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Study under review: The efficacy and safety of nutrient supplements in the treatment of mental disorders: a meta-review of meta-analyses of randomized controlled trials.
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There are a few reasons to suspect that nutritional supplements could play a role in improving mental health. The first is that mental illnesses and poor nutrition are associated with each other, which could lead to nutritional deficiencies in theory. And certain deficiencies have in fact been observed. For instance, zinc and folate deficiency is relatively common in people with depression and schizophrenia. Ditto for folate and vitamin D. Also, inflammation and oxidative stress have also been shown to play a role in some mental illnesses, and some nutritional supplements like omega-3 fatty acids and N-acetylcysteine could influence these processes, which could in turn help impact psychiatric conditions.
But just because nutritional supplements could help doesn’t mean they do. Fortunately, there’s been quite a bit of research looking into how supplements can affect mental health. But, due to just how much research is out there, it can be hard to figure out what the evidence supports and what it doesn’t. Fortunately, umbrella reviews can help with this.
We’ve covered several umbrella reviews in the past, but as a refresher: an umbrella review is a review of reviews. It takes a look at all reviews and (usually) meta-analyses around a given topic, and summarizes the state of the evidence.
Recently, a large umbrella review took a look at the evidence for nutritional supplements’ impact on various mental illnesses. The fifteen authors scoured the literature using a preregistered protocol, looking for systematic reviews and meta-analyses for how supplements for nutrients commonly found in the human diet impact mental health and summarized the results. They excluded reviews that examined changes in diet and that looked at herbal supplements: they just stuck to things like supplemental vitamins, minerals, fatty acids, and amino acids. They ultimately uncovered 33 meta-analyses of randomized controlled trials, that covered 10,951 people.
Given that it took 15 people to write the umbrella review, it shouldn’t be a surprise that there’s lots and lots of details we’re skipping over in this Mini. Fortunately, the full text is open access, so you can check out the details yourself if you’d like, and discuss the nuances in the Examine Members Facebook forum. Here, we’re just going to summarize the results of one of the stronger findings of the paper: the evidence for supplements that have “sufficient data”, which the authors defined as having results from meta-analyses involving more than 400 people. These results are summarized in Figure 1. These larger meta-analyses are less likely to have much random error in their estimates, which is part of the reason why they’re worth highlighting over smaller meta-analyses, which by their nature provide less accurate effect estimates. However, as you can see in the “author’s notes” column of Figure 1, even larger meta-analyses may not always be reliable.
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Other Articles in Issue #61 (November 2019)
Mini: Can exercising help alleviate primary dysmenorrhea?
We summarize the main take-aways from a recent Cochrane review exploring exercise's effects on primary dysmenorrhea.
Cutting through liver fat with citrus
Hesperidin, a compound found in the peels of citrus fruits, has shown promising results in rats for improving fatty liver. This trial put hesperidin to the test in people with nonalcoholic fatty liver disease.
Rate of weight loss and body composition: does “slow and steady” win the race?
More severe energy restriction usually leads to higher amounts of weight loss, but it could also lead to a higher proportion of muscle or bone loss. This study explored the effects of the rate of weight loss in postmenopausal women.
Investigating the effects of eating every other day on body composition and aging-related factors
The effects of alternate-day fasting haven't been well-explored in metabolically healthy people without obesity. This study aimed to help fill that gap.
Investigating dairy to improve insulin resistance
This meta-analysis suggests that dairy intake can help curb insulin resistance and shrink waistlines a little. But "dairy" is a pretty wide-ranging category...
Casting a wider net for marine oil’s cardiovascular benefits
We previously covered a major meta-analysis which found that marine-derived omega-3 supplementation didn't have clear cardiovascular benefits. However, three large trials have been released since then. Do they make a difference?
Pro-bono: protein for bone retention
When people say they want to lose weight, they usually mean losing the weight from fat. However, weight loss can also lead to bone loss. This study explored whether high-protein diets can help retain bone.
- Diet as a hot topic in psychiatry: a population-scale study of nutritional intake and inflammatory potential in severe mental illness. World Psychiatry. (2018) Firth J, et al.
- Zinc in depression: a meta-analysis. Biol Psychiatry. (2013) Swardfager W, et al.
- Is low folate a risk factor for depression? A meta-analysis and exploration of heterogeneity. J Epidemiol Community Health. (2007) Gilbody S, Lightfoot T, Sheldon T.
- Risk factors and peripheral biomarkers for schizophrenia spectrum disorders: an umbrella review of meta-analyses. Acta Psychiatr Scand. (2018) Belbasis L, et al.
- Vitamin D deficiency and depression in adults: systematic review and meta-analysis. Br J Psychiatry. (2013) Anglin RE, et al.
- Vitamin D and psychosis: mini meta-analysis. Schizophr Res. (2013) Belvederi Murri M, et al.
- So depression is an inflammatory disease, but where does the inflammation come from?. BMC Med. (2013) Berk M, et al.
- Meta-analysis of cytokine alterations in schizophrenia: clinical status and antipsychotic effects. Biol Psychiatry. (2011) Miller BJ, et al.
- Pathways underlying neuroprogression in bipolar disorder: focus on inflammation, oxidative stress and neurotrophic factors. Neurosci Biobehav Rev. (2011) Berk M, et al.
- Omega-3 fatty acids in inflammation and autoimmune diseases. J Am Coll Nutr. (2002) Simopoulos AP.
- N-acetylcysteine for antioxidant therapy: pharmacology and clinical utility. Expert Opin Biol Ther. (2008) Dodd S, et al.
- The efficacy and safety of nutrient supplements in the treatment of mental disorders: a meta-review of meta-analyses of randomized controlled trials. World Psychiatry. (2019) Firth J, et al.