Table 2 General characteristics and significant findings of ketogenic diet in association with gut microbiota and neurological diseases in clinical-trial studies

Ferraris C., et al. (2021) [12]

Italy

Single-arm, uncontrolled, quasi experimental

Patients with epilepsy

Age:

2-46 yr

Male:3

Female:4

N = 7

N = 7

N.A

One month

Cytotoxicity, genotoxicity, measuring SCFA

Decrease in fecal SCFA, (acetate, propionate, butyrate), isobutyrate

Decrease in seizures attacks (> 50%) and involuntary movements

Bahr L., et al. (2018) [22]

Germany

Single-center, randomized, controlled, parallel-group study

Patients with relapsing–remitting MS

Age:

18-65 yr

Male:

N.A

Female:

N.A

N = 111 (37 patients in each KD, FD and SD groups)

N = 74 (37 patients in KD group and 37 patients in FD group)

N = 37

Nine months

Biochemical measures

Increase in serum beta hydroxybutyrate level

Improve cognition in KD group

Lee R., et al. (2018) [14]

United States

Open-label, observer-blinded, quasi experimental

children with ASD

Mean age: 7.9 ± 3.3 yr

Male:13

Female:2

N = 15

N = 15

N.A

Three months

Biochemical measures

Increase in serum beta hydroxybutyrate level

Improve behaviors

Swidsinski A., et al. (2017) [15]

Germany

Controlled, randomized clinical trials

Patients with MS

Mean age: N.A

Male: N.A

Female: N.A

N = 24 (10 patients in KD and 14 patients in control group)

N = 10

N = 14

Six months

FISH with ribosomal RNA derived probs

Decrease in pioneer bacterial groups, increase in Akkermansia

Positive effects on MS patients

Xie G., et al. (2017) [16]

China

Controlled, randomized clinical trials

Children with epilepsy

Mean age: 1.95 ± 3.1 yr

Male: 11

Female: 3

N = 44 (14 patients in KD group and 30 healthy infants in control group)

N = 14

N = 30

One week

16 s rRNA sequencing

Decrease in Proteobacteria Cronobacter, no change in Bacteroides, increase in Prevotella, Bifidobacterium

Clinical improvement (64%), decrease in seizure frequency (50%)

Tagliabue A., et al. (2016) [17]

Italy

Prospective, single-center, single-arm quasi experimental

Epileptic patients affected by GLUT1 DS

Age:

8-34 yr

Male:3

Female:3

N = 6

N = 6

N.A

Three months

RT-PCR and bacterial DNA extraction

Increase in Desulfovibrio spp.

No change