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Cited by 115Cholesterol and Lipid MetabolismLipoproteins and Cardiovascular HealthSteroid Chemistry and Biochemistry

Metabolic variables of cholesterol during squalene feeding in humans: comparison with cholestyramine treatment

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Strandberg, TE, Tilvis, RS, Miettinen, TA·1990·Journal of Lipid Research
DOI 10.1016/s0022-2275(20)42347-8
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Abstract

Squalene, a key intermediate of cholesterol synthesis, is present especially in olive oil. Regulation of cholesterol metabolism by dietary squalene in man is unknown, even though olive oil users in Mediterranean areas have low serum cholesterol levels. We have investigated absorption and serum levels of squalene and cholesterol and cholesterol synthesis with the sterol balance technique and serum levels of cholesterol precursors in humans during squalene feeding (900 mg/d for 7-30 days). The results were compared with those during cholestyramine treatment. Fecal analysis suggested that about 60% of dietary squalene was absorbed. Serum squalene levels were increased 17 times, but serum triglyceride and cholesterol contents were unchanged. The squalene feeding significantly (P less than 0.05) increased serum levels of free (1.7-2.3 times) and esterified (1.9-2.4 times) methyl sterol contents, while elevations of free and esterified delta 8-cholesterol and lathosterol levels were inconsistent. Cholestyramine treatment modestly augmented free methyl sterol levels (1.3-1.7 times), less consistently than those of esterified ones, while, in contrast to the squalene feeding, serum contents of free and esterified delta 8-cholesterol and lathosterol were dramatically increased (3.3-8 times). Neither of the treatments significantly affected serum plant sterol and cholestanol levels. The squalene feeding had no consistent effect on absorption efficiency of cholesterol, but significantly increased (paired t-test, P less than 0.05) the fecal excretions of cholesterol and its nonpolar derivatives coprostanol, epicoprostanol, and coprostanone (655 +/- 83 SE to 856 +/- 146 mg/d) and bile acids (212 +/- 24 to 255 +/- 24 mg/d), indicating an increase of cholesterol synthesis by about 50%. We suggest that a substantial amount of dietary squalene is absorbed and converted to cholesterol in humans, but this squalene-induced increase in synthesis is not associated with consistent increases of serum cholesterol levels. The clearly increased serum contents of esterified methyl sterols may reflect stimulated tissue acyl CoA: cholesterol acyltransferase (ACAT, EC 2.3.1.26) activity during squalene feeding as these sterols are not esterified in serum.

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  • Most evidence on the potential health beneficial effects of olive minor components comes from in vitro studies or preclinical animal studies, while clinical studies in humans on the cardiometabolic effects of these compounds are scarce and limited to the use of pure components as drug therapy or dietary supplements.

    “Most of the evidence on the potential health beneficial effects of olive minor components come from in vitro studies in different cell models or from preclinical animal studies [reviewed in 6]. However, clinical studies in humans on the cardiometabolic effects of these compounds are scarce, limited to the use of pure components such as squalene or triterpenic acids as drug therapy or dietary suppl”

    From Olive pomace oil can improve blood lipid profile: a randomized, blind, crossover, controlled clinical trial in healthy and at-risk volunteers (2022) · cites this paper as [22]

  • Of the three trials developed in hypercholesterolemic patients, only one reported reduced TC and LDL-C, and increased HDL-C concentrations when participants were supplemented with 869 mg/d of squalene for 20 weeks.

    “Of the three trials developed in hypercholesterolemic patients, only one reported reduced TC and LDL-C, and increased HDL-C concentrations when participants were supplemented with 869 mg/d of squalene for 20 weeks [22].”

    From Olive pomace oil can improve blood lipid profile: a randomized, blind, crossover, controlled clinical trial in healthy and at-risk volunteers (2022) · cites this paper as [22]

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Authors
Strandberg, T., Tilvis, R., & Miettinen, T.
Affiliations
University of Helsinki (FI)
Venue
Journal of Lipid Research
Publisher
Elsevier BV
Published
1990-09
Volume
31
Issue
9
Pages
1637-1643
ISSN
0022-2275 (ISSN-L)
DOI
10.1016/s0022-2275(20)42347-8
OpenAlex
W2148299677
Cited by
115
References
23
Citations by year
2024: 5 · 2023: 1 · 2022: 2 · 2021: 4 · 2020: 7 · 2019: 3 · 2018: 4 · 2017: 6 · 2016: 2 · 2015: 3 · 2014: 4 · 2013: 6 · 2012: 4
FWCI
1.08
Type
journal article
Language
en
Open access
Licence
Locations
  • Journal of Lipid Research (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Topics
  • Health Sciences › Medicine › Surgery › Cholesterol and Lipid Metabolism
  • Health Sciences › Medicine › Surgery › Lipoproteins and Cardiovascular Health
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Steroid Chemistry and Biochemistry
Keywords
squalene, cholesterol biosynthesis, cholesterol metabolism, cholestyramine, lathosterol, coprostanol, bile acids, acyl-CoA:cholesterol acyltransferase, olive oil, serum cholesterol, phytosterols
MeSH terms
Cholesterol, Cholestyramine Resin, Dietary Fats, Unsaturated, Cholestanol, Feces, Female, Humans, Hydroxymethylglutaryl CoA Reductases, Intestinal Absorption, Lipoproteins, Male, Squalene, Sterols, Lipid Metabolism

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