Mayonnaise contributes to increasing postprandial serum ß-carotene concentration through the emulsifying property of egg yolk in rats and humans.

We performed in vitro, animal, and human studies to clarify the effect of mayonnaise on ß-carotene intake and its mechanism. In an artificial gastric juice model, we examined the transfer of ß-carotene from grated carrot to mayonnaise or vegetable oil. Mayonnaise was more easily dispersed in artificial gastric juice than vegetable oil. The ß-carotene concentration was greater in mayonnaise than vegetable oil. In rats, the postprandial serum ß-carotene concentration in the mayonnaise group (ß-carotene with mayonnaise) was higher than that in the control (ß-carotene only) and vegetable oil (ß-carotene with vegetable oil) groups. Continuous feeding of dietary ß-carotene (14 d), employing mayonnaise or egg yolk, resulted in an increased accumulation of ß-carotene in the liver. In a human study, diets were provided in the form of (1) carrot as a control (CON), (2) carrot juice (JU), (3) carrot with oil (OIL) and (4) carrot with mayonnaise (MS). Following collection of fasting blood samples, nine adult males consumed one of the four diets in random order. Fasting and postprandial changes in serum ß-carotene were assessed at 2, 3, 4, 6 and 8 h following ingestion of each diet. The incremental areas under the curves of serum ß-carotene concentration were higher following MS than following both CON and JU. In conclusion, we suggest that mayonnaise contributes to raising the serum ß-carotene concentration when consumed with carrots rich in ß-carotene, and that its mechanism is related to the emulsifying property of the egg yolk contained in mayonnaise.

Effects of mayonnaise on postprandial serum lutein/zeaxanthin and beta-carotene concentrations in humans.

To clarify the effects of different physical forms of oil on postprandial serum lutein/zeaxanthin and beta-carotene concentrations, we performed a vegetable meal loading test. Eighteen healthy subjects participated in the test, which consisted of broccoli as a control (CON) meal, broccoli with oil (OIL), and broccoli with mayonnaise (MS), consumed in random order. After collection of fasting blood samples, subjects consumed one of the three test meals. Fasting and postprandial changes in serum carotenoids were assessed 2, 4, and 6 h after ingestion of each test meal. Serum lutein/zeaxanthin and beta-carotene concentrations were measured. Although no significant change was noted after the CON meal, the serum lutein/zeaxanthin concentration was higher at 4 h after consumption of the OIL meal, and at 2, 4 and 6 h after consumption of the MS meal, as compared with the fasting state. Serum beta-carotene concentrations did not change after ingestion of either the CON or the OIL meal but were elevated 2, 4, and 6 h after MS ingestion as compared with the fasting state. The incremental areas under the curves (IAUCs) of serum lutein/zeaxanthin and beta-carotene concentrations were higher after the MS meal than after the CON meal. IAUCs after the OIL meal exhibited no statistically significant differences from the CON and MS meals. We suggest that mayonnaise contributes to increase serum lutein/zeaxanthin and beta-carotene concentrations when consumed with vegetables rich in these carotenoids.

[Minimal effective dose on serum cholesterol concentration and the safety evaluation of dressing containing plant sterol in Japanese subjects].

We examined the minimal effective dose on serum cholesterol concentration and the safety of dressing containing plant sterol in humans. EXP.1: Sixty-eight healthy Japanese males (total cholesterol (TC) > or = 170 mg/dL) were randomly divided into four groups, and were given 0, 400, 800 or 1200 mg/day of plant sterol in 15 g dressing for 4 weeks followed by the washout period of 4 weeks. Although there were no significant differences in serum TC and low-density lipoprotein cholesterol (LDL-C) concentrations among all groups after feeding plant sterol for 4 weeks, in 36 subjects with TC > or = 220 mg/dL, serum LDL-C concentration tended to reduce when received 800 or 1200 mg of plant sterol, and the difference between 0 and 1200 mg groups was statistically significant. The difference between 0 and 800 mg groups was near significant (p=0.053). Intake of 400 mg of plant sterol did not change serum LDL-C concentration. EXP.2: Twenty-one healthy Japanese subjects (TC > or = 180 mg/dL, 10 men, 11 women) were given 2400 mg/day of plant sterol in 45 g dressing for 4 weeks. Clinical data were all remained normal. These results indicated that minimal effective dose of the plant sterol on serum cholesterol concentration in healthy male subjects is around 800 mg/day, and intake of 2400 mg/day of plant sterol is regarded to be safe.

[Effects of dressing containing plant sterol on serum cholesterol concentration and the safety evaluation in borderline or mildly hypercholesterolemic Japanese subjects].

In a placebo-controlled double-blind study, we examined the effects of dressing containing plant sterol (PS) on blood lipids and the safety in Japanese borderline or mildly hypercholesterolemic subjects. Fifty-nine subjects [total cholesterol (TC) concentration > or = 200 mg/dL] were randomly divided into two groups and were given daily 15 g of dressing containing 800 mg of PS [PS(+)-group] or without PS [PS(-)-group] for 12 weeks. Every 4 weeks, fasting blood was examined and subjective symptoms were analyzed. Serum TC, low-density lipoprotein cholesterol (LDL-C) and apolipoprotein B (ApoB) concentrations did not change in the PS(-)-group, while TC and ApoB significantly decreased in the PS(+)-group at 8 and 12 weeks and LDL-C at 4, 8 and 12 weeks. Moreover, serum TC, LDL-C and ApoB concentrations were significantly lower than those of PS(-)-group at 8 and 12 weeks. Other laboratory tests were all in normal ranges and no adverse events were observed. The results indicated that PS-containing dressing decreased serum TC, LDL-C and ApoB concentrations in borderline or mildly hypercholesterolemic subjects. It is therefore proved that the dressing containing PS is helpful in maintaining blood cholesterol level normal and hence, the health of Japanese.

Egg ovomucin attenuates hypercholesterolemia in rats and inhibits cholesterol absorption in Caco-2 cells.

This experiment was designed to evaluate the effect of casein or ovomucin (OV) on the micellar solubility of cholesterol and the taurocholate binding capacity in vitro. We also evaluated the effects of casein or OV on cholesterol metabolism in rats and Caco-2 cells. OV had a significantly greater bile acid-binding capacity than that of casein in vitro. Micellar cholesterol solubility in vitro was significantly lower in the presence of OV compared to casein. The cholesterol micelles containing OV significantly suppressed cholesterol uptake by Caco-2 cells compared to the cholesterol micelles containing casein. Consistent with these in vitro findings, OV-feeding significantly increased the fecal excretion of bile acids or cholesterol compared with casein-feeding. Serum total cholesterol was significantly lower in rats fed OV than in those fed casein. The concentrations of total lipids in liver were significantly lower in the OV-fed group compared with the casein group. These results suggest that the suppression of cholesterol absorption by direct interaction between cholesterol mixed micelles and OV in the jejunal epithelia is part of the mechanism underlying the hypocholesterolemic action of OV. OV may also inhibit the reabsorption of bile acids in the ileum, thus lowering the serum cholesterol level.