Browse the evidence

Resistance training has small effects on muscle morphology (mass/size) in older adults, and no single training volume variable significantly predicts these morphological changes.

If your goal is muscle size (not just strength), expect small gains. Use moderate weights (51-69% 1RM), train 3 times a week, and rest 120 seconds between sets. Focus on long-term consistency (over a year) rather than specific volume metrics, as no single volume variable strongly predicts muscle growth in older adults.

Patients with non-alcoholic steatohepatitis (NASH) exhibit a significantly lower relative abundance of Bacteroidetes in their intestinal microbiota compared to healthy controls and those with simple steatosis, an association that persists independently of BMI and dietary fat intake.

If you have NASH, your gut bacteria profile is likely distinct from healthy individuals, specifically showing lower levels of Bacteroidetes. This difference is not just because of being overweight or eating fat, but is linked to the liver inflammation itself. While this paper doesn't prescribe a fix, it highlights that restoring gut balance (potentially through fiber or specific prebiotics that support Bacteroidetes) might be a relevant therapeutic avenue to discuss with your hepatologist, separate from weight loss efforts.

Elevated serum creatine kinase (CK) following exercise is primarily a marker of cellular energy regulation and membrane permeability changes driven by AMPK, rather than a direct indicator of structural muscle damage or necrosis.

Do not use serum CK levels alone to judge workout quality or injury risk. High CK is a normal physiological response to energy demands and membrane permeability changes, often regulated by AMPK, and does not automatically imply structural damage. Focus on performance metrics and recovery feelings instead.

Selenium supplementation improves fertility in dairy cows, primarily by reducing embryonic mortality during the first month of pregnancy, with effects not replicated by vitamin E alone.

If you are managing livestock in selenium-deficient areas, standard antioxidant supplementation (like Vitamin E) is insufficient. Targeted selenium supplementation is required to significantly reduce early embryonic loss and improve overall fertility rates.

Administration of antiangiogenic agents (specifically angiostatin, endostatin, or TNP-470) induces dose-dependent, reversible weight loss and adipose tissue loss in obese animal models without reducing food intake.

This research suggests that blocking the blood vessel growth required for fat tissue expansion can cause fat loss even if you eat the same amount of food. While this is currently only proven in mice using specific drugs (like angiostatin or endostatin), it implies that future treatments might target the blood supply to fat cells rather than just focusing on diet and exercise.

Exposure to environmental factors such as road traffic noise and fine particulate matter increases the risk of type 2 diabetes by 20-40% for every 10 dB increase in noise or 10 μg/m3 increase in fine dust.

Minimize your exposure to road traffic noise and fine particulate matter, as living near busy roads increases diabetes risk by 20-40%. Use air purifiers, soundproof your home, and spend time in greener areas to reduce this environmental risk factor.

Initiation of testosterone therapy (TT) in men aged 65 years and older is associated with a significantly increased risk of non-fatal myocardial infarction within the first 90 days of prescription.

If you are a man over 65 starting testosterone therapy, be aware that your risk of a heart attack is roughly doubled in the first three months. This risk is highest in men with existing heart disease. Discuss this risk with your doctor, who may monitor you more closely or consider alternative treatments if you have significant cardiovascular history.

Initiation of testosterone therapy (TT) in men under 65 years with a pre-existing history of heart disease is associated with a significantly increased risk of non-fatal myocardial infarction within the first 90 days of prescription.

If you are under 65 but have a history of heart disease, starting testosterone therapy significantly increases your risk of a heart attack in the first three months. This risk is nearly three times higher than baseline. You should discuss this specific risk with your doctor, who may recommend closer monitoring or alternative treatments.

Testosterone therapy (TT) does not significantly increase the risk of non-fatal myocardial infarction in men under 65 years without a history of heart disease.

If you are under 65 and have no history of heart disease, starting testosterone therapy does not appear to significantly increase your risk of a heart attack in the first three months. However, you should still discuss potential risks with your doctor, especially if you have other cardiovascular risk factors.

Gut microbiota composition directly influences systemic inflammation through the production of specific metabolites: Short-Chain Fatty Acids (SCFAs) like butyrate inhibit pro-inflammatory pathways (e.g., NFκB), while Lipopolysaccharides (LPS) and Trimethylamine N-Oxide (TMAO) promote inflammatory cascades and insulin resistance.

Focus on dietary fiber to feed beneficial gut bacteria that produce anti-inflammatory short-chain fatty acids (like butyrate). Reduce intake of high-fat, low-fiber 'Western' diets which may promote pro-inflammatory bacteria and LPS release. Probiotic therapies targeting specific strains (e.g., Faecalibacterium) show promise for reducing inflammation, but individual responses vary.

Sirt1 activation promotes mitochondrial biogenesis through the deacetylation and activation of PGC-1α, a process supported by evidence from caloric restriction and specific Sirt1 activators like resveratrol and SRT1720.

Caloric restriction and compounds that activate Sirt1 (like resveratrol) may support mitochondrial health by activating PGC-1α. However, the evidence is mixed, and results depend heavily on the specific context, dosage, and individual metabolic state. It is not a guaranteed or universal solution for mitochondrial biogenesis.

Sirt1 promotes mitophagy (the turnover of defective mitochondria) through mechanisms involving NAD+ levels and potentially the PINK1/Parkin pathway.

Sirt1 activation, potentially through nicotinamide or SRT1720, may promote the removal of damaged mitochondria (mitophagy). This is part of a broader cellular quality control mechanism that may contribute to longevity and health. More research is needed to fully understand how to harness this for therapeutic benefit.

Exogenous leptin promotes angiogenesis and endothelial cell proliferation by binding to Ob-R receptors and activating tyrosine kinase-dependent pathways (specifically Erk1/2).

This research suggests that high levels of leptin, common in obesity, may actively fuel the growth of new blood vessels in fat tissue. This creates a feedback loop where more fat leads to more leptin, which builds more blood vessels, allowing even more fat storage. Managing leptin levels through weight loss may help reverse this vascular support for adipose tissue.

Testosterone therapy in adult men significantly increases hemoglobin and hematocrit levels and decreases high-density lipoprotein (HDL) cholesterol, but does not significantly affect mortality, cardiovascular events, or prostate outcomes.

If you are considering testosterone therapy, expect your red blood cell counts (hemoglobin/hematocrit) to rise and your good cholesterol (HDL) to drop slightly. You will need regular blood tests to monitor these changes. Current large-scale reviews do not show that testosterone increases your risk of heart attacks, strokes, or prostate cancer, but the long-term safety data is still considered low quality due to short study durations.

GLP-1 receptor agonists (e.g., exenatide, liraglutide) and DPP-IV inhibitors preserve beta-cell mass by stimulating proliferation, neogenesis, and inhibiting apoptosis.

GLP-1 based drugs (injections like exenatide/liraglutide or oral DPP-IV inhibitors like sitagliptin) can help your pancreas make more beta-cells and stop them from dying. This is achieved by mimicking or extending the action of the GLP-1 hormone.

Resveratrol extends lifespan in invertebrate models (yeast, C. elegans, Drosophila) by activating sirtuins (specifically Sir2/SIRT1), mimicking the effects of calorie restriction, though this mechanism is controversial in vertebrates and humans.

Resveratrol extends lifespan in simple organisms like worms and flies by activating sirtuins, similar to calorie restriction. However, this effect is not clearly replicated in humans or other vertebrates, and the mechanism is debated. Do not rely on it as a substitute for healthy living.

Specific SCFAs (propionate and acetate) increase energy expenditure and fat oxidation by activating FFA3 and FFA2 receptors, respectively, independent of changes in food intake.

While you cannot directly inject SCFAs, consuming fermentable fibers (resistant starch, inulin) allows your gut bacteria to produce them. This process may subtly boost your fat burning and energy expenditure by stimulating your sympathetic nervous system, acting as a small but consistent metabolic booster alongside exercise.

Caloric restriction and fasting-mimicking diets modulate aging pathways (NF-κB, mTOR, MAPK) to reduce pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) and counteract inflamm-aging.

Intermittent fasting or caloric restriction may help reduce chronic inflammation in older adults by modulating key aging pathways. However, these approaches require careful planning and may not be suitable for everyone, especially those with poor nutrition.

Administration of the probiotic VSL#3 prevents and reverses diet-induced obesity and type 2 diabetes in mice by increasing gut flora-derived butyrate, which stimulates GLP-1 secretion from intestinal L-cells, thereby reducing food intake and improving glucose tolerance.

This research suggests that specific probiotic formulations (like VSL#3) may help manage weight and blood sugar by boosting gut bacteria that produce butyrate. Butyrate then triggers the release of GLP-1, a hormone that reduces appetite and improves glucose handling. While promising in mice, this is not yet a standard human treatment, and individual results may vary based on existing gut microbiome composition.

Aging (immunosenescence) leads to a decline in adaptive immunity, particularly a reduction in naive T cells and thymic involution, increasing susceptibility to infections and reducing vaccine efficacy.

As you age, your immune system naturally changes, making you more susceptible to infections and less responsive to vaccines. While you cannot reverse thymic involution, maintaining optimal nutritional status through diet or targeted supplementation may help mitigate some of these age-related immune declines.

Very low sodium intake (<3g/day) can increase cardiovascular risk by activating the renin-angiotensin-aldosterone system and sympathetic nervous system, leading to insulin resistance and increased mortality.

Avoid extremely low sodium diets. While reducing excess salt is good, going to the other extreme can trigger stress hormones and increase heart risk. A moderate intake is best for most people.

In North America, living in low-income or minority neighborhoods is associated with constrained access to supermarkets and higher prices for healthy foods, which contributes to higher obesity rates; this contextual effect is not consistently observed in the UK, Australia, or the Netherlands.

If you live in the US or Canada, your neighborhood's lack of healthy food options and higher prices may be a significant barrier to healthy eating, contributing to weight gain. However, if you live in the UK, Australia, or similar regions, simply moving to an area with more supermarkets may not solve obesity issues, as studies show no consistent link between store proximity and diet quality there. Focus on individual dietary choices and physical activity, as environmental constraints may be less decisive in your region.

Fast-food outlets are more prevalent in poorer and minority neighborhoods in North America, and this density is associated with higher obesity rates and cardiovascular outcomes, whereas this association is not consistently found in the UK or Australia.

If you live in an area with many fast-food outlets, you are likely exposed to higher energy-dense foods, which contributes to obesity. This is particularly true in North America. Be aware of your surroundings and try to limit consumption of these high-calorie, low-nutrient foods, even if they are convenient and affordable.

Adipokines such as resistin and leptin play a role in insulin resistance, with resistin exhibiting insulin-antagonistic effects and leptin signaling influencing adiponectin expression.

Managing body weight can help normalize adipokine levels, potentially improving insulin sensitivity by reducing resistin and restoring healthy leptin-adiponectin balance.