# Probiotics and Paraprobiotics--New Proposal for Functional Food
## 4 The Health Benefits of Functional Food with Paraprobiotics
After 12 weeks, natural killer cells (NK) were enhanced along with an increase in interleukin (IL)-12 and immunoglobulin IgG1 as well as interferon-g (IF-\(\gamma\)) concentrations, and the authors concluded that immune function was improved. Similar results were obtained by [PERSON] et al. [67] with heat-inactivated _Lactobacillus plantarum_ LM1004 isolated from Korean kimchi. In a randomized group of 100 subjects receiving capsules with paraprobiotics versus the placebo, the treatment group showed increased activity of NK cells along with increased levels of IL-12. Also, [PERSON] et al. [68], in a placebo-controlled randomized trial of 100 subjects receiving heat-treated _Lactiplantiobacillus plantarum_ nF1, confirmed the improvement of the innate immune function (an increase in NK cell activity and IL-2 level). In the presented studies, the authors do not report on adverse events. The main and traditional indications of probiotics usage are gastrointestinal dysfunction and diseases. However, they have an impact on countless human functions and biological processes. In general, the health benefits are mediated by the positive probiotic microorganism's influence on the human microbiome, especially in illnesses with accompanied gut dysbiosis. It is possible to speculate that paraprobiotics will also be effective in digestive tract disorders. [PERSON] et al. [69] reported that milk beverages supplemented with inactivated _Lactobacillus gasseri_ CP2305 FM showed a positive regulation effect on intestinal function, resulting in the improvement of patients suffering from constipation. Figure 3: The advantages of paraprobiotics, according to [PERSON] et al. [7], [PERSON] et al. [29]. The intestinal microbiota consists of more than 80% of _Firmicutes_ and _Bacteroidetes_. The ratio F/B (_Firmicutes to Bacteroides_) is higher in obese individuals, in people with dementia, and in patients suffering from coronary artery disease [70; 71; 72]. In the study of [PERSON] et al. [73], the heat-killed strain of _Lactobacillus plantarum_ L-137 in 15 healthy volunteers proved to be effective in achieving the intestinal microbiota balance. After 12 months of daily intake of paraprobiotics (capsule formula), the F/B fecal ratio significantly decreased. Additionally, the fecal short-chain fatty acid (SCFA) content increased, including, i.e., n-butyric acid and propionic acid, which increased as well as T-cell proliferative capacity, indicating a wide range of paraprobiotics and their possible bioactivity. This report is important because of long-term follow-up. Some food products are usually consumed regularly; therefore, it is worth mentioning the safety of the extended usage of paraprobiotics reported in this study. Many other health benefits related to specific probiotictic strains and their usage in food products are reported in the literature. Live probiotics can be beneficial for human well-being. It is to be expected that similar health profits may be associated with the use of paraprobiotics, but this should be confirmed by a larger number of studies. [PERSON] et al. [74] reported that a whey-grape juice drink supplemented with and inactivated by ohmic heating _Lacticasobacillus casei_ 01 was effective as well as live strains in the reduction in postprandial glycemia in healthy adults. The authors conclude that paraprobiotic beverages can be an alternative to replace probiotics [74]. Another field of potential paraprobiotic application is atopic diseases. In the study of [PERSON] et al. [75], citrus juice fermented with heat-killed _Lactobacillus plantarum_ YIT 0132 was assessed in patients with mild-to-moderate atopic dermatitis. The paraprobiotic beverage consumption alleviated symptoms of dermatitis and improved the patient's quality of life. Additionally, an immunomodulatory effect was achieved, which was expressed by a reduction in IgE and the eosinophil cationic protein (ECP) level [75]. Some of the probiotic strains were shown to be effective in neurological and psychiatric disorders.