Effects of probiotic supplements
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Effects of Probiotic Supplements on Body Weight and Metabolic Health
Probiotic supplementation has been shown to produce small but significant reductions in body weight, body mass index (BMI), and fat percentage in individuals who are overweight or obese, although the effect on fat mass itself is not significant . In adults with metabolic syndrome, probiotics may help lower total cholesterol, but do not appear to significantly affect other metabolic or anthropometric measures such as weight, BMI, waist circumference, or blood sugar . In patients with nonalcoholic fatty liver disease, probiotics can improve liver enzyme levels and lipid profiles, suggesting benefits for metabolic health in specific populations . For pregnant women, probiotics have been found to improve glucose metabolism, particularly by lowering fasting insulin and insulin resistance, but do not significantly affect lipid levels .
Probiotic Supplements and Gut, Immune, and Gastrointestinal Health
In healthy adults, probiotics can temporarily increase the concentration of specific beneficial bacteria in the gut, but there is little evidence that these changes are long-lasting . Probiotics have been shown to improve immune responses, stool consistency, bowel movements, and vaginal lactobacilli concentration in healthy adults . However, the overall effect of probiotics on circulating immune and inflammatory markers in healthy adults is limited, with only some studies showing increases in immune cells or decreases in proinflammatory cytokines Khalesi2018Mohr2020. In athletes, probiotic supplementation may reduce the frequency, severity, and duration of respiratory and gastrointestinal illnesses, likely through interactions with the gut microbiota and immune system .
Probiotics and Mental Health, Cognitive Function, and Oxidative Stress
Probiotic supplementation has demonstrated beneficial effects on mental health in patients with psychiatric disorders, including significant reductions in depression scores and markers of inflammation and oxidative stress such as C-reactive protein and malondialdehyde . In people with cognitive impairment or Alzheimer’s disease, probiotics have been shown to significantly improve cognitive function, especially when single strains are used at higher doses and for longer durations . Additionally, probiotics and synbiotics can increase antioxidant capacity and reduce oxidative stress in adults, as indicated by higher levels of total antioxidant capacity, glutathione, and nitric oxide, and lower levels of malondialdehyde .
Limitations and Areas for Further Research
While probiotics show promise for improving certain health outcomes, the effects are often modest and may be limited to specific populations or conditions. Evidence for persistent changes in gut microbiota or improvements in blood lipid profiles in healthy adults is insufficient . The impact on immune and inflammatory markers in healthy adults is also limited and inconsistent . More research is needed to determine the long-term benefits and optimal strains, doses, and durations of probiotic supplementation for different health outcomes.
Conclusion
Probiotic supplements can offer modest benefits for body weight, metabolic health, immune function, gastrointestinal health, mental health, and cognitive function, particularly in individuals with specific health conditions. However, the effects are generally small, and more research is needed to clarify their long-term impact and effectiveness in healthy populations.
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