they were more likely to have highly aggressive, biologically active disease. Patients were randomized to receive healthcare education materials alone or in conjunction with a structured exercise program over a 3-year follow-up period. The exercise intervention, delivered in person or virtually, focused on increasing recreational aerobic activity over baseline by at least 10 metabolic equivalent task (MET). An increment of 10 MET hours per week is not too vigorous. It is essentially the equivalent of adding about 45-60 minutes of brisk walking or 25-30 minutes of jogging 3-4 times a week. Patients were asked to increase MET over the first 6 months and then maintain or further increase the amount over the next 2.5 years. They were permitted to structure their own exercise program by choosing the type, frequency, intensity, and duration of aerobic exercise. The primary endpoint was disease-free survival, with secondary endpoints assessing overall survival, patient-reported outcomes, and other outcomes. Although designed to detect differences at 3 years, follow-up was also performed out to 5 and 8 years. At a median follow-up of 7.9 years, exercise reduced the relative risk of disease recurrence, new primary cancer, or death by 28% ( P =.02). This benefit persisted — and even strengthened — over time, with disease-free survival increasing by 6.4 and 7.1 percentage points at 5 and 8 years, respectively. Musculoskeletal adverse events were slightly higher in the exercise group compared with the health education group (18.5% vs 11.5%, respectively), but only 10% were directly attributed to the exercise. There are considerations when interpreting these results. First, there was an attrition over time for compliance and training. It would be interesting to see whether that impacted the results. Second, it's unclear whether patient pedigree or a genomic pathway may predispose to a benefit here for the exercise group. But overall, this phase 3 trial provides class 1 evidence supporting exercise as a low-cost, high-impact intervention to reduce cancer recurrence. Adjuvant Aspirin in Colon Cancer Subset That's a perfect segue into another recent study looking at the effects of adjuvant aspirin on the prevention of recurrence. The ALASCCA trial— conducted across centers in Sweden, Denmark, Finland, and Norway — assessed patients with stage I-III rectal cancer or stage II-III colon cancer. It focused on a subset of patients with an oncogenic abnormality called PIK3CA (phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha). PIK3CA occurs in approximately a third of colon cancers and is associated with significant chemotherapy resistance and a higher rate of disease progression. Of the included patients, 1103 (37%) had alterations in the PIK3CA pathway. Researchers randomized patients to receive either 160 mg of aspirin or placebo daily for 3 years, starting within 3 months of surgery. Among patients with PIK3CA mutations, aspirin dramatically reduced the risk for time to recurrence by nearly 50% at 3 years ( P =.044). Adverse events associated with aspirin were minimal, including one case each of gastrointestinal bleeding, hematoma, and allergic reaction. There is no evidence that higher aspirin doses provide greater prevention of colorectal cancer recurrence. The 160 mg use in the current study is fairly normal, roughly equivalent to two low-dose (81 mg) aspirin tablets. Now, it's worth noting that the use of aspirin for the primary prevention of cardiovascular disease was initially recommended by the US Preventive Task Services Force in 2016. This recommendation was then recanted in 2022, when the same group reported limited net benefit to this approach. Two Proactive Actions These studies highlight two interventions — exercise and aspirin — that are low cost, accessible, and appeal to patients eager to help prevent their cancer from recurring. Exercise is broadly beneficial and can be recommended immediately. For aspirin, patients should work with their oncologist to determine their PIK3CA mutation status, as this subgroup appears to benefit the most. These findings offer patients meaningful, proactive interventions they can apply to support their recovery and reduce the risk of recurrence. Hopefully these new findings will help guide your clinical conversations. I'm Dr David Johnson. Thanks for listening.
Medscape
2 days ago
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Think of Exercise as a Vaccine for Your Body
This transcript has been edited for clarity. Let's talk today about how exercise can be viewed as a type of vaccine. With a traditional vaccine, there is a controlled exposure to something harmful, which is typically a viral particle. That exposure, though, allows the immune system to be prepared to deal with that virus if it sees it again later on. Exercise also has the appearance of harm on the surface. It doesn't always feel good in the moment. The whole body is working harder to meet the demands of the exercise. As a result of that extra stress during the exercise activity, the body is then better prepared to deal with stress that can occur from disease processes later on. As a result of the aging process,organ systems are going to decline a little bit in function, and exercise is the best way to combat those declines. Let's think about something like pneumonia, where somebody might have a fever; they're going to be breathing heavy, and their heart's going to be working harder. For someone who's been exercising on a regular basis, their organ systems are better prepared to meet the higher demands associated with a disease process such as pneumonia. In contrast, for someone who has not been exercising frequently, their organ systems have declined in function, and then as a result, they're more likely to be overwhelmed during the disease process. Someone might need medications to support their blood pressure during a pneumonia situation. Someone else might need a mechanical ventilator. In this way, you could view exercise as training for the worst day of your life from a medical perspective. You want to make sure your organs are equipped to deal with stress when it's occurring in an uncontrolled environment, like from an infection such as pneumonia. Vaccines may be a controversial topic for some, but I think exercise is one type of vaccine whose benefits we can all agree upon.
Medscape
2 days ago
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Treatment Considerations for End-Stage COPD
This transcript has been edited for clarity. Hi, everyone. Dr Chandrasekaran here, and today I'm going to talk about end-stage COPD (chronic obstructive pulmonary disease). We commonly diagnose COPD based off one of three things. One being imaging, showing emphysema or bronchitis; one being pulmonary function tests that can show obstruction; and one being symptom-based. Together, these help us to stage, define, manage, and treat patients with COPD. Once they do reach end-stage COPD, this becomes a healthcare burden associated with increased hospitalizations. We manage these patients by making sure they are on triple-therapy inhalers, including a LAMA (long-acting muscarinic antagonist), LABA (long-acting beta agonist), and inhaled corticosteroids. In addition, we can add theophylline or roflumilast to help decrease hospital readmissions. Chronic azithromycin therapy, 250 mg three times a week, has been shown to decrease shortness of breath and recurrent hospital admissions. Prior to starting this, sensorineural hearing tests along with QTc must be done to make sure that they are not increasing or addition, noninvasive ventilation can help these patients, as they do suffer from sleep-disordered breathing, and help decrease the hypercapnia that these patients face. Long-term oxygen therapy needs to be considered for end-stage COPD, along with lung volume reduction surgery in a handful of patients that do qualify and endobronchial valves in patients who have emphysema and qualify for these mechanisms.
