TABLE 7.

Effect of SCFA supplementation on immune cell populations in peripheral blood in participants of all ages¹

Author, Year (Country)	Design/Level of evidence	Quality2	Participants, age, n	Intervention, daily dose	Control, daily dose	Duration	Effect of SCFA intervention on peripheral immune cell populations
de Groot et al., 2020 (The Netherlands) (62)	RCT/II, x-over	Ø	Subjects with longstanding type 1 diabetes with BMI 19–25 kg/m2, 18–45 y, n = 30	Sodium butyrate capsules, 4 g	Placebo	4 wk/arm4 wk w/o	↔ CD8+ T cells (×1000 PBMC)
							↔ β7/CD49d CD8+ T cells (×1000 PBMC)
							↔ CXCR3/CCR5 CD8+ T cells (×1000 PBMC)
							↔ CD4+ T cells (×1000 PBMC)
							↔ β7/CD49d CD4+ T cells (×1000 PBMC)
							↔ CXCR3/CCR5 CD4+ T cells (×1000 PBMC)
							↔ B cells (×1000 PBMC)
							↔ NK cells (×1000 PBMC)
							↔ Regulatory T cells (×1000 PBMC)

¹Outcomes determined peripheral blood cell populations using flow cytometry. Abbreviations: CCR5, C-C chemokine receptor type 5; CXCR3, C-X-C motif chemokine receptor 3; PBMC, peripheral blood mononuclear cells; RCT, randomized controlled trial; x-over, crossover; Ø represents neutral study quality; + represents positive study quality. ↓ indicates decrease; ↑ indicates increase; ↔ indicates no change.

²Methodological study quality was determined using the American Dietetic Association critical appraisal checklist.