Site-specific differences in the fatty acid composition of abdominal adipose tissue in an obese population from a Mediterranean area: relation with dietary fatty acids, plasma lipid profile, serum insulin, and central obesity.

BACKGROUND: Abdominal obesity is associated with coronary risk, although causality is not well established. OBJECTIVE: In an obese Mediterranean population, we measured the fatty acid composition of adipose tissue, its relation with dietary fatty acids and central fat deposition, and its influence on plasma lipids and insulin. DESIGN: Adipose tissue samples were obtained from 84 obese patients (29 men, 55 women) aged 30-70 y (body mass index, in kg/m(2): 27-35). We measured concentrations of insulin and lipids in plasma and fatty acids in subcutaneous, omental, and perivisceral fat. Dietary fatty acid intake was assessed with a 7-d diet record. RESULTS: The population studied was normolipidemic and normoinsulinemic. There were important differences in fatty acid composition between tissue sites: saturated fatty acids were higher and monounsaturated fatty acids were lower in perivisceral than in subcutaneous fat (P < 0.05). Significant correlations were found for oleic, linoleic, alpha-linolenic, and total n-6 polyunsaturated fatty acids between the subject's habitual diet and adipose tissue composition. Oleic and n-3 fatty acids from adipose regions were negatively correlated with apolipoprotein B and triacylglycerols; adipose tissue 22:1n-9, 20:2n-6, stearic acid, and eicosapentaenoic acid were positively correlated with HDL and apolipoprotein A; and adipose tissue myristic acid was negatively correlated with apolipoprotein A (P < 0.05). Central obesity was positively associated with n-6 polyunsaturated fatty acids and inversely associated with monounsaturated fatty acids and n-3 polyunsaturated fatty acids in adipose tissue (P < 0.05). CONCLUSION: The differences found in the composition and metabolism of perivisceral, omental, and subcutaneous fats may indicate that their atherogenic capacities also differ.     

Adipose tissue biomarkers of fatty acid intake

BACKGROUND: Biomarkers can provide a more accurate measure of long-term intake than can dietary questionnaires. OBJECTIVE: The objective was to identify which adipose tissue fatty acids are suitable biomarkers of intake as assessed with a validated food-frequency questionnaire. DESIGN: Costa Rican men with a mean (+/- SD) age of 56 +/- 11 y (n = 367) and women aged 60 +/- 10 y (n = 136) completed a 135-item food-frequency questionnaire and provided an adipose tissue sample. Fifty fatty acids were identified by capillary gas chromatography. Correlation coefficients were calculated after adjustment for age, sex, body mass index, and smoking status. RESULTS: The best adipose tissue marker for total intake of saturated fatty acids was 15:0 + 17:0 (r = 0.18). Both 15:0 and 17:0 were also the best correlates of dairy product intake (r = 0.31 for each). The diet-adipose tissue correlations for n-3 fatty acids were r = 0.34 for 18:3, r = 0.15 for 20:5, and r = 0.18 for 22:6. Fish intake correlated significantly with these adipose tissue n-3 fatty acids. Dietary and adipose tissue n-6 fatty acids were highly correlated: 18:2 (r = 0.58) and 18:3 (r = 0.24). The best indicators of total trans fatty acid intake were ct18:2n-6 and tc18:2n-6 (r = 0.58 for each); total 18:1 trans fatty acid (r = 0.45) and 16:1 trans fatty acid (r = 0.16) were the next best indicators. CONCLUSIONS: Adipose tissue is a suitable biomarker of dietary fatty acid intake, particularly for n-3 and n-6 cis polyunsaturated fatty acids and trans fatty acids. Ideally, adipose tissue and dietary questionnaires should complement, rather than substitute for, each other in epidemiologic studies.     

Uptake of individual fatty acids into adipose tissue in relation to their presence in the diet

BACKGROUND: The fatty acid composition of adipose tissue triacylglycerol reflects, but is not identical to, the fatty acid composition of the habitual diet. OBJECTIVE: We investigated whether the fatty acid composition of adipose tissue is explained by differences between fatty acids in early storage in adipose tissue after a meal. DESIGN: Nine healthy men ate a meal containing several fatty acids. Blood samples were taken for 6 h after the meal from an arterialized hand vein and a vein draining the anterior abdominal subcutaneous adipose tissue. RESULTS: Net storage of fatty acids in adipose tissue occurred between 1 and 4 h after the meal. In relation to the amount fed, storage of fatty acids differed (P < 0. 01) between classes (n-3 polyunsaturated < saturated < n-6 polyunsaturated < monounsaturated); oleic acid was stored in the greatest amounts. These differences agreed closely with published data, except for n-3 polyunsaturated fatty acids. The only individual metabolic step at which significant differences between fatty acids was shown was incorporation of fatty acids into chylomicron triacylglycerol. Differences between fatty acids in rate of extraction from chylomicron triacylglycerol and net uptake into adipose tissue in the postprandial period were significant (P < 0. 01), but not when expressed in relation to proportions in chylomicron triacylglycerol. CONCLUSIONS: The characteristic fatty acid pattern of adipose tissue may predominantly reflect the early metabolic handling of different fatty acids. Adipose tissue uptake of n-3 polyunsaturated fatty acids is slow in relation to that of other fatty acids.     

Adipose tissue fatty acid composition and its relations to diet and plasma lipid concentrations in hemodialysis patients

Adipose tissue fatty acid composition, serum lipid profile, and dietary intake of 37 patients on maintenance hemodialysis were studied. In August 1982, 1984, and 1986, analyses were carried out in 15 normotriglyceridemic (NTG) and 22 hypertriglyceridemic (HTG; type IV hyperlipidemia) patients. No correlations were found between dietary intake of polyunsaturated fatty acids (PUFAs), ratio of polyunsaturated to saturated fatty acids (P-S ratio), and carbohydrate content on the one hand and serum lipid concentrations on the other in the two groups. Adipose tissue linolenic acid correlated negatively with serum cholesterol in both groups. Strong correlations were found between dietary intake of PUFAs and adipose tissue linoleic acid content, between PUFAs and the double-bond index, between P-S ratio and adipose tissue linoleic acid content, and between P-S ratio and the double-bond index. No significant differences in dietary intake or adipose tissue fatty acid composition were observed between NTG and HTG patients. Thus, no evidence was found for exogenous dietary influences on serum lipid concentrations. The adipose tissue linoleic acid content did reflect the dietary intake of PUFAs.     

Depression and long chain n-3 fatty acids in adipose tissue in adults from Crete

BACKGROUND: Only one study has investigated the relationship of essential fatty acids in the adipose tissue with depression in adults and suggested an inverse relationship between docosahexaenoic acid (22:6 n-3) (DHA) and depression. OBJECTIVE: To examine the relation between adipose tissue polyunsaturated fatty acids especially n-3 and n-6 fatty acids, an index of long-term or habitual fatty acid intake, and depression in adults. DESIGN: Cross-sectional study of healthy adults from the island of Crete. SETTING: The Preventive Medicine and Nutrition Clinic, University of Crete, Greece. SUBJECTS: A total of 130 healthy adults (59 males, 71 females) aged 22-58 years. The sample was a sub-sample of the Greek ApoEurope study group. METHODS: Fatty acids were determined by gas chromatography in adipose tissue. Information about depression was obtained through the Zung Self-rating Depression Scale. RESULTS: Adipose tissue DHA was inversely related with depression. Multiple linear regression analysis taking into account the possible confounding effect of age, gender, body mass index, smoking and educational level confirmed this association. CONCLUSIONS: The inverse relationship between adipose DHA and depression in adults, replicates findings of a previous study. This relationship indicates that a low long-term dietary intake of DHA is associated with an increased risk for depression in adults.     

Comparison between habitual intake of polyunsaturated fatty acids and their concentrations in serum lipid fractions

To evaluate the validity of the cross-check dietary history method for the assessment of the habitual intake of polyunsaturated fatty acids, the relationship was investigated between the estimated intake of these fatty acids and their relative amounts in the various serum lipid fractions. Food intake data were obtained from a group of volunteers participating in a long-term epidemiological study in the Dutch town of Zutphen. The fatty acid composition of total lipids, phospholipids, triglycerides and cholesterol esters was determined in fasting serum samples from these volunteers. Although correlations between the calculated dietary intake of timnodonic acid (20:5(n-3), TA) and cervonic acid (22:6(n-3), CA), on the one hand, and the relative amounts of these fatty acids in the various serum lipid fractions, on the other, appeared to be statistically significant, no more than about 20 per cent of the variance in the serum values could be explained on the basis of dietary intake. For linoleic acid (18:2(n-6), LA) this was 55 per cent. It is concluded that the cross-check dietary history method is an acceptable technique for estimating the habitual intake of linoleic acid of a given individual. For the fish-related fatty acids, however, this method is less reliable. This discrepancy most probably results from the large differences in TA and CA contents in the same foods. In addition, a negative association with the calculated LA intake on the proportional amount of TA for most of the serum lipid fractions was demonstrated. This indicates an interference of dietary LA on the metabolism of TA.     

Subcutaneous adipose-tissue fatty acids and vitamin E in humans: relation to diet and sampling site

The influence of diet and sampling site on subcutaneous adipose-tissue fatty acid composition and vitamin E content was examined in 20 healthy subjects. A dietary history and adipose-tissue biopsies from the buttock were obtained from 14 individuals. In another six individuals, samples were taken from both waist and buttock. The relative dietary intake of both polyunsaturated and saturated fatty acids correlated with the relative content in adipose tissue (r = 0.6, p = 0.02). Adipose-tissue vitamin E was strongly associated with dietary intake (r = 0.76, p = 0.004). The content of n - 3 (omega-3) fatty acids in adipose tissue was shown to influence adipose-tissue vitamin E negatively. Waist and buttock fat differed (p less than 0.05) with regard to fatty acid composition whereas no systematic variation was seen in the vitamin E content. The use of adipose-tissue biopsies in epidemiologic studies as measures of the habitual relative intake of fatty acids and vitamin E is suggested.     

Effects of dietary n-3 polyunsaturated fatty acids, breed and dietary vitamin E on the fatty acids of lamb muscle, liver and adipose tissue

The effect of feeding n-3 PUFA on the fatty acid composition of muscle, adipose tissue and liver of lambs was investigated. Groups of eight ram lambs per breed, SuffolkxLleyn (24 kg live weight) and Scottish Blackface (18 kg live weight), were each fed one of six diets containing one of three fat sources (50 g fatty acids/kg DM; Megalac((R)) (calcium soap of palm fatty acid distillate; Volac Ltd, Royston, Herts., UK) and formaldehyde-treated whole linseed (Trouw Nutrition UK, Northwich, Ches., UK) either alone or with fish oil (1:1, w/w) and either 100 or 500 mg alpha-tocopheryl acetate/kg DM. Feed was offered ad libitum until slaughter at approximately half breed mature live weight. The type of dietary fat had no effect on intake, growth rate or feed conversion ratio. The 3.0-fold higher concentration of 18 : 3n-3 in the linseed compared with the Megalac((R)) diet approximately doubled (P<0.001) the concentration in the neutral and polar lipid fractions of musculus semimembranosus and liver, and in adipose tissue it increased 2.5-fold. Feeding protected linseed also increased (P<0.001) concentrations of 20 : 5n-3 and 22 : 5n-3 in muscle polar lipids and both lipid fractions of liver. The linseed-fish oil raised the 20 : 5n-3 concentrations above those for the linseed diet and also increased 22 : 6n-3. Scottish Blackface lambs had lower concentrations of 18 : 3n-3 in all lipids compared with Suffolk x Lleyn lambs, but more 20 : 5n-3 in the polar lipids of muscle and liver. High levels of dietary vitamin E were associated with small decreases in the concentration of monounsaturated fatty acids and increases in PUFA. Linseed raised the PUFA : saturated fatty acid ratios in liver and adipose tissue but not in muscle, and improved the n-6 : n-3 fatty acid ratio, as did the linseed-fish oil. Different combinations of dietary fatty acids and better protection against rumen biohydrogenation are required to improve muscle PUFA : saturated fatty acids ratios.     

不同膳食脂肪酸对大鼠乳腺癌组织脂肪酸组成和脂代谢基因表达的影响

目的探讨不同膳食脂肪酸组成影响大鼠乳腺癌发生、发展的可能分子机制。方法用8种不同膳食脂肪酸组成(SFA、MUFA、n-6PUFA、n-3PUFA、1∶1n-6/n-3、5∶1n-6/n-3、10∶1n-6/n-3、1∶2∶1S/M/P其中n-6/n-31∶1)喂养SD雌性大鼠,并在大鼠乳腺癌模型的基础上,用气相色谱内标法观察大鼠乳腺组织脂肪酸组成改变,RT-PCR分析组织脂代谢调控基因(FAS、COX-2和5-LOX)的表达。结果在不同膳食脂肪酸构成中,只有1∶1n-6/n-3能有效抑制大鼠乳腺癌的发生。不同膳食脂肪酸构成可导致大鼠乳腺组织脂肪酸组成发生相应变化,且各组间的脂肪酸含量有显著差异。高乳腺癌诱发的SFA、MUFA、n-6PUFA、5∶1n-6/n-3、10∶1n-6/n-3和1∶2∶1S/M/P喂养组乳腺组织含有较多的C18∶1、C18∶2和C20∶4,而EPA和DHA含量极少。无或低乳腺癌诱发的n-3PUFA和1∶1n-6/n-3喂养组乳腺组织EPA和DHA明显增多,C20∶4含量显著减少。RT-PCR结果显示1∶1n-6/n-3低诱癌组较相应对喂组上调FAS、COX-2和5-LOXmRNA表达力度明显弱于其它高乳腺癌诱发组。结论不同膳食脂肪酸组成能明显改变大鼠乳腺组织脂肪酸组成,进而影响脂代谢基因FAS、COX-2和5-LOX表达,可能是大鼠乳腺癌发生的分子机制之一。     

Influence of dietary intake of energy and carbohydrate on the proportion of saturated and monounsaturated fatty acids in adipose tissue of middle aged men

The fatty acid composition of subcutaneous tissue has been determined in a population sample of apparently healthy middle aged men from Southern Italy. Dietary appraisal has been carried out by evaluating the usual pattern of food consumption during the year preceding the interview. The whole population sample was subdivided into three tertiles on the basis of the energy intake by the different individuals. The proportion of adipose tissue polyunsaturated fatty acids was relatively low in the high energy tertile III and high in the low energy tertile reflecting parallel differences in the intake of polyunsaturated fatty acids. The percentage of monounsaturated fatty acids (mainly oleic acid) was relatively high (p less than 0.01) and that of saturated fatty acids (mainly palmitic acid) relatively low (p less than 0.05) in the high energy tertile (III) as compared to the low energy tertile (I); these differences were independent of the amount and type of dietary fatty acids. Total energy was positively correlated (r = .87, p less than 0.01) to carbohydrate intake (g/day). Dietary carbohydrates (g/day) were inversely related to adipose tissue saturated fatty acids (r = -.40, p less than 0.001) and directly correlated to adipose tissue monounsaturated fatty acids (p = .40, p less than 0.001). Carbohydrate intake was related to adipose tissue monounsaturated and saturated fatty acids independently of daily energy intake. On the other hand when the influence of dietary carbohydrates was eliminated, no correlation was detectable any longer between energy intake and adipose tissue fatty acids.(ABSTRACT TRUNCATED AT 250 WORDS)     

Fatty acid composition of subcutaneous adipose tissue and diet in postmenopausal US women

The distributions of fatty acids in subcutaneous-adipose-tissue aspirates and their relation to intake as assessed by a semiquantitative food-frequency questionnaire were investigated in 115 postmenopausal US women free from cancer. Percentages of fatty acids in adipose tissue were significantly correlated with the percentage of total fat intake for polyunsaturated fatty acids (Spearman correlation = 0.37), n-3 fatty acids of marine origin (Spearman correlation = 0.48), and trans fatty acids (Spearman correlation = 0.51) but not for saturated and monounsaturated fatty acids. Correlations were somewhat stronger in 78 women with stable weight over the 6 mo before fat aspiration. These data suggest that intakes of polyunsaturated fatty acids, including n-3 fatty acids, and trans fatty acids are reflected in the adipose tissue but that intakes of saturated and monounsaturated fatty acids are not. The data also provide further support for the validity of the food-frequency questionnaire in the assessment of fat intake.     

Comparison of adipose tissue fatty acids with dietary fatty acids as measured by 24-hour recall and food frequency questionnaire in Black and White Adventists: the Adventist Health Study

PURPOSE: To calibrate and compare intake of different fats and individual fatty acids as assessed with a food frequency questionnaire (FFQ) against that estimated with (i) a series of dietary recalls and; (ii) the relative fat concentration in an adipose tissue biopsy. The FFQ was specially designed for use in a cohort of Seventh-day Adventists. In preparation for a large cohort study investigating the effect of diet on risk of colon, prostate and breast cancer. METHODS: The association of adipose tissue fatty acids and dietary fat intake was assessed in 49 black and 72 white Seventh-day Adventists subjects using 8 different 24-hour recalls, a 200-item food frequency questionnaire (FFQ) and adipose tissue biopsies from each subject. RESULTS: Pearson correlation between fatty acids in adipose tissue and dietary intake as assessed by multiple 24-hour recalls were as follows: Linoleic acid: 0.77 in black and 0.71 in white subjects, respectively; Linolenic acid: 0.68 (blacks) and 0.62 (whites); Total Polyunsaturated fat (PUFA): 0.78 (blacks) and 0.70 (whites); Total Monounsaturated fat (MUFA): 0.35 (blacks) and 0.03 (whites); Total Saturated fat (SFA): 0.46 (blacks) and 0.56 (whites). Correlations between fatty acids in adipose tissue and dietary intake as assessed by FFQ were: Linoleic acid: 0.61 (blacks) and 0.52 (whites), respectively; Linolenic acid: 0.29 (blacks) and 0.49 (whites); PUFA: 0.62 (blacks) and 0.53 (whites); MUFA: 0.07 (blacks) and 0.31 (whites), SFA: 0.21 (blacks) and 0.31 (whites). CONCLUSIONS: Our study confirms findings of others that 24-hour recalls are valid for assessing dietary intake of different types of fat. The FFQ we developed and used in this study gave reasonably valid measures of fatty acid intake in our population and is thus suitable for use in large cohort studies. It had validity comparable to that observed for other FFQs.     

Relationship of diet to the fatty acid composition of human adipose tissue structural and stored lipids

The habitual intake of 20 healthy free-living subjects was determined by two 7-day food records. Documented fatty acid intakes were utilized to examine the influence of fatty acid intake on fatty acid composition of stored and structural lipids in subcutaneous adipose tissue. Subjects with higher intakes of saturated fatty acids exhibited increased levels of total saturated fatty acids and decreased polyunsaturated fatty acids in adipose tissue triglycerides (p less than 0.01). The dietary P/S ratio was significantly related to the saturated and polyunsaturated content of stored lipids. In the phospholipid fraction, relationships were found between dietary C18:2(6) and the P/S ratio of phosphatidylcholine (p less than 0.05). The essential fatty acid content of the two phospholipids studied was related to the dietary fats consumed. Relationships were identified between major fatty acids in the triglyceride and phospholipid fraction. Although diet was found to relate to fatty acid composition, the structural lipids in human adipose tissue appear more resistant to compositional change than stored triglycerides.     

Evaluation of a food frequency questionnaire with weighed records, fatty acids, and alpha-tocopherol in adipose tissue and serum.

The authors examined the validity of a self-administered 180-item food frequency questionnaire in 125 Norwegian men aged 20-55 years who filled in the questionnaire and completed 14-day weighed records in fall 1995 to winter 1995/6. Spearman correlation coefficients between the two measurements ranged from 0.42 for percent of energy from fat to 0.66 for sugar intake (median r = 0.51). On average, 39% of the men were classified in the same quartile with the two methods, and 3% in the opposite quartile. Correlation coefficients between intake of fatty acids estimated from the questionnaire and the relative amounts of fatty acids in adipose tissue were: linoleic acid (18:2, n-6), r = 0.38; alpha-linolenic acid (18:3, n-3), r = 0.42; eicosapentaenoic acid (20:5, n-3), r = 0.52; and docosahexaenoic acid (22:6, n-3), r = 0.49. The correlations for these fatty acids between the total serum lipids and the diet were 0.16, 0.28, 0.51 and 0.52, respectively. The data suggest that very-long-chain n-3 fatty acids in adipose tissue and total serum lipids reflect the dietary intake of very-long-chain n-3 fatty acids to the same degree. No associations were observed between intake of alpha-tocopherol and concentration in adipose tissue and serum.     

Long-chain n-3-to-n-6 polyunsaturated fatty acid ratios in breast adipose tissue from women with and without breast cancer

Animal studies suggest that dietary polyunsaturated fatty acids (PUFAs) of the n-6 class, found in corn and safflower oils, may be precursors of intermediates involved in the development of mammary tumors, whereas long-chain (LC) n-3 PUFAs, found in fish oil, can inhibit these effects. This case-control study was designed to examine the relationship between the PUFA composition of breast adipose tissue and the risk of breast cancer. Using fatty acid levels in breast adipose tissue as a biomarker of past qualitative dietary intake of fatty acids, we examined the hypothesis that breast cancer risk is negatively associated with specific LC n-3 PUFAs (eicosapentaenoic acid and docosahexaenoic acid) and positively associated with n-6 PUFAs (linoleic acid and arachidonic acid). Breast adipose tissue was collected from 73 breast cancer patients and 74 controls with macromastia. The fatty acid levels were determined by gas-liquid chromatography. A logistic regression model was used to obtain odds ratio estimates while adjusting for age. The age-adjusted n-6 PUFA (linoleic acid and arachidonic acid) content was significantly higher in cases than in controls (P = 0.02). There was a trend in the age-adjusted data suggesting that, at a given level of n-6 PUFA, LC n-3 PUFAs (eicosapentaenoic acid and docosahexaenoic acid) may have a protective effect (P = 0.06). A similar inverse relationship was observed with LC n-3-to-n-6 ratio when the data were adjusted for age (P = 0.09). We conclude that total n-6 PUFAs may be contributing to the high risk of breast cancer in the United States and that LC n-3 PUFAs, derived from fish oils, may have a protective effect.     

Effect of placental function on fatty acid requirements during pregnancy

The fetus has an absolute requirement for the n-3/n-6 fatty acids and docosahexaenoic acid (22:6 n-3; DHA) in particular is essential for the development of the brain and retina. Most of the fat deposition in the fetus occurs in the last 10 weeks of pregnancy. The likely rate of DHA utilisation during late pregnancy cannot be met from dietary sources alone in a significant proportion of mothers. De novo synthesis makes up some of the shortfall but the available evidence suggests that the maternal adipose tissue makes a significant contribution to placental transport to the fetus. The placenta plays a crucial role in mobilising the maternal adipose tissue and actively concentrating and channelling the important n-3/n-6 fatty acids to the fetus via multiple mechanisms including selective uptake by the syncytiotrophoblast, intracellular metabolic channelling, and selective export to the fetal circulation. These mechanisms protect the fetus against low long-chain polyunsaturated fatty acid (LCPUFA) intakes in the last trimester of pregnancy and have the effect of reducing the maternal dietary requirement for preformed DHA at this time. As a result of these adaptations, small changes in the composition of the habitual maternal diet before pregnancy are likely to be more effective in improving LCPUFA delivery to the fetus than large dietary changes in late pregnancy. There is little evidence that DHA intake/status in the second half of pregnancy affects visual and cognitive function in the offspring, but more studies are needed, particularly in children born to vegetarian and vegan and mothers who may have very low intakes of DHA.     

Tocotrienol levels in adipose tissue of benign and malignant breast lumps in patients in Malaysia

Data on dietary exposure to vitamin E by plasma or adipose tissue concentrations of alpha-tocopherol (alpha-T) in observational studies have failed to provide consistent support for the idea that alpha-T provides women with any protection from breast cancer. In contrast, studies indicate that alpha, gamma, and delta-tocotrienols but not alpha-T have potent anti-proliferative effects in human breast cancer cells. Our aim was to investigate whether there was a difference in tocopherol and tocotrienol concentrations in malignant and benign adipose tissue, in a Malaysian population consuming predominantly a palm oil diet. The study was undertaken using fatty acid levels in breast adipose tissue as a biomarker of qualitative dietary intake of fatty acids. The major fatty acids in breast adipose tissue of patients (benign and malignant) were oleic acid (45-46%), palmitic (28-29%) and linoleic (11-12%). No differences were evident in the fatty acid composition of the two groups. There was a significant difference (p=0.006) in the total tocotrienol levels between malignant (13.7 +/- 6.0 microg/g) and benign (20+/-6.0 microg/g) adipose tissue samples. However, no significant differences were seen in the total tocopherol levels (p=0.42) in the two groups. The study reveals that dietary intake influences adipose tissue fatty acid levels and that adipose tissue is a dynamic reservoir of fat soluble nutrients. The higher adipose tissue concentrations of tocotrienols in benign patients provide support for the idea that tocotrienols may provide protection against breast cancer.     

Differences in adipose tissue fatty acid composition between black and white men in New Orleans

We report fatty acid composition in perirenal and buttock adipose tissue in 714 deceased black and white men aged 25-44 yr in New Orleans. Percent saturated fatty acids were higher (p less than 0.001) whereas percent monounsaturated fatty acids were lower (p less than 0.001) in perirenal than in buttock fat. Percent linoleic acid was similar in both races. We conclude that dietary intake of linoleic acid is similar in both races. The trend of decreasing linoleic acid with advancing age suggests that either intake of linoleic acid progressively decreases or its mobilization rate increasingly exceeds deposition rate or both. Percent palmitoleic acid (16:1) is lower (p less than 0.001) and that of stearic acid (18:0) is higher (p less than 0.001) in blacks than in whites. We believe no explanation can rest solely on differences in habitual dietary fat intake.     

Single measurement of serum phospholipid fatty acid as a biomarker of specific fatty acid intake in middle-aged Japanese men

OBJECTIVE: To assess the utility of serum phospholipid fatty acid (FA) levels as a biochemical indicator of habitual dietary fatty acid intake in Japanese, whose diet is characterized by low fat intake and high intake of n-3 polyunsaturated fatty acids (PUFA) of marine origin. SUBJECTS AND METHODS: Eighty-seven male volunteers from four public health center districts that were part of the Japan Public Health Center based Prospective Study (JPHC Study) cohort I, were included in this study. Habitual intake of fatty acid was obtained by 7 day weighed dietary records four times (in one area only twice) in 1994--1995. Blood was collected twice, in February and August of the same year, and the composition of FA in serum phospholipid was analyzed by gas chromatography. The correlation coefficient between serum phospholipid FA levels and fatty acid intake was calculated. RESULTS: High correlations were observed for eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA), which are marine origin n-3 PUFA (r=0.75, 0.49, 0.50, respectively). No significant correlation was observed for saturated fatty acid (SFA), although the monounsaturated fatty acid (MUFA), palmitoleic acid and oleic acid intake were moderately correlated (r=0.22, 0.35, respectively). The correlations for EPA, DPA and DHA were similar in both samples collected in February and August. CONCLUSIONS: These data suggest that in populations with a high and stable over time intake of n-3 PUFA of marine origin, a single measurement of serum phospholipids reflects the ranking of habitual intake of marine origin n-3 PUFA.     

Are the n-3 fatty acids from dietary fish oil deposited in the triglyceride stores of adipose tissue?

Adipose tissue is the chief reservoir of the essential fatty acids (n-3 and n-6). To study the incorporation of the dietary n-3 fatty acids eicosapentaenoic acid (EPA) (20:5) and docosahexaenoic acid (DHA) (22:6), and a unique monounsaturated fatty acid, cetoleic acid (22:1n-11), into adipose tissue, rabbits were fed two different processed fish oils: MaxEPA (high in EPA and DHA; Seven Sea Ltd, Hull, UK) and herring oil (high in cetoleic acid). EPA and DHA increased from 0% of total adipose tissue fatty acid, in the adipose tissue of control rabbits to 2.2% and 4.9%, respectively, in MaxEPA-fed rabbits. The DHA-to-EPA ratio in the adipose tissue was higher than that in the diet, indicating alternative metabolic pathways for EPA. In the adipose tissue of herring-oil-fed rabbits, cetoleic acid increased from 0% to 7.9% of total fatty acids. The deposition of EPA and DHA was 1.8% and 2.8%, respectively. Our data indicated that these unique long-chain unsaturated fatty acids from dietary fish oils were readily incorporated into the fat stores from whence they could be mobilized.