Vitamin A-enriched diet modulates reverse cholesterol transport in hypercholesterolemic obese rats of the WNIN/Ob strain

Linear association of compound dietary antioxidant index with hyperlipidemia: a cross-sectional study

Background

There is growing evidence that antioxidant-rich diets may prevent hyperlipidemia. However, the relationship between the Composite Dietary Antioxidant Index (CDAI) and hyperlipidemia is unclear. The CDAI is a composite score reflecting the antioxidant content of an individual's diet, and this study aimed to investigate the relationship between CDAI and hyperlipidemia.

Methods

The study used the 2003-2018 National Health and Nutrition Examination Survey (NHANES) database for cross-sectional analyses and included 27,626 participants aged 20 years and older. The CDAI, which includes vitamins A, C, and E, zinc, selenium, and carotenoids, was calculated based on dietary intake reported in a 24-h recall interview. Hyperlipidemia was defined by the National Cholesterol Education Program (NCEP). Covariates included age, sex, race, education, marriage, household poverty-to-income ratio (PIR), glomerular filtration rate (eGFR), body mass index (BMI), energy, carbohydrates, total fat, cholesterol, smoking, alcohol consumption, hypertension, diabetes mellitus, coronary heart disease, and lipid-lowering medications. The association between CDAI and hyperlipidemia was explored through multiple logistic regression analyses and smoothed curve fitting. We also performed subgroup analyses and interaction tests to verify the relationship's stability.

Results

After adjusting for potential confounders, CDAI was negatively associated with the risk of developing hyperlipidemia (OR 0.98, 95% CI 0.96-0.99, p < 0.01). The results of weighted regression models stratified by quartiles of CDAI (-8.664 ≤ Q1 ≤ -2.209, -2.209 < Q2 ≤ -0.002, -0.002 < Q3 ≤ 2.774, 2.774 < Q4 ≤ 124.284), fully adjusted for confounding variables, indicated that compared with the bottom quartile (Q1) of the CDAI, Q2, Q3, and Q4 of participants had a lower advantage ratio (Q2: OR 0.91, 95% CI 0.78-1.06, p < 0.21; Q3: OR 0.85, 95% CI 0.73-1.00, p < 0.05; and Q4: OR 0.77, 95% CI 0.64-0.94, p < 0.01), which was confirmed by a test for trend (p < 0.05). Smoothed curve fit analysis showed linearity (p for non-linear = 0.0912). In summary, there is a linear negative relationship between CDAI and the risk of developing hyperlipidemia. Subgroup analyses by age, sex, ethnicity, education level, marriage, tobacco status, alcoholic drinking, body mass index (BMI), hypertension, and diabetes did not indicate strong interactions.

Conclusion

In this large cross-sectional study, there was a linear negative association between CDAI and hyperlipidemia among US adults. Therefore increase antioxidant rich foods in your life as a prevention of hyperlipidemia.

Association between Serum Vitamin A, Blood Lipid Level and Dyslipidemia among Chinese Children and Adolescents

Background: To study the relationship between serum vitamin A (VA) level and blood lipid profiles in children and adolescents aged 6−18 years, as well as the effect of VA on dyslipidemia. Methods: The project adopted a multistage stratified cluster sampling method. The Food Frequency Questionnaire (FFQ) was used to obtain dietary factors data. Blood samples of subjects were taken via venipuncture. Generalized linear models were used to explore the correlation be-tween VA and biochemical indicators, as well as stratified and inter-actions analysis to explore the influence of confounders on these relationships. Generalized linear models were constructed to explore the association between VA and blood lipids. Restricted cubic splines were used to characterize dose−response associations between serum VA and dyslipidemia based on logistic regression. Results: Serum VA was positively correlated with TC, TG and HDL-C (p < 0.05), but these associations were influenced by age (p < 0.05). The adjusted odds ratio (OR) values of VA for hypercho lesterolemia, hypertriglyceridemia, mixed hyperlipidemia and low high-density lipoprotein cholesterolemia were 3.283, 3.239, 5.219 and 0.346, respectively (p < 0.01). Meanwhile, significant age interactions affected the relationship between VA and TC, as well as TG and LDL-C (p < 0.01). Conclusion: Serum VA was positively correlated with blood lipids, but these associations were influenced by age. VA was a risk factor for dyslipidemias, such as hypercholesterolemia, hypertriglyceridemia and mixed hyperlipidemia, but was a protective factor for low high-density lipoprotein cholesterolemia.

Impact of Dietary Lipids on the Reverse Cholesterol Transport: What We Learned from Animal Studies

Reverse cholesterol transport (RCT) is a physiological mechanism protecting cells from an excessive accumulation of cholesterol. When this process begins in vascular macrophages, it acquires antiatherogenic properties, as has been widely demonstrated in animal models. Dietary lipids, despite representing a fundamental source of energy and exerting multiple biological functions, may induce detrimental effects on cardiovascular health. In the present review we summarize the current knowledge on the mechanisms of action of the most relevant classes of dietary lipids, such as fatty acids, sterols and liposoluble vitamins, with effects on different steps of RCT. We also provide a critical analysis of data obtained from experimental models which can serve as a valuable tool to clarify the effects of dietary lipids on cardiovascular disease.

Study of Cardiovascular Risk Factors in Adolescents: Association between Intake of Vitamins A and E and Lipid Profile

Background:

The diet of Brazilian adolescents is characterized by high intake of fats and sugars and low consumption of antioxidant micronutrients, particularly vitamins A and E. In addition to dietary inadequacies, a significant number of these adolescents present changes in plasma lipoproteins, which may be caused by environmental and lifestyle factors.

Objective:

To investigate the association between inadequate intake of vitamins A and E and changes in plasma lipoprotein concentrations in Brazilian adolescents.

Methods:

Cross-sectional, descriptive, multicenter, school-based, nationwide study with 37,023 Brazilian adolescents aged 12 to 17 years were included. Data on sociodemographic characteristics, vitamin A and E intake, and lipid and anthropometric profile were collected. The Student’s t-test was used to compare means and a logistic regression to verify associations; analyses were conducted in the STATA software version 14.0. The study was approved by the Ethics Committees of the participating institutions and all participants signed an Assent Form.

Results:

The average vitamin A intake was higher among boys, but consumption below recommendation was found in both sexes. Inadequate intake of vitamins A and E was associated with a higher risk of low HDL-c levels in male and public school adolescents. Low vitamin E intake was associated with a higher risk of hypercholesterolemia and hypertriglyceridemia in Brazilian adolescents.

Conclusion:

This study showed a high prevalence of inadequate intake of vitamins A and E among Brazilian adolescents and data suggesting associations between low intake of these micronutrients and changes in plasma lipoprotein concentrations in this public.

All-Trans Retinoic Acid Inhibits Bone Marrow Mesenchymal Stem Cell Commitment to Adipocytes via Upregulating FRA1 Signaling

Obesity, caused by an increased number and volume of adipocytes, is a global epidemic that seriously threatens human health. Bone marrow mesenchymal stem cells (BMSCs) can differentiate into adipocytes. All-trans retinoic acid (atRA, the active form of vitamin A) inhibits the adipogenic differentiation of BMSCs through its receptor RARG. The expression level of FRA1 (FOS like 1, AP-1 transcription factor subunit) in atRA-treated BMSCs increased, suggesting that atRA-mediated inhibition of BMSCs adipogenesis involves FRA1. BMSCs were transfected with adenovirus overexpressing Fra1 (ad-fra1) or silenced for Fra1 (si-fra1) and then treated with atRA. BMSCs treated with atRA and treated with ad-fra1 showed decreased mRNA and protein levels of key adipogenic genes (Pparg2, Cebpa) and adipogenesis-associated genes (Cd36, Fabp, Lpl, and Plin); atRA had a stronger inhibitory effect on adipogenesis compared with that in the ad-fra1 group. Adipogenic gene expression in Fra1-silenced BMSCs was significantly upregulated. Compared with that in the atRA group, the si-fra1 + atRA also upregulated adipogenic gene expression. However, compared with si-fra1, si-fra1 + atRA significantly inhibited adipogenic differentiation. Chromatin immunoprecipitation showed that RARG directly regulates Fra1 and FRA1 directly regulates Pparg2 and Cebpa. The results supported the conclusion that atRA inhibits BMSC adipogenesis partially through the RARG-FRA1-PPARG2 or the CEBPA axis or both. Thus, vitamin A might be used to treat obesity and its related diseases.

Elevated Serum Retinol and Low Beta-Carotene but not Alpha-Tocopherol Concentrations Are Associated with Dyslipidemia in Brazilian Adolescents

The purpose of this study was to investigate the status of retinol, beta-carotene, and alpha-tocopherol serum concentrations in adolescents with dyslipidemia. A case series dyslipidemia study was conducted, with an attached control group, including 104 adolescents of public schools in Recife during the months of March/April 2013. Retinol, beta-carotene and alpha-tocopherol serum concentrations were analysed by high efficiency liquid chromatography. Sociodemographic, anthropometric, clinical and biochemical variables were analysed. Dyslipidemic adolescents had high serum concentrations of both retinol (p=0.007) and beta-carotene/apolipoprotein A-I ratio (p=0.034); they also had low concentrations of beta-carotene/total cholesterol (p<0.0001) and beta-carotene/apolipoprotein B ratios (p=0.033) when compared to the controls. The alpha-tocopherol serum status was not associated with dyslipidemia. Overweight, abdominal obesity, lipid profile markers, and systolic and diastolic blood pressures were more prevalent in dyslipidemic adolescents. The findings show an association between vitamin A and dyslipidemia in adolescents. However, additional investigations of this risk group are necessary to clarify the mechanisms of action of this nutrient in the pathogenesis of this syndrome, aiming at reducing cardiometabolic risks as of earlier ages.