PROBIOTICS AND PREBIOTICS
In one study, supplementation with probiotic Lactobacillus reuteri increased anagen hair follicle counts by 106% when compared to a control group. Researchers determined that the probiotic-fed male mice had 74% of their hairs in the active, anagen phase, while the control group only had 36%. In comparison, in the control group 64% of hairs were in the non-growth, telogen phase .
Probiotics and prebiotics are popular due to the associated nutritional claims and reported health benefits such as improving digestive transit time, supporting weight loss, relief of depression or anxiety and boosting immunity. Rigorous laboratory studies looking at improvements in specific parameters can involve a small number of biomarkers and quality control during the manufacturing process can be somewhat lax. Of the studies that can show differences in biomarkers (such as cholesterol or glucose levels), none show any clinical benefit; rather assumptions are made from extrapolated laboratory values.
A study looking at the effects of probiotics that generated short chain fatty acids, butyrate, showed probiotics did not reverse chronic alopecia areata in 16 weeks of treatment, but there was a 15% improvement in T-cell counts compared to an improvement of 12% in the control group .
From 2016 to 2017 the FDA inspected more than 650 probiotic facilities and found 50 percent had violations including low purity, low strength and incorrectly categorised bacterial strains in the final product .
In Italy, a national survey of probiotic suppliers claimed that bifidobacterial was present when none contained the bacteria at all . Another study found of 16 probiotic products, only the contents of one matched its label claims, some contained little or no viable bacteria . A third study investigating 26 probiotics products found misidentification at species (27 incorrectly identified) and genus levels (19 incorrectly identified) [10, 11].
Safety concerns have been raised concerning the use of probiotics and the resulting abnormal read counts (number of times a particular bacterium was identified) in otherwise healthy subjects. A study looking at the impact of probiotics found a significantly lower abundance of Bifidobacteria which could potentially have a detrimental effect on health.
There are potential harms as well as some benefits with consuming probiotics and prebiotics. Some prebiotic supplements have been found to contain harmful bacteria that produce toxins (such as Bacillus cereus).
Probiotics can adversely modify gut bacteria and clinical studies on their effects are questionable. Whilst probiotics and prebiotics can offer some health perks, they may not be appropriate for long term change and stability in resident gut bacteria diversity and species richness. Zinc supplementation, however, is a solid and proven method of increasing gut bacteria diversity within the species parameters that are correct for the individual.