According to the Lancet, at least 264 million people suffer from depression globally. Following the COVID pandemic, depression and anxiety are being referred to as the next pandemic and, thus, of great concern across all industries. So, what role can the nutraceutical industry play in addressing the major burden of depression?
Researchers from Indonesia recently analysed 63 papers addressing depression with dietary supplementation (DOI: 10.2147/JMDH.S360029). Looking at depression, the neurotransmitters that impact mood and emotions include dopamine, epinephrine, norepinephrine, GABA and glutamate. Furthermore, melatonin could be linked with SAD [seasonal affective disorder].
When it comes to treating depression, antidepressants are often used and divided into four groups, including “tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), monoamine oxidase inhibitors (MAOIs), serotonin-norepinephrine reuptake inhibitors, and non-TCA antidepressants.” Antidepressants appear to be most beneficial in treating upper-end and severe depression; they can also lead to addiction. The fear of addiction pushes consumers to look for alternative medicine (CAM), including nutraceuticals and dietary supplementation.
After reviewing 63 in-depth clinical studies, researchers separated the supplement groups used for the research: PUFA—polyunsaturated fatty acid (n = 17), vitamin D (n= 15), probiotic (n = 8), a combination of vitamins and nutrients (n = 6), and other supplements (n = 17).
Interestingly, researchers found that “the most commonly used supplementation in treating depression was the PUFA group, which was a combination of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA).” They further noted that 8 out of 12 clinical studies that used PUFA showed positive benefits of improving depression. For these studies, the daily optimal dose for PUFA supplementation ranged from 0.7 g to 2.0 g EPA and 0.4 g to 0.8g DHA delivered between 1 to 9 daily doses. Researchers also found PUFA benefitted pregnancy—to prevent depression related to pregnancy and to support foetal brain and retina development. When looking at synergy supplementation, PUFA and vitamin E mix shows benefits against depression (1000 mg PUFA / 400 IU vitamin E daily).
When looking at vitamin D, 15 studies showed benefits to improve depression at dosages ranging from 2000 IU/day to 50,000 IU/week, though results showed benefits from 2 months to 24 months. One study highlighted mixed vitamin D with probiotic and zinc supplementations—both of which showed health benefits to improve depression.
When looking at probiotic’s effects on depression, 5 out of 8 studies shows that probiotics improved depression. The species used in these studies include, as summarised by researchers, “various bacteria from the genus Lactobacillus (L. acidophilus, L. casei, L. fermentum, L.rhamnosus, and L. bulgaricus) and the genus Bifidobacterium (Bifidobacterium bifidum and Bifidobacterium lactis) with various dosage ranges above 108 CFU in the form of yogurt, capsules, and sachets.”
When looking at the combination of vitamins and nutrients, multiple nutrients including vitamin B12, vitamin D, folate, zinc, and selenium were suggested to prevent pregnancy-related depression. Further, when looking at other interventions, researchers found that supplements linked to improving depression included carnitine, coenzyme Q10, nanocurcumin, curcumin, magnesium oxide, melatonin, myo-inositol, sumac (Rhus coriaria L.), vitamin A, vitamin B, folic acid, zinc, and zinc sulphate. Interestingly, researchers observed that “carnitine’s effect in lowering depression parameter scores was linked to improved mitochondrial performance, antioxidant effects, increased cholinergic neurotransmission, enhanced protein, and gene expression, which affected brain metabolism, thereby aiding the improvement of neuropsychological function.”
Overall, based on the findings of the current commentary, researchers would propose the use of PUFA, vitamin D and probiotics to target and manage depression with supplementation.