Do We No Longer Need To Worry about Dietary Cholesterol?

Synthesis of cholesterol analogues and comparison on their effect on plasma cholesterol with β-Sitosterol

The application of plant sterols in the treatment of hypercholesterolemia is promising. We hypothesize that plant sterols can reduce blood cholesterol because they have a side chain of at least three branches. Three cholesterol analogues were synthesized: CA0 (no side chain), CA3 (a 3‑carbon chain with one branch), and CA14 (a 14‑carbon side chain with two branches), and then compared their effect on blood cholesterol with that of β-sitosterol. Structurally, β-sitosterol has a 10‑carbon side chain with three branches. Results demonstrated that β-sitosterol could effectively reduce plasma total cholesterol (TC) by 20.3%, whereas CA0, CA3 and CA14 did not affect plasma TC in hypercholesterolemia hamsters. β-Sitosterol was absent in the plasma and liver, indicating it was not absorbed. We concluded that β-sitosterol with three branches had plasma TC-lowering activity. In contrast, cholesterol analogues with a side chain of two or fewer branches did not affect plasma cholesterol.

Interactions between dietary cholesterol and intestinal flora and their effects on host health

The interactions between dietary cholesterol and intestinal microbiota strongly affect host health. In recent years, relevant studies have greatly advanced this field and need to be summarized to deepen the understanding of dietary cholesterol-intestinal microbiota interactions and their effects on host health. This review covers the most recent frontiers on the effects of dietary cholesterol on the intestinal microbiota and its metabolites, the metabolism of cholesterol by the intestinal microbiota, and the effects of the interactions on host health. Several animal-feeding studies reported that dietary cholesterol altered different intestinal microbiota in the body, while mainly causing alterations in intestinal microbial metabolites such as bile acids, short-chain fatty acids, and tryptophan derivatives. Alterations in these metabolites may be a novel mechanism mediating cholesterol-related diseases. The cholesterol microbial metabolite, coprostanol, has a low absorption rate and is excreted in the feces. Thus, microbial conversion of cholesterol-to-coprostanol may be an important way of cholesterol-lowering by the organism. Cholesterol-3-sulfate is a recently discovered microbial metabolite of cholesterol, mainly metabolized by Bacteroides containing the Bt_0416 gene. Its effects on host health have been preliminarily characterized and are mainly related to immune modulation and repair of the intestinal epithelium.

The Association of Dietary Cholesterol from Egg Consumption on Cardiovascular Diseases Risk Varies from Person to Person

The public and scientists remain skeptical about egg consumption, given that cardiovascular diseases (CVDs) are the leading causes of death in worldwide. This review mainly explained the recurrence of contradictory conclusions about relationships between egg consumption and CVD risk and discussed effects of egg cholesterol intake on cholesterol homeostasis. Factors including individual health status and cholesterol sensitivity, dietary pattern, region, and race should be distinguished when understanding generalized conclusions. Identified compensatory mechanisms in response to dietary cholesterol and the resulting balance in cholesterol biosynthesis, absorption, and efflux supported the view that moderate egg consumption had no substantial overall impacts on cholesterol homeostasis in healthy people. Excessive cholesterol intake is not recommended in individuals with distempered metabolism. More than cholesterol metabolism, impacts of egg consumption as a part of overall diet on CVD risk should be considered from aspects of nutrient intake, lipid metabolism, and energy supply in the future.

Egg Consumption and Risk of All-Cause and Cause-Specific Mortality: A Systematic Review and Dose-Response Meta-analysis of Prospective Studies

The association between egg consumption and mortality is extremely debatable. This study aimed to investigate the potential dose-response association of egg consumption with risk of mortality from all causes and cause-specific in the general population. The primary comprehensive literature search was conducted in PubMed/Medline, Scopus, ISI Web of Science, and Embase up to March 2021, as well as reference lists of relevant original papers and key journals. We calculated summary RRs and their 95% CIs for the highest and lowest categories, as well as the linear trend estimation of egg intake, using the random-effects model. Thirty-three (32 publications) cohort studies were included. These studies enrolled 2,216,720 participants and recorded 232,408 deaths from all causes. Comparing highest versus lowest egg intake categories was not associated with the risk of mortality from all causes (RR: 1.02; 95% CI: 0.94, 1.11; n = 25), cardiovascular disease (CVD) (RR: 1.04; 95% CI: 0.87, 1.23, n = 11), coronary heart disease (CHD) (RR: 0.98; 95% CI: 0.84, 1.16; n = 10), stroke (RR: 0.81; 95% CI: 0.64, 1.02; n = 9), and respiratory disease (RR: 0.96; 95% CI: 0.53, 1.71; n = 3); however, it was associated with a higher risk of cancer mortality (RR: 1.20; 95% CI: 1.04, 1.39; n = 13). In the linear dose-response analysis, an additional intake of 1 egg per week was associated with a 2% and 4% increased risk of all-cause and cancer mortality, respectively, and a 4% decreased risk of stroke mortality. The certainty of the evidence was rated as low to moderate. Higher egg consumption was not associated with an increased risk of mortality from all causes, CVD, CHD, stroke, or respiratory disease, whereas an elevated risk was observed for cancer mortality. These findings suggest that eggs be consumed in low to moderate amounts (≤1 egg/d) as part of a healthy diet.

Anticancer Potential of Lipophilic Constituents of Eleven Shellfish Species Commonly Consumed in Korea

The present study was aimed to investigate the composition and contents and the major lipophilic compounds, including the sterols, fatty acids, and tocols of shellfish species. Moreover, to explore the antitumor activity of these lipophilic constituents, their cytotoxicity potentials were determined against five different human cancer cells, including colon carcinoma (HCT116), epithelial melanoma (A2058), glioblastoma multiforme (T98G), lung carcinoma (A549), and adenocarcinoma (HeLa). The results show a significant variation in the contents and composition of lipophilic constituents among the studied species. The highest omega-3 (n-3) polyunsaturated fatty acids (PUFAs) were recorded from arrow squid and pacific oysters, accounting for 53.2% and 53.0% of their total fatty acids, respectively. However, the highest cholesterol content was also recorded in arrow squid (154.4 mg/100 g; 92.6% of total sterols). In contrast, in the Japanese littleneck, Yesso scallop, and common orient clam, cholesterol was just 17.1%, 18.3%, and 18.9% of total sterols, respectively, making them the richest source of non-cholesterol sterols (NCS). Lipids extracted from shellfish species showed ABTS+•- and DPPH•-scavenging activities. In the cytotoxicity analysis, lipids extracted from the Argentine red shrimp showed the highest cytotoxicity against glioblastoma multiforme T98G cells, with an IC50 value of 12.3 µg/mL. The composition and cytotoxicity data reported herein may help explore the nutritional and anticancer potentials of shellfish species.

Age of Laying Hens Significantly Influences the Content of Nutritionally Vital Lipophilic Compounds in Eggs

This study aimed to comparatively analyze the carotenoids, tocopherols, fatty acids, and sterols (e.g., cholesterol) in the eggs of laying hens of early (24 weeks), intermediate (42 weeks), and late age (74 weeks), utilizing high-performance liquid chromatography (HPLC), gas chromatography (GC), and GC–mass spectrometry (MS). The results revealed the significantly (p < 0.05) highest content of nutritionally vital compounds (per g of egg yolk, fresh weight), which included (all-E-)-lutein (21.8 µg), (all-E-)-zeaxanthin (13.4 µg), α-tocopherol (76.5 µg), oleic acid (C18:1n9c; 83.3 mg), α-linolenic acid (C18:3n3; 0.68 mg), γ-linolenic acid (C18:3n6; 0.47 mg), arachidonic acid (C20:4n6; 8.11 mg), docosahexaenoic acid (DHA; C22:6n3; 2.06 mg), and total monounsaturated fatty acids (MUFAs; 94.7 mg) and n-3 polyunsaturated fatty acids (PUFAs; 2.74 mg) in the eggs of early-age laying hens compared to intermediate and late-age. Surprisingly, cholesterol was not significantly different in the eggs obtained from the different age groups. In contrast, the fat quality indices, including the lowest atherogenic index (AI) and thrombogenic index (TI) values and high hypocholesterolemic/hypercholesterolemic (h/H) fatty acid ratio, indicated the health-beneficial potential associated with fat intake from the eggs of intermediate and late-age laying hens. Overall, the results of the present investigation suggest that eggs from early-age laying hens can be recommended for a higher intake of antioxidant carotenoids and tocopherols, while the eggs from intermediate and late-age hens can be recommended for the intake of good quality fats.

Red Shrimp Are a Rich Source of Nutritionally Vital Lipophilic Compounds: A Comparative Study among Edible Flesh and Processing Waste

This study was aimed at comparatively analyzing the sterols, tocopherols and fatty acids from edible flesh and processing waste obtained from three shrimp species, utilizing rapid liquid chromatography (LC)-atmospheric-pressure chemical ionization (APCI)-tandem mass spectrometry (MS/MS) and gas chromatography-mass spectrometry (GC-MS). Results revealed the presence of significantly (p < 0.05) high proportions of health-beneficial omega-3 (n3) polyunsaturated fatty acids (PUFAs) in Argentine red shrimp (34.3% in waste and 38.2% in the flesh), compared to black tiger shrimp (16.5–24.2%) and whiteleg shrimp (13.2–22.6%). Among sterols, cholesterol was found most dominant, accounting in the range 349.4 (white shrimp flesh) to 559.3 µg/g fresh weight (FW) (black shrimp waste). Surprisingly, waste was found to contain a substantially higher amount of α-tocopherol, for instance, 21.7 µg/g FW in edible flesh and 35.3 µg/g FW in the waste of black tiger shrimp. The correlation analysis indicated that shrimp with low total contents of lipids might have higher proportions of health-beneficial long-chain (LC)-n3-PUFAs eicosapentaenoic (EPA) and docosahexaenoic acid (DHA). The fat quality indices, including the high ratios of hypocholesterolemic (h)/hypercholesterolemic (H) fatty acids, and lowest values of the atherogenic index (AI) and thrombogenic index (TI) indicated the health-beneficial potential associated with fat intake from red shrimp. Overall, a significant amount of health-beneficial compounds in edible flesh of studied shrimp confers its extraordinary nutritional benefits. Moreover, considering the richness of processing waste with these compounds, their valorization can be prompted.

Longitudinal and nonlinear relations of dietary and Serum cholesterol in midlife with cognitive decline: results from EMCOA study

Background

Previous studies regarding the cholesterol-cognition relationship in midlife have generated conflicting results. We thus investigated whether dietary and blood cholesterol were associated with cognitive decline.

Methods

Participants were drawn from a large cohort study entitled the Effects and Mechanism Investigation of Cholesterol and Oxysterol on Alzheimer’s disease (EMCOA) study. We included 2514 participants who completed a selection of comprehensive cognitive tests and were followed for an average of 2.3 years. Blood concentrations of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and triglycerides (TG) were assessed and dietary intakes were investigated by food frequency questionnaire (FFQ) at baseline. Apolipoprotein E (APOE) was genotyped by Kompetitive Allele Specific PCR (KASP) sequencing. Non-high-density lipoprotein cholesterol (Non-HDL-C) and LDL-C/HDL-C ratio were calculated. The longitudinal effects of dietary and blood cholesterol on risk of global cognitive decline (decrease in Montreal Cognitive Assessment (MoCA) > 2 points) were examined using Cox proportional hazards models. The nonlinear associations with global and domain-specific cognitive decline was evaluated with mixed effect linear models.

Results

In Cox proportional hazards models, neither cholesterol nor egg intake was associated with a higher risk of accelerated global cognitive decline. In contrast, the higher serum concentrations of TC, LDL-C, non-HDL-C and LDL-C/HDL-C ratio were positively associated with accelerated global cognitive decline regardless of being evaluated continuously or categorically while higher HDL-C was positively associated with accelerated global cognitive decline only when being evaluated categorically (all P < 0.05). In mixed effect linear models, quadratic and longitudinal relations of dietary cholesterol and egg intakes to global cognition, processing speed and executive function were observed. Moreover, there were inverted U-shaped relations of HDL-C, with processing speed and executive function but U-shaped relations of HDL-C and LDL-C/HDL-C ratio with verbal memory. Adverse linear associations of higher LDL-C and LDL-C/HDL-C ratio with multiple cognitive comes were also revealed. Additionally adjusting for APOE genotype did not modify cholesterol-cognition associations. Dietary and serum cholesterol had variable associations with global and domain-specific cognitive decline across educational groups.

Conclusion

Differential associations between dietary/serum cholesterol and cognitive decline across different domains of function were observed in a particular population of middle-aged and elderly Chinese. Interventions to improve cognitive reserve regarding dietary instruction and lipid management should be tailored according to specific target.

Trial registration

EMCOA, ChiCTR-OOC-17011882, Registered 5th, July 2017-Retrospectively registered, http://www.medresman.org/uc/project/projectedit.aspx?proj=2610

Plasma Cholesterol-Lowering Activity of Soybean Germ Phytosterols

Soybean germ phytosterols (SGP) largely exist in soybean germ oil. Our previous study demonstrated that soybean germ oil was effective in reducing plasma cholesterol. However, it remains unknown if its phytosterols are the active ingredients responsible for the plasma cholesterol-lowering activity. The present study aimed to test the effect of SGP on plasma cholesterol and to investigate its associated underlying mechanisms using hamsters as animal model. Male hamsters (n = 40) were randomly divided into five groups (n = 8/group) and fed one of the five diets: a non-cholesterol diet (NCD), a high cholesterol diet (HCD), a HCD diet containing 0.5% cholestyramine (PC), and two HCD diets containing 0.1% (LP) and 0.2% (HP) SGP, respectively, for six weeks. Results showed that SPG reduced plasma cholesterol level in a dose-dependent manner, whereas it dose-dependently increased the excretion of both fecal neutral and acidic sterols. SGP was also effective in displacing cholesterol from micelles. It was concluded that SGP possessed hypocholesterolemic activity, likely by inhibiting cholesterol absorption in the intestine and promoting fecal sterol excretion.

Association between Dietary Cholesterol and Their Food Sources and Risk for Hypercholesterolemia: The 2012⁻2016 Korea National Health and Nutrition Examination Survey

It remains unclear whether cholesterol intake can increase serum cholesterol. Therefore, the present study aimed to investigate the hypothesis that the risk for hypercholesterolemia was not associated with intake of dietary cholesterol after adjusting for saturated fatty acid (SFA). Based on the data from the 2012–2016 KNHANES, dietary cholesterol was positively associated with the risk for abnormalities in total cholesterol (TC) (odds ratio (OR): 1.153, 95% confidence interval (CI): 0.995–1.337; p = 0.028) and low-density lipoprotein cholesterol (LDL-C) (OR: 1.186, 95% CI: 1.019–1.382; p = 0.018) levels before adjusting for SFA; after adjusting for SFA, no significant associations were found between these variables. The mediation analysis showed that dietary cholesterol had no direct effects on the serum levels of TC and LDL-C; in contrast, SFA had significant indirect effects on the association between dietary cholesterol and serum levels of TC and LDL-C. Furthermore, processed meats, but not eggs and other meats, were positively associated with the risk for abnormalities in both TC (OR: 1.220, 95% CI: 1.083–1.374; p = 0.001) and LDL-C (OR: 1.193, 95% CI: 1.052–1.354; p = 0.004) levels. The present study suggested that higher intake of processed meats with high SFA, but not dietary cholesterol was associated with higher risk for abnormalities in TC and LDL-C levels.

Soybean germ oil reduces blood cholesterol by inhibiting cholesterol absorption and enhancing bile acid excretion

Soybean germ oil is beneficial in management of hypercholesterolemia in hamsters fed a high cholesterol diet.

Dose-Dependent Increases in Liver Cholesterol but Not Plasma Cholesterol from Consumption of One to Five Whole Eggs and No Effects from Egg Whites on Liver or Plasma Cholesterol in Hamsters

The dose-dependent effect of egg consumption on plasma cholesterol in humans remains inconclusive. It is unknown if egg white consumed in a normal amount can reduce plasma cholesterol. We used hamsters as a model to (i) investigate the dose-dependent effect of consuming zero to five whole eggs on plasma total cholesterol (TC) and (ii) examine if egg white, equivalent to one to five eggs, possessed any reducing effects on plasma TC. In experiment 1, hamsters were divided into six groups ( n = 8 each) and fed either a control diet or one of five experimental diets supplemented with whole-egg powder equivalent to one to five eggs per 2000 kcal. Results showed that supplementation with one egg increased plasma TC by 25% compared with that of the control (226 ± 16 versus 282 ± 56 mg/dL, p < 0.05), whereas supplementation with two to five eggs did not significantly produce any additional effects on plasma cholesterol. However, supplementation with one to five eggs in diets caused a dose-dependent accumulation of cholesterol in the liver from 21.5 ± 4.4 to 71.3 ± 7.3 mg/g ( p < 0.01). In the second experiment, hamsters were divided into six groups and fed either a high-cholesterol control diet or one of five experimental diets supplemented with egg-white powder from one to five eggs. Results showed that egg-white powder affected neither plasma nor liver cholesterol levels. The egg-white powder did not affect fecal sterol excretion, suggesting it had no effect on cholesterol absorption. It was therefore concluded that consumption of two to five eggs did not significantly produce any additional effects on plasma cholesterol, whereas egg white did not possess a plasma-cholesterol-lowering activity if it was consumed at amounts similar to those in a normal human diet.

Egg consumption and the risk of cardiovascular disease and all-cause mortality: Guangzhou Biobank Cohort Study and meta-analyses

PURPOSE

Eggs are highly nutritious but concerns over their cholesterol content have led to dietary avoidance among many. There are also important international differences in relevant dietary guidance. We conducted the first prospective study in China investigating the association of egg consumption, cardiovascular disease (CVD) mortality, and a meta-analysis.

METHODS

We included 28,024 participants without CVD at baseline (2003-8) in Guangzhou Biobank Cohort Study. All-cause and CVD mortality were identified through record linkage. We used Cox proportional hazards regression. We followed the Meta-analysis Of Observational Studies in Epidemiology reporting guidelines.

RESULTS

During 275,343 person-years follow-up (average 9.8 years), we found 2685 all-cause and 873 CVD deaths. We found no significant difference in all-cause mortality between higher (7+ eggs/week) and low consumption (< 1 egg/week) [adjusted hazard ratio (HR) 1.08, 95% confidence interval (CI) 0.93-1.24], and mortality from CVD (0.99, 95% CI 0.76-1.27), ischemic heart disease (IHD) (0.92, 95% CI 0.63-1.36), or stroke (0.88, 95% CI 0.57-1.35). The updated meta-analyses including our results showed that 7+ eggs/week was not associated with all-cause mortality (HR 1.09, 95% CI 0.997-1.200) or IHD (HR 0.97, 95% CI 0.90-1.05), but associated with a small reduction in stroke (HR 0.91. 95% CI 0.85-0.98).

CONCLUSIONS

Eating one egg daily is not associated with increase in CVD or all-cause mortality. The small observed reduction in stroke risk needs to be confirmed. Our findings support current guidelines recommending eggs as part of a healthy diet, and should be considered in other dietary recommendations.