The innate immune system responds in a rapid and non‐specific manner against immunologic threats; inflammation is part of this response. This is followed by a slower but targeted and specific response termed the adaptive or acquired immune response. There is emerging evidence that dietary components, including yeast‐derived β‐glucans, can aid host defense against pathogens by modulating inflammatory and antimicrobial activity of neutrophils and macrophages. Innate immune training refers to a newly recognized phenomenon wherein compounds may “train” innate immune cells, such that monocyte and macrophage precursor biology is altered to mount a more effective immunological response. Although various human studies have been carried out, much uncertainty still exists and further studies are required to fully elucidate the relationship between β‐glucan supplementation and human immune function. This review offers an up‐to‐date report on yeast‐derived β‐glucans as immunomodulators, including a brief overview of the current paradigm regarding the interaction of β‐glucans with the immune system. The recent pre‐clinical work that has partly decrypted mode of action and the newest evidence from human trials are also reviewed. According to pre‐clinical studies, β‐1,3/1,6‐glucan derived from baker's yeast may offer increased immuno‐surveillance, although the human evidence is weaker than that gained from pre‐clinical studies.

Arthrospira platensis (spirulina), a filamentous fresh-water planktonic cyanobacterium, possesses diverse biological activities and a unique nutritional profile, due to its high content of valuable nutrients. This study aimed to further improve the bioactive profile of spirulina, by fermenting it with the lactic acid bacterium Lactobacillus plantarum. In vitro comparison of the total phenolic content (TPC), C-phycocyanin, free methionine, DPPH radical scavenging capacity, ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC) and protein fragmentation via SDS-PAGE in untreated versus 12 to 72 h fermented spirulina is reported here. After 36 h fermentation, TPC was enhanced by 112%, FRAP by 85% and ORAC by 36%. After 24 h, the DPPH radical scavenging capacity increased 60%, while the free methionine content increased by 94%, after 72 h. Past 36 h of fermentation, the total antioxidant capacity (TAC) diminished, possibly due to deterioration of the heat-sensitive antioxidants. However, protein fragmentation and free methionine content increased, linearly, with the fermentation time. Cyanobacterial peptides and other bioactive compounds trapped within the spirulina cell wall are released during fermentation and have a significant potential as a functional ingredient in nutraceuticals and pharmaceuticals, in addition to their nutritive value.

Background Leucine-enriched protein (LEU-PRO) and long-chain (LC) n–3 (ω–3) PUFAs have each been proposed to improve muscle mass and function in older adults, whereas their combination may be more effective than either alone. Objective The impact of LEU-PRO supplementation alone and combined with LC n–3 PUFAs on appendicular lean mass, strength, physical performance and myofibrillar protein synthesis (MyoPS) was investigated in older adults at risk of sarcopenia. Methods This 24-wk, 3-arm parallel, randomized, double-blind, placebo-controlled trial was conducted in 107 men and women aged ≥65 y with low muscle mass and/or strength. Twice daily, participants consumed a supplement containing either LEU-PRO (3 g leucine, 10 g protein; n = 38), LEU-PRO plus LC n–3 PUFAs (0.8 g EPA, 1.1 g DHA; LEU-PRO+n–3; n = 38), or an isoenergetic control (CON; n = 31). Appendicular lean mass, handgrip strength, leg strength, physical performance, and circulating metabolic and renal function markers were measured pre-, mid-, and postintervention. Integrated rates of MyoPS were assessed in a subcohort (n = 28). Results Neither LEU-PRO nor LEU-PRO+n–3 supplementation affected appendicular lean mass, handgrip strength, knee extension strength, physical performance or MyoPS. However, isometric knee flexion peak torque (treatment effect: −7.1 Nm; 95% CI: −12.5, −1.8 Nm; P < 0.01) was lower postsupplementation in LEU-PRO+n–3 compared with CON. Serum triacylglycerol and total adiponectin concentrations were lower, and HOMA-IR was higher, in LEU-PRO+n–3 compared with CON postsupplementation (all P < 0.05). Estimated glomerular filtration rate was higher and cystatin c was lower in LEU-PRO and LEU-PRO+n–3 postsupplementation compared with CON (all P < 0.05). Conclusions Contrary to our hypothesis, we did not observe a beneficial effect of LEU-PRO supplementation alone or combined with LC n–3 PUFA supplementation on appendicular lean mass, strength, physical performance or MyoPS in older adults at risk of sarcopenia. This trial was registered at clinicaltrials.gov as NCT03429491.

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