Milk polar lipids reduce lipid cardiovascular risk factors in overweight postmenopausal women: towards a gut sphingomyelin-cholesterol interplay

Abstract

Objective: To investigate whether milk polar lipids (PL) impact human intestinal lipid absorption, metabolism, microbiota and associated markers of cardiometabolic health.

Design: A double-blind, randomised controlled 4-week study involving 58 postmenopausal women was used to assess the chronic effects of milk PL consumption (0, 3 or 5 g-PL/day) on lipid metabolism and gut microbiota. The acute effects of milk PL on intestinal absorption and metabolism of cholesterol were assessed in a randomised controlled crossover study using tracers in ileostomy patients.

Results: Over 4 weeks, milk PL significantly reduced fasting and postprandial plasma concentrations of cholesterol and surrogate lipid markers of cardiovascular disease risk, including total/high-density lipoprotein-cholesterol and apolipoprotein (Apo)B/ApoA1 ratios. The highest PL dose preferentially induced a decreased number of intestine-derived chylomicron particles. Also, milk PL increased faecal loss of coprostanol, a gut-derived metabolite of cholesterol, but major bacterial populations and faecal short-chain fatty acids were not affected by milk PL, regardless of the dose. Acute ingestion of milk PL by ileostomy patients shows that milk PL decreased cholesterol absorption and increased cholesterol-ileal efflux, which can be explained by the observed co-excretion with milk sphingomyelin in the gut.

Conclusion: The present data demonstrate for the first time in humans that milk PL can improve the cardiometabolic health by decreasing several lipid cardiovascular markers, notably through a reduced intestinal cholesterol absorption involving specific interactions in the gut, without disturbing the major bacterial phyla of gut microbiota.

Trial registration number: NCT02099032 and NCT02146339; Results.

Keywords: colonic microflora; lipid absorption; lipid metabolism; lipoprotein-cholesterol; nutrition.

Conflict of interest statement

Competing interests: This work was supported in part by a grant from the French Dairy Interbranch Organization (CNIEL). M-CM has received research funding for other research projects from CNIEL, Danone-Nutricia Research, Sodiaal-Candia R&D. M-CM has consultancy activities for food, fats and oils and dairy companies. M-CM is a member of the scientific advisory board of ITERG, the Industrial Technical Centre for the oils and fats business sector. These activities had no link with the present study. BM has received research funding from Sofiprotéol with no link with the present study. PG is an employee of ACTALIA Produits Laitiers, an Agri-Food Technical Institute, with a strong specialisation in dairy research and development, and food safety. KR was an employee of ACTALIA Produits Laitiers and is now employee of Terra Lacta, a dairy cooperative. J-PB: ENILIA had research funding from dairy companies Laiterie des Fayes and Eurial. These activities had no link with the present study. GG-G has received research funding for other research projects from Savencia, Danone, Sodiaal-Candia R&D, Boccard. She has consultancy activities for dairy companies and filtration equipment providers. These activities had no link with the present study. MLa is a member of the Scientific Committee of Roquette and had research collaborations with Mondelez and Bridor. These activities had no link with the present study. The authors have no additional financial interests. Other authors declared no conflict of interest. There are no awarded or filed patents pertaining to the results presented in the paper.

© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

Figures

Figure 1

Impact of 4-week intervention with up to 5 g milk PL in cream cheese on postprandial concentrations of lipid CV risk markers (VALOBAB-C trial). Panel explanation (A) and kinetics of serum total C (B), serum TAG (C), plasma ApoB/ApoA1 ratio (D) and plasma ApoB48 (E) before (V1, dotted line) and after (V2, full line) the daily consumption of 100 g of cheese with or without PL during 4 weeks. Data are represented as mean±SEM. The pgroup and pposthoc are shown for the 8-hour postprandial period (linear mixed model followed by post hoc analyses on ΔV2−V1); ptimexgroup was not significant. Group size: control n=18, 3 g-PL n=18, 5 g-PL n=20. See also online supplementary figure S1 for study design. Apo, apolipoprotein; C, cholesterol; CVD, cardiovascular disease; CV, cardiovascular; PL, polar lipids; TAG, triacylglycerols.

Figure 2

Modulation of postprandial chylomicron parameters after 4-week intervention with control, 3 g-PL or 5 g-PL cream cheese (VALOBAB-C trial). Panel explanation (A) and plasma kinetics of CMRF TAG (B), CMRF C (C) and CMRF size (D) before (V1, dotted line) and after (V2, full line) the daily consumption of 100 g of cheese with or without PL during 4 weeks. Data are represented as mean±SEM. pgroup and pposthoc are shown for postprandial period from 120 to 480 min (linear mixed model followed by post hoc analyses on ΔV2−V1). ptimexgroup was not significant. (B, C): after adjustment on quartiles of volunteer age and waist circumference: pgroup<0.05. For technical reason, analyses performed in centre 1 only, sample size: control n=9, 3 g-PL n=9, 5 g-PL n=10. CMRF, chylomicron-rich fraction; PL, polar lipids; TAG, triacylglycerols.

Figure 3

Impact of 4-week intervention with milk polar lipids (PL)-enriched cream cheese on faecal lipids in the VALOBAB-C trial. Faecal loss variations (ΔV2−V1) of total lipids (A), cholesterol (B), coprostanol (C) and coprostanol/cholesterol ratio (D) after daily consumption of 100 g of cheese with or without PL during 4 weeks. Coprostanol/cholesterol ratio before (V1) and after (V2) the 4-week consumption of 100 g of cheese with or without PL (E). Spearman’s correlation between faecal coprostanol/cholesterol ratio and serum low-density lipoprotein-cholesterol (LDL-C) (F) and total cholesterol (C) (G) after (V2) daily consumption of 100 g of cheese with or without PL during 4 weeks (orange: control group, light blue: 3 g-PL group, dark blue: 5 g-PL group). Spearman’s correlation between faecal coprostanol/cholesterol ratio and serum total C (H) and LDL-C (I) at V2 in the 5 g-PL group. Data are indicated as median with IQR. The pgroup is shown to compare intervention effect between the three groups (analysis on ranks on ΔV2−V1); PPL is shown to compare intervention effect between the control group and both PL groups regardless of dose. For technical reasons, analyses performed in centre 1 only, sample size: (A) n=9 (control) to 10 (PL); (B–C) n=4 (control) to 7 (PL); (D–I) n=7 (control) to 9 (PL). NB: regardless of group and visit, the observed faecal losses of cholesterol (range 0.2–1 mg/g faeces) and coprostanol (range 0.45–5.2 mg/g faeces) were consistent with previous published data (cholesterol: 1.88±0.53 to 5.8±1.56 mg/g dry faeces; coprostanol: 3–27.4 mg/g lyophilised faeces, considering that dry matter is ~25% of total faeces weight).

Figure 4

Major phylogenetic groups and bacterial species of gut microbiota after 4-week intervention with up to 5 g milk polar lipids (PL) in cream cheese in the VALOBAB-C trial. Variations (log-fold change V2/V1) of the abundance of the main bacterial groups and species that were measured as log 16S rDNA gene copies per g of faeces: (A) total bacteria, (B) Firmicutes, (C) Bacteroides-Prevotella group, (D) Akkermancia muciniphila, (E) Bifidobacterium spp, (F) Lactobacillus-Leuconostoc-Pediococcus group, (G) Clostridium coccoides group, (H) Clostridium leptum group, (I) Faecalibacterium prausnitzii, (J) Roseburia-Eubacterium rectale group, (K) Veillonella spp, (L) Enterobacteriaceae family, (M) Escherichia coli and (N) Bilophila wadworthia. Data are indicated as median with IQR; pgroup is shown. Group size: control n=18, 3 g-PL n=18, 5 g-PL n=20.

Figure 5

Faecal profile of short-chain fatty acids before (V1) and after (V2) 4-week intervention with up to 5 g/day milk polar lipids (PL) in cream cheese in the VALOBAB-C trial. (A) Acetate, propionate and butyrate, (B) isobutyrate, formate, succinate and lactate. Data are represented as mean±SEM, pgroup are shown. NB: regarding the total amount of major short-chain fatty acids in (A), acetate+propionate+butyrate: pgroup=0.35. For technical reasons, analyses performed in centre 2 only, sample size: control n=8, 3 g-PL n=7, 5 g-PL n=8.

Figure 6

Milk polar lipids (PL) impact on intestinal cholesterol absorption in the VALOBAB-D pilot study in ileostomy volunteers. Panel explanation (A), cumulated enrichment over 0–480 min of [2H]-cholesterol in plasma (B) and chylomicron-rich fraction (CMRF) (C), ileal losses of total cholesterol (D) and sphingomyelin (SM) (E), during the 0–240 min and 240–480 min postprandial periods (see also online supplementary figure S3G for SM composition in ileal efflux). Data are expressed as mean±SEM; n=4 per group. (B) Friedman test (pmeal) followed by Dunn’s post hoc tests for control and 5 g-PL groups. (C) Repeated measures one-way analysis of variance (ANOVA) (pmeal) followed by Tukey’s post hoc tests. (D, E) Repeated measures two-way ANOVA (pmeal, ptime, pmeal×time) followed by Tukey’s post hoc tests. *Pposthoc<0.05 vs control group. The pPL compares the effect of control meal with both PL meals regardless of dose. Sample size: n=4 subjects, crossover design (see online supplementary figure S2). NB: The 8-hour total cholesterol efflux (tracer+tracee in both free and esterified forms) after the control meal (642±57 mg) was consistent with previous reports; here after 3 g-PL meal the 8-hour total cholesterol efflux was 1510±417 and 1752±354 mg after 5 g-PL meal. NB: The proportion vs ingested milk SM of the 8-hour ileal efflux of milk SM after cheese matrix (20%–25% of ingested dose) was similar with 19% reported after pure milk SM in six ileostomy subjects.