Table 5.

Characteristics of human studies included in the review.

Study	Disease/Condition	Study Type/ SQ Source	Sample/ Population	Methodology	Results (SQ and CVD Only)	Comments/Outcomes
Study 1 Strandberg et al. 1990 [45]	Cerebrovascular and cardiovascular disorders with different degrees of hypercholesterolemia	Human study   SQ capsule   The source was not disclosed	Fifteen patients (8 males and 7 females) of cerebrovascular and cardiovascular disorders   Prior to the study, the patients were on a standard hospital diet for several weeks with the mean cholesterol and SQ intakes as 300 and 7 mg/day, respectively.	The patients were divided into two groups: i) SQ (n = 9), administered in capsules (300 mg) three times daily with meals, in which three subjects were fed for a minimum period (one-week) and six subjects were fed for an extended period (30 days), and   ii) cholestyramine group (n = 6), administered 8 g of cholestyramine resin four times daily with meals.   Blood was measured in intervals: basal, 7 days, and 30 days: i) cholesterol, SQ, and non-cholesterol sterol in serum and ii) cholesterol, SQ, and precursor sterol concentrations in different lipoproteins.	Fecal analysis showed that approximately 60% of dietary squalene was absorbed.   Serum triglyceride and cholesterol contents were unchanged. Serum SQ levels were increased 17 times. The SQ feeding significantly increased serum levels of free and esterified methyl sterol contents (p < 0.05), while elevations of free and esterified cholesterol and lathosterol levels were inconsistent.   The SQ feeding had no consistent effect on absorption efficiency of cholesterol yet significantly increased the fecal excretions of cholesterol, its nonpolar derivatives, and bile acids (p < 0.05).	SQ supplementation can increase cholesterol synthesis; however, no association was found with the consistency increment of serum cholesterol level.
Study 2 Miettinen and Vanhanen 1994 [50]	Hypercholesterolemia	Human study   Source of SQ was not disclosed	Eighteen male subjects mean (± SE) age: 50 ± 3 y, with basal serum concentrations of cholesterol > 6 mmol/L and triglycerides < 2.5 mmol/L.	This study had four periods as follows: 1) baseline: home diet (n = 18); 2) rapeseed oil (n = 18), 6 weeks: 50 g of daily dietary fat intake was replaced with 50 g of a rapeseed oil mayonnaise per day for six weeks; 3) rapeseed oil (n = 8) or rapeseed oil + 1 g SQ/d (n = 10), 9 weeks (at week 15): ten subjects consumed rapeseed oil mayonnaise with 1 g SQ while the control group consumed rapeseed oil without SQ for nine weeks; and 4) rapeseed oil (n = 8) or rapeseed oil plus 0.5 g SQ/d (n = 10), 6 weeks (at week 21): ten subjects consumed rapeseed oil mayonnaise with 0.5 g SQ while the control group consumed rapeseed oil without SQ for six weeks.   Fasting blood samples were collected for serum lipid (cholesterol, TG, phospholipids, apolipoprotein B, and HDL lipoprotein). Serum precursor sterols were also measured.	The addition of 1 g SQ to the diet at week 15 showed a significant increase in total cholesterol when compared to rapeseed oil-consuming only at week 6 and control rapeseed oil at week 15 and week 21 (p ≤ 0.05).   The addition of 1 g SQ to the diet at week 15 showed significant increments (p ≤ 0.05) in LDL-C, total TG, and VLDL when compared at week 6 (rapeseed-given only).   The addition of 0.5 g SQ to the diet at the 4th period showed a significant reduction in IDL cholesterol, triglycerides, and phospholipids (p ≤ 0.05).   The reduction of SQ intake to only 0.5 g/d decreased the serum lipid concentrations to the rapeseed oil control and pre-squalene concentrations.   Serum precursor sterols were significantly increased (p < 0.05) when compared at week 6 (rapeseed-given only).	A long-term (9 weeks) and large-amount SQ intake (1 g/d) might cause increased total cholesterol in serum due to augmented number of LDL particles with low surface lipids (free cholesterol and phospholipids)   Small SQ doses (0.5 g/d) did not increase total cholesterol, which might be related to inhibition of endogenous pre-SQ cholesterol synthesis, which does not affect the LDL receptors or serum cholesterol. Long-term use of SQ resulted in the adaptation of cholesterol metabolism.
Study 3 Chan et al. 1996 [49]	Hypercholesterolemia	Human study, double-blind, randomized, placebo- controlled trial SQ capsule (Goldian Co., Singapore)	One hundred and two elderly (age > 65) patients with primary hypercholesterole-mia (TC > 250 mg/dL, TG < 300 mg/dL) were randomly assigned.   The patients were enrolled after a three-month dietary intervention with the American Heart Association (AHA) Step I Diet.   Patients with homozygous familial hypercholesterolemia, types I or III–V; hyperlipoproteinemia; cardiovascular; renal; hepatic; gastrointestinal; or metabolic diseases and malignancies were excluded.	Prior to randomization, any previous treatment with lipid-lowering drugs was discontinued for two months and a single-blind placebo lead-in period of four weeks was administered along with the dietary treatment. All patients then start consuming one of the following treatments with evening meal for a 20-week period: 1) 10 mg pravastatin; 2) two capsules (430 mg each) of SQ; 3) a combination of pravastatin and SQ; or 4) matching placebo.   Levels of TC, HDL-C, and TG were determined at baseline after the fourth week lead-in placebo treatment and again after 4, 8, 12, and 20 weeks of the active treatment. LDL-C levels were determined by calculation. During each visit, blood was measured for concentrations of lipids and lipoproteins and for liver function and creatine kinase.	Supplementation of SQ 860 mg/day for 20 weeks had significantly decreased TC and LDL-C levels when compared to the baseline level and placebo group (p < 0.05).   Supplementation of squalene 860 mg/day for 20 weeks had decreased TG levels by 5.3% while increased the HDL-C level by 1.8%.	Dietary squalene appeared to exert hypocholesterolemic activity.   The authors proposed that this effect was due to the downregulation of HMG-CoA reductase activity by the enhanced squalene-derived synthesis of cholesterol.