Serum and biliary lipid pattern in rabbits feeding a diet enriched with unsaturated fatty acids

Informatics for Nutritional Genetics and Genomics

While traditional nutrition science is focusing on nourishing population, modern nutrition is aiming at benefiting individual people. The goal of modern nutritional research is to promote health, prevent diseases, and improve performance. With the development of modern technologies like bioinformatics, metabolomics, and molecular genetics, this goal is becoming more attainable. In this chapter, we will discuss the new concepts and technologies especially in informatics and molecular genetics and genomics, and how they have been implemented to change the nutrition science and lead to the emergence of new branches like nutrigenomics, nutrigenetics, and nutritional metabolomics.

Feeding a thermally oxidised fat inhibits atherosclerotic plaque formation in the aortic root of LDL receptor-deficient mice

Activators of PPARα have been demonstrated to inhibit atherosclerosis development due to lipid lowering in plasma and direct protective effects on the vasculature. Because dietary oxidised fats (OF) have strong PPARα-activating and lipid-lowering properties, we hypothesised that dietary OF has also an inhibitory influence on atherosclerosis development. To verify our hypothesis, we investigated the effect of feeding diets containing an OF (a 92 : 8 mixture of heated (170°C, 48 h) hydrogenated palm fat and fresh sunflower oil) compared with a fresh fat (fresh hydrogenated palm fat) on the development of atherosclerotic lesions in LDL receptor-deficient (LDLR- / - ) mice. We observed that a dietary OF caused a strong up-regulation of PPARα-regulated genes in the liver and a marked reduction in plasma concentrations of cholesterol and TAG (P < 0·05). Cross-sectional lesion area and the lipids and collagen levels in the aortic root were approximately 40-50 % lower in mice fed diets containing OF than in those fed diets containing fresh fat (P < 0·05). Immunohistochemical analysis of aortic root sections revealed an about 8-fold increased expression of PPARα and a markedly reduced expression of the proinflammatory vascular cell adhesion molecule-1 and smooth muscle cell (SMC)-specific marker α-actin in LDLR- / - mice fed OF (P < 0·05). We postulate that OF exert anti-atherogenic effects by activation of PPARα both in the liver, which contributes to lipid lowering in plasma, and in the vasculature, which inhibits pro-atherogenic events such as monocyte recruitment and SMC proliferation and migration.

Lipid peroxidation, oxidative stress genes and dietary factors in breast cancer protection: a hypothesis

We have recently proposed that lipid peroxidation may be a common mechanistic pathway by which obesity and hypertension lead to increased renal cell cancer risk. During this exercise, we noted a risk factor swap between breast and kidney cancer (oophorectomy and increased parity, detrimental for kidney, beneficial for breast; high blood pressure, detrimental for kidney, beneficial for breast when it occurs during pregnancy; alcohol, beneficial for kidney, detrimental for breast, and so on). We have subsequently proposed the hypothesis that lipid peroxidation represents a protective mechanism in breast cancer, and reviewed the evidence of the role of lipid peroxidation on established hormonal and non-hormonal factors for breast cancer. Here, we review the evidence in support of lipid peroxidation playing a role in the relationships between dietary factors and breast cancer. Available evidence implicates increased lipid peroxidation products in the anti-carcinogenic effect of suspected protective factors for breast cancer, including soy, marine n-3 fatty acids, green tea, isothiocyanates, and vitamin D and calcium. We also review the epidemiological evidence supporting a modifying effect of oxidative stress genes in dietary factor-breast cancer relationships.

Role of Lipid Peroxidation in the Epidemiology and Prevention of Breast Cancer

We have recently proposed a common mechanistic pathway by which obesity and hypertension lead to increased renal cell cancer risk. Our hypothesis posits lipid peroxidation, which is a principal mechanism in rodent renal carcinogenesis, as an intermediate step that leads to a final common pathway shared by numerous observed risks (including obesity, hypertension, smoking, oophorectomy/hysterectomy, parity, preeclampsia, diabetes, and analgesics) or protective factors (including oral contraceptive use and alcohol) for renal cell cancer [Cancer Causes Control 2002;13:287-93]. During this exercise, we have noticed how certain risk factors for renal cell carcinoma are protective for breast cancer and how certain protective factors for renal cell carcinoma increase risk for breast cancer. Parity and oophorectomy, for example, are positively associated with renal cell carcinoma but are negatively associated with breast cancer. Similarly, obesity and hypertension are positively associated with renal cell carcinoma, but obesity is negatively associated with breast cancer in premenopausal women and hypertension during pregnancy is negatively associated with breast cancer. Furthermore, alcohol intake, negatively associated with renal cell carcinoma, is also positively associated with breast cancer. We propose here the possibility that lipid peroxidation may represent a protective mechanism in breast cancer. Although this runs counter to the conventional view that lipid peroxidation is a process that is harmful and carcinogenic, we present here the chemical and biological rationale, based on epidemiologic and biochemical data, which may deserve further consideration and investigation.

Thermally oxidized dietary fats increase the susceptibility of rat LDL to lipid peroxidation but not their uptake by macrophages

The aim of this study was to investigate the effect of dietary oxidized fats on the lipoprotein profile and the atherogenicity of LDL. Two experiments with male Sprague-Dawley rats were conducted. In Experiment 1, diets with either fresh fat or oxidized fat, prepared by heating at temperatures of 50, 105 or 190 degrees C, containing either 25 or 250 mg alpha-tocopherol equivalents/kg were used. In Experiment 2, diets with fresh or oxidized fat, heated at a temperature of 55 degrees C, containing 25 mg alpha-tocopherol equivalents/kg, were used. In Experiment 1, rats fed all types of oxidized fats had higher concentrations of HDL cholesterol and lower ratios between plasma and HDL cholesterol than rats fed the diet containing the fresh fat. As determined from the lag time, the susceptibility of LDL to copper-induced lipid peroxidation was higher in rats fed oxidized fats heated at 105 or 190 degrees C than in rats fed the diets containing the fresh fat or the oxidized fat treated at 50 degrees C, irrespective of the dietary vitamin E concentration. However, in Experiment 2, the composition of LDL apolipoproteins and uptake of LDL by macrophages were not different between rats fed the fresh fat diet and those fed the oxidized fat diet. We conclude that ingestion of oxidized fats does not adversely affect the lipoprotein profile in the rat model used, and does not cause modifications of apolipoproteins that would lead to enhanced uptake of LDL via macrophage scavenger receptors.

Oxidized fatty acids promote atherosclerosis only in the presence of dietary cholesterol in low-density lipoprotein receptor knockout mice

Studies suggest that heated oils contribute to the presence of oxidized components in the circulating lipoproteins and to the development of atherosclerosis in animals. We evaluated the effects of 11-13 wk of consumption of a well defined dietary oxidized fatty acid, 13-hydroxylinoleic acid (13-HODE) (8 mg), on atherosclerotic lesion development and plasma cholesterol concentrations in mice fed diets varying in fat and cholesterol contents. LDL receptor knockout mice were used in two feeding studies. In study 1, oxidized fatty acid consumption in association with a high fat diet increased aortic lesion areas by >100% (P < 0.05). Surprisingly, oxidized fatty acid intake also tended to increase plasma total cholesterol (P = 0.12) and LDL cholesterol (P < 0.05) as well as oxidative stress as measured by higher levels of autoantibodies to oxidatively modified proteins (P = 0.008). However, in mice fed a nonpurified diet, oxidized fatty acids were not atherogenic and may even have been beneficial, as indicated by a lower plasma triglyceride (TG) concentration (P < 0.05). In study 2, mice were fed either a high fat, medium fat or low fat diet to evaluate whether the increase in aortic lesions due to oxidized fatty acid consumption in study 1 was a result of the associated higher plasma total and LDL cholesterol concentrations. In study 2, 13-HODE-treated mice in the medium and low fat diet groups but not those fed the high fat diet had larger atherosclerotic lesions (P < 0.05). Additionally, plasma total and LDL cholesterol as well as TG were not affected by HODE treatment. However, the total cholesterol:HDL cholesterol ratio was higher in treated mice (P < 0.05) and HDL cholesterol was lower in HODE-treated mice that were fed the low fat diet (P < 0.05). Our results suggest that, in mice fed cholesterol, oxidized fatty acids may be atherogenic, both in terms of increased oxidative stress (as seen in study 1) and by increasing the atherogenicity of the plasma cholesterol profile.

Changes by progesterone derivatives in fatty acids from phosphatidylcholine and phosphatidylethanolamine fractions in rat liver endoplasmic reticulum

The effects of two progesterone metabolites on fatty acid composition of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) from total liver and liver microsomes were studied in female rats. 16 alpha-Hydroxyprogesterone significantly increased the amount of fatty acids esterified to PC and PE fractions in total liver and liver microsomes. Both saturated and unsaturated fatty acyl components were enhanced. In contrast, 5 beta-pregnan-3 alpha-ol-20-one caused a reduction of fatty acids bound to PC and PE fractions from total liver and liver microsomes. Pregnanolone decreased both saturated and unsaturated fatty acids. Changes in specific fatty acids occurred in palmitic and stearic acids among saturated components, and palmitoleic, oleic, linoleic, eicosatrienoic, arachidonic and docosahexenoic acids among unsaturated ones. The unsaturated: saturated fatty acid ratio was raised by 16-alpha-hydroxyprogesterone and lowered by 5 beta-pregnan-3 alpha-ol-20-one in all phospholipid fractions. The induction of drug metabolizing enzymes by 16 alpha-hydroxyprogesterone may be related to an enhanced synthesis of microsomal phospholipids containing unsaturated fatty acids, particularly arachidonic and docosahexenoic acids. In contrast, the inhibition of drug metabolism by 5 beta-pregnan-3 alpha-ol-20-one is associated with reduced formation of unsaturated fatty acyl side chains.