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How to reduce brain inflammation: 4 actions you can take today
Dr Ruscio is a Doctor of Natural Medicine, Doctor of Chiropractic, clinical researcher and author. His podcast, Dr Ruscio Radio presents cutting edge information in health, nutrition and functional medicine distilled into practical advice that can be used to improve our health.
2023
Abstract
Dr Ruscio focuses on the link between brain inflammation and neurodegenerative diseases such as Alzheimer’s and Parkinson’s but also brain fog and mood. He summarises how it might be possible to reduce neuroinflammation through diet, looking at the links with dysbiosis and leaky gut but also exercise, sleep hygiene, and stress management. A concise overview of the evidence for diets such as Paleo, Low FODMAP, Ketogenic and Low Carb, as well as the Mediterranean diet for reducing inflammation and supporting brain health is provided. The potential for lab testing via anti and pro-inflammatory markers is also reviewed.
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Multispecies probiotic administration reduces emotional salience and improves mood in subjects with moderate depression: a randomised, double-blind, placebo-controlled study.
Baião, R, Capitão, LP, Higgins, C, Browning, M, Harmer, CJ, Burnet, PWJ
Psychological medicine. 2023;53(8):3437-3447
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Gut microbiota may be able to augment an individual’s mood, brain processing and cognition. Supplements containing live bacteria or a diet high in fibre which act as a substrate for beneficial gut bacteria may be of benefit to individuals with depression or mental illness. This 4-week randomised control trial aimed to determine the effect of a probiotic containing several different gut bacteria species on emotional processing and cognition in people with mild to moderate depression. The results showed that compared to placebo, probiotic intake increased empathy with others and improved some but not all aspects of cognition. Probiotic intake did not affect biological measures of stress but did improve feelings of depression. It was concluded that multispecies probiotics may change the emotional processing of people with depression. This study could be used by healthcare professionals to understand that the use of probiotics may be a good option to reduce the risk of people with mild to moderate depression developing a major depressive disorder.
Abstract
BACKGROUND The potential antidepressant properties of probiotics have been suggested, but their influence on the emotional processes that may underlie this effect is unclear. METHODS Depressed volunteers (n = 71) were recruited into a randomised double-blind, placebo-controlled study to explore the effects of a daily, 4-week intake of a multispecies probiotic or placebo on emotional processing and cognition. Mood, anxiety, positive and negative affect, sleep, salivary cortisol and serum C-reactive peptide (CRP) were assessed before and after supplementation. RESULTS Compared with placebo, probiotic intake increased accuracy at identifying faces expressing all emotions (+12%, p < 0.05, total n = 51) and vigilance to neutral faces (mean difference between groups = 12.28 ms ± 6.1, p < 0.05, total n = 51). Probiotic supplementation also reduced reward learning (-9%, p < 0.05, total n = 51), and interference word recall on the auditory verbal learning task (-18%, p < 0.05, total n = 50), but did not affect other aspects of cognitive performance. Although actigraphy revealed a significant group × night-time activity interaction, follow up analysis was not significant (p = 0.094). Supplementation did not alter salivary cortisol or circulating CRP concentrations. Probiotic intake significantly reduced (-50% from baseline, p < 0.05, n = 35) depression scores on the Patient Health Questionnaire-9, but these did not correlate with the changes in emotional processing. CONCLUSIONS The impartiality to positive and negative emotional stimuli or reward after probiotic supplementation have not been observed with conventional antidepressant therapies. Further studies are required to elucidate the significance of these changes with regard to the mood-improving action of the current probiotic.
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Effect of Docosahexaenoic Acid and Eicosapentaenoic Acid Supplementation on Sleep Quality in Healthy Subjects: A Randomized, Double-Blinded, Placebo-Controlled Trial.
Yokoi-Shimizu, K, Yanagimoto, K, Hayamizu, K
Nutrients. 2022;14(19)
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Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are unsaturated Omega-3 fatty acids, primarily found in fish and seafood. The fatty acids fulfil many vital roles in the body, such as creating cell membranes, supporting brain functions and being associated with many disease-protective benefits. These fatty acids also influence sleep in children and young adults, but less is known about their effect in older people. Hence, this Japanese study investigated the impact of EPA and DHA on sleep quality in people above the age of ≥ 45. 66 males and females with poor sleep participated in this randomized, placebo-controlled, double-blinded, parallel-grouped study. They either received 860 mg of combined DHA/EPA per day (576 mg DHA/284 mg EPA) or a placebo of corn oil for 12 weeks. The outcome was assessed subjectively via sleep quality and mood questionnaires, as well as objectively with a sleep scanner and blood samples. Blood samples and blood pressure where also monitored as a safety measure. Upon completion of the study there was a subjective improvement, which was backed-up by the results of the sleep scanner. This study confirmed that DHA/EPA improves sleep quality in the middle aged and older population and does so at doses lower than those administered in previous studies. The authors had set the daily minimum intake of DHA/EPA at 860 mg/day for this trial, as previous research showed no effects at lower doses. They also noted that poor responders tended to be people with pre-existing conditions or those who were pregnant. This population may require higher dosages of DHA/EPA than healthy patients. Overall, the intervention was well tolerated. Ensuring adequate DHA and EPA levels and intake could be part of nutritional strategies for sleep support.
Abstract
Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA)-omega-3 fatty acids with various functions-influence sleep in children and young adults. However, only limited studies on their effects on sleep in middle- and old-aged adults have been reported. Therefore, we investigated the effects of DHA and EPA on sleep quality in subjects aged ≥ 45 years. We performed a randomized, placebo-controlled, double-blinded, parallel-grouped study, in which we randomly assigned 66 healthy Japanese males and females. Each individual received six 480 mg capsules containing 576 mg DHA and 284 mg EPA per day (DHA/EPA group, n = 33), or corn oil (placebo group, n = 33), for 12 weeks. Before and after the intervention, the Oguri-Shirakawa-Azumi sleep inventory MA version (OSA-MA) and the sleep state test were conducted. In the DHA/EPA group, factor III (frequent dreaming) scores among the OSA-MA scores were significantly improved compared to the placebo group. Additionally, sleep state tests revealed that sleep efficiency improved in the DHA/EPA group. To our knowledge, this study is the first to report that DHA/EPA improves sleep quality in middle- and old-aged individuals, even at doses lower than those administered in previous studies.
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Micronutrients for Attention-Deficit/Hyperactivity Disorder in Youths: A Placebo-Controlled Randomized Clinical Trial.
Johnstone, JM, Hatsu, I, Tost, G, Srikanth, P, Eiterman, LP, Bruton, AM, Ast, HK, Robinette, LM, Stern, MM, Millington, EG, et al
Journal of the American Academy of Child and Adolescent Psychiatry. 2022;61(5):647-661
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Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental condition that affects about 5-7% of children. Characteristics of ADHD are age-inappropriate hyperactivity, impulsivity, and difficulties in focusing attention which arise from an impaired ability to regulate executive and emotional functions. The condition often persists into adulthood, where it presents an increased risk for poor educational achievements, substance abuse, incarceration, and mental health problems. In many cases, drug treatment can improve ADHD symptoms, yet concern remains about the side effects of these treatments. Some research has investigated the impact of nutrient supplementation on ADHD management, as many nutrients are essential for healthy brain function and are also involved in the production of neurotransmitters. In previous studies, supplementation with nutrients has shown some benefits but likewise also inconsistent results. This eight-week randomised placebo-controlled clinical trial evaluated the effects of a multi-nutrient supplement in 135 children with ADHD, aged 6-12 years. The study specifically focused on irritable mood symptoms. The multi-nutrient formula contained vitamins, minerals, amino acids, and antioxidants. Outcomes were measured by scores rated by clinicians (Clinical Global Impression-Improvement aka CGI-I) and scores rated by parents (Child and Adolescent Symptom Inventory-5 aka CASI-5). The multi-nutrient formula showed overall benefit in the blinded clinician rating but not by parental reports. According to the parents, overall improvement was reported, both in the placebo and intervention groups. The authors discussed how this absence of difference can be explained. Yet, on a subscale, the multi-nutrient group parents were more likely to report improvements. In addition, children with the additional micronutrients demonstrated greater height growth during the intervention. The supplement was well tolerated with good adherence and the monitored blood markers demonstrated safety of use.
Expert Review
Conflicts of interest:
None
Take Home Message:
This fully-blinded RCT of micronutrients addresses several concerns related to existing ADHD treatment, including the possibility of counteracting height suppression and treating associated irritable mood, emotional dysregulation, and aggression.
Although further research is needed, multinutrient supplementation should be considered for children with ADHD.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction
Attention-deficit hyperactivity disorder (ADHD) is a common psychiatric condition that can result in low educational performance and achievement. Around 5-7% of children are believed to be affected. Alongside inattention and hyperactivity, emotional dysregulation is a common feature of ADHD. Psychiatric problems can continue into adulthood and an increased risk of incarceration and substance abuse have been reported.
Treatment with prescription medications may improve symptoms of ADHD, however, potential side effects include mild growth suppression, and mood and emotional dysregulation. Non-pharmacological treatments are therefore being investigated.
Previous research on single nutrients have shown mixed results for emotional dysregulation and mood issues in ADHD. The aim of this study was to test whether supplementation with a multi-nutrient could be beneficial to children aged 6-12 years with ADHD and irritability.
Methods
126 unmedicated children from North America with ADHD (mean age 9.8 years) completed this 8-week study. All participants had at least 1 symptom of anger, irritability, peer conflict or Disruptive Mood Dysregulation Disorder (DMDD).
Randomisation was into an intervention (n=71) or placebo (N=55) group with a 3:2 ratio to promote enrolment. Participants were required to take 6-12 capsules daily, depending on age and tolerance, of micronutrients or a placebo. Micronutrient dosages were above the recommended dietary allowance (RDA). Outcomes were measured using clinician and parent rated assessments and by a further adult who knew the child well.
The trial was blinded to all participants, parents and study staff.
Results
The clinician-rated results found 54% of the micronutrient group and 18% of the placebo group had improvements in irritability symptoms (Risk ratio =2.97, 97.5% CI: 1.5, 5.90, p<0.001). This was not replicated in the parent/adult rated results. Children in the micronutrient group grew on average 6mm more than the placebo group (p=0.002). No serious adverse treatment effects were reported. Adherence to protocol was met by >74% of participants (n=93).
Conclusions
In this study, clinicians reported that micronutrients showed greater benefits than placebo for treating irritability and supporting growth in children with ADHD.
The study and authors received funding from several research and association bodies. However, no funder was involved in the study design or reporting. No conflicts of interest were declared.
Clinical practice applications:
- Multinutrient supplementation including vitamins, minerals, amino acids, and antioxidants may support height growth in children who take pharmacologic treatment
- Multi nutrient supplementation may also help with irritable mood, emotional dysregulation, and aggression in ADHD children
- Micronutrients given at doses between the Recommended Dietary Allowance and Upper Tolerable Intake Level appear safe and may be developed into an alternative or complementary treatment for ADHD.
Considerations for future research:
- Further large scale research is needed into the potential benefits of micronutrients for children with ADHD and irritability
Abstract
OBJECTIVE To evaluate whether micronutrients (vitamins/minerals) benefit attention-deficit/hyperactivity disorder (ADHD) and irritability in a North American pediatric sample. METHOD A 3-site, 8-week, placebo-controlled, randomized clinical trial of micronutrients was conducted in nonmedicated children aged 6 to 12 years with ADHD and at least 1 impairing irritability symptom by parent report on the Child and Adolescent Symptom Inventory-5 (CASI-5). A priori-defined primary outcomes were Clinical Global Impression-Improvement (CGI-I) (CGI-I of 1 or 2 = treatment responder) and parent-rated CASI-5 composite score of ADHD, oppositional defiant, disruptive mood dysregulation, and peer conflict symptoms, including impairment scores. RESULTS Of 135 randomized (mean age 9.8 years), 126 youths (93%) comprised the modified intention-to-treat population. Blinding was maintained. For the CGI-I, 54% of the micronutrient and 18% of the placebo group were responders (risk ratio = 2.97, 97.5% CI = 1.50, 5.90, p < .001). CASI-5 composite scores improved significantly for both groups (p < .01), with a mean change of -0.31 (95% CI = -0.39, -0.23) in the micronutrient group and a mean change of -0.28 (95% CI = -0.38, -0.19) in the placebo group. However, the between-group difference was not significant (mean change = -0.02; 97.5% CI = -0.16, 0.12, effect size = 0.07, p = .70). The micronutrient group grew 6 mm more than the placebo group (p = .002). No serious adverse events or clinically significant changes from baseline in blood and urine tests occurred. CONCLUSION Micronutrients showed global benefit over placebo by blinded clinician rating, but not by parent-report CASI-5 composite rating in a population with ADHD and irritability. Micronutrients showed greater height growth. Micronutrients were well tolerated, and the majority of participants adhered to the number of capsules prescribed. This randomized controlled trial replicates safety and efficacy reported for ADHD in 2 smaller trials of a similar formula containing all vitamins and known essential minerals in amounts between the Recommended Dietary Allowance and Upper Tolerable Intake Level. CLINICAL TRIAL REGISTRATION INFORMATION Micronutrients for ADHD in Youth (MADDY) Study; https://clinicaltrials.gov; NCT03252522.
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Functional Medicine and Women’s Health: Interview with Joel Evans, MD Part 2: Menopause & Stress
Metagenics Institute is a trusted, peer-to-peer, evidence-based educational resource for nutrition and personalized medicine. Their mission is to transform healthcare by inspiring and educating practitioners, and their patients, about personalized lifestyle medicine.
2021
Abstract
In this article, the Metagenics Institute meets Joel Evans, MD and asks him questions in regards to which functional medicine options women can refer to when dealing with menopause and stress. They give useful insights to women on how to address discomfort, sleep disturbances, hot flushes, mood and sexual health. Furthermore, they explain which functional medicine tests can be recommended to assess stress and fatigue levels, and which are the biochemical consequences that these two can have on the body of menopausal women - and therefore which imbalances need to be taken into consideration.
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Patti & Michael Discuss The Gut-Brain Axis (Rebroadcast)
Genova Diagnostics' podcast, The Lab Report, is focused on functional & integrative medicine, specialty laboratory diagnostics, and natural therapeutics. Join hosts Michael Chapman, ND,Patti Devers, DO, and assorted guests, as they bring their own unique style to the health & wellness discussion. It is aimed at providing the same type of educational content that Genova is well-known for, but to the larger audience of functional & integrative practitioners of all experience levels.
2021
Abstract
In this episode, Patti and Michael discuss some of the mechanisms by which this axis sends and receives those signals. They also talk about the importance of addressing both when optimizing health. The commensal bacteria in our gut and their metabolites can directly affect our memory and mood, while our brain can alter bacterial patterns and GI function. They also chat about the communication mechanisms from the GI tract to the brain, how the brain affects the gut and how to support treatment - also using Genova diagnostics functional tests. To conclude, they talk about the latest research in regards to psychobiotics and their role in influencing neurotransmitter production and, consequently, our mood.
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Molecular Mechanisms Underlying the Beneficial Effects of Exercise on Brain Function and Neurological Disorders.
Nay, K, Smiles, WJ, Kaiser, J, McAloon, LM, Loh, K, Galic, S, Oakhill, JS, Gundlach, AL, Scott, JW
International journal of molecular sciences. 2021;22(8)
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Exercise as therapy for mental health disorders has become common due to its reported benefits and low cost. There are many biological ways in which exercise may help mood disorders and diseases associated with brain degeneration and this review article aimed to highlight these. The authors first highlighted the research indicating that exercise may be protective in mood disorders with studies showing reduction of symptoms of depression, anxiety, schizophrenia, autism, and bipolar disorder. Exercise may also be of benefit in several brain degenerative disorders with studies indicating a positive impact in individuals with Parkinson’s disease, Alzheimer’s disease, Huntington’s disease, and Multiple Sclerosis. Studies have also indicated that individuals with brain injuries, such as stroke may also benefit. Several reasons for this were highlighted. When muscle is stimulated during exercise a key brain signalling molecule may be produced, known as brain-derived neurotrophic factor (BDNF). BDNF may have the effect of preventing brain degeneration and promoting regeneration. Exercise may also increase gut microbial diversity and increase beneficial bacteria which may benefit the brain in several ways. It was concluded that exercise may have beneficial effects for individuals with brain disorders. This study could be used by healthcare professionals to understand how exercise may be of benefit to individuals with mood disorders, brain degenerative diseases and brain injuries as part of a holistic treatment plan.
Abstract
As life expectancy has increased, particularly in developed countries, due to medical advances and increased prosperity, age-related neurological diseases and mental health disorders have become more prevalent health issues, reducing the well-being and quality of life of sufferers and their families. In recent decades, due to reduced work-related levels of physical activity, and key research insights, prescribing adequate exercise has become an innovative strategy to prevent or delay the onset of these pathologies and has been demonstrated to have therapeutic benefits when used as a sole or combination treatment. Recent evidence suggests that the beneficial effects of exercise on the brain are related to several underlying mechanisms related to muscle-brain, liver-brain and gut-brain crosstalk. Therefore, this review aims to summarize the most relevant current knowledge of the impact of exercise on mood disorders and neurodegenerative diseases, and to highlight the established and potential underlying mechanisms involved in exercise-brain communication and their benefits for physiology and brain function.
Sponsored Blog Post
8.
Gut-Brain Axis
OptiBac Probiotics specialise entirely in probiotics. One of their core values is encouraging people to take health into their own hands in a responsible manner. Training and education is a cornerstone of this, and with their expertise, they hope to help raise awareness of probiotics and their potential to help change lives.
2020
Abstract
The idea of a gut-brain axis is not new, however the science continues to grow on the mechanisms behind the link between these two organs. Against a background of the physical connection between the gut and brain, this blog post provides details of the way that the gut microbiome communicates with the brain, influencing levels of anxiety, sleep, behaviour and mood. With details of specific probiotic strains used in a trial on depression, a TED talk link given by Guilia Enders on this topic and plenty of references to the microbiome and mental health, this is a good read for Nutrition Practitioners exploring mental health and links to the gut.
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PROFAST: A Randomized Trial Assessing the Effects of Intermittent Fasting and Lacticaseibacillus rhamnosus Probiotic among People with Prediabetes.
Tay, A, Pringle, H, Penning, E, Plank, LD, Murphy, R
Nutrients. 2020;12(11)
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The prevalence of diabetes is increasing worldwide, and with it, the risk of cardiovascular disease is also increasing. Intermittent fasting has been shown to reduce weight and improve glycaemic control. Weight control and glycaemic control were also improved with probiotic Lacticaseibacillus rhamnosus HN001 supplementation. This pilot, 12-week, double-blinded, two-armed, randomized 1:1 study aimed to investigate the combined effects of intermittent fasting with daily probiotic Lacticaseibacillus rhamnosus HN001 supplementation on glycaemic management in participants with prediabetes. For two days, participants restricted their calorie intake to 600-650 kcal, followed by five days of ad libitum consumption (5:2). Intermittent fasting for 12 weeks improved glycaemic control (reduced HbA1c) and reduced body weight by 5%. The supplementation with Lacticaseibacillus rhamnosus HN001 did not significantly improve these outcomes. Probiotic supplementation significantly improved mental health and social functioning in participants. There is a need for further large, robust studies to assess the effects of intermittent fasting alone and when it is combined with different exercise forms and different prebiotic and probiotic supplements on cardiometabolic markers and mental health. The findings of this study may be useful to healthcare professionals in understanding the effects of fasting on metabolism as well as the psychological benefits of Lacticaseibacillus rhamnosus HN001 supplementation.
Abstract
Both intermittent fasting and specific probiotics have shown promise in improving glucose tolerance with a potential for synergistic effects through alterations to gut microbiota. In this randomized, double-blinded, two-arm feasibility study, we investigated whether intermittent fasting, supplemented with Lacticaseibacillus rhamnosus HN001 probiotic, reduces HbA1c in individuals with prediabetes. All participants with HbA1c 40-50 mmol/mol commenced intermittent fasting (2 days per week of calorie restriction to 600-650 kcal/day) and were randomized 1:1 to either daily probiotic (Lacticaseibacillus rhamnosus HN001) or placebo for 12 weeks. The primary outcome was a change in HbA1c. Secondary outcomes included changes in anthropometry, body composition, glucoregulatory markers, lipids, hunger hormones, liver enzymes, inflammatory markers, gut hormones, calorie and macronutrient intake, quality of life, hunger, mood and eating behavior. Of 33 participants who commenced the trial, 26 participants (mean age 52 years, body mass index (BMI) 34.7 kg/m2) completed the intervention (n = 11 placebo, n = 15 probiotic). HbA1c decreased from 43 ± 2.7 mmol/mol to 41 ± 2.3 mmol/mol, p < 0.001, with average of 5% weight loss. No significant between-group differences were seen in primary or secondary outcomes except for social functioning (p = 0.050) and mental health (p = 0.007) scores as improvements were seen in the probiotic group, but not in the placebo group. This study shows additional psychological benefits of probiotic supplementation during intermittent fasting to achieve weight loss and glycemic improvement in prediabetes.
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Association between intake of non-sugar sweeteners and health outcomes: systematic review and meta-analyses of randomised and non-randomised controlled trials and observational studies.
Toews, I, Lohner, S, Küllenberg de Gaudry, D, Sommer, H, Meerpohl, JJ
BMJ (Clinical research ed.). 2019;364:k4718
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Consumption of non-sugar sweeteners (NSS) has recently increased due to an emphasis on a low sugar diet. However, the exact health effects of this switch are uncertain. The aim of this systematic review and meta-analysis of 56 randomised and non-randomised trials aimed to determine the health effects of NSS’s in adults and children. The results showed that amongst adults body weight, blood sugar, daily energy intake, and blood pressure were all lower when exposed to NSS’s. Other health measures such as cancer and neurological disorders remained unaffected. Amongst children blood sugar was significantly higher and a small increase in body mass index was also observed when exposed to NSS’s. It was concluded that most health outcomes were unaffected by NSS’s, and there appears to be no health benefits on a broad range of outcomes when switching from sugar. Potential harm from regular NSS consumption could not be ruled out from this study. Healthcare professionals could use this study to understand that recommending diets which switch from sugar to NSS’s may have limited health benefits.
Abstract
OBJECTIVE To assess the association between intake of non-sugar sweeteners (NSS) and important health outcomes in generally healthy or overweight/obese adults and children. DESIGN Systematic review following standard Cochrane review methodology. DATA SOURCES Medline (Ovid), Embase, Cochrane CENTRAL, WHO International Clinical Trials Registry Platform, Clinicaltrials.gov, and reference lists of relevant publications. ELIGIBILITY CRITERIA FOR SELECTING STUDIES Studies including generally healthy adults or children with or without overweight or obesity were eligible. Included study designs allowed for a direct comparison of no intake or lower intake of NSS with higher NSS intake. NSSs had to be clearly named, the dose had to be within the acceptable daily intake, and the intervention duration had to be at least seven days. MAIN OUTCOME MEASURES Body weight or body mass index, glycaemic control, oral health, eating behaviour, preference for sweet taste, cancer, cardiovascular disease, kidney disease, mood, behaviour, neurocognition, and adverse effects. RESULTS The search resulted in 13 941 unique records. Of 56 individual studies that provided data for this review, 35 were observational studies. In adults, evidence of very low and low certainty from a limited number of small studies indicated a small beneficial effect of NSSs on body mass index (mean difference -0.6, 95% confidence interval -1.19 to -0.01; two studies, n=174) and fasting blood glucose (-0.16 mmol/L, -0.26 to -0.06; two, n=52). Lower doses of NSSs were associated with lower weight gain (-0.09 kg, -0.13 to -0.05; one, n=17 934) compared with higher doses of NSSs (very low certainty of evidence). For all other outcomes, no differences were detected between the use and non-use of NSSs, or between different doses of NSSs. No evidence of any effect of NSSs was seen on overweight or obese adults or children actively trying to lose weight (very low to moderate certainty). In children, a smaller increase in body mass index z score was observed with NSS intake compared with sugar intake (-0.15, -0.17 to -0.12; two, n=528, moderate certainty of evidence), but no significant differences were observed in body weight (-0.60 kg, -1.33 to 0.14; two, n=467, low certainty of evidence), or between different doses of NSSs (very low to moderate certainty). CONCLUSIONS Most health outcomes did not seem to have differences between the NSS exposed and unexposed groups. Of the few studies identified for each outcome, most had few participants, were of short duration, and their methodological and reporting quality was limited; therefore, confidence in the reported results is limited. Future studies should assess the effects of NSSs with an appropriate intervention duration. Detailed descriptions of interventions, comparators, and outcomes should be included in all reports. SYSTEMATIC REVIEW REGISTRATION Prospero CRD42017047668.