The Scientific Basis of Medicine
John S. Axford, Chris A. O'Callaghan in Medicine for Finals and Beyond, 2023
The structural units of lipids are fatty acids, containing long chains of 4–24 carbon atoms joined to a carboxylic acid group (Figure 2.4). Fatty acids may be saturated or non-saturated depending on the presence of double bonds within their hydrocarbon tail. Polyunsaturated fatty acids contain multiple double bonds. One of the most important in vivo functions performed by lipids is the formation of cellular membranes. Phospholipids contain a hydrophilic phosphate group, linked by glycerol to a hydrophobic fatty acid tail. The amphipathic nature of phospholipids allows them to form a sealed membrane bilayer in aqueous solution. Another physiologically important group of lipids are the cholesterol derivatives (steroids). These molecules contain four hydrocarbon rings, one of which carries a hydroxyl group which gives the molecule an amphipathic nature.
Dyslipidemia
Jahangir Moini, Matthew Adams, Anthony LoGalbo in Complications of Diabetes Mellitus, 2022
Secondary causes of dyslipidemia are common in adults. In developed countries, a sedentary lifestyle with excessive intake of total calories, cholesterol, saturated fat, and trans fats is the main cause. Trans fats are monounsaturated or polyunsaturated fatty acids with hydrogen atoms added. Trans fats were previously used in a variety of processed foods, and caused as much atherogenesis as saturated fats. The first country to ban trans fats was Denmark (in 2003). Other countries followed, including Norway, Iceland, Hungary, Austria, and Switzerland. In 2015, the U.S. Food and Drug Administration began steps to remove artificial trans fats in processed foods. As of January 1, 2020, full compliance had to be met. Manufacturers can no longer legally add partially hydrogenated fats (PHOs) to foods – they are the major source of artificial trans fats. The World Health Organization estimates that trans fats will be banned worldwide by 2023. Additional secondary causes of dyslipidemia include diabetes mellitus, alcohol overuse, chronic kidney disease, hypothyroidism, and cholestatic liver diseases such as primary biliary cirrhosis. Also, many drugs can cause dyslipidemia. These include beta-blockers, thiazides, highly active antiretroviral agents, retinoids, cyclosporine, estrogen, progestins, tacrolimus, and glucocorticoids. Low HDL cholesterol can be caused by anabolic steroids, cigarette smoking, HIV infection, and nephrotic syndrome.
Consumption of Foods, Food Groups, and Cardiometabolic Risk
Nathalie Bergeron, Patty W. Siri-Tarino, George A. Bray, Ronald M. Krauss in Nutrition and Cardiometabolic Health, 2017
Traditionally, the cardioprotective effect of fish has been explained by the rich amounts of polyunsaturated fatty acids (PUFA) found in fish, especially omega-3 fatty acids such as eicosapentaenoic and docosahexaenoic acid. As discussed further in Chapter 10, the physiological benefits of these fatty acids are numerous and act through various molecular pathways to lower inflammation and maintain vascular function (Mozaffarian and Wu 2011). Furthermore, various studies have indicated that omega-3 fatty acids decrease the risk of cardiac arrest, reduce blood pressure, improve the lipid profile, and decrease platelet aggregation (Dyerberg et al. 1978, Kris-Etherton et al. 2002, Nestel 1990, Siscovick et al. 1995). Nonetheless, Rizos et al. (2012) concluded in a meta-analysis of 20 clinical trials of 68,680 patients that fish oil supplementation conferred no significant benefit for total CVD, CVD subtypes, or all-cause mortality. Similarly, Chowdhury et al. (2012) found a significant protective effect of fish in epidemiologic studies, but no benefit of omega-3 supplementation in randomized trials.
A systematic review and meta-analysis of the omega-3 fatty acids effects on brain-derived neurotrophic factor (BDNF)
Published in Nutritional Neuroscience, 2023
Somayeh Ziaei, Shooka Mohammadi, Motahareh Hasani, Mehrnaz Morvaridi, Andrej Belančić, Elnaz Daneshzad, Saleh A. K. Saleh, Heba M. Adly, Javad Heshmati
Omega-3 polyunsaturated fatty acids (omega-3 FAs) refer to a group of fatty acids distinguished by having multiple carbon–carbon double bonds in their chemical structure, with the initial double bond situated on the third carbon atom counting from the end methyl group [1, 2]. They are found in fish, seafood, vegetable oils, nuts, and seeds [3]. The effects of omega-3 FAs have been investigated in clinical and experimental studies. These fatty acids exert beneficial effects on cardiovascular disease, cancer, diabetes, periodontal disease, rheumatoid arthritis, cognitive disorders, depression, and mental illnesses [4]. It is reported that omega-3 FAs such as Docosahexaenoic acid (DHA) have neuroprotective effects in the brain. While there is limited documentation regarding how they function, certain studies indicate that omega-3 FAs have an effect on the levels of brain-derived neurotrophic factor (BDNF) in the central nervous system [5–7].
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].
Dietary supplement use in younger and older men exercising at gyms in Cape Town
Published in South African Journal of Clinical Nutrition, 2021
Marjanne Senekal, Shelly Meltzer, Anri Horne, Nicole CG Abrey, Lauren Papenfus, Stefan van der Merwe, Norman J Temple
The results show that MAIO supplements were commonly used by younger and older men, specifically multi-vitamins, vitamin C, B vitamins, calcium, and omega-3 fatty acids. Both age groups reported that general health was the main reason for use of these supplements, although approximately a fifth of the younger men also indicated sport/exercise performance as their reason. The one noteworthy difference between the two age groups was that older men were more than twice as likely to use omega-3 fatty acids. These fatty acids are promoted for reduction in risk of cardiovascular disease, cancer and cognitive decline.27,28 The only ergogenic aid for which use was significantly higher in the older group was glucosamine. This supplement was included in the ergogenic aid group as it has been suggested as a treatment for cartilage damage in athletes.29 The very low use of glucosamine by younger men and the fact that older men seemed to use it for protection of joints may indicate that glucosamine is not generally perceived to have ergogenic properties, but is rather used as a supplement for ageing individuals for joint protection.
Related Knowledge Centers
- Biochemistry
- Carboxylic Acid
- Chemistry
- Cholesteryl Ester
- Diet
- Ester
- Phospholipid
- Aliphatic Compound
- Branched-Chain Fatty Acid
- Triglyceride