Fat and Cholesterol
Maria A. Fiatarone Singh, John Sutton Chair in Exercise, Nutrition, and the Older Woman, 2000
As noted above, the presence of a cis or trans double bond impacts the conformation of the fatty acid acyl chains. Trans fatty acids occur naturally in dairy fat and meat. They result from the fermentation in ruminant animals such as cows. Additionally, trans fatty acids are also formed during the hydrogenation of fat, a process used to transform oil from a liquid to semi-solid state. The conversion of cis to trans double bonds results in a fatty acid with a straighter conformation, more similar to a saturated fatty acid. Hydrogenated fat is used to make margarines and vegetable shortenings (for home use and in the preparation of commercially baked and fried foods). Similar to saturated fatty acids, trans fatty acids have been associated with elevated plasma cholesterol levels.
Epidemiology and health policy
Sol Levine, Abraham M. Lilienfeld in Epidemiology and Health Policy, 1987
The problem of unintended consequences is further illustrated by current difficulties in producing foods to implement nutrition policy. Most dietary policy has recommended (a) a decrease in dietary saturated fat and cholesterol and (b) the substitution of polyunsaturated fat for saturated fat. The second recommendation has led to tremendous growth in the vegetable oil and margarine industries. While the cholesterol lowering effects of vegetable oils is well known, this desired effect may not have occurred in people consuming the actual products manufactured by this burgeoning industry due to unanticipated effects of the hydrogenation process. Hydrogenation is used in industrial processing of vegetable oils to improve appearance, taste, and texture. This process reduces the amount of linoleic acid and generates trans fatty acids. Linoleic acid is the principal essential fatty acid responsible for the cholesterol lowering effect of vegetable oils. Further, although the data are conflicting, trans fatty acids may raise serum cholesterol.
Nutrition and Type-1 Diabetes Mellitus
Jeffrey I. Mechanick, Elise M. Brett in Nutritional Strategies for the Diabetic & Prediabetic Patient, 2006
The majority of studies related to the health effects of fat intake in patients with diabetes have been performed in subjects with type-2 diabetes mellitus (T2DM). In one study involving patients with T1DM, lipid profiles improved (lower low-density lipoprotein [LDL], lower very low-density lipoprotein [VLDL]) following a diet high in monounsaturated fatty acids (MUFA) (43–46% carbohydrate, 37–40% fat, 17–20% MUFA) compared with a high-carbohydrate, low-fat diet (54–57% carbohydrate, 27–30% fat, 10–13% MUFA) [43]. An earlier study showed higher circulating postprandial atherogenic lipoproteins after a high-MUFA (40% fat, 45% carbohydrate) vs. a high-carbohydrate diet (24% fat vs. 61% carbohydrate) [44]. Omega-3 fatty acids have been shown to decrease cholesterol ester transfer protein, and therefore the potential atherogenicity of LDL particles, in patients with T1DM [45]. The American Diabetes Association (ADA) recommends that patients with diabetes limit their intake of saturated fats to < 10% of energy and limit dietary intake of cholesterol to 300 mg/day [46]. Further restrictions to < 7% saturated fat and 200 mg/day of cholesterol are recommended if the patient’s LDL is >100 mg/dL [46]. Trans-fatty acids should also be minimized to avoid increases in LDL and decreases in high-density lipoprotein (HDL). Current recommendations for fat intake do not distinguish between patients with T1DM vs. T2DM.
The association between serum fatty acids and pregnancy in PCOS women undergoing ovulation induction
Published in Gynecological Endocrinology, 2022
Mingyue Li, Ye Tian, Yonghuan Lv, Yanping Xu, Xiaohong Bai, Huijuan Zhang, Yanxia Wang, Xueru Song
Fatty acids, which provide an essential energy resource, are crucial to reproduction as they affect ovulation and embryo quality [4]. Depending on molecular structure, fatty acids are classified as saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), and polyunsaturated fatty acids (PUFAs). According to the position of the first carbon double bond from methyl carbon, unsaturated fatty acids are divided into n – 3, n – 6, n – 7, and n – 9 series. According to the different spatial structure of fatty acids, unsaturated fatty acids are divided into cis fatty acids and trans-fatty acids (TFAs). Studies of the relationship between fatty acids and reproductive diseases have received increasing attention. However, the influence of different types of fatty acids on reproductive diseases is still controversial. Although most studies suggest that supplementing n – 3 PUFAs, such as eicosapentaenoic acid (EPA), could significantly improve hyperandrogenism, obesity, chronic inflammation, and oocyte quality [5] as well as have beneficial effects on pregnancy achievement in PCOS patients [6]. An retrospective study of 1228 women attempting pregnancy found that a higher level of serum total PUFAs was associated with lower probability of pregnancy [7].
Fatty acid metabolism in the host and commensal bacteria for the control of intestinal immune responses and diseases
Published in Gut Microbes, 2020
Koji Hosomi, Hiroshi Kiyono, Jun Kunisawa
Lipid metabolism by bacteria also generates several fatty acid metabolites, such as conjugated fatty acids and trans-fatty acids that are biologically active and affect host functions (Figure 3). For example, conjugated linoleic acid is now recognized as a beneficial fatty acid metabolite and is used widely as a functional food.41 Dietary intake of conjugated linoleic acid shows beneficial effects, including reduced body fat42,43 and prevention of diabetes,44 colitis,45 atherosclerosis,46 and cancer.47 As an underlying mechanism, conjugated linoleic acid is a potent agonist of peroxisome proliferator-activated receptor (PPAR)-α and increases catabolism of lipids in liver. In addition, conjugated linoleic acid modulates macrophage function and induces anti-inflammatory M2 macrophages in a PPAR-γ-dependent manner. Similarly, conjugated α-linolenic acid is produced in the intestine and possesses several bioactivities. For example, jacaric acid, an isomer of conjugated α-linolenic acid, shows antitumor48 and anti-obesity49 effects. Conversely, consumption of trans-fatty acids increases the risk of coronary heart disease by increasing low-density lipoprotein cholesterol and reducing high-density lipoprotein cholesterol levels.50 Therefore, trans-fatty acids are thought to be harmful for health.
Plasma Fatty Acids as Surrogate for Prostate Levels
Published in Nutrition and Cancer, 2018
Jeannette M. Schenk, Xiaoling Song, Colm Morrissey, Robert L. Vessella, Daniel W. Lin, Marian L. Neuhouser
Table 1 gives mean prostate tissue PLFA profiles from specimens ≤ 20 mg and > 20 mg. Mean PUFA concentrations in tissue specimens ≤ 20 mg were nearly identical to those in specimens > 20 mg. Correlations of PUFA concentrations from specimens ≤ 20 mg and > 20 mg ranged from 0.10 to 0.99 (Table 1). Correlations between tissue specimens of varying size were strongest for ω-3 fatty acids, ranging from 0.67 for ALA to 0.95 for total omega-3 and 0.99 for EPA. For selected trans-fatty acid concentrations, correlations between specimens ≤ 20 mg and > 20 mg varied substantially, ranging from 0.10 for trans-18:2, to 0.83 for trans-18:1. Correlations for individual omega-6 fatty acid concentrations were moderate (0.51 to 0.72), although still statistically significant. The magnitude of Pearson and age-adjusted Pearson correlations was comparable.
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