Biomedical subjects

Richard E Ostlund

Publications and source records attributed to Richard E Ostlund.

17 recordsLinked to original sources

PubMed2006

Rapid transient absorption and biliary secretion of enantiomeric cholesterol in hamsters.

To probe the pathway and specificity of cholesterol absorption, the synthetic enantiomer of cholesterol (ent-cholesterol) and cholesterol were labeled with deuterium, gavaged into hamsters, and measured by negative ion mass spectrometry. Initial uptake of both tracers into the intestinal mucosa at 30 min was similar but cholesterol was temporarily retained there, whereas mucosal ent-cholesterol declined rapidly with concomitantly increased enrichment in both the systemic circulation and the gut lumen. In a 3 day fecal recovery study, ent-cholesterol was quantitatively recovered in the stool, whereas cholesterol absorption was 53.2%. ent-Cholesterol given by intracardiac injection was selectively secreted into bile, and the ratio of ent-cholesterol to cholesterol tracers in the gut lumen increased down the length of the small bowel, with the largest value being found in stool. ent-Cholesterol is efficiently taken up by the intestinal mucosa and undergoes transient enterohepatic recirculation, but it is quantitatively eliminated over 3 days as a result of selective secretion into bile and selective enrichment within the lumen of the intestine. These findings suggest that cholesterol absorption is structurally specific and likely to be mediated by enantiospecific cellular proteins.

Administration, Oral↗

PubMed2006

A targeted apoB38.9 mutation in mice is associated with reduced hepatic cholesterol synthesis and enhanced lipid peroxidation.

Familial hypobetalipoproteinemia (FHBL) due to truncation-specifying mutations of apolipoprotein B (apoB), which impair hepatic lipid export in very low-density lipoprotein (VLDL) particles, is associated with fatty liver. In an FHBL-like mouse with the apoB38.9 mutation, fatty liver develops despite reduced hepatic fatty acid synthesis. However, hepatic cholesterol contents in apoB38.9 mice are normal. We found that cholesterogenic enzymes (3-hydroxy-3-methylglutaryl-coenzyme A reductase, sterol-C5-desaturase, and 7-dehydrocholesterol reductase) were consistently downregulated in two separate expression-profiling experiments using a total of 19 mice (n = 7 each for apob(+/+) and apob(+/38.9), and n = 5 for apob(38.9/38.9)) and Affymetrix Mu74Av2 GeneChip microarrays. Results were confirmed by real-time PCR. Cholesterol synthesis rates in cultured hepatocytes were reduced by 35% and 25% in apob(38.9/38.9) and apob(+/38.9), respectively, vs. apob(+/+). Hepatic triglycerides and lipid peroxides, the latter measured by thiobarbituric acid-reactive substances (TBARS) assay, were significantly elevated in apob(+/38.9) (117%) and apob(38.9/38.9) (132%) vs. apob(+/+) (100%), as were mRNA expression of the microsomal lipid peroxidizing enzymes Cyp4A10 and Cyp4A14. Hepatic lipid peroxide levels were positively correlated with triglyceride contents (r = 0.601, P = 0.0065). Thus the fatty liver due to a VLDL secretion defect is associated with insufficient adaptation to triglyceride accumulation and with increased lipid peroxidation. In contrast, apoB38.9 mice effectively maintain cholesterol homeostasis in the liver, at least in part, by reducing hepatic cholesterol synthesis.

Animals↗

PubMed2006

Effect of plant stanol tablets on low-density lipoprotein cholesterol lowering in patients on statin drugs.

The objective of this study was to show that plant sterols in tablet form provide additional low-density lipoprotein (LDL) cholesterol lowering for patients on statin therapy. Dispersible phytosterol tablets were tested in a double-blind, placebo-controlled, parallel clinical trial. Twenty-six patients who were following the American Heart Association Heart Healthy Diet and on long-term statin therapy were studied for 9 weeks. After 3 weeks of placebo treatment, the subjects were randomized to receive either 1.8 g of soy stanols or placebo for 6 weeks in addition to their usual statin regimen. Stanol tablets reduced LDL cholesterol 9.1% (p = 0.007) or 12.2 mg/dl. Total cholesterol was reduced by 12.9 mg/dl (p = 0.03). A strong inverse correlation (r(s) = -0.82, p = 0.0007) was found between the baseline LDL cholesterol and the percent change in LDL cholesterol observed after stanol treatment. The additional LDL cholesterol lowering with stanol/lecithin tablets provided a potential adjunctive therapy for patients who have not reached their target LDL cholesterol goal during statin therapy.

Adult↗

PubMed2006

Regulation of cholesterol absorption by phytosterols.

Phytosterols are chemical homologs of cholesterol that are found in most plant foods and are particularly abundant in vegetable oils and whole grains. They interfere with the micellar solubilization of cholesterol in the intestine and reduce the efficiency of cholesterol absorption. The net absorption of phytosterols themselves is very small and most clinical studies suggest that consumption is safe. Phytosterols naturally present in foods appear to be bioactive, but many commercial phytosterol supplements are comprised of purified crystals with limited bioavailability. Proper formulation to improve bioavailability is critical for phytosterol supplements. Phytosterols appear to be quantitatively as important to cholesterol lowering as reducing saturated fat consumption, and they provide an additional tool for regulation of circulating cholesterol through lifestyle changes.

Absorption↗

PubMed2006

Altered D-chiro-inositol urinary clearance in women with polycystic ovary syndrome.

OBJECTIVE: Evidence suggests that some actions of insulin are effected by inositolphosphoglycan (IPG) mediators. We hypothesize that a deficiency in D-chiro-inositol (DCI) and/or a DCI-containing IPG (DCI-IPG) may contribute to insulin resistance in humans. RESEARCH DESIGN AND METHODS: To assess this possibility in polycystic ovary syndrome (PCOS), we determined insulin sensitivity (Si by frequently sampled intravenous glucose tolerance test), plasma and urinary DCI and myo-inositol (MYO) levels (by gas chromatography/mass spectrometry), and the release of insulin and DCI-IPG during the oral glucose tolerance test (area under the curve [AUC]) in 23 women with PCOS and 26 normal women. RESULTS: Women with PCOS were heavier than control subjects (P = 0.002 for BMI), but also had decreased Si (P < 0.001) and increased AUC(insulin) (P < 0.001) compared with normal women, even when corrected for BMI. The urinary clearance of DCI (uCl(DCI)) was increased almost sixfold in PCOS compared with normal women (P = 0.001), but not MYO clearance (P = 0.10). uCl(DCI) correlated inversely with Si when all women were analyzed together (n = 49, r = -0.50, P < 0.001) and was one of the three best independent parameters predicting Si. Finally, the ratio of AUC(DCI-IPG) to AUC(insulin) was decreased threefold in women with PCOS (P < 0.001). CONCLUSIONS: uCl(DCI) is inversely correlated with insulin sensitivity in women and is a strong independent predictor of insulin resistance in multivariate models. PCOS, which is characterized by insulin resistance, is associated with a selective increase in uCl(DCI) and impaired DCI-IPG release in response to insulin. These findings are consistent with a defect in tissue availability or utilization of DCI in PCOS that may contribute to the insulin resistance of the syndrome.

Adolescent↗

PubMed2005

Reduced intestinal fat absorptive capacity but enhanced susceptibility to diet-induced fatty liver in mice heterozygous for ApoB38.9 truncation.

Fatty liver is prevalent in apolipoprotein B (apoB)-defective familial hypobetalipoproteinemia (FHBL). Similar to humans, mouse models of FHBL produced by gene targeting (apob(+/38.9)) manifest low plasma cholesterol and increased hepatic triglycerides (TG) even on a chow diet due to impaired hepatic VLDL-TG secretive capacity. Because apoB truncations shorter than apoB48 are expressed in the intestine, we examined whether FHBL mice may have limited capacity for intestinal dietary TG absorption. In addition, we investigated whether FHBL mice are more susceptible to diet-induced hepatic TG accumulation. Fat absorption capacity was impaired in apoB38.9 mice in a gene dose-dependent manner. Relative fractional fat absorption coefficients for apob(+/+), apob(+/38.9), and apob(38.9/38.9) were 1.00, 0.96, and 0.71, respectively. To raise hepatic TG, we fed high-fat (HF) and low-fat (LF) pellets. Hepatic TG level was observed in rank order: HF > LF > chow. On both LF and HF, liver TG level was higher in the apob(+/38.9) than in apob(+/+). Hepatic TG secretion remained impaired in the apob(+/38.9) on the HF diet. Thus the FHBL mice are more susceptible to diet-induced fatty liver despite relatively reduced intestinal TG absorption capacity on a HF diet.

Animals↗

PubMed2005

Phytostanol tablets reduce human LDL-cholesterol.

The feasibility of using solid dosage forms containing stanol lecithin to lower human LDL-cholesterol was investigated. The particle size distribution of a coarse aqueous dispersion of a stanol lecithin mixture was determined at various weight ratios of the components. At a stanol-to-lecithin weight ratio of 1.00-1.50, dispersions could be spray dried and the solid reconstituted with water to produce a particle size distribution that was similar to that of the aqueous dispersion from which it was derived. Two solid dosage forms containing this spray-dried stanol lecithin preparation had different disintegration times--tablets less than 10 min and capsules greater than 45 min. Each delivery system was then tested for LDL-cholesterol reduction activity in a placebo-controlled, double-blind clinical trial containing a total of 52 subjects. After a six-week treatment period, the group that received rapidly disintegrating stanol lecithin tablets (1.26 g stanols daily) experienced a decrease in both LDL-cholesterol and the ratio of LDL-cholesterol to HDL-cholesterol by 10.4% (P = 0.01) and 11.5% (P = 0.03), respectively, relative to placebo. On the other hand, with slowly disintegrating capsules (1.01 g daily) there was no statistically significant difference in any lipid parameter between the active group and placebo group. Taken together, these studies demonstrate that for maximum LDL-cholesterol reduction activity the stanol lecithin formulation must be delivered in a rapidly dispersible form to reach the site of cholesterol absorption.

Administration, Oral↗

PubMed2004

Pinitol supplementation does not affect insulin-mediated glucose metabolism and muscle insulin receptor content and phosphorylation in older humans.

This study assessed the effect of oral pinitol supplementation on oral and intravenous glucose tolerances and on skeletal muscle insulin receptor content and phosphorylation in older people. Fifteen people (6 men, 9 women; age 66 +/- 8 y; BMI 27.9 +/- 3.3 kg/m(2); hemoglobin A1c 5.39 +/- 0.46%, mean +/- SD) completed a 7-wk protocol. Subjects were randomly assigned to groups that during wk 2-7 consumed twice daily either a non-nutritive beverage (Placebo group, n = 8) or the same beverage with 1000 mg pinitol dissolved into it (Pinitol group, n = 7, total dose = 2000 mg pinitol/d). Testing was done at wk 1 and wk 7. In the Pinitol group with supplementation, 24-h urinary pinitol excretion increased 17-fold. The fasting concentrations of glucose, insulin, and C-peptide, and the 180-min area under the curve for these compounds, in response to oral (75 g) and intravenous (300 mg/kg) glucose tolerance challenges, were unchanged from wk 1 to wk 7 and were not influenced by pinitol. Also, pinitol did not affect indices of hepatic and whole-body insulin sensitivity from the oral glucose tolerance test and indices of insulin sensitivity, acute insulin response to glucose, and glucose effectiveness from the intravenous glucose tolerance test, estimated using minimal modeling. Pinitol did not differentially affect total insulin receptor content and insulin receptor phosphotyrosine 1158 and insulin receptor phosphotyrosine 1162/1163 activation in vastus lateralis samples taken during an oral-glucose-induced hyperglycemic and hyperinsulinemic state. These data suggest that pinitol supplementation does not influence whole-body insulin-mediated glucose metabolism and muscle insulin receptor content and phosphorylation in nondiabetic, older people.

Aged↗

PubMed2004

Phytosterols and cholesterol metabolism.

PURPOSE OF REVIEW: Phytosterols are plant sterols structurally similar to cholesterol that act in the intestine to lower cholesterol absorption. Because they have very low systemic absorption and are already present in healthy diets, increasing the intake of phytosterols may be a practical way to reduce coronary heart disease with minimum risk. RECENT FINDINGS: Phytosterols displace cholesterol from intestinal micelles, reducing the pool of absorbable cholesterol, but they are also rapidly taken up by enterocytes and increase expression of the adenosine triphosphate-binding cassette A1 sterol transporter. Phytosterol esters dissolved in food fat reduce LDL-cholesterol by 10% at a maximum effective dose of 2 g/day. However, this work probably understates the true effectiveness of phytosterols because it does not account for those naturally present in baseline diets. Single meal studies show that phytosterols in intact foods are bioactive at doses as low as 150 mg. The potential effectiveness of phytosterols has been improved in several ways. Individuals most likely to respond have been identified as having high cholesterol absorption and low cholesterol biosynthesis. Phytosterols can be emulsified with lecithin and delivered in non-fat or low-fat foods and beverages, and the amount of fat in fat-based preparations can be reduced substantially with the retention of bioactivity. SUMMARY: Phytosterols effectively reduce LDL-cholesterol when given as supplements, and the smaller amounts in natural foods also appear to be important. Future work will focus on the better delivery of phytosterols in natural foods and supplements and on further defining the mechanisms of action.

Animals↗

PubMed2004

Resistive training and chromium picolinate: effects on inositols and liver and kidney functions in older adults.

This study assessed the effects of resistive training (RT) with or without chromium picolinate (Cr-pic) supplementation on the 24-h urinary excretions of myo-inositol, D-chiro-inositol, and pinitol, as well as clinical indices of kidney and liver functions. Thirty-two nondiabetic subjects, age 62 +/- 4 y, performed RT twice weekly for 12 wk and consumed either 924 ug Cr/d as Cr-pic (n = 17) or a placebo (n = 15). Whole-body strength increased in all subjects by 20 % and urinary chromium excretion increased 47-fold in the Cr-pic group. Urinary myo-inositol, D-chiro-inositol, and pinitol were not changed with RT or influenced by Cr-pic. Serum indices of kidney and liver functions were within clinically normal ranges at baseline and the end of the study. These results suggest that RT did not influence the urinary excretions of inositols. High dose Cr-pic did not influence the urinary excretion of inositols and the selected indices of kidney and liver functions in conjunction with RT.

Area Under Curve↗

PubMed2003

Fat-free foods supplemented with soy stanol-lecithin powder reduce cholesterol absorption and LDL cholesterol.

OBJECTIVE: The objective of this work was to show that fat-free, lecithin-formulated soy stanols lower cholesterol absorption and serum LDL cholesterol. DESIGN: Reduction in cholesterol absorption was measured in paired single-meal tests with or without formulated soy stanols (acute test), and changes in serum lipids were investigated in a 10-week, randomized, double-blind parallel trial in which formulated stanols or lecithin vehicle were given three times daily for the last 4 weeks (chronic test). SUBJECTS/SETTING: Forty-five normal or mildly hypercholesterolemic subjects were recruited for both studies. The 21 subjects (16 female, 5 male; mean age 32.5 years) in the absorption studies had the following mean lipid values: LDL cholesterol, 2.79 mmol/L and total cholesterol, 4.73 mmol/L. For the lipid reduction, 24 subjects (16 female, 8 male; mean age 50.6 years) were enrolled with mean LDL cholesterol and total cholesterol of 3.72 mmol/L and 5.66 mmol/L, respectively. INTERVENTION: Reduction in cholesterol absorption was measured using a lemonade beverage or egg whites that contained 625 mg stanols. Throughout the chronic study, subjects followed the American Heart Association Step I diet. During the 4-week treatment phase, subjects consumed daily a lemonade-flavored beverage containing either placebo or formulated soy stanols (1.9 g). MAIN OUTCOME MEASURES: Inhibition of cholesterol absorption was determined from the difference in plasma deuterated cholesterol enrichment after a test meal containing stanol-lecithin and one with lecithin vehicle only. In the chronic study, the primary endpoints were changes in LDL and total cholesterol. STATISTICAL ANALYSES PERFORMED: Paired or unpaired t tests were used to determine statistical significance. RESULTS: Stanol-lecithin reduced cholesterol absorption by 32.1% (P=.0045, n=10) and by 38.2% (P=.0022, n=11) when delivered in a lemonade-flavored beverage and in egg whites, respectively. Reduction in cholesterol absorption was strongly related to the initial level of absorbed cholesterol tracer in serum (r(s)=-0.739). Stanol-lecithin given in a beverage reduced total serum cholesterol by 10.1% (P=.0019, n=24) and LDL cholesterol by 14.3% (P=.0016, n=24). APPLICATIONS/CONCLUSIONS: Powdered soy stanol-lecithin lowers cholesterol absorption and LDL cholesterol when consumed in fat-free foods.

Adult↗

PubMed2003

Inhibition of cholesterol absorption by phytosterol-replete wheat germ compared with phytosterol-depleted wheat germ.

BACKGROUND: Low-fat vegetable foods contain phytosterols, but it is not known whether they are in biologically active forms or whether their concentrations are high enough to reduce cholesterol absorption and favorably affect lipid metabolism. OBJECTIVE: The objective was to establish whether the selective removal of phytosterols from wheat germ would increase the cholesterol absorption measured from test meals composed of wheat germ muffins. DESIGN: Wheat germ, which has a high content of phytosterols relative to total fat, was chosen as a low-fat test food. Cholesterol absorption was measured 3 times in 10 subjects. Each test meal was a muffin containing 30 mg heptadeuterated cholesterol tracer and, in random order, 80 g original wheat germ containing 328 mg phytosterols, wheat germ from which phytosterols had been selectively extracted, or extracted wheat germ reconstituted with purified phytosterols. Changes in cholesterol absorption were monitored by the measurement of tracer enrichment of plasma cholesterol 4 and 5 d after each meal with the use of negative ion mass spectrometry. RESULTS: Tracer enrichment of plasma cholesterol was 42.8% higher after consumption of phytosterol-free wheat germ than after that of the original wheat germ (0.415 +/- 0.035 compared with 0.291 +/- 0.024 micro mol tracer/mmol cholesterol; P < 0.01). Tracer enrichment of plasma cholesterol was not significantly different between the wheat germ with extracted-and-reconstituted phytosterol (0.305 +/- 0.022 micro mol tracer/mmol cholesterol) and the original wheat germ. CONCLUSION: The efficiency of cholesterol absorption from test meals was substantially lower after consumption of original wheat germ than after consumption of phytosterol-free wheat germ, which suggests that endogenous phytosterols in wheat germ and possibly in other low-fat vegetable foods may have important effects on cholesterol absorption and metabolism that are independent of major nutrients.

Absorption↗

PubMed2002

Phytosterols in human nutrition.

Phytosterols are cholesterol-like molecules found in all plant foods, with the highest concentrations occurring in vegetable oils. They are absorbed only in trace amounts but inhibit the absorption of intestinal cholesterol including recirculating endogenous biliary cholesterol, a key step in cholesterol elimination. Natural dietary intake varies from about 167-437 mg/day. Attempts to measure biological effects in feeding studies have been impeded by limited solubility in both water and fat. Esterification of phytosterols with long-chain fatty acids increases fat solubility by 10-fold and allows delivery of several grams daily in fatty foods such as margarine. A dose of 2 g/day as the ester reduces low density lipoprotein cholesterol by 10%, and little difference is observed between Delta(5)-sterols and 5alpha-reduced sterols (stanols). Phytosterols can also be dispersed in water after emulsification with lecithin and reduce cholesterol absorption when added to nonfat foods. In contrast to these supplementation studies, much less is known about the effect of low phytosterol levels in the natural diet. However, reduction of cholesterol absorption can be measured at a dose of only 150 mg during otherwise sterol-free test meals, suggesting that natural food phytosterols may be clinically important. Current literature suggests that phytosterols are safe when added to the diet, and measured absorption and plasma levels are very small. Increasing the aggregate amount of phytosterols consumed in a variety of foods may be an important way of reducing population cholesterol levels and preventing coronary heart disease.

Cholesterol↗

PubMed2002

Phytosterols that are naturally present in commercial corn oil significantly reduce cholesterol absorption in humans.

BACKGROUND: Although supplementing the diet with large quantities of phytosterols reduces cholesterol absorption and LDL-cholesterol concentrations, very little is known about the smaller amounts of phytosterols present naturally in food. Vegetable oils are the richest dietary source of phytosterols; corn oil contains 0.77% phytosterols by weight. OBJECTIVE: We tested the hypothesis that removing phytosterols from corn oil would increase cholesterol absorption when measured in single-meal tests containing corn oil as a source of fat. DESIGN: Free and esterified phytosterols were removed from corn oil on a kilogram scale by a new technique of competitive saturation adsorption to silica. Healthy subjects with a mean (+/-SEM) serum cholesterol concentration of 5.10 +/- 0.18 mmol/L received an otherwise sterol-free test breakfast on 2 occasions 2 wk apart that contained 35 mg hexadeuterated cholesterol and 30-35 g of a corn oil preparation. The plasma enrichment of tracer was measured by negative ion mass spectrometry. RESULTS: Cholesterol absorption was 38.0 +/- 10.2% higher after consumption of the sterol-free corn oil than after consumption of commercial corn oil with an identical fatty acid content (P = 0.005; n = 10). When corn oil phytosterols were added back to sterol-free corn oil at a concentration of 150 mg/test meal, cholesterol absorption was reduced by 12.1 +/- 3.7% (P = 0.03; n = 5) and by 27.9 +/- 9.1% (P = 0.01; n = 10) after inclusion of 300 mg phytosterols. CONCLUSIONS: Phytosterols comprising < 1% of commercial corn oil substantially reduced cholesterol absorption and may account for part of the cholesterol-lowering activity of corn oil previously attributed solely to unsaturated fatty acids.

Absorption↗

PubMed2002

Cholesterol absorption.

Cholesterol absorption is a key regulatory point in human lipid metabolism because it determines the amount of endogenous biliary as well as dietary cholesterol that is retained, thereby influencing whole body cholesterol balance. Plant sterols (phytosterols) and the drug ezetimibe reduce cholesterol absorption and low-density lipoprotein cholesterol in clinical trials, complementing the statin drugs, which inhibit cholesterol biosynthesis. The mechanism of cholesterol absorption is not completely known but involves the genes ABC1, ABCG5, and ABCG8, which are members of the ATP-binding cassette protein family and appear to remove unwanted cholesterol and phytosterols from the enterocyte. ABC1 is upregulated by the liver X (LXR) and retinoid X (RXR) nuclear receptors. Acylcholesterol acytransferase-2 is an intestinal enzyme that esterifies absorbed cholesterol and increases cholesterol absorption when dietary intake is high. New clinical treatments based on better understanding of absorption physiology are likely to substantially improve clinical cholesterol management in the future.

Journal Article↗

PubMed2002

Gastrointestinal absorption and plasma kinetics of soy Delta(5)-phytosterols and phytostanols in humans.

Our objective was to measure the systemic absorption of lecithin-emulsified Delta(5)-phytosterols and phytostanols during test meals by use of dual stable isotopic tracers. Ten healthy subjects underwent two single-meal absorption tests in random order 2 wk apart, one with intravenous dideuterated Delta(5)-phytosterols and oral pentadeuterated Delta(5)-phytosterols and the other with the corresponding labeled stanols. The oral-to-intravenous tracer ratio in plasma, a reflection of absorption, was measured by a sensitive negative ion mass spectroscopic technique and became constant after 2 days. Absorption from 600 mg of Delta(5)-soy sterols given with a standard test breakfast was 0.512 +/- 0.038% for sitosterol and 1.89 +/- 0.27% for campesterol. The absorption from 600 mg of soy stanols was 0.0441 +/- 0.004% for sitostanol and 0.155 +/- 0.017% for campestanol. Reduction of the double bond at position 5 decreased absorption by 90%. Plasma t(1/2) for stanols was significantly shorter than that for Delta(5)-sterols. We conclude that the efficiency of phytosterol absorption is lower than what was reported previously and is critically dependent on the structure of both sterol nucleus and side chain.

Adult↗

PubMed2002

Effects of trace components of dietary fat on cholesterol metabolism: phytosterols, oxysterols, and squalene.

The effect of dietary fats on serum cholesterol is widely assumed to be due solely to the fatty acids and cholesterol they contain. Phytosterols, sterol oxidation products, and sterol precursors such as squalene, however, are often present in dietary fats. Little is known of the physiology of these substances in natural foods and most published diet studies do not consider them at all. Supplementation of the diet with high-dose phytosterols is now recommended for prevention of heart disease, but both recent and old data strongly suggest that the lower levels of phytosterols naturally present in vegetable fats may also reduce cholesterol absorption and serum cholesterol substantially. Moreover, unmeasured phytosterols may confound otherwise well-controlled diet studies because there is an inverse correlation between phytosterol and saturated fatty acid content of vegetable fats. Sterol oxidation products, many of which are found in foods, are potent regulators of lipoprotein and cholesterol transport pathways in vitro. Squalene is a phytosterol precursor abundant in olive oil that is at least partly absorbed and then quantitatively converted to cholesterol. The effects of dietary triglyceride-derived fatty acids have not been experimentally separated from the effects of trace fat components in most clinical studies. A better understanding of the activity of sterol-related dietary components is needed to reduce variability in diet studies, accurately assess the effects of dietary fatty acids and to maximize the effectiveness of dietary treatment for hypercholesterolemia.

Cholesterol↗