Zinc Affects Cholesterol Oxidation Products and Fatty Acids Composition in Rats' Serum.

The purpose of this work was to evaluate the effect of the nanosized or microsized zinc (Zn) particles on fatty acid profile, enzyme activity and the level of cholesterol, squalene and oxysterols in rats with breast cancer. Rats (female, n = 24) were divided into the following groups: control, and two test groups, whose diets were enriched with either Zn microparticles (342 nm) or Zn nanoparticles (99 nm). All rats were treated twice with the carcinogenic agent; 7,12-dimethylbenz[a]anthracene. In rats whose diet was enriched with zinc (especially in the form of nanoparticles), the number and sizes of tumors were lower. Diet supplementation also significantly reduced the cholesterol (p = 0.027) and COPs (cholesterol oxidation products) levels (p = 0.011) in rats serum. Enriching the diet with Zn microparticles decreased the Δ6-desaturase activity (p < 0.001). Zn influences fatty acids' profile in rats' serum as well as inhibiting desaturating enzymes. A reduced amount of pro-inflammatory arachidonic acid derivatives may be the expected effect.

Plasma phospholipid fatty acid biomarkers of dietary fat quality and endogenous metabolism predict coronary heart disease risk: a nested case-control study within the Women's Health Initiative observational study.

BACKGROUND: Although the relationship between dietary fat quality and coronary heart disease (CHD) risk has been evaluated, typically using diet questionnaires, results are inconsistent and data in postmenopausal women are limited. Plasma phospholipid fatty acid (PL-FA) profiles, reflecting dietary intake and endogenous FA metabolism, may better predict diet-CHD risk. METHODS AND RESULTS: Using a nested case-control design, we assessed the association between plasma PL-FA profiles and CHD risk in 2448 postmenopausal women (1224 cases with confirmed CHD and 1224 controls matched for age, enrollment date, race/ethnicity, and absence of CHD at baseline and after 4.5 years of follow-up) participating in the Women's Health Initiative observational study. PL-FA profile was measured using gas chromatography. Product/precursor ratios were used to estimate stearoyl-CoA-desaturase (16:1n-7/16:0, 18:1n-9/18:0), Δ6-desaturase (20:3n-6/18:2n-6), and Δ5-desaturase (20:4n-6/20:3n-6) activities, indicators of endogenous FA metabolism. Multivariate conditional logistic regression was used to obtain odds ratios (95% CIs) for CHD risk. While no associations were observed for the predominant PL fatty acid (16:0, 18:0, 18:1n-9, and 18:2n-6), plasma PL-saturated fatty acid (1.20 [1.08 to 1.32]) and endogenously synthesized PL ω6 fatty acids (20:3n-6; 3.22 [1.95 to 5.32]), 22:5n-6; 1.63 [1.20 to 2.23]) and Δ6-desaturase (1.25 [1.11 to 1.41]) were positively associated with CHD risk. PL-ω3 fatty acids (20:5n-3; 0.73 [0.58 to 0.93], 22:5n-3; 0.56 [0.33 to 0.94], 22:6n-3; 0.56 [0.39 to 0.80]), 18:1n-7 (0.54 [0.29 to 0.99]), and Δ5-desaturase (0.78 [0.70 to 0.88]) were inversely associated with CHD risk. Results support current guidelines regarding regular fish consumption. Additional findings include associations between endogenously synthesized fatty acids and CHD risk, which were partly explained by changes in Δ6-desaturase and Δ5-desaturase indexes, suggesting that in vivo metabolism may also play an important role in predicting CHD risk in this cohort of postmenopausal women. CLINICAL TRIAL REGISTRATION URL: http://ClinicalTrials.gov, Unique identifier: NCT01864122.

Erythrocyte n-3 polyunsaturated fatty acids and the risk of type 2 diabetes in Koreans: a case-control study.

BACKGROUND: There is inconsistent epidemiologic evidence for an association between tissue levels of n-3 polyunsaturated fatty acids (PUFAs) and the risk of type 2 diabetes. The purpose of the present study was to investigate whether erythrocyte levels of n-3 PUFAs are negatively associated with the risk of type 2 diabetes and correlated with levels of glucose and HbA1c in Koreans. METHODS: A total of 130 patients with type 2 diabetes and 260 age- and sex-matched controls participated in this study. RESULTS: The risk of type 2 diabetes was negatively associated with erythrocyte levels of 22:5n3 and 22:6n3, which were negatively correlated with HbA1c levels after adjusting for age, sex and body mass index. Additionally, the risk of type 2 diabetes was negatively associated with erythrocyte levels of 18:0 and 20:4n6, but positively associated with erythrocyte levels of 16:0, 18:1n9, 18:3n3, 18:2n6, 18:3n6, n-6/n-3 PUFA ratio, 18:1t and 18:2n6t, and Δ-6 desaturase (18:3n6/18:2n6) and Δ-9 desaturase (18:1n9/18:0) activities. CONCLUSIONS: The risk of type 2 diabetes was negatively associated with erythrocyte levels of n-3 PUFA, which were negatively correlated with HbA1c levels in Koreans, suggesting that n-3 PUFAs might reduce the risk of type 2 diabetes in Asians.

High levels of stearic acid, palmitoleic acid, and dihomo-γ-linolenic acid and low levels of linoleic acid in serum cholesterol ester are associated with high insulin resistance.

The association of fatty acid composition with insulin resistance and type 2 diabetes has been reported in Western populations, but there is limited evidence of this association among the Japanese, whose populace consume large amounts of fish. To test the hypothesis that high palmitic, palmitoleic, and dihomo-γ-linolenic acids and low levels of linoleic and n-3 fatty acids are associated with higher insulin resistance among the Japanese, the authors investigated the relationship between serum fatty acid composition and serum C-peptide concentrations in 437 Japanese employees aged 21 to 67 years who participated in a workplace health examination. Serum cholesterol ester and phospholipid fatty acid compositions were measured by gas-liquid chromatography. Desaturase activity was estimated by fatty acid product-to-precursor ratios. A multiple regression was used to assess the association between fatty acid and C-peptide concentrations. C-peptide concentrations were associated inversely with linoleic acid levels in cholesterol ester and phospholipid (P for trend = .01 and .02, respectively) and positively with stearic and palmitoleic acids in cholesterol ester (P for trend =.02 and .006, respectively) and dihomo-γ-linolenic acid in cholesterol ester and phospholipid (P for trend < .0001 for both). C-peptide concentrations were not associated with n-3 polyunsaturated fatty acids. C-peptide concentrations significantly increased as δ-9-desaturase (16:1 n-7/16:0) and δ-6-desaturase (18:3 n-6/18:2 n-6) increased (P for trend = .01 and .03, respectively) and δ-5-desaturase (20:4 n-6/20:3 n-6) decreased (P for trend = .004). In conclusion, a fatty acid pattern with high levels of serum stearic, palmitoleic, or dihomo-γ-linolenic acids; δ-9-desaturase (16:1 n-7/16:0) or δ-6-desaturase (18:3 n-6/18:2 n-6) activities; and low levels of serum linoleic acid or δ-5-desaturase (20:4 n-6/20:3 n-6) activity might be associated with higher insulin resistance in Japanese adults.

Diet and gene expression: delta-5 and delta-6 desaturases in healthy Chinese and European subjects.

AIM: To compare the composition of fatty acids (FAs) in diet, and the expression of delta-6 desaturase (D6D) and delta-5 desaturase (D5D) genes in peripheral blood mononuclear cells (PBMCs) between Chinese and Europeans. METHODS: Three-day dietary records from 20 subjects from Beijing, China (n = 10) and Kent, UK (n = 10) were analysed. Expression of PBMC D6D and D5D genes of the subjects was determined using RT-PCR. RESULTS: The dietary intake of Chinese subjects contained less saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs), but more essential fatty acids (EFAs) than that of Europeans. Levels of expression of PBMC D6D and D5D genes of Chinese subjects were significantly lower than those of Europeans. A significant positive correlation was found between dietary intake of total SFAs and total MUFAs and expression of PBMC D6D and D5D genes, but a significant negative correlation between dietary intake of linoleic acid (LA) and alpha-linolenic acid (LNA) and the expression of PBMC D6D and D5D genes. CONCLUSION: Intake of high SFAs and MUFAs appears to increase expression of PBMC D6D and D5D genes, whilst high EFAs intake appears to decrease expression of PBMC D6D and D5D genes. A follow-up study of the expression of D6D and D5D genes in Chinese who live in European countries with high SFA and MUFA diets would be of interest.