Minkyung
Kim
a,
Minjoo
Kim
a,
Miso
Kang
bc,
Hye Jin
Yoo
bc,
Min Sun
Kim
bc,
Young-Tae
Ahn
d,
Jae-Hun
Sim
d,
Sun Ha
Jee
e and
Jong Ho
Lee
*abc
aResearch Center for Silver Science, Institute of Symbiotic Life-TECH, Yonsei University, Seoul, Korea
bNational Leading Research Laboratory of Clinical Nutrigenetics/Nutrigenomics, Department of Food and Nutrition, College of Human Ecology, Yonsei University, Seoul, Korea. E-mail: jhleeb@yonsei.ac.kr; Fax: +82-2-364-9605; Tel: +82-2-2123-3122
cDepartment of Food and Nutrition, Brain Korea 21 PLUS Project, College of Human Ecology, Yonsei University, Seoul, Korea
dKorea Yakult Co., Ltd, Yongin, Gyeonggi, Korea
eInstitute for Health Promotion, Graduate School of Public Health, Yonsei University, Seoul, Korea
First published on 12th December 2016
Our previous study showed that supplementation with a combination of Lactobacillus curvatus (L. curvatus) HY7601 and Lactobacillus plantarum (L. plantarum) KY1032 reduced the body weight, body fat percentage, body fat mass and L1 subcutaneous fat area in overweight subjects. We aimed to evaluate whether the changes in adiposity after supplementation with Lactobacillus strains were associated with metabolic intermediates. A randomized, double-blind, placebo-controlled study was conducted on 66 non-diabetic and overweight individuals. Over a 12-week period, the probiotic group consumed 2 g of probiotic powder, whereas the placebo group consumed the same product without the probiotics. To investigate metabolic alterations, we performed plasma metabolomics using ultra-performance liquid chromatography and mass spectrometry (UPLC-LTQ/Orbitrap MS). Probiotic supplementation significantly increased the levels of octenoylcarnitine (C8:1), tetradecenoylcarnitine (C14:1), decanoylcarnitine (C10) and dodecenoylcarnitine (C12:1) compared with the levels from placebo supplementation. In the probiotic group, the changes in the body weight, body fat percentage, body fat mass and L1 subcutaneous fat area were negatively associated with changes in the levels of C8:1, C14:1, C10 and C12:1 acylcarnitines. In overweight individuals, probiotic-induced weight loss and adiposity reduction from the probiotic supplementation were associated with an increase in medium-chain acylcarnitines.
Metabolites as intermediates and end products of biological processes are most predictable for the phenotype of an organism.11 Therefore, metabolites may serve as biomarkers for changes in the physiological status, particularly for alterations in metabolic pathways in humans.11 However, studies on endogenous metabolic changes caused by probiotic-induced weight loss are limited. To the best of our knowledge, this is the first human intervention study to investigate the effects of probiotic supplementation on both probiotic-induced weight loss and metabolic changes. Therefore, in this study, we aimed to determine whether supplementation with a combination of L. curvatus HY7601 and L. plantarum KY1032 or placebo resulted in changes from the baseline in fasting metabolic intermediates. Furthermore, we aimed to evaluate whether changes in adiposity after probiotic or placebo supplementation were associated with changes in fasting metabolic intermediates. The plasma metabolic profiles of the probiotic group and the control group were analyzed using ultra-performance liquid chromatography and mass spectrometry (UPLC-LTQ/Orbitrap MS).
The metabolomics data were exported to SIMCA-P+ 14.0 (Umetrics, Inc., Umeå, Sweden) for multivariate analysis. The data were Pareto scaled, and an orthogonal partial least squares-discriminant analysis (OPLS-DA) was used to predict our models. The validity of the models was measured using a default cross-validation procedure of 7-fold cross-validation and R2Y and Q2Y parameters.
Total (n = 66) | P a | P b | P c | ||||
---|---|---|---|---|---|---|---|
Placebo group (n = 34) | Probiotic group (n = 32) | ||||||
Baseline | Follow-up | Baseline | Follow-up | ||||
Mean ± SE. Pa-Values derived from independent t-test for baseline values. Pb-Values derived from independent t-test for follow-up values. Pc-Values derived from independent t-test for changed values. Pd-Values adjusting for baseline. †P < 0.10, *P < 0.05, **P < 0.01, ***P < 0.001 derived from paired t-test. | |||||||
Weight (kg) | 73.2 ± 1.72 | 73.6 ± 1.82 | 71.9 ± 1.43 | 71.3 ± 1.50* | 0.581 | 0.334 | |
Change | 0.46 ± 0.24 | −0.60 ± 0.30 | 0.008 | ||||
Body mass index (kg m−2) | 27.1 ± 0.27 | 27.2 ± 0.28 | 26.6 ± 0.23 | 26.4 ± 0.25* | 0.173 | 0.024 | |
Change | 0.15 ± 0.09 | −0.23 ± 0.11 | 0.008 | ||||
DEXA evaluation | |||||||
Fat percentage (%) | 31.2 ± 1.00 | 31.3 ± 0.96 | 30.6 ± 0.98 | 30.0 ± 1.03* | 0.712 | 0.357 | |
Change | 0.12 ± 0.20 | −0.67 ± 0.27 | 0.020 | ||||
Fat mass (g) | 22![]() |
23![]() |
22![]() |
21![]() |
0.392 | 0.079 | |
Change | 242.9 ± 200.1 | −717.3 ± 225.1 | 0.002 | ||||
CT evaluation (L1) | |||||||
Total fat area (cm2) | 243.8 ± 11.1 | 256.0 ± 10.0** | 247.3 ± 7.6 | 246.9 ± 8.14 | 0.797 | 0.486 | |
Change | 12.2 ± 3.70 | −0.43 ± 4.04 | 0.024 | ||||
Visceral fat area (cm2) | 101.8 ± 7.87 | 110.1 ± 7.38** | 115.2 ± 6.53 | 116.8 ± 7.09 | 0.199 | 0.519 | |
Change | 8.33 ± 2.61 | 1.64 ± 3.19 | 0.108 | ||||
Subcutaneous fat area (cm2) | 142.0 ± 6.87 | 145.84 ± 6.66* | 132.2 ± 5.65 | 130.1 ± 5.77† | 0.275 | 0.080 | |
Change | 3.84 ± 1.88 | −2.07 ± 1.42 | 0.016 | ||||
Visceral/subcutaneous fat ratio (%) | 0.78 ± 0.08 | 0.83 ± 0.09* | 0.94 ± 0.08 | 0.97 ± 0.08 | 0.163 | 0.251 | |
Change | 0.05 ± 0.02 | 0.03 ± 0.03 | 0.603 | ||||
CT evaluation (L4) | |||||||
Total fat area (cm2) | 308.0 ± 8.60 | 314.5 ± 8.10 | 301.6 ± 7.10 | 296.6 ± 7.40 | 0.569 | 0.109 | |
Change | 6.46 ± 4.33 | −4.99 ± 4.22 | 0.063 | ||||
Visceral fat area (cm2) | 88.8 ± 5.51 | 90.2 ± 5.44 | 86.5 ± 5.22 | 83.1 ± 4.29 | 0.764 | 0.313 | |
Change | 1.32 ± 2.18 | −3.43 ± 3.49 | 0.246 | ||||
Subcutaneous fat area (cm2) | 219.2 ± 8.08 | 224.3 ± 8.12 | 215.0 ± 7.77 | 213.5 ± 7.58 | 0.714 | 0.335 | |
Change | 5.14 ± 3.97 | −1.55 ± 2.68 | 0.172 | ||||
Visceral/subcutaneous fat ratio (%) | 0.44 ± 0.04 | 0.43 ± 0.04 | 0.43 ± 0.04 | 0.41 ± 0.03 | 0.935 | 0.657 | |
Change | 0.00 ± 0.02 | −0.02 ± 0.02 | 0.506 |
Furthermore, no significant differences existed at the baseline, and no significant mean changes were observed after the 12-week treatment in systolic and diastolic blood pressure, levels of triglycerides, total HDL and LDL cholesterol, glucose, insulin, hs-CRP and the HOMA-IR index (data not shown) in the placebo and probiotic groups. Additionally, the estimated total calorie intake, the amount of physical activity, the percentage of protein intake, the percentage of fat intake and the percentage of carbohydrate intake did not differ significantly between the two groups at the baseline, week 6 and week 12 (data not shown).
The quality of each OPLS-DA model was examined using the R2 and Q2 values to confirm that the models were not over-fitted and evaluate the predictive ability of each model. R2 represents the goodness-of-fit parameter and is defined as the proportion of variance in the data described by the model. Q2 represents the predictive ability parameter and is defined as the proportion of variance in the data predicted by the model. R2 and Q2 values greater than 0.5 indicate a high-quality OPLS-DA model.14 The two-component OPLS-DA scatter plots of the plasma metabolites for the first combination of groups did not show distinct clustering or a clear separation of participants in the placebo group at the baseline or at the 12-week follow-up assessment (R2Y = 0.729, Q2Y = 0.093). These analyses, however, revealed that the second and third models (Fig. 1) displayed greater than 86% goodness-of-fit (R2Y = 0.948 and R2Y = 0.864 for the second and third combinations of groups, respectively) and a predictive ability greater than 61% (Q2Y = 0.642 and Q2Y = 0.614 for the second and third combinations of groups, respectively), which demonstrated that the second and third OPLS-DA models in the present study were well-fitted and displayed an acceptable predictive ability. The present results clearly showed that plasma metabolomic profiles could distinguish groups based on probiotics, changes in probiotic-induced biochemical characteristics, or both. To extract potential variables contributing to the detected differences, S-plots from the OPLS-DA models were constructed. S-Plots of p(1) and p(corr)(1) were generated using centroid scaling (Fig. 1d–f). The S-plots revealed that metabolites with higher or lower p(corr) values were more relevant for discriminating between the two groups.
Identity | Molecular formula | Mono-isotopic mass | Peak intensities | VIP | q a | q b | q c | ||||
---|---|---|---|---|---|---|---|---|---|---|---|
Placebo group (n = 34) | Probiotic group (n = 32) | Baseline vs. follow-up in test group | Placebo follow-up vs. test follow-up | ||||||||
Baseline | Follow-up | Baseline | Follow-up | ||||||||
Median ± SD. VIP: variable importance in projection. All q-values were tested following a logarithmic transformation; qa-value is the adjusted P-value, which is derived from an independent t-test for baseline values and controls the false discovery rate. qb-Value is the adjusted P-value, which is derived from an independent t-test for follow-up values and controls the false discovery rate. qc-Value is the adjusted P-value, which is derived from an independent t-test for changed value differences and controls the false discovery rate. | |||||||||||
2-Octenoylcarnitine | C15H27NO4 | 286.200 | 34![]() ![]() |
42![]() ![]() |
35![]() ![]() |
67![]() ![]() |
4.081 | 2.527 | 0.632 | 0.001 | |
Change | 7669 ± 19![]() |
27![]() ![]() |
0.003 | ||||||||
Adrenoyl ethanolamide | C24H41NO2 | 376.317 | 18![]() ![]() |
34![]() ![]() |
18![]() |
30![]() ![]() |
2.891 | 0.581 | 0.376 | 0.755 | |
Change | 8849 ± 37![]() |
12![]() ![]() |
0.975 | ||||||||
Anandamide (18:4, n-3) | C20H33NO2 | 320.255 | 98![]() ![]() |
37![]() ![]() |
69![]() ![]() |
23![]() ![]() |
3.282 | 1.605 | 0.436 | 0.708 | |
Change | −57![]() ![]() |
−40![]() ![]() |
0.977 | ||||||||
Bilirubin | C33H36N4O6 | 585.268 | 8186 ± 5437 | 12![]() |
12![]() |
12![]() ![]() |
1.068 | 0.421 | 0.253 | 0.497 | |
Change | 4819 ± 9914 | 519 ± 16![]() |
0.984 | ||||||||
Chenodeoxycholic acid glycine conjugate | C26H43NO5 | 450.319 | 15![]() ![]() |
22![]() ![]() |
8581 ± 11![]() |
23![]() ![]() |
2.206 | 0.543 | 0.220 | 0.697 | |
Change | 2572 ± 35![]() |
6540 ± 31![]() |
0.947 | ||||||||
cis-5-Tetradecenoylcarnitine | C21H39NO4 | 370.294 | 15![]() ![]() |
18![]() ![]() |
20![]() ![]() |
42![]() ![]() |
3.426 | 2.518 | 0.466 | <0.001 | |
Change | 1821 ± 13![]() |
18![]() ![]() |
0.001 | ||||||||
Decanoylcarnitine | C17H33NO4 | 316.247 | 41![]() ![]() |
51![]() ![]() |
50![]() ![]() |
127![]() ![]() |
6.787 | 4.897 | 0.373 | <0.001 | |
Change | 7920 ± 40![]() |
72![]() ![]() |
<0.001 | ||||||||
Lactosylceramide (d18:1/12:0) | C42H79NO13 | 806.563 | 577![]() ![]() |
635![]() ![]() |
601![]() ![]() |
600![]() ![]() |
4.148 | 3.561 | 0.497 | 0.636 | |
Change | 50![]() ![]() |
48![]() ![]() |
0.983 | ||||||||
Linoleyl carnitine | C25H45NO4 | 424.340 | 51![]() ![]() |
53![]() ![]() |
49![]() ![]() |
59![]() ![]() |
1.424 | 1.174 | 0.574 | 0.386 | |
Change | 5896 ± 22![]() |
5012 ± 20![]() |
0.964 | ||||||||
L-Leucine/L-isoleucine | C6H13NO2 | 132.101 | 259![]() ![]() |
277![]() ![]() |
257![]() ![]() |
254![]() ![]() |
1.070 | 2.095 | 0.604 | 0.200 | |
Change | 24![]() ![]() |
425 ± 42![]() |
0.453 | ||||||||
L-Phenylalanine | C9H11NO2 | 166.085 | 298![]() ![]() |
308![]() ![]() |
286![]() ![]() |
298![]() ![]() |
1.098 | 1.350 | 0.418 | 0.317 | |
Change | 16![]() ![]() |
18![]() ![]() |
0.978 | ||||||||
L-Tryptophan | C11H12N2O2 | 205.096 | 420![]() ![]() |
405![]() ![]() |
387![]() ![]() |
380![]() ![]() |
1.453 | 2.009 | 0.444 | 0.285 | |
Change | 6171 ± 65![]() |
−7153 ± 55![]() |
0.964 | ||||||||
L-Tyrosine | C9H11NO3 | 182.080 | 128![]() ![]() |
142![]() ![]() |
128![]() ![]() |
142![]() ![]() |
1.062 | 0.823 | 0.550 | 0.602 | |
Change | 8322 ± 20![]() |
10![]() ![]() |
0.980 | ||||||||
L-Valine | C5H11NO2 | 118.086 | 106![]() ![]() |
113![]() ![]() |
107![]() ![]() |
109![]() ![]() |
0.453 | 1.167 | 0.546 | 0.200 | |
Change | 9254 ± 14![]() |
4818 ± 15![]() |
0.441 | ||||||||
LysoPC (14:0) | C22H46NO7P | 468.306 | 191![]() ![]() |
197![]() ![]() |
160![]() ![]() |
138![]() ![]() |
1.371 | 3.692 | 0.220 | 0.010 | |
Change | −2249 ± 92![]() |
−4864 ± 71![]() |
0.961 | ||||||||
LysoPC (15:0) | C23H48NO7P | 482.322 | 136![]() ![]() |
135![]() ![]() |
125![]() ![]() |
123![]() ![]() |
1.299 | 1.720 | 0.426 | 0.288 | |
Change | 1279 ± 43![]() |
−700 ± 58![]() |
0.980 | ||||||||
LysoPC (16:0) | C24H50NO7P | 496.337 | 7![]() ![]() ![]() |
7![]() ![]() ![]() ![]() |
7![]() ![]() ![]() ![]() |
7![]() ![]() ![]() |
8.505 | 9.633 | 0.320 | 0.282 | |
Change | −309![]() ![]() ![]() |
340![]() ![]() ![]() |
0.981 | ||||||||
LysoPC (16:1) | C24H48NO7P | 494.321 | 358![]() ![]() |
352![]() ![]() |
285![]() ![]() |
320![]() ![]() |
1.449 | 2.485 | 0.284 | 0.255 | |
Change | −25![]() ![]() |
35![]() ![]() |
0.983 | ||||||||
LysoPC (17:0) | C25H52NO7P | 510.353 | 169![]() ![]() |
169![]() ![]() |
163![]() ![]() |
168![]() ![]() |
1.732 | 1.369 | 0.516 | 0.746 | |
Change | 8430 ± 58![]() |
2026 ± 84![]() |
0.981 | ||||||||
LysoPC (18:0) | C26H54NO7P | 524.368 | 2![]() ![]() ![]() |
2![]() ![]() ![]() |
2![]() ![]() ![]() |
2![]() ![]() ![]() |
5.657 | 6.066 | 0.516 | 0.496 | |
Change | −72![]() ![]() |
96![]() ![]() |
0.979 | ||||||||
LysoPC (18:1) | C26H52NO7P | 522.353 | 2![]() ![]() ![]() |
2![]() ![]() ![]() |
2![]() ![]() ![]() |
1![]() ![]() ![]() |
4.929 | 5.711 | 0.439 | 0.392 | |
Change | −13![]() ![]() |
−81![]() ![]() |
0.982 | ||||||||
LysoPC (18:2) | C26H50NO7P | 520.337 | 2![]() ![]() ![]() |
2![]() ![]() ![]() |
2![]() ![]() ![]() |
2![]() ![]() ![]() |
5.104 | 6.841 | 0.278 | 0.304 | |
Change | −27![]() ![]() |
−11![]() ![]() |
0.982 | ||||||||
LysoPC (18:3) | C26H48NO7P | 518.319 | 2![]() ![]() ![]() |
2![]() ![]() ![]() |
2![]() ![]() ![]() |
2![]() ![]() ![]() |
4.552 | 4.522 | 0.254 | 0.307 | |
Change | −27![]() ![]() |
77![]() ![]() |
0.975 | ||||||||
LysoPC (20:2) | C28H54NO7P | 548.368 | 48![]() ![]() |
45![]() ![]() |
43![]() ![]() |
43![]() ![]() |
0.738 | 1.047 | 0.280 | 0.333 | |
Change | −5237 ± 13![]() |
−1080 ± 17![]() |
0.983 | ||||||||
LysoPC (20:3) | C28H52NO7P | 546.353 | 261![]() ![]() |
215![]() ![]() |
226![]() ![]() |
216![]() ![]() |
1.995 | 3.072 | 0.265 | 0.198 | |
Change | −8869 ± 77![]() |
−18![]() ![]() |
0.974 | ||||||||
LysoPC (20:4) | C28H50NO7P | 544.337 | 1![]() ![]() ![]() |
1![]() ![]() ![]() |
1![]() ![]() ![]() |
1![]() ![]() ![]() |
3.374 | 3.635 | 0.413 | 0.610 | |
Change | −19![]() ![]() |
93![]() ![]() |
0.979 | ||||||||
LysoPC (20:5) | C28H48NO7P | 542.322 | 900![]() ![]() |
885![]() ![]() |
830![]() ![]() |
807![]() ![]() |
2.503 | 4.029 | 0.425 | 0.202 | |
Change | 41![]() ![]() |
−1727 ± 172![]() |
0.937 | ||||||||
LysoPC (22:5) | C30H52NO7P | 570.353 | 80![]() ![]() |
78![]() ![]() |
71![]() ![]() |
72![]() ![]() |
0.951 | 1.454 | 0.472 | 0.237 | |
Change | 2394 ± 29![]() |
−3078 ± 27![]() |
0.956 | ||||||||
LysoPC (22:6) | C30H50NO7P | 568.337 | 347![]() ![]() |
364![]() ![]() |
361![]() ![]() |
328![]() ![]() |
2.024 | 2.858 | 0.631 | 0.286 | |
Change | 30![]() ![]() |
−7672 ± 117![]() |
0.935 | ||||||||
LysoPC (P-16:0) | C24H50NO6P | 480.343 | 112![]() ![]() |
106![]() ![]() |
103![]() ![]() |
109![]() ![]() |
1.505 | 1.141 | 0.614 | 0.687 | |
Change | −3702 ± 36![]() |
8568 ± 46![]() |
0.978 | ||||||||
LysoPE (16:0) | C21H44NO7P | 454.291 | 62![]() ![]() |
59![]() ![]() |
49![]() ![]() |
50![]() ![]() |
1.034 | 1.372 | 0.380 | 0.221 | |
Change | −4162 ± 20![]() |
5346 ± 30![]() |
0.981 | ||||||||
LysoPE (18:1) | C23H46NO7P | 480.306 | 59![]() ![]() |
53![]() ![]() |
40![]() ![]() |
37![]() ![]() |
0.941 | 1.930 | 0.219 | 0.023 | |
Change | 689 ± 24![]() |
−5829 ± 21![]() |
0.957 | ||||||||
LysoPE (18:2) | C23H44NO7P | 478.291 | 149![]() ![]() |
132![]() ![]() |
96![]() ![]() |
97![]() ![]() |
1.325 | 2.816 | 0.220 | 0.135 | |
Change | −389 ± 68![]() |
−12![]() ![]() |
0.974 | ||||||||
LysoPE (20:3) | C25H46NO7P | 504.304 | 38![]() ![]() |
39![]() ![]() |
34![]() ![]() |
31![]() |
0.626 | 1.076 | 0.375 | 0.218 | |
Change | −570 ± 13![]() |
−783 ± 15![]() |
0.974 | ||||||||
LysoPE (20:4) | C25H44NO7P | 502.290 | 101![]() ![]() |
99![]() ![]() |
86![]() ![]() |
85![]() ![]() |
0.914 | 1.546 | 0.223 | 0.229 | |
Change | −9526 ± 39![]() |
−1367 ± 32![]() |
0.985 | ||||||||
LysoPE (20:5) | C25H42NO7P | 500.275 | 42![]() ![]() |
45![]() ![]() |
32![]() ![]() |
32![]() ![]() |
0.740 | 1.774 | 0.223 | 0.010 | |
Change | 1247 ± 18![]() |
−1354 ± 14![]() |
0.937 | ||||||||
LysoPE (22:6) | C27H44NO7P | 526.291 | 117![]() ![]() |
141![]() ![]() |
122![]() ![]() |
119![]() ![]() |
1.049 | 1.862 | 0.482 | 0.213 | |
Change | 16![]() ![]() |
−1734 ± 41![]() |
0.939 | ||||||||
Oleamide | C18H35NO | 282.278 | 1![]() ![]() ![]() |
1![]() ![]() ![]() |
1![]() ![]() ![]() |
949![]() ![]() |
5.943 | 9.144 | 0.264 | 0.222 | |
Change | −73![]() ![]() |
430 ± 543![]() |
0.976 | ||||||||
Palmitamide | C16H33NO | 256.262 | 283![]() ![]() |
255![]() ![]() |
226![]() ![]() |
195![]() ![]() |
2.309 | 4.296 | 0.234 | 0.226 | |
Change | 8205 ± 169![]() |
−27![]() ![]() |
0.972 | ||||||||
PC (34:1) | C42H82NO8P | 760.581 | 209![]() ![]() |
145![]() ![]() |
167![]() ![]() |
197![]() ![]() |
2.689 | 3.688 | 0.459 | 0.019 | |
Change | −23![]() ![]() |
33![]() ![]() |
0.158 | ||||||||
PC (34:3) | C42H78NO8P | 756.550 | 101![]() ![]() |
104![]() ![]() |
114![]() ![]() |
129![]() ![]() |
1.320 | 2.079 | 0.392 | 0.224 | |
Change | 1167 ± 39![]() |
9921 ± 50![]() |
0.952 | ||||||||
PC (36:2) | C44H84NO8P | 786.597 | 349![]() ![]() |
306![]() ![]() |
302![]() ![]() |
301![]() ![]() |
2.534 | 1.839 | 0.274 | 0.659 | |
Change | −25![]() ![]() |
16![]() ![]() |
0.817 | ||||||||
PC (36:3) | C44H82NO8P | 784.581 | 244![]() ![]() |
268![]() ![]() |
256![]() ![]() |
254![]() ![]() |
2.360 | 2.070 | 0.592 | 0.677 | |
Change | 20![]() ![]() |
5295 ± 107![]() |
0.969 | ||||||||
PC (36:5) | C44H78NO8P | 780.549 | 1![]() ![]() ![]() |
1![]() ![]() ![]() |
1![]() ![]() ![]() |
1![]() ![]() ![]() |
6.076 | 5.518 | 0.596 | 0.703 | |
Change | 117![]() ![]() |
83![]() ![]() |
0.974 | ||||||||
PC (38:5) | C46H82NO8P | 808.581 | 161![]() ![]() |
165![]() ![]() |
152![]() ![]() |
163![]() ![]() |
2.067 | 1.111 | 0.372 | 0.654 | |
Change | −7615 ± 47![]() |
9464 ± 43![]() |
0.886 | ||||||||
PC (40:6) | C48H84NO8P | 834.597 | 77![]() ![]() |
81![]() ![]() |
73![]() ![]() |
68![]() ![]() |
1.007 | 0.826 | 0.492 | 0.727 | |
Change | 5324 ± 27![]() |
7111 ± 32![]() |
0.982 | ||||||||
PC (P-38:6) | C46H80NO7P | 790.570 | 48![]() ![]() |
57![]() ![]() |
47![]() ![]() |
54![]() ![]() |
1.530 | 1.143 | 0.486 | 0.587 | |
Change | 5753 ± 31![]() |
8692 ± 23![]() |
0.981 | ||||||||
SM (d18:0/16:1) | C39H79N2O6P | 703.572 | 57![]() ![]() |
59![]() ![]() |
57![]() ![]() |
66![]() ![]() |
1.822 | 1.194 | 0.561 | 0.591 | |
Change | 44 ± 26![]() |
2789 ± 47![]() |
0.960 | ||||||||
Taurocholic acid | C26H45NO7S | 516.303 | 109![]() ![]() |
106![]() ![]() |
88![]() ![]() |
99![]() ![]() |
0.796 | 1.381 | 0.318 | 0.276 | |
Change | −7591 ± 43![]() |
11![]() ![]() |
0.985 | ||||||||
trans-2-Dodecenoylcarnitine | C19H35NO4 | 342.262 | 17![]() ![]() |
22![]() ![]() |
21![]() ![]() |
46![]() ![]() |
3.716 | 2.852 | 0.427 | <0.001 | |
Change | 2764 ± 13![]() |
20![]() ![]() |
0.002 | ||||||||
Uric acid | C5H4N4O3 | 169.035 | 146![]() ![]() |
152![]() ![]() |
127![]() ![]() |
138![]() ![]() |
0.809 | 1.181 | 0.437 | 0.220 | |
Change | 10![]() ![]() |
−989 ± 26![]() |
0.944 |
ACs are derived from mitochondrial and peroxisomal acyl-CoA metabolites by the substitution of the carnitine moiety for CoA. They are the product of incomplete fatty acid oxidation in the mitochondria and are elevated in obesity and type 2 diabetes; they are also positively associated with insulin resistance15–18 even after adjusting the BMI.19 However, in this study, no significant differences were observed from the baseline in fasting glucose, insulin, C-peptide levels or the HOMA-IR index in the probiotic group at the 12-week follow-up. We observed that the probiotic-induced weight and adiposity loss were coupled with an increase in lipid-derived medium-chain ACs. Therefore, the current study provides new findings on the effects of probiotic-induced weight loss on metabolic intermediates and particularly on increases in plasma medium-chain ACs. Brady et al.20 previously found an increase in ACs after starvation in both lean and obese Zucker rats. Additionally, Redman et al.21 observed that the weight loss with calorie restriction in overweight subjects resulted in an increase in serum ACs. Huffman et al.22 also reported that fasting ACs were increased after 3 months of calorie restriction. In a recent study, the assessment of plasma acylcarnitines before and after the weight loss in obese subjects showed increased levels of acylcarnitines and a strong correlation between non-esterified fatty acids (NEFA) and several acylcarnitines during the weight loss. Since plasma NEFA are indicative of lipolysis,23 increased lipolysis might drive the generation of acylcarnitines.24 Similarly, in the present study, increased ACs in the probiotic group may have resulted from increased lipolysis during body fat reduction. Additionally, tetradecenoylcarnitine (C14:1) increases in altered fatty acid oxidation states, such as very long chain acyl-CoA dehydrogenase deficiency.25 Indeed, Yoo et al.26 found that the combination of the probiotics L. curvatus and L. plantarum was effective in inhibiting the gene expression of various fatty acid synthesis enzymes in the liver in parallel with the decrease in fatty acid oxidation-related enzymatic activity and gene expression in mice. Therefore, increased lipolysis together with decreased fatty acid oxidation may result in elevations in medium-chain acylcarnitines during the weight loss after probiotic consumption.
Several mechanisms regarding the effects of Lactobacillus strains on adiposity reduction have been proposed. In a study reporting the effect of L. plantarum KY1032 on fat mass reduction, L. plantarum KY1032 cell extracts were suggested as directly decreasing fat mass, by modulating the adipogenesis of 3T3-L1 cells.27 Yoo et al.26 demonstrated that two Lactobacillus strains, L. plantarum KY1032 and L. curvatus HY7601, have an adverse effect on fat accumulation in adipose tissue in diet-induced obese mice by changing the gut microbiome composition or modulating cholesterol metabolism. Additionally, another study reported on the roles of L. plantarum KY1032 and L. curvatus HY7601 in the gut; the two probiotics may reduce fat accumulation by inducing competition for nutrients within the gut or by reducing gut microbiota diversity.26 In the present study, we observed weight loss in the probiotic group while they consumed a weight maintenance diet. Therefore, we hypothesize that the administration of the Lactobacillus strains may have partly affected adipogenesis in adipose tissue or the gut microbiome in our study subjects, resulting in decreased fat accumulation.
Previous studies have reported elevated C3 and C5 ACs, which are the by-products of leucine, isoleucine and valine (branched chain amino acid, BCAA) catabolism, and higher levels of BCAAs and other amino acids including phenylalanine, tryptophan and tyrosine in obese individuals than in lean individuals, which is possibly because of higher insulin resistance.17,28 Prez-Cornago et al.29 showed a significant reduction in serum isoleucine in overweight adults following a weight loss intervention. In the present study, the subjects were overweight and had slightly higher HOMA-IR indexes (mean HOMA-IR index at baseline = 2.7) compared to the reference range for Koreans.30 Since an association exists between the HOMA-IR index and BCAAs,17,28 we expected that possible associations might exist among the probiotic-induced weight loss, the HOMA-IR index, and the changes of metabolic intermediates, such as BCAAs. However, in the probiotic group of this study, changes in amino acids were not associated with changes in body weight and body adiposity. Only the placebo group showed significant elevations from the baseline in BCAAs, phenylalanine and tyrosine at the 12-week follow-up and positive correlations between the changes in BCAAs and changes in body weight. No significant change was observed in the HOMA-IR index or the fasting glucose, insulin and C-peptide levels after the 12-week follow-up with no correlation observed between the HOMA-IR index and BCAAs in the placebo or probiotic groups. These findings appear to show a lack of association and interaction between the HOMA-IR index and BCAAs and may be inconsistent with previous studies.17,28 However, the significant increase of BCAAs observed in the placebo group at the 12-week follow-up may imply that the maintenance of an overweight state may accelerate the increase of BCAAs, whereas the consumption of the probiotics may inhibit their increase. Although we did not observe a correlation between the HOMA-IR index and BCAAs, increased BCAAs may influence insulin resistance in overweight individuals as previously described in several studies.17,28 Therefore, taken together, we propose that the intake of probiotics may help inhibit rising BCAAs in overweight individuals.
This study has some limitations. We specifically focused on overweight individuals without diabetes. Therefore, our data cannot be generalized to obese individuals or diabetic patients. Additionally, numerous metabolic intermediates were observed using UPLC-LTQ/Orbitrap MS in this study; however, most of these metabolites remain unidentified because the databases of endogenous biomolecules have not yet been constructed for this technique.31 Therefore, we identified only a limited number of metabolites among the 238 variables that contributed to the separation between the placebo and probiotic groups. Moreover, since the metabolomics analyses were conducted in some of the participants from the previous study, the statistical power to detect changes in metabolites may be reduced. Regarding gut microbiome alterations in our study subjects, we cannot characterize such changes because we did not measure the amount of the probiotics present in the feces of our study participants. Finally, we cannot determine whether the changes in the metabolic intermediates observed in the present study are derived from the direct effects of the probiotics themselves or the probiotic-induced adiposity reduction.
Despite these limitations, we found significant differences in octenoylcarnitine (C8:1), tetradecenoylcarnitine (C14:1), decanoylcarnitine (C10) and dodecenoylcarnitine (C12:1) in the group of healthy overweight individuals who consumed a weight maintenance diet supplemented with the two probiotic strains compared with the placebo-supplemented group. Furthermore, in the probiotic group, a significant decrease in body weight, whole body adiposity (percentage body fat or body fat mass) and the L1 subcutaneous fat area was strongly associated with an increase in C8:1, C14:1, C10 and C12:1 ACs. However, the precise mechanisms underlying the metabolic changes in the probiotic-induced weight loss should be examined in further studies.
AC | Acylcarnitine |
BCAA | Branched chain amino acid |
BMI | Body mass index |
CT | Computed tomography |
DEXA | Dual-energy X-ray absorptiometry |
L1 | 1st lumbar |
L4 | 4th lumbar |
lysoPC | Lysophosphatidylcholine |
lysoPE | Lysophosphatidylethanolamine |
HOMA-IR | Homeostasis model assessment of insulin resistance |
hs-CRP | High-sensitivity C-reactive protein |
OPLS-DA | Orthogonal partial least squares-discriminant analysis |
PC | Phosphatidylcholine |
SE | Standard error |
UPLC-LTQ/Orbitrap MS | Ultra-performance liquid chromatography-linear-trap quadrupole-Orbitrap mass spectrometry |
VIP | Variable importance in projection |
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