Impact of buttermilk consumption on plasma lipids and surrogate markers of cholesterol homeostasis in men and women

Comparison of the impact of SFAs from cheese and butter on cardiometabolic risk factors: a randomized controlled trial

Background: Controversies persist concerning the association between intake of dietary saturated fatty acids (SFAs) and cardiovascular disease risk.Objective: We compared the impact of consuming equal amounts of SFAs from cheese and butter on cardiometabolic risk factors.Design: In a multicenter, crossover, randomized controlled trial, 92 men and women with abdominal obesity and relatively low HDL-cholesterol concentrations were assigned to sequences of 5 predetermined isoenergetic diets of 4 wk each separated by 4-wk washouts: 2 diets rich in SFAs (12.4-12.6% of calories) from either cheese or butter; a monounsaturated fatty acid (MUFA)-rich diet (SFAs: 5.8%, MUFAs: 19.6%); a polyunsaturated fatty acid (PUFA)-rich diet (SFAs: 5.8%, PUFAs: 11.5%); and a low-fat, high-carbohydrate diet (fat: 25%, SFAs: 5.8%).Results: Serum HDL-cholesterol concentrations were similar after the cheese and butter diets but were significantly higher than after the carbohydrate diet (+3.8% and +4.7%, respectively; P < 0.05 for both). LDL-cholesterol concentrations after the cheese diet were lower than after the butter diet (-3.3%, P < 0.05) but were higher than after the carbohydrate (+2.6%), MUFA (+5.3%), and PUFA (+12.3%) diets (P < 0.05 for all). LDL-cholesterol concentrations after the butter diet also increased significantly (from +6.1% to +16.2%, P < 0.05) compared with the carbohydrate, MUFA, and PUFA diets. The LDL-cholesterol response to treatment was significantly modified by baseline values (P-interaction = 0.02), with the increase in LDL cholesterol being significantly greater with butter than with cheese only among individuals with high baseline LDL-cholesterol concentrations. There was no significant difference between all diets on inflammation markers, blood pressure, and insulin-glucose homeostasis.Conclusions: The results of our study suggest that the consumption of SFAs from cheese and butter has similar effects on HDL cholesterol but differentially modifies LDL-cholesterol concentrations compared with the effects of carbohydrates, MUFAs, and PUFAs, particularly in individuals with high LDL cholesterol. In contrast, SFAs from either cheese or butter have no significant effects on several other nonlipid cardiometabolic risk factors. This trial was registered at clinicaltrials.gov as NCT02106208.

Nutritional and Lipid Modulation of PCSK9: Effects on Cardiometabolic Risk Factors

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a serine protease involved in the regulation of LDL receptor (LDLR) expression and apolipoprotein B lipoprotein cholesterol metabolism. Hepatic PCSK9 protein expression, activity, and secretion have been shown to affect cholesterol homeostasis. An upregulation of hepatic PSCK9 protein leads to increased LDLR degradation, resulting in decreased uptake of apoB lipoproteins and a consequent increase in the plasma concentration of these lipoproteins, including LDL and chylomicron remnants. Hence, PCSK9 has become a novel target for lipid-lowering therapies. The aim of this review is to outline current findings on the metabolic and dietary regulation of PCSK9 and effects on cholesterol, apoB lipoprotein metabolism, and cardiovascular disease (CVD) risk. PCSK9 gene and protein expression have been shown to be regulated by metabolic status and the diurnal pattern. In the fasting state, plasma PCSK9 is reduced via modulation of the nuclear transcriptional factors, including sterol regulatory element-binding protein (SREBP) 1c, SREBP2, and hepatocyte nuclear factor 1α. Plasma PCSK9 concentrations are also known to be positively associated with plasma insulin and homeostasis model assessment of insulin resistance, and appear to be regulated by SREBP1c independently of glucose status. Plasma PCSK9 concentrations are stable in response to high-fat or high-protein diets in healthy individuals; however, this response may differ in altered metabolic conditions. Dietary n-3 polyunsaturated fatty acids have been shown to reduce plasma PCSK9 concentration and hepatic PCSK9 mRNA expression, consistent with their lipid-lowering effects, whereas dietary fructose appears to upregulate PCSK9 mRNA expression and plasma PCSK9 concentrations. Further studies are needed to elucidate the mechanisms of how dietary components regulate PCSK9 and effects on cholesterol and apoB lipoprotein metabolism, as well as to delineate the clinical impact of diet on PCSK9 in terms of CVD risk.

Supplementation of Infant Formula with Bovine Milk Fat Globule Membranes

Studies have shown that supplementation of infant formula with bovine milk fat globule membranes (MFGMs) may substantially narrow the gap in health outcomes between formula-fed and breastfed infants. In one study, consumption of a formula supplemented with a lipid-rich MFGM concentrate between 2 and 6 mo of age improved cognitive performance at 24 wk of age. In another study, a formula supplemented with a protein-rich MFGM concentrate given between 2 and 6 mo of age improved cognitive performance at 12 mo of age, decreased infectious morbidity until 6 mo of age, and yielded serum cholesterol concentrations closer to those of breastfed infants. A third study that assessed the safety of supplementing infant formula with a lipid-rich or a protein-rich MFGM concentrate found a noninferior weight gain for both groups compared with a nonsupplemented formula. In this study, there was an increased risk of eczema in the protein-rich group, but no serious adverse events. Infant formulas with supplemental MFGMs have been launched on the market in several countries. However, the evidence base must still be considered quite limited. Based on 3 randomized controlled trials that are not comparable, the intervention seems safe, but there is not enough evidence for a general recommendation on which MFGM fraction to use and at what concentration as formula supplement for a given outcome.

Recent Advances in Phospholipids from Colostrum, Milk and Dairy By-Products

Milk is one of the most important foods for mammals, because it is the first form of feed providing energy, nutrients and immunological factors. In the last few years, milk lipids have attracted the attention of researchers due to the presence of several bioactive components in the lipid fraction. The lipid fraction of milk and dairy products contains several components of nutritional significance, such as ω-3 and ω-6 polyunsaturated fatty acids, CLA, short chain fatty acids, gangliosides and phospholipids. Prospective cohort evidence has shown that phospholipids play an important role in the human diet and reinforce the possible relationship between their consumption and prevention of several chronic diseases. Because of these potential benefits of phospholipids in the human diet, this review is focused on the recent advances in phospholipids from colostrum, milk and dairy by-products. Phospholipid composition, its main determination methods and the health activities of these compounds will be addressed.

Food and Cardiac Health

Emerging influence of Cardiovascular Diseases (CVDs) and its impact on the society has raised much awareness for its prevention. Healthy food habits and physical exercise has drawn a lot of attention of the people from scientific as well as common world. The role of food-based bioactive compounds in reducing risk of CVDs has been established with various health benefits apart from the basic nutrition have been reported. The present chapter provides an overview of the role of different foods on cardiovascular health of humans. Biological effects of plant derived food products and their bioactive compounds in the context of relevance to cardiovascular health promotion are discussed in detail. The chapter also covers the effects of the consumption of functional food on the intermediate clinical markers of CVDs including cholesterolemia, hypertension, endothelial function and inflammation. The chapter will enable the better understanding of the current knowledge on the potential health benefits of different functional foods and bioactive compounds on cardiovascular health.

Nutritional management of hyperapoB

Plasma apoB is a more accurate marker of the risk of CVD and type 2 diabetes (T2D) than LDL-cholesterol; however, nutritional reviews targeting apoB are scarce. Here we reviewed eighty-seven nutritional studies and present conclusions in order of strength of evidence. Plasma apoB was reduced in all studies that induced weight loss of 6–12 % using hypoenergetic diets (seven studies; 5440–7110 kJ/d; 1300–1700 kcal/d; 34–50 % carbohydrates; 27–39 % fat; 18–24 % protein). When macronutrients were compared in isoenergetic diets (eleven studies including eight randomised controlled trials (RCT); n 1189), the diets that reduced plasma apoB were composed of 26–51 % carbohydrates, 26–46 % fat, 11–32 % protein, 10–27 % MUFA, 5–14 % PUFA and 7–13 % SFA. Replacement of carbohydrate by MUFA, not SFA, decreased plasma apoB. Moreover, dietary enriching with n-3 fatty acids (FA) (from fish: 1·1–1·7 g/d or supplementation: 3·2–3·4 g/d EPA/DHA or 4 g/d EPA), psyllium (about 8–20 g/d), phytosterols (about 2–4 g/d) or nuts (30–75 g/d) also decreased plasma apoB, mostly in hyperlipidaemic subjects. While high intake of trans-FA (4·3–9·1 %) increased plasma apoB, it is unlikely that these amounts represent usual consumption. Inconsistent data existed on the effect of soya proteins (25–30 g/d), while the positive association of alcohol consumption with low plasma apoB was reported in cross-sectional studies only. Five isoenergetic studies using Mediterranean diets (including two RCT; 823 subjects) reported a decrease of plasma apoB, while weaker evidence existed for Dietary Approaches to Stop Hypertension (DASH), vegetarian, Nordic and Palaeolithic diets. We recommend using a Mediterranean dietary pattern, which also encompasses the dietary components reported to reduce plasma apoB, to target hyperapoB and reduce the risks of CVD and T2D.

Dairy food products: good or bad for cardiometabolic disease?

Prevalence of type 2 diabetes mellitus (T2DM) is rapidly increasingly and is a key risk for CVD development, now recognised as the leading cause of death globally. Dietary strategies to reduce CVD development include reduction of saturated fat intake. Milk and dairy products are the largest contributors to dietary saturated fats in the UK and reduced consumption is often recommended as a strategy for risk reduction. However, overall evidence from prospective cohort studies does not confirm a detrimental association between dairy product consumption and CVD risk. The present review critically evaluates the current evidence on the association between milk and dairy products and risk of CVD, T2DM and the metabolic syndrome (collectively, cardiometabolic disease). The effects of total and individual dairy foods on cardiometabolic risk factors and new information on the effects of the food matrix on reducing fat digestion are also reviewed. It is concluded that a policy to lower SFA intake by reducing dairy food consumption to reduce cardiometabolic disease risk is likely to have limited or possibly negative effects. There remain many uncertainties, including differential effects of different dairy products and those of differing fat content. Focused and suitably designed and powered studies are needed to provide clearer evidence not only of the mechanisms involved, but how they may be beneficially influenced during milk production and processing.

Effects of dietary milk- and soya-phospholipids on lipid-parameters and other risk indicators for cardiovascular diseases in overweight or obese men - two double-blind, randomised, controlled, clinical trials

The present study examined the effect of milk phospholipids (milk-PL) on lipid metabolism and on other risk factors for CVD, in comparison with milk fat (control) or soya phospholipids (soya-PL), respectively. Two double-blind parallel-group intervention trials were conducted in overweight or obese male subjects. In the first trial (trial 1), sixty-two men consumed milk enriched with either 2 g milk-PL or 2 g milk fat (control) for 8 weeks. In trial 2, fifty-seven men consumed milk enriched with either 3 g milk-PL or 2·8 g soya-PL for 7 weeks. In trial 1, milk-PL as compared with control reduced waist circumference but did not affect plasma lipids (total, HDL- and LDL-cholesterol, total cholesterol:HDL-cholesterol ratio, TAG, phospholipids), apoB, apoA1, glucose, insulin, insulin sensitivity index, C-reactive protein, IL-6, soluble intracellular adhesion molecule and total homocysteine (tHcy). Serum activities of alanine transaminase and aspartate transaminase were not changed. Activity of γ-glutamyl transferase (GGT), a marker of fatty liver, increased in the control but not in the milk-PL group, with a significant intervention effect. In trial 2, milk-PL as compared with soya-PL did not affect the above-mentioned parameters, but decreased GGT. Subjects with the methylenetetrahydrofolate reductase mutations CT and TT had 11 % (P < 0·05) higher baseline tHcy concentrations than those with the wild-type CC. However, genotype did not modulate the phospholipid intervention effect on tHcy. In conclusion, supplementation with milk-PL as compared with control fat reduced waist circumference and, as compared with both control fat and soya-PL, GGT activity.

Organization of lipids in milks, infant milk formulas and various dairy products: role of technological processes and potential impacts

The microstructure of milk fat in processed dairy products is poorly known despite its importance in their functional, sensorial and nutritional properties. However, for the last 10 years, several research groups including our laboratory have significantly contributed to increasing knowledge on the organization of lipids in situ in dairy products. This paper provides an overview of recent advances on the organization of lipids in the milk fat globule membrane using microscopy techniques (mainly confocal microscopy and atomic force microscopy). Also, this overview brings structural information about the organization of lipids in situ in commercialized milks, infant milk formulas and various dairy products (cream, butter, buttermilk, butter serum and cheeses). The main mechanical treatment used in the dairy industry, homogenization, decreases the size of milk fat globules, changes the architecture (composition and organization) of the fat/water interface and affects the interactions between lipid droplets and the protein network (concept of inert vs active fillers). The potential impacts of the organization of lipids and of the alteration of the milk fat globule membrane are discussed, and technological strategies are proposed, in priority to design biomimetic lipid droplets in infant milk formulas.

Relevance of dietary glycerophospholipids and sphingolipids to human health

Glycerophospholipids and sphingolipids participate in a variety of indispensable metabolic, neurological, and intracellular signaling processes. In this didactic paper we review the biological roles of phospholipids and try to unravel the precise nature of their putative healthful activities. We conclude that the biological actions of phospholipids activities potentially be nutraceutically exploited in the adjunct therapy of widely diffused pathologies such as neurodegeneration or the metabolic syndrome. As phospholipids can be recovered from inexpensive sources such as food processing by-products, ad-hoc investigation is warranted.

Milk Polar Lipids Affect In Vitro Digestive Lipolysis and Postprandial Lipid Metabolism in Mice

BACKGROUND

Polar lipid (PL) emulsifiers such as milk PLs (MPLs) may affect digestion and subsequent lipid metabolism, but focused studies on postprandial lipemia are lacking.

OBJECTIVE

We evaluated the impact of MPLs on postprandial lipemia in mice and on lipid digestion in vitro.

METHODS

Female Swiss mice were gavaged with 150 μL of an oil-in-water emulsion stabilized with 5.7 mg of either MPLs or soybean PLs (SPLs) and killed after 1, 2, or 4 h. Plasma lipids were quantified and in the small intestine, gene expression was analyzed by reverse transcriptase-quantitative polymerase chain reaction. Emulsions were lipolyzed in vitro using a static human digestion model; triglyceride (TG) disappearance was followed by thin-layer chromatography.

RESULTS

In mice, after 1 h, plasma TGs tended to be higher in the MPL group than in the SPL group (141 μg/mL vs. 90 μg/mL; P = 0.07) and nonesterified fatty acids (NEFAs) were significantly higher (64 μg/mL vs. 44 μg/mL; P < 0.05). The opposite was observed after 4 h with lower TGs (21 μg/mL vs. 35 μg/mL; P < 0.01) and NEFAs (20 μg/mL vs. 32 μg/mL; P < 0.01) in the MPL group compared with the SPL group. This was associated at 4 h with a lower gene expression of apolipoprotein B (Apob) and Secretion Associated, Ras related GTPase 1 gene homolog B (Sar1b), in the duodenum of MPL mice compared with SPL mice (P < 0.05). In vitro, during the intestinal phase, TGs were hydrolyzed more in the MPL emulsion than in the SPL emulsion (decremental AUCs were 1750%/min vs. 180%/min; P < 0.01). MPLs enhance lipid intestinal hydrolysis and promote more rapid intestinal lipid absorption and sharper kinetics of lipemia.

CONCLUSIONS

Postprandial lipemia in mice can be modulated by emulsifying with MPLs compared with SPLs, partly through differences in chylomicron assembly, and TG hydrolysis rate as observed in vitro. MPLs may thereby contribute to the long-term regulation of lipid metabolism.

Potential role of milk fat globule membrane in modulating plasma lipoproteins, gene expression, and cholesterol metabolism in humans: a randomized study

BACKGROUND

Butter is rich in saturated fat [saturated fatty acids (SFAs)] and can increase plasma low density lipoprotein (LDL) cholesterol, which is a major risk factor for cardiovascular disease. However, compared with other dairy foods, butter is low in milk fat globule membrane (MFGM) content, which encloses the fat. We hypothesized that different dairy foods may have distinct effects on plasma lipids because of a varying content of MFGM.

OBJECTIVE

We aimed to investigate whether the effects of milk fat on plasma lipids and cardiometabolic risk markers are modulated by the MFGM content.

DESIGN

The study was an 8-wk, single-blind, randomized, controlled isocaloric trial with 2 parallel groups including overweight men and women (n = 57 randomly assigned). For the intervention, subjects consumed 40 g milk fat/d as either whipping cream (MFGM diet) or butter oil (control diet). Intervention foods were matched for total fat, protein, carbohydrates, and calcium. Subjects were discouraged from consuming any other dairy products during the study. Plasma markers of cholesterol absorption and hepatic cholesterol metabolism were assessed together with global gene-expression analyses in peripheral blood mononuclear cells.

RESULTS

As expected, the control diet increased plasma lipids, whereas the MFGM diet did not [total cholesterol (±SD): +0.30 ± 0.49 compared with -0.04 ± 0.49 mmol/L, respectively (P = 0.024); LDL cholesterol: +0.36 ± 0.50 compared with +0.04 ± 0.36 mmol/L, respectively (P = 0.024); apolipoprotein B:apolipoprotein A-I ratio: +0.03 ± 0.09 compared with -0.05 ± 0.10 mmol/L, respectively (P = 0.007); and non-HDL cholesterol: +0.24 ± 0.49 compared with -0.14 ± 0.51 mmol/L, respectively (P = 0.013)]. HDL-cholesterol, triglyceride, sitosterol, lathosterol, campesterol, and proprotein convertase subtilisin/kexin type 9 plasma concentrations and fatty acid compositions did not differ between groups. Nineteen genes were differentially regulated between groups, and these genes were mostly correlated with lipid changes.

CONCLUSIONS

In contrast to milk fat without MFGM, milk fat enclosed by MFGM does not impair the lipoprotein profile. The mechanism is not clear although suppressed gene expression by MFGM correlated inversely with plasma lipids. The food matrix should be considered when evaluating cardiovascular aspects of different dairy foods. This trial was registered at clinicaltrials.gov as NCT01767077.

Structure-function relationship of the milk fat globule

PURPOSE OF REVIEW

The complex biochemical composition and physical structure of the milk fat globule (MFG) are presented as a basis for its paradoxical metabolic fate: MFG is a rapid conveyor of energy through its triacylglycerol (TAG) core but contains some low-digestible bioactive complex lipids and proteins, which influence lipid metabolism and contribute to intestinal and systemic health.

RECENT FINDINGS

MFG structure modulates gastrointestinal lipolysis, postprandial lipemia and even the postprandial fate of ingested fatty acids. Proof-of-concept of the nutritional programming induced by early consumption of an emulsion biomimetic of MFG compared with a typical infant formula was published in an animal model (mice). The metabolic response to a high-fat diet during adulthood was improved following neonatal exposure to the biomimetic emulsion.

SUMMARY

MFG TAG are tailored with a unique regiodistribution delivering in priority short to medium-chain fatty acids in gastric phase, an important amount of quickly metabolizable oleic acid and protecting palmitic acid in sn-2 position. MFG digestion may not only trigger rapid TAG and chylomicron plasma peaks with fast clearance but also the luminal release of nonhydrolysable bioactive compounds (glycosylated compounds and sphingomyelin), which contribute to intestinal and systemic health by shaping the microbiota and modulating the immune system. These bioactive compounds form self-assembled structures, protect specific micronutrients and lower cholesterol absorption. The health benefits of MFG consumption or of some of its fractions (MFGM) under specific structures are steadily being demonstrated with still much unsolved questions especially for populations with high nutritional needs (e.g. elderly, infants).

Effects of lutein-enriched egg yolk in buttermilk or skimmed milk on serum lipids & lipoproteins of mildly hypercholesterolemic subjects

BACKGROUND AND AIMS

Earlier studies in our group suggested that traditionally prepared buttermilk influences cholesterol metabolism. We therefore designed a study to evaluate whether traditionally prepared buttermilk lowers serum low-density lipoprotein cholesterol (LDL-C) and/or prevents the LDL-C raising effect of egg yolks.

METHODS AND RESULTS

Mildly hypercholesterolemic subjects were randomly allocated to one of four diet groups consuming daily at lunch 80 ml skimmed milk with (n = 23) or without (n = 25) lutein-enriched egg yolk (28 g from 1.5 eggs providing 323 mg cholesterol) or traditionally prepared buttermilk with (n = 23) or without (n = 21) lutein-enriched egg yolk during a 12 week period. Fasting blood samples were taken to measure concentrations of serum lipids, (apo)lipoproteins, liver and kidney function markers, and plasma lutein, zeaxanthin and high-sensitive C-reactive protein (hsCRP). Egg yolk consumption significantly increased serum total cholesterol (total-C) (p = 0.035) and LDL-C concentrations (p = 0.022). Buttermilk did not change the effects of egg yolk on serum lipids and (apo)lipoproteins. There was a trend towards significant lower total-C (p = 0.077), but not LDL-C (p = 0.204) concentrations in the buttermilk groups. Plasma lutein and zeaxanthin concentrations increased significantly (p < 0.001) in the egg yolk groups.

CONCLUSION

In mildly hypercholesterolemic subjects, daily consumption of traditionally prepared buttermilk for 12 weeks did not lower serum total-C or LDL-C concentrations, nor did it prevent the serum total-C and LDL-C raising effect of daily egg yolk consumption.

REGISTRATION NUMBER

This study is registered at www.clinicaltrials.gov as NCT01566305.

Effects of dairy protein and fat on the metabolic syndrome and type 2 diabetes

The incidence of the metabolic syndrome (MetS) and type 2 diabetes (T2D) is increasing worldwide. Evidence supports a negative relationship between the consumption of dairy products and risk of MetS and T2D. Dairy proteins are known to have a directly beneficial effect on hypertension, dyslipidemia, and hyperglycemia, but a detailed understanding of the underlying mechanisms is missing. It has been confirmed by observations that the insulinotropic effect of dairy proteins is associated with the amino acid composition; in particular branched-chain amino acids (BCAA) seem to be of vital importance. Dairy protein-derived peptides may also contribute to the insulinotropic effect via dipeptidyl peptidase-4 (DPP-4) inhibitory activity, and may lower the blood pressure (BP). The lipid metabolism may be improved by whey protein (WP), which acts to reduce the postprandial triglyceride (TG) response. The effect of dairy fat is much more controversial because of the potentially harmful effect exerted by saturated fatty acid (SFA) on metabolic health. Recent observations suggest less adverse effects of SFA on metabolic health than previous assumed. However, little is known about dairy lipid fractions belonging to the groups of monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), and phospholipids (PL). Dairy fat seems to act differently depending on the dairy product and the composition of macronutrients in the meal. Therefore, for a better understanding of the mechanisms behind the dairy protein and fat effect on MetS, we suggest that more human studies should be carried out to clarify the interactions of dairy protein and fat with macronutrients in the meal and other dairy components, such as micronutrients and microorganisms from fermented products.

Effect of buttermilk consumption on blood pressure in moderately hypercholesterolemic men and women

OBJECTIVES

Milk fat globule membrane (MFGM) found in buttermilk is rich in unique bioactive proteins. Several studies suggest that MFGM proteins possess biological activities such as cholesterol-lowering, antiviral, antibacterial, and anticancer properties, but data in humans are lacking. Furthermore, to our knowledge, no study has yet investigated the antihypertensive potential of MFGM proteins from buttermilk. The aim of this study was to investigate the effects of buttermilk consumption on blood pressure and on markers of the renin-angiotensin-aldosterone (RAS) system in humans.

METHODS

Men and women (N = 34) with plasma low-density lipoprotein cholesterol < 5 mmol/L and normal blood pressure (< 140 mm Hg) were recruited in this randomized, double-blind, placebo-controlled, crossover study. Their diets were supplemented with 45 g/d of buttermilk and with 45 g/d of a macro-/micronutrient-matched placebo in random order (4 wk for each diet).

RESULTS

Buttermilk consumption significantly reduced systolic blood pressure (-2.6 mm Hg; P = 0.009), mean arterial blood pressure (-1.7 mm Hg; P = 0.015), and plasma levels of the angiotensin I-converting enzyme (-10.9%; P = 0.003) compared with the placebo, but had no effect on plasma concentrations of angiotensin II and aldosterone.

CONCLUSION

Short-term buttermilk consumption reduces blood pressure in normotensive individuals.