![[Feedback]](/icons/banner/feedbackACT.gif){kind=icon}
![[For Subscribers]](/icons/banner/subscriberACT.gif){kind=icon}
![[Archive]](/icons/banner/archiveACT.gif){kind=icon}
![[Search]](/icons/banner/searchACT.gif){kind=icon}
![[Contents]](/icons/banner/tocACT.gif){kind=icon}
|
|
|
|
|
||
-Tocopherol in Rats
Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita-9, Nishi-9, Kita-ku, Sapporo 060-8589, Japan
1To whom correspondence should be addressed. E-mail: hara{at}chem.agr.hokudai.ac.jp.
 |
ABSTRACT |
|---|
 TOP ABSTRACT MATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
-tocopherol absorption in male rats fitted with a thoracic lymph cannula. The lymphatic output was collected after administration of 1 mL of emulsified test oils containing lycopene and/or -tocopherol in 3 separate experiments. The sodium taurocholate–emulsified test oils contained soybean oil (SO; 113 µmol triglyceride), SO containing soybean PC (SPC; 82.5 µmol SO plus 30.5 µmol purified soybean PC) or SO containing egg PC (EPC; 82.5 µmol SO plus 30.5 µmol purified egg PC) with both lycopene and -tocopherol (Expt. 1) or SO, SPC, or EPC with lycopene (Expt. 2) or -tocopherol alone (Expt. 3). In rats administered SPC or EPC, the lymphatic outputs of TG and lycopene were higher, and that of -tocopherol was lower compared with rats administered SO (Expt. 1). The absorption rate for lycopene increased from 0.59% (SO group) to 2.16 and 1.28% in the SPC and EPC groups (P < 0.05), respectively, whereas the corresponding rates for tocopherol were 21.5% for the SO, 14.8% for the SPC, and 12.9% for the EPC groups. The increase in lycopene, but not in triglyceride absorption, was higher in the SPC than in the EPC groups. The promotive effects of SPC and EPC were decreased when lycopene alone was added to the test lipids (Expt. 2), and the inhibitory effects of PC were reduced when -tocopherol alone was added to the test lipids (Expt. 3). Dietary PC increased the lymphatic output of lycopene and TG and decreased that of -tocopherol, suggesting that differences exist between lycopene and -tocopherol in the absorptive mechanisms. The present results also show that the promotive effects of PC on lycopene absorption are influenced by the type of fatty acids in PC.
KEY WORDS: • phosphatidylcholine • lycopene • -tocopherol • rats
Lycopene is the major carotenoid in tomatoes and exists as a red color pigment in many fruits and vegetables. Most lycopene is consumed from tomatoes and tomato products such as juice, paste, and sauce. Other sources of lycopene are watermelon, guava, and pink grapefruit. Carotenoids including lycopene are singlet oxygen quenchers.
Epidemiologic studies provide evidence that a high intake of vegetables and fruits protects against certain types of cancers, including colon cancer (1,2). Among the various constituents of fruits and vegetables, only -tocopherol, ascorbic acid, and ß-carotene have been studied extensively as potential anticarcinogenic agents. In recent years, there have been a number of epidemiologic studies suggesting that carotenoids may reduce the risk of cervical, colon, prostate, rectal, and stomach cancers (1,3–5). Giovannucci et al. (2) conducted a cohort study among men for 1 y, with the consumption of fresh tomatoes, tomato sauce, and pizza accounting for the bulk of lycopene intake, and showed a significant negative relationship between lycopene consumption and the incidence of prostate cancer. Moreover, Korytko et al. (6) demonstrated that oral administration of lycopene can increase the lycopene concentration of plasma and tissues, specifically in prostate. These findings prompted a considerable interest in the role of lycopene in the diet. In addition, lycopene displays stronger quenching activity against singlet oxygen than does ß-carotene (7), and may have health benefits such as the prevention of cardiovascular disease (8,9).
Carotenoids, including lycopene, are not readily absorbed compared with other dietary lipids and fat-soluble food components. Several studies showed that the concurrent consumption of a dietary lipid significantly increases carotenoid absorption (10,11). The amount and type of lipid also affect the absorption of carotenoids (12,13); however, the effects of dietary lipids on carotenoid absorption are not yet fully understood. Moreover, the absorption of carotenoids depends on type (14–17), and the chemical structures responsible for the differences in carotenoid absorption have not yet been clarified. On the other hand, it was reported that lycopene absorption reaches saturation at a dose of 6 mg (18).
-Tocopherol, a fat-soluble vitamin found mainly in vegetable oils (e.g., soybean, rape seed, corn), has antioxidant activity similar to that of carotenoids and acts as a peroxyl radical scavenger (19). Further, it has been shown that its consumption with lipids significantly increases its absorption (20), although the promotive effect depends on the amount and type of the lipid (13).
Our previous study (21) showed that dietary phosphatidylcholine (PC)2 increased lymphatic absorption of triglyceride (TG). In addition, several studies (22–25) suggested that luminal dietary and biliary PC enhance the absorption of TG, through their influence on the rate of chylomicron formation and the partitioning of fatty acids between lymphatic and portal transport. These results suggest that dietary PC might enhance the absorption of other fat-soluble nutrients. The aim of the present study was to determine whether PC enhances lymphatic absorption of lycopene and -tocopherol, and whether the effects are dependent on PC type. This study was conducted using conscious, lymphatic duct–cannulated rats.
|
MATERIALS AND METHODS |
|---|
|
TOPABSTRACTMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
-tocopherol (all-rac--tocopherol, Sigma Chemical) (Expt. 1), or 0.372 µmol lycopene (Expt. 2), or 4.6 µmol -tocopherol (Expt. 3). These test lipids were emulsified with sodium taurocholate (10 g/L) using a sonicator (150 W for 1.5 min, SONICATOR, 5202, Ohtake Seisakusyo). Animals. Male Wistar/ST rats (Japan SLC), aged 9 wk, were fed a semipurified casein sucrose–based diet (AIN 76 formula) for 5 d. After 24 h of food deprivation, a vinyl catheter (SV-35; 0.5-mm i.d., 0.8-mm o.d.; Natsume Seisakusyo) and a silicone catheter (Silascon SH No. 00; 0.5-mm i.d., 1.0-mm o.d.; Kaneka Medix) were implanted in the thoracic lymph duct (26) and the duodenum, respectively, under anesthesia (sodium pentobarbital, 40 mg/kg body weight).
After the operation, the rats were placed in individual restraining cages. An isoosmotic solution containing 139 mmol/L glucose and 85 mmol/L NaCl was infused continuously at a rate of 3 mL/h through the duodenal catheter during the 1-d recovery and experimental periods except during test lipid administration. Rats were continuously infused with isoosmotic solution to maintain a basal nonstimulated secretion of digestive enzyme in all groups. After collection of the lymph for 30 min (initial lymph) on the day after the operation, rats were infused with 1 mL of an emulsified test solution for 1 min; then infusion of the glucose-NaCl solution was continued at 3 mL/h through the duodenal tube until the end of the experiment. The lymph was collected in a test tube at 0.5-h intervals during the first 2 h and at 1-h intervals during the next 2 h after the administration of the test solution. The collected lymph was frozen immediately and kept at –80°C until subsequent analyses.
This study was approved by the Hokkaido University Animal Committee, and rats were maintained in accordance with the Hokkaido University guidelines for the care and use of laboratory animals.
Analyses.
TG and phospholipid (PL) concentrations in the lymph fluid were measured by enzymatic procedures (TG-EN and PL-EN, Kainos Laboratories). Lycopene and -tocopherol in the lymph were extracted with chloroform:methanol (2:1, v:v) containing 0.02% 2,6-di-t-butyl-4-methylphenol as an antioxidant and separated by HPLC (Waters 2695 separation module) with TSK gel Silica 60 (4.6 x 250 mm, Tosoh). The mobile phase was hexane:isopropanol (99:1, v:v) with a flow rate of 1.0 mL/min. Lycopene and -tocopherol were identified and quantified at a wavelength of 475 and 290 nm, respectively, using a Waters 2996 Photodiode Array. The concentrations were determined from standard curves using 2,2,5,7,8-pentamethyl-6-chromanol as the internal standard.
Statistics. Data were analyzed by 1-way (Table 1) or repeated measure (Figs. 1 , 2, and 3) ANOVA. Duncan’s multiple range test was used to determine whether means were significantly different (P < 0.05). If the variance was unequal, log transformations of the data were performed before ANOVA. Values are shown as means ± SEM.
|
|
|
|
|
RESULTS |
|---|
|
TOPABSTRACTMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
-tocopherol.
The lymphatic output of lycopene during the first 2 h after the infusion was higher in rats given SPC and EPC than in those given SO. Moreover, the lycopene output in the SPC group was higher than that in the EPC group (Fig. 1A). The ratio of lycopene absorbed over the 4 h to the total amount of lycopene administered was higher in the SPC and EPC groups than in the SO group (Table 1).
The lymphatic output of -tocopherol increased in all rats administered the test lipids, and the outputs reached peak values at 90 min after the infusion in the SPC and EPC groups, and at 120 min in the SO group. The -tocopherol output was higher in the rats given SO than in those given SPC and EPC at 120–240 min (Fig. 1B). The ratio of -tocopherol absorbed over the 4 h to the total amount of -tocopherol administered was higher in the SO group than in the SPC and EPC groups (Table 1).
The lymphatic output of TG in rats given SPC and EPC was higher at 60–90 min than that in those given SO (Fig. 1C), and the absorption rate over the 4 h was higher in the SPC and EPC groups than in the SO group (Table 1). Changes in lymphatic PL output were much smaller than those for TG, and there were no intergroup differences (Fig. 1D). Lymph flow rate increased at 0–30 min after the infusion (from 1.5 to 3–3.5 g/h in all groups), and decreased rapidly after 30 min in all groups, with no intergroup differences.
Expt. 2: infusion of test lipids mixed with lycopene alone. The lymphatic output of lycopene during the first 90 min after the infusion was higher in rats given SPC than in those given SO and EPC (Fig. 2A), and peak values were observed at this point in all groups. The ratio of lycopene absorbed over the 4 h to the total amount of lycopene administered was higher in the SPC group than in the SO and EPC groups (Table 1). Changes in the lymphatic output of TG (Fig. 2B) and PL (data not shown) were very similar to those observed in Expt. 1. Lymph flow rate in rats given SPC (3.5 ± 0.4 g/h) was higher than that in rats given SO (2.2 ± 0.3 g/h) at 0–30 min after the infusion (EPC; 2.6 ± 0.2 g/h).
Expt. 3: infusion of lipids mixed with -tocopherol alone.
The lymphatic output of -tocopherol at 30–180 min after the infusion was higher in rats given SO than in those given SPC and EPC (Fig. 3A). The ratio of -tocopherol absorbed over the 4 h to the total amount of -tocopherol administered was higher in the SO group than in the SPC and EPC groups (Table 1). Changes in lymphatic output of TG (Fig. 3B) and PL, and lymphatic flow rate (data not shown) were very similar to those observed in Expt. 1.
|
DISCUSSION |
|---|
|
TOPABSTRACTMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
-tocopherol, and flavonoids in the prevention and treatment of a wide variety of illnesses (8,27). Furthermore, it is important to supply fat-soluble nutrients such as carotenoids and vitamin E to patients with impaired digestive and absorptive functions, for example, before and after surgical operations and in cases of Crohn’s disease (28). Our previous study (21) showed that dietary PC increased lymphatic absorption of TG independent of TG digestion. This result suggests that dietary PC may enhance the absorption of other fat-soluble nutrients. The present study showed that the lymphatic absorption of lycopene and -tocopherol was changed by the addition of PC to a soybean oil emulsion. We expected that PC would enhance the absorption of both lycopene and -tocopherol, and although lycopene absorption was increased, -tocopherol absorption was decreased by PC supplementation. These new findings demonstrate that PC clearly affects the absorption of fat-soluble compounds, although the effects are complex. In the present study, we chose intraduodenal infusion to avoid the effects of differences in gastric emptying between groups because we found that the addition of soybean PC suppressed gastric emptying more than SO in our previous study. The lymphatic output of lycopene was increased in the presence of both SPC and EPC, and the promotive effect was greater in the SPC than in the EPC groups (Fig. 1A). It was reported that PC inhibits the lymphatic absorption of some carotenoids such as ß-carotene (29,30). These previous results seem to be contrary to the present findings. However, it was reported that the inhibitory effect of PC is abolished when PC is hydrolyzed by phospholipase A2 or by the substitution of PC with lysoPC (30). Moreover, the efficiency of lipid absorption is enhanced when PC and lysoPC are mixed in micelles rather than when the micelles are composed of PC or lysoPC alone (31,32). A possible explanation for the disagreement between our results and those of previous studies is the degree of PC digestion in the absorptive surface of the micelles. In our present study, the PC hydrolysis conditions might have been particularly suited to lycopene absorption in the small intestine. Further, in the previous studies, but not in our study, predigested TG was used (29,30). The important point is that we observed the promotive effects of PC on lycopene absorption under physiologic conditions, i.e., using intact PC and TG. Another possibility for the differences in the effects of PC on lycopene and other carotenoids is their chemical structure. It was reported that lycopene absorption is about half that of ß-carotene (30,33). Therefore, differences in the solubility of PC-containing lipids with different chemical structures (e.g., with or without an annular structure) might be involved in the differences in absorption between ß-carotene and lycopene.
In contrast to lycopene, the lymphatic output of -tocopherol was decreased by the supply of SPC or EPC. There are several reports demonstrating that PC inhibits lymphatic absorption of -tocopherol (31,34–36) and that the inhibitory effect is abolished by the hydrolysis of PC to lysoPC (35). The presence of a large amount of intact PC in micelles, which increases lycopene absorption, may slow the transfer of -tocopherol from micelles to the intestinal epithelial cell and inhibit the cellular uptake of -tocopherol. Also, it was reported that the same mechanism is associated with the inhibitory effect of PC on cholesterol absorption (31).
The degree of the increase in lycopene absorption was higher than that for TG (Fig. 1A vs. 1B). In our previous study (21), we concluded that dietary PC increased lymphatic absorption of TG independent of emulsion and micelle formation or dissociation of micelles. However, these stages are important for the absorption of fat-soluble vitamins. We observed lower lycopene solubility in PC-containing soybean oil than in the oil without PC (data not shown). This poor solubilization may accelerate the removal of lycopene from the emulsion and micelles, and contribute to the enhancement of the lymphatic output of lycopene more than to that of TG. The high solubility of -tocopherol in PC (37,38) is possibly associated with the inhibition of -tocopherol release from micelles and the low lymphatic output by PC.
A possible mechanism for the promotion of lymphatic TG output by PC is the increase in the intestinal synthesis of apoproteins (apo). Other workers demonstrated that bile diversion reduces apo A-IV synthesis and output by the intestinal mucosa (39,40). Fujimoto et al. (41) showed that the lipid-induced increase in apo A-IV synthesis and secretion was inhibited by L-81. These results suggest that luminal lecithin enhances chylomicron formation through the intestinal synthesis of apoB-48 and apo A-IV, which may increase the lymphatic output of lycopene. However, the lymphatic output of -tocopherol did not increase. This result may be caused by the polarity of this compound. The polarity of lycopene is higher than that of -tocopherol; therefore, it is possible that lycopene is more easily incorporated into chylomicron constructed mainly with triglyceride.
In Expts. 2 and 3, rats were fed an emulsion containing either lycopene or -tocopherol alone. The changes in their absorption with supplementation of PC were similar to those in Expt. 1 (Figs. 2A and 3A); however, the amounts of lymphatic lycopene and -tocopherol output were clearly lower than those in Expt. 1 in spite of similar amounts of lymphatic TG output. Therefore, lycopene and -tocopherol may affect each other’s lymphatic output, according to their coexistence in the emulsion (42).
In the present study, there were significant differences in the effects of SPC and EPC on the absorption of lycopene. Several reports (15,43,44) showed that carotenoids are better absorbed from an oleic acid emulsion containing olive oil than from one containing PUFA-rich oils. Tso et al. (13) also demonstrated that fatty acids affect the absorption of -tocopherol and retinal, depending on their type and esterified position in TG. Our results concerning the differences in the effects of SPC and EPC on lycopene absorption agree with those earlier results.
The changes in lymphatic PL output were much smaller than those in TG (Figs. 1C and 1D), whereas total lymphatic output of PL in rats administered PC (SPC; 6.3 ± 1.6, EPC; 6.0 ± 1.5 µmol/4h in Expt. 1) tended to be higher than that in rats not given PC (SO; 4.2 ± 0.8 µmol/4h in Expt. 1, P = 0.498). This finding is consistent with those of previous studies showing that exogenous PL does not greatly influence the lymphatic output of PL (45). It was also reported that lysoPC is further hydrolyzed to fatty acids and glycerol 3-phosphocholine in the enterocytes. The major part of the fatty acids in PL may be incorporated into TG after absorption. The lack of a significant difference between groups in PL output may be due to the low recovery of PL in the lymph.
In conclusion, dietary PC largely increased the lymphatic output of lycopene, but somewhat decreased that of -tocopherol. Also, the promotive effect of PC on lycopene absorption was influenced by the type of PC. Our findings may be helpful in overcoming the very low availability of lycopene, a problem with this carotenoid, and in promoting the beneficial effects of lycopene as a fat-soluble antioxidant.
|
FOOTNOTES |
|---|
Manuscript received 26 January 2004. Initial review completed 19 February 2004. Revision accepted 21 May 2004.
|
LITERATURE CITED |
|---|
|
TOPABSTRACTMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
1. Batieha, A. M., Armenian, H. K., Norkus, E. P., Morris, J. S., Spate, V. E. & Comstock, G. W. (1993) Serum micronutrients and the subsequent risk of cervical cancer in a population-based nested case-control study. Cancer Epidemiol. Biomark. Prev. 2:335-339.[Abstract]
2. Giovannucci, E. (1999) Tomatoes, tomato-based products, lycopene, and cancer: review of the epidemiologic literature. J. Natl. Cancer Inst. 91:317-331.
3. Block, G., Patterson, B. & Subar, A. (1992) Fruit, vegetables, and cancer prevention: a review of the epidemiological evidence. Nutr. Cancer 18:1-29.[Medline]
4. Giovannucci, E., Ascherio, A., Rimm, E. B., Stampfer, M. J., Colditz, G. A. & Willett, W. C. (1995) Intake of carotenoids and retinol in relation to risk of prostate cancer. J. Natl. Cancer Inst. 87:1767-1776.
5. Snowdon, D. A., Gross, M. D. & Butler, S. M. (1996) Antioxidants and reduced functional capacity in the elderly: findings from the Nun Study. J. Gerontol. A Biol. Sci. Med. Sci. 51:M10-M16.[Abstract]
6. Korytko, P. J., Rodvold, K. A., Crowell, J. A., Stacewicz-Sapuntzakis, M., Diwadkar-Navsariwala, V., Bowen, P. E., Schalch, W. & Levine, B. S. (2003) Pharmacokinetics and tissue distribution of orally administered lycopene in male dogs. J. Nutr. 133:2788-2792.
7. Di Mascio, P., Kaiser, S. & Sies, H. (1989) Lycopene as the most efficient biological carotenoid singlet oxygen quencher. Arch. Biochem. Biophys. 274:532-538.[Medline]
8. Gaziano, J. M. (1996) Antioxidants in cardiovascular disease: randomized trials. Nutrition 12:583-588.[Medline]
9. Giovannucci, E. & Clinton, S. K. (1998) Tomatoes, lycopene, and prostate cancer. Proc. Soc. Exp. Biol. Med. 18:129-139.
10. Gartner, C., Stahl, W. & Sies, H. (1997) Lycopene is more bioavailable from tomato paste than from fresh tomatoes. Am. J. Clin. Nutr. 66:116-122.
11. Shiau, A., Mobarhan, S., Stacewicz-Sapuntzakis, M., Benya, R., Liao, Y., Ford, C., Bowen, P., Friedman, H. & Frommel, T. O. (1994) Assessment of the intestinal retention of beta-carotene in humans. J. Am. Coll. Nutr. 13:369-375.[Abstract]
12. Parker, R. S. (1996) Absorption, metabolism, and transport of carotenoids. FASEB J 10:542-551.[Abstract]
13. Tso, P., Lee, T. & DeMichele, S. J. (2001) Randomized structured triglycerides increase lymphatic absorption of tocopherol and retinol compared with the equivalent physical mixture in a rat model of fat malabsorption. J. Nutr. 131:2157-2163.
14. Clark, R. M. & Furr, H. C. (2001) Absorption of canthaxanthin by the rat is influenced by total lipid in the intestinal lumen. Lipids 36:473-475.[Medline]
15. Clark, R. M., Yao, L., She, L. & Furr, H. C. (2000) A comparison of lycopene and astaxanthin absorption from corn oil and olive oil emulsions. Lipids 35:803-806.[Medline]
16. Bierer, T. L., Merchen, N. R. & Erdman, J. W., Jr (1995) Comparative absorption and transport of five common carotenoids in preruminant calves. J. Nutr. 125:1569-1577.
17. Clark, R. M., Yao, L., She, L. & Furr, H. C. (1998) A comparison of lycopene and canthaxanthin absorption: using the rat to study the absorption of non-provitamin A carotenoids. Lipids 33:159-163.[Medline]
18. Diwadkar-Navsariwala, V., Novotny, J. A., Gustin, D. M., Sosman, J. A., Rodvold, K. A., Crowell, J. A., Stacewicz-Sapuntzakis, M. & Bowen, P. E. (2003) A physiological pharmacokinetic model describing the disposition of lycopene in healthy men. J. Lipid Res. 44:1927-1939.
19. Sies, H. & Stahl, W. (1995) Vitamins E and C, beta-carotene, and other carotenoids as antioxidants. Am. J. Clin. Nutr. 62:1315S-1321S.
20. Kayden, H. J. & Traber, M. G. (1993) Absorption, lipoprotein transport, and regulation of plasma concentrations of vitamin E in humans. J. Lipid Res. 34:343-358.[Medline]
21. Nishimukai, M., Hara, H. & Aoyama, Y. (2003) Enteral administration of soyabean lecithin enhanced lymphatic absorption of triglyceride in rats. Br. J. Nutr. 90:565-571.[Medline]
22. Tso, P., Kendrick, H., Balint, J. A. & Simmonds, W. J. (1981) Role of biliary phosphatidylcholine in the absorption and transport of dietary triolein in the rat. Gastroenterology 80:60-65.[Medline]
23. Mansbach, C. M., II & Dowell, R. F. (1993) Portal transport of long acyl chain lipids: effect of phosphatidylcholine and low infusion rates. Am. J. Physiol. 264:G1082-G1089.
24. Parlier, R. D., Frase, S. & Mansbach, C. M., II (1989) Intraenterocyte distribution of absorbed lipid and effects of phosphatidylcholine. Am. J. Physiol. 256:G349-G355.
25. Mansbach, C. M., II, Arnold, A. & Cox, M. A. (1985) Factors influencing triacylglycerol delivery into mesenteric lymph. Am. J. Physiol. 249:G642-G648.
26. Vahouny, G. V., Woo, C. H. & Treadwell, C. R. (1958) Quantitative effects of bile salt and fatty acid on cholesterol absorption in the rat. Am. J. Physiol. 193:41-46.
27. Mayne, S. T. (1996) Beta-carotene, carotenoids, and disease prevention in humans. FASEB J 10:690-701.[Abstract]
28. Bousvaros, A., Zurakowski, D., Duggan, C., Law, T., Rifai, N., Goldberg, N. E. & Leichtner, A. M. (1998) Vitamins A and E serum levels in children and young adults with inflammatory bowel disease: effect of disease activity. J. Pediatr. Gastroenterol. Nutr. 26:129-135.[Medline]
29. Baskaran, V., Sugawara, T. & Nagao, A. (2003) Phospholipids affect the intestinal absorption of carotenoids in mice. Lipids 38:705-711.[Medline]
30. Sugawara, T., Kushiro, M., Zhang, H., Nara, E., Ono, H. & Nagao, A. (2001) Lysophosphatidylcholine enhances carotenoid uptake from mixed micelles by Caco-2 human intestinal cells. J. Nutr. 131:2921-2927.
31. Homan, R. & Hamelehle, K. L. (1998) Phospholipase A2 relieves phosphatidylcholine inhibition of micellar cholesterol absorption and transport by human intestinal cell line Caco-2. J. Lipid Res. 39:1197-1209.
32. Ikeda, I., Matsuoka, R., Hamada, T., Mitsui, K., Imabayashi, S., Uchino, A., Sato, M., Kuwano, E., Itamura, T., Yamada, K., Tanaka, K. & Imaizumi, K. (2002) Cholesterol esterase accelerates intestinal cholesterol absorption. Biochim. Biophys. Acta 1571:34-44.[Medline]
33. Johnson, E. J., Qin, J., Krinsky, N. I. & Russell, R. M. (1997) Ingestion by men of a combined dose of beta-carotene and lycopene does not affect the absorption of beta-carotene but improves that of lycopene. J. Nutr. 127:1833-1837.
34. Noh, S. K. & Koo, S. I. (2001) Enteral infusion of phosphatidylcholine increases the lymphatic absorption of fat, but lowers alpha-tocopherol absorption in rats fed a low zinc diet. J. Nutr. Biochem. 12:330-337.[Medline]
35. Koo, S. I. & Noh, S. K. (2001) Phosphatidylcholine inhibits and lysophosphatidylcholine enhances the lymphatic absorption of -tocopherol in adult rats. J. Nutr. 131:717-722.
36. Noh, S. K. & Koo, S. I. (2003) Egg sphingomyelin lowers the lymphatic absorption of cholesterol and -tocopherol in rats. J. Nutr. 133:3571-3576.
37. Asai, Y. (2003) Dispersal technology for oil-soluble vitamins in aqueous medium using lecithin. Foods Food Ingredients J. Jpn. 208:513-520.
38. Asai, Y., Nomura, T. & Watanabe, S. (1999) Interaction of alpha-tocopherol and soybean oil with phosphatidylcholine and their formation of small dispersed particles. J. Colloid Interface Sci. 214:79-84.[Medline]
39. Davidson, N. O., Kollmer, M. E. & Glickman, R. M. (1986) Apolipoprotein B synthesis in rat small intestine: regulation by dietary triglyceride and biliary lipid. J. Lipid Res. 27:30-39.[Abstract]
40. Fukagawa, K., Gou, H. M., Wolf, R. & Tso, P. (1994) Circadian rhythm of serum and lymph apolipoprotein AIV in ad libitum-fed and fasted rats. Am. J. Physiol. 267:R1385-R1390.
41. Fujimoto, K., Cardelli, J. A. & Tso, P. (1992) Increased apolipoprotein A-IV in rat mesenteric lymph after lipid meal acts as a physiological signal for satiation. Am. J. Physiol. 262:G1002-G1006.
42. Wang, X. D., Marini, R. P., Hebuterne, X., Fox, J. G., Krinsky, N. I. & Russell, R. M. (1995) Vitamin E enhances the lymphatic transport of beta-carotene and its conversion to vitamin A in the ferret. Gastroenterology 108:719-726.[Medline]
43. Hollander, D. & Ruble, P. E., Jr (1978) beta-carotene intestinal absorption: bile, fatty acid, pH, and flow rate effects on transport. Am. J. Physiol. 235:E686-E691.
44. Lee, A., Thurnham, D. I. & Chopra, M. (2000) Consumption of tomato products with olive oil but not sunflower oil increases the antioxidant activity of plasma. Free Radic. Biol. Med. 29:1051-1055.[Medline]
45. Noh, S. K. & Koo, S. I. (1997) The lymphatic absorption of lipids is normalized by enteral phosphatidylcholine infusion in ovariectomized rats with estrogen replacement. J. Nutr. Biochem. 8:152-161.
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
