Diana M. DiMarco

Evidence for the Effects of Yogurt on Gut Health and Obesity

ABSTRACT Obesity is associated with increased risk for chronic diseases, and affects both developed and developing nations. Yogurt is a nutrient-dense food that may benefit individuals with lactose intolerance, constipation and diarrheal diseases, hypertension, cardiovascular diseases, diabetes, and certain types of cancer. Emerging evidence suggests that yogurt consumption might also improve the health of obese individuals. Obesity is often accompanied by chronic, low-grade inflammation perpetuated by adipose tissue and the gut. In the gut, obesity-associated dysregulation of microbiota and impaired gut barrier function may increase endotoxin exposure. Intestinal barrier function can be compromised by pathogens, inflammatory cytokines, endocannabinoids, diet, exercise, and gastrointestinal peptides. Yogurt consumption may improve gut health and reduce chronic inflammation by enhancing innate and adaptive immune responses, intestinal barrier function, lipid profiles, and by regulating appetite. While this evidence suggests that yogurt consumption is beneficial for obese individuals, randomized-controlled trials are needed to further support this hypothesis.

The Regulation of Reverse Cholesterol Transport and Cellular Cholesterol Homeostasis by MicroRNAs.

MicroRNAs (miRNAs) are small, non-coding RNAs that have the ability to post-transcriptionally regulate gene expression. Hundreds of miRNAs have been identified in humans and they are involved in the regulation of almost every process, including cholesterol transport, metabolism, and maintenance of cholesterol homeostasis. Because of their small size and their ability to very specifically regulate gene expression, miRNAs are attractive targets for the regulation of dyslipidemias and other lipid-related disorders. However, the complex interactions between miRNAs, transcription factors, and gene expression raise great potential for side effects as a result of miRNA overexpression or inhibition. Many dietary components can also target specific miRNAs, altering the expression of downstream genes. Therefore, much more research is necessary to fully understand the role(s) of each miRNA in the body and how they may be impacted by diet and health. The present review aims to summarize the known roles of miRNAs in the regulation of reverse cholesterol transport and the maintenance of cholesterol homeostasis, as well as the potential clinical consequences of their manipulation.

Intake of up to 3 Eggs per Day Is Associated with Changes in HDL Function and Increased Plasma Antioxidants in Healthy, Young Adults

Background: HDL function may be more important than HDL concentration in determining risk for cardiovascular disease. In addition, HDL is a carrier of carotenoids and antioxidant enzymes, which protect HDL and LDL particles against oxidation.Objective: The goal of this study was to determine the impact of consuming 0-3 eggs/d on LDL and HDL particle size, HDL function, and plasma antioxidants in a young, healthy population.Methods: Thirty-eight healthy men and women [age 18-30 y, body mass index (in kg/m2) 18.5-29.9] participated in this 14-wk crossover intervention. Subjects underwent a 2-wk washout (0 eggs/d) followed by sequentially increasing intake of 1, 2, and 3 eggs/d for 4 wk each. After each period, fasting blood was collected for analysis of lipoprotein subfractions, plasma apolipoprotein (apo) concentration, lutein and zeaxanthin concentration, and activities of lecithin-cholesterol acyltransferase, cholesteryl ester transfer protein, and paraoxonase-1.Results: Compared with intake of 0 eggs/d, consuming 1-3 eggs/d resulted in increased large-LDL (21-37%) and large-HDL (6-13%) particle concentrations, plasma apoAI (9-15%), and lecithin-cholesterol acyltransferase activity (5-15%) (P < 0.05 for all biomarkers). Intake of 2-3 eggs/d also promoted an 11% increase in apoAII (P < 0.05) and a 20-31% increase in plasma lutein and zeaxanthin (P < 0.05), whereas intake of 3 eggs/d resulted in a 9-16% increase in serum paraoxonase-1 activity compared with intake of 1-2 eggs/d (P < 0.05). Egg intake did not affect cholesteryl ester transfer protein activity.Conclusions: Intake of 1 egg/d was sufficient to increase HDL function and large-LDL particle concentration; however, intake of 2-3 eggs/d supported greater improvements in HDL function as well as increased plasma carotenoids. Overall, intake of ≤3 eggs/d favored a less atherogenic LDL particle profile, improved HDL function, and increased plasma antioxidants in young, healthy adults. This trial was registered at clinicaltrials.gov as NCT02531958.

The Potential of Non-Provitamin A Carotenoids for the Prevention and Treatment of Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is an obesity-associated spectrum of comorbidities defined by the presence of metabolic dysfunction, oxidative stress, inflammation, and fibrosis in the liver. If left untreated, NAFLD can progress to cirrhosis, liver failure, or hepatocellular carcinoma. NAFLD is recognized as the most common liver disease in the United States, affecting around 30% of the population. Identification of dietary components capable of reducing or preventing NAFLD is therefore essential to battle this condition. Dietary carotenoids including astaxanthin, lycopene, lutein, and zeaxanthin have been demonstrated to be potent antioxidants as well as to exhibit anti-inflammatory effects. Many studies report the protective effect(s) of these carotenoids against different conditions such as atherosclerosis, diabetic complications, age-related macular degeneration, and liver diseases. In this review, we will focus on the effects of these carotenoids in the prevention or reduction of NAFLD as seen in epidemiological observations and clinical trials, as well as the suggested mechanism of action derived from animal and cell studies.

Compared to an Oatmeal Breakfast, Two Eggs/Day Increased Plasma Carotenoids and Choline without Increasing Trimethyl Amine N-Oxide Concentrations

ABSTRACT Background: Habitual consumption of eggs has been hypothesized to positively modify biomarkers of cardiovascular disease risk through proposed antioxidant properties. Objectives: To examine this relationship, 50 young, healthy men and women were enrolled into a randomized crossover clinical intervention. Methods: Participants consumed either 2 eggs per day or one packet of oatmeal a day for 4 weeks, followed by a 3-week wash-out and crossed over to the alternate breakfast. Fasting blood samples and peripheral blood mononuclear cells (PBMCs) were collected at the end of each intervention period. Results: Increases in plasma large high-density lipoprotein (HDL) and large low-density lipoprotein (LDL) particle concentrations as measured by nuclear magnetic resonance were found following egg consumption (p < 0.001, p < 0.05), respectively, with increases in apolipoprotein concentration as well (p < 0.05). Though there was no difference in the intake of antioxidants lutein and zeaxanthin, a significant increase in plasma concentrations of these carotenoids was observed (p < 0.001) after egg consumption. There was no change in lecithin–cholesterol acyl transferase, cholesteryl ester transfer protein, or paroxanase-1 arylesterase activities between breakfast interventions. Dietary and plasma choline were both higher following egg consumption compared to oatmeal consumption (p < 0.001); however, there was no change in plasma trimethylamine N-oxide (TMAO) concentrations. Two eggs per day had no impact on PBMC gene expression related to cholesterol metabolism, oxidation, or TMAO production. Conclusions: These results suggest that compared to oatmeal, consumption of 2 eggs for breakfast provided increased plasma carotenoids and improved biomarkers of cardiovascular disease (CVD) risk while not affecting TMAO levels in this population.

Low-fat yogurt consumption reduces biomarkers of chronic inflammation and inhibits markers of endotoxin exposure in healthy premenopausal women: a randomised controlled trial.

The anti-inflammatory mechanisms of low-fat dairy product consumption are largely unknown. The objective of this study was to determine whether low-fat yogurt reduces biomarkers of chronic inflammation and endotoxin exposure in women. Premenopausal women (BMI 18·5-27 and 30-40 kg/m2) were randomised to consume 339 g of low-fat yogurt (yogurt non-obese (YN); yogurt obese (YO)) or 324 g of soya pudding (control non-obese; control obese (CO)) daily for 9 weeks (n 30/group). Fasting blood samples were analysed for IL-6, TNF-α/soluble TNF II (sTNF-RII), high-sensitivity C-reactive protein, 2-arachidonoyl glycerol, anandamide, monocyte gene expression, soluble CD14 (sCD14), lipopolysaccharide (LPS), LPS binding protein (LBP), IgM endotoxin-core antibody (IgM EndoCAb), and zonulin. BMI, waist circumference and blood pressure were also determined. After 9-week yogurt consumption, YO and YN had decreased TNF-α/sTNFR-RII. Yogurt consumption increased plasma IgM EndoCAb regardless of obesity status. sCD14 was not affected by diet, but LBP/sCD14 was lowered by yogurt consumption in both YN and YO. Yogurt intervention increased plasma 2-arachidonoylglycerol in YO but not YN. YO peripheral blood mononuclear cells expression of NF-κB inhibitor α and transforming growth factor β1 increased relative to CO at 9 weeks. Other biomarkers were unchanged by diet. CO and YO gained approximately 0·9 kg in body weight. YO had 3·6 % lower diastolic blood pressure at week 3. Low-fat yogurt for 9 weeks reduced biomarkers of chronic inflammation and endotoxin exposure in premenopausal women compared with a non-dairy control food. This trial was registered as NCT01686204.

Effects of Freeze-Dried Grape Powder on High-Density Lipoprotein Function in Adults with Metabolic Syndrome: A Randomized Controlled Pilot Study

BACKGROUND High-density lipoprotein (HDL) particles are protective against atherosclerosis. However, HDL function is impaired in metabolic syndrome (MetS) due to low-grade inflammation and dyslipidemia. Foods containing polyphenols, such as grapes, may prevent HDL dysfunction via antioxidant or anti-inflammatory effects. We evaluated the effects of grape powder ingestion on measures of HDL function in adults with MetS. METHODS Twenty adults (age: 32-70 years; body mass index: 25.3-45.4 kg/m2) consumed either 60 grams/day of freeze-dried grape powder (GRAPE) or a placebo for 4 weeks, separated by a 3-week washout period, in a randomized, double-blind crossover study. The primary outcome was serum paraoxonase-1 (PON1) arylesterase activity, a measure of HDL antioxidant function. Secondary outcomes included PON1 lactonase activity, plasma lipids, metabolic markers, cholesterol efflux capacity, and other HDL functional markers. RESULTS After 4 weeks, GRAPE did not alter the serum PON1 activity or other markers of HDL function compared with placebo. Measures of HDL function were positively correlated with each other and inversely with measures of insulin resistance and inflammation. GRAPE intake led to a significant reduction in fasting plasma triglycerides compared with placebo (P = 0.032). No other significant effects of GRAPE were observed for other plasma lipids, anthropometrics, or metabolic measures. CONCLUSIONS Grape powder consumption did not impact HDL function in this cohort of adults with MetS. However, it was shown to improve fasting triglycerides, a risk factor for cardiovascular disease.

Premeal Low-Fat Yogurt Consumption Reduces Postprandial Inflammation and Markers of Endotoxin Exposure in Healthy Premenopausal Women in a Randomized Controlled Trial

Abstract Background Metabolic endotoxemia is associated with obesity and contributes to postprandial inflammation. Objective We aimed to determine if low-fat yogurt consumption prevents postprandial inflammation and dysmetabolism in healthy women by inhibiting biomarkers of metabolic endotoxemia. Methods Premenopausal women defined as obese and nonobese [body mass index (BMI, in kg/m2) 30–40 and 18.5–27, respectively, n = 120] were randomly assigned to consume 339 g of low-fat yogurt (YN, yogurt nonobese; YO, yogurt obese) or 324 g of soy pudding (CN, control nonobese; CO, control obese) for 9 wk (n = 30/group). The intervention foods each supplied 330 kcal with 3 g fat, 66 g carbohydrate, and 4–6 g protein. At weeks 0 and 9, participants ingested 226 g of yogurt or 216 g of soy pudding before a meal providing 56–60 g fat, 82 g carbohydrate, and 28–30 g protein. Plasma soluble CD14 (sCD14), lipopolysaccharide-binding protein (LBP), LPS activity, interleukin-6 (IL-6), glucose, triglyceride, and insulin were measured hourly for 4 h to assess differences in postprandial responses between groups by 2-factor ANOVA. Results Premeal yogurt consumption prevented the postprandial decrease in sCD14 net incremental area under the curve (net iAUC) by 72% in obese individuals at week 0 (P = 0.0323). YN and YO had ≥40% lower net iAUC of LBP-to-sCD14 ratio and plasma IL-6 concentration than CN and CO, respectively (P < 0.05). CO had postprandial hyperglycemia which was not evident in YO; in contrast YN had 57% less postprandial hypoglycemia than did CN (P-interaction = 0.0013). After 9 wk of yogurt consumption, ΔAUC of LBP-to-sCD14 ratios of YO and YN were less than half of those of the control groups (P = 0.0093). Conclusion Yogurt consumption improved postprandial metabolism and biomarkers of metabolic endotoxemia in healthy premenopausal women. Premeal yogurt consumption is a feasible strategy to inhibit postprandial dysmetabolism and thus may reduce cardiometabolic risk. This trial was registered at clinicaltrials.gov as NCT01686204.

TA-65, A Telomerase Activator, Improves Cardiovascular Markers in Patients with Metabolic Syndrome

BACKGROUND Telomerase Activator 65 (TA-65), a compound extracted from Astragalus membranaceus has been used in Chinese traditional medicine for extending lifespan. Scarce information exists on the effects of TA-65 on parameters of metabolic syndrome (MetS). METHODS We recruited 40 patients with MetS to determine the effects of TA-65 on dyslipidemias, hypertension, and oxidative stress in this at-risk population. The study was a double-blind, randomized crossover design in which patients were allocated to consume either 16 mg daily of a TA-65 supplement or a placebo for 12 weeks. Following a 3-week washout, participants were allocated to the alternate treatment for an additional 12 weeks. Anthropometric and biological markers were measured at the end of each treatment. Plasma lipids, glucose, CReactive Protein (CRP), liver enzymes, and glycosylated hemoglobin were measured using a Cobas c-111. Inflammatory cytokines were measured by Luminex technology and markers of oxidative stress by the use of spectroscopy. RESULTS Compared to the placebo period, HDL cholesterol (HDL-C) was higher while body mass index, waist circumference, and the LDL/HDL ratio were lower (p < 0.05) during TA-65 treatment. In addition, plasma tumor necrosis factor-α (TNF-α) was lower during the TA-65 period (p < 0.05). Positive correlations were observed in changes between the placebo and the TA-65 periods in HDL-C and CRP (r = -0.511, p < 0.01), alanine aminotransferase (r = -0.61, p < 0.001) and TNF-α (r = -0.550, p < 0.001) suggesting that the favorable changes observed in HDL were associated with decreases in inflammation. CONCLUSION TA-65 improved key markers of cardiovascular disease risk, which were also associated with reductions in inflammation.

Intake of up to 3 Eggs/Day does not Impact Expression of Genes Related to Cholesterol Homeostasis, Uptake, and Transport in a Healthy Population

Abstract Objective: Eggs are a main dietary source of cholesterol and choline, two nutrients that have at times been controversial. In both cases, the nutrient itself – or its byproduct(s) – is capable of regulating the expression of genes related to the risk for cardiovascular disease (CVD). Therefore, concern exists as to whether regular egg intake may unfavorably alter these pathways and increase CVD risk. Pathways of concern include cholesterol synthesis (3-hydroxy-3-methylglutaryl coenzyme A reductase – HMGCR;24-dehydrocholesterol reductase – DHCR24), cholesterol transport (ATP-binding cassette transporter - ABCA1; LDL receptor - LDLR; scavenger receptor B1 - SCARB1), macrophage cholesterol uptake (cluster of differentiation 36 - CD36; scavenger receptor A - SRA), and synthesis of trimethylamine-N-oxide (TMAO), a choline-derivedproatherogenic compound and product of flavin monoxygenase 3(FMO3). Methods: To examine these pathways, 38 young, healthy individuals (age 24.2 ± y, BMI 24.2 ± 2.3 kg/m2) underwent a 2-week egg-free washout followed by intake of 1, 2, and 3 eggs/ day for 4 weeks each. Peripheral blood mononuclear cells (PBMC) were isolated following each dietary period for analysis of gene expression using qRT-PCR. Results: Egg intake did not impact expression of HMGCR, LDLR, SCARB1, CD36, or FMO3, though expression of SCARB1 was positively correlated with HDL cholesterol (r = 0.499, p = 0.0002). Expression of ABCA1, DHCR24, and SRA was not detectable in PBMC in this population, suggesting that egg intake did not have any measurable impact on these genes. Conclusion: Overall, these results suggest that intake of up to 3 eggs/day does not impact expression of genes related to cholesterol homeostasis, uptake, or plasma TMAO, resulting in no change in these pathways associated with CVD risk in a young,healthy population.