## 7 Effects of the Interventions into Microbiota on the Micronutrient Status of Humans
This is quite an interesting result, especially since no serum concentration of this mineral changed significantly in the same study. Although the authors stated that they have measured the concentration of elements in hair to assess the nutritional status of participants, this is not a conventional way of achieving their aim, especially since the guideline levels of micronutrient adequacy refer to their blood concentration. Nevertheless, further studies of changes in mineral status measured in parallel in blood and hair may be of interest since the human body may sequester micronutrients in different parts to different extents, and hair sampling is much less invasive compared to blood sampling. Since microbiota interventions may impact the micronutrient status of humans and were shown not only to improve body composition and anthropometry [182] but also glucose and lipid homeostasis [183; 184], combined treatments of pro- and/or prebiotics with micronutrients could bring even better effects than each of these supplements on its own. Apart from studies on bariatric patients, the research summarized in Table 7 answered the question about the combined efficacy of microbiota and micronutrient intervention on metabolic parameters in only two cases. [PERSON] et al., 2019, found that not only did vitamin D status improve more in women with gestational diabetes mellitus who were administered this vitamin along with probiotics, but also that the decrease of TG, TC, and very low-density lipoprotein cholesterol, as well as an increase in HDL, were all greater in the treatment group compared to the control that received probiotics only [176]. On the other hand, the study by [PERSON] et al., 2021, reported that yogurt enriched with probiotics _L. acidophilus_ La-B5, _B. lactis_ Bb-12, and vitamin D did not have an advantageous effect on the lipid profile and anthropometric indices of adults with obesity compared to the control that was given plain non-probiotic yogurt with vitamin D or the placebo (only non-probiotic yogurt) [177]. There are other studies that demonstrated the favorable effects of combining microbiota and micronutrient interventions in people with obesity and metabolic disorders. For example, an 8-week intervention with symbiotic (Protexin(r) containing _L. casei, L. rhamnosus, S. thermophilus, B. breve, L. acidophilus, B. longum, L. bulgaricus,_ and FOS) and vitamin E, at approx. 360 mg a day, brought a greater decrease in FG, FI, TC, and LDL levels of patients with NAFLD than each of these supplements alone [185]. Further, symbiotic (GeriLact(r) containing _L. casei, L. rhamnus, S. thermophilus, B. breve, L. acidophilus B. longum, L. bulgaricus,_ and FOS) and vitamin D administered daily and weekly at 50,000 IU, respectively, were shown to reduce body fat percentage in women with excess weight more than each of these supplements on its own (although, in the case of symbiotic alone, the difference was not statistically significant) in an 8-week trial, where no explicit lifestyle modification was applied [186]. Also, a meta-analysis of five studies published up to February 2022 where joint probiotic and Se (at 50-200 ug/day) supplements in groups of adults representing various populations were applied showed that the treatment resulted in a significant WMD of FG (\(-\)4.0 mg/dL), FI (\(-\)2.5 uIU/mL), HOMA-IR (\(-\)0.6), TG (\(-\)14.4 mg/dL), TC (\(-\)12.8 mg/dL), and LDL (\(-\)7.1 mg/dL) [187]. All of these values except for FI and HOMA-IR were much greater than those found by meta-analyses studying the effects of Se alone (see Tables 5 and 6), suggesting that joint Se and probiotic treatment may indeed be more effective in improving the homeostasis of glucose and lipids. On the other hand, in an 8-week study, no significant change in metabolic parameters of adults with excess weight was reported in response to joint \(\Omega\)-3, vitamin D (at 200 IU/day), and symbiotic (_L. paracasei_ LCP-37, _L. acidophilus_ NCFM, _B. lactis_ Bi-07, and _B.