- Title
- Differential effects of saturated fatty acids of varying chain length on lipid profiles in healthy individuals
- Creator
- Panth, Nisha
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2019
- Description
- Masters Research - Master of Philosophy (MPhil)
- Description
- Saturated fatty acid (SFA) intake has been linked with increased blood lipid concentrations and increased cardiovascular disease (CVD) risk. Current dietary guidelines consider all SFA as a single group and encourage to reduce saturated fat consumption to 10% of daily energy intake. However, not only the number, position and configuration of double bonds, but also the chain length of SFA have been shown to be a major determinant of their metabolic fate. Short-chain (SCFA, 2-4 carbons long, found in butter and products of fibre and resistant starch fermentation) and medium-chain (MCFAS, 6-12 carbons long, found in coconut and palm kernel oil) are absorbed directly through the villi of the intestinal mucosa and transported to the liver via the portal circulation. In contrast, long-chain (LCSFAS, >12 carbons, found in animal fats and dairy products) follow complex metabolic pathways including chylomicron synthesis in the intestinal villi, secretion into the thoracic lymph, hydrolysis of some triglycerides by lipoprotein lipase into free fatty acids which are transferred to the peripheral tissues (including muscle) followed by chylomicron remnants being taken up into the liver for further metabolism. This, together with the fact that humans spend most of their time in the postprandial state, suggests that saturated fat type may play an important role in overall lipid metabolism and modulation of CVD risk. Therefore, it was hypothesised that consumption of SCFA and MCFAS reduce blood lipid levels compared with LCSFAS. Our first aim, addressed in chapter 3, was to to establish the basis for our hypothesis, conducting systematic review and meta analysis of the literature assessing the differential effects of chain lengths of SFA on blood lipids. The findings from this chapter demonstrate that the consumption of MCFAS enriched diets increased high-density lipoprotein cholesterol (HDL-C) and apolipoprotein A-I (apo A-I) levels compared to LCSFAS diet without any significant effect on triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) and total cholesterol (TC) levels. In chapter 4, we aimed to determine if SFA of different chain lengths would differentially influence postprandial lipid levels. In a randomised cross-over design, we investigated the effect of a meal (sweet biscuits) rich in either SCFA or MCFAS or LCSFAS on postprandial lipids (TG, TC, LDL-C, and HDL-C). The results presented in this chapter demonstrate that the postprandial triglyceride response following MCFAS was lower compared to LCSFAS and that predominant fatty acid in the meal is a determinant of the lipemic response. In conclusion, while this study has highlighted the differential effects of chain lengths of SFA on blood lipids. These results draw attention to the evidence that guidelines on SFA must consider the fatty acid chain length and importantly, the diverse SFA containing foods (processed and unprocessed meats, dairy products, eggs, coconut and palm oils, chocolate) that may possess harmful, neutral or even beneficial effects in relation to cardiovascular health.
- Subject
- adults; saturated fatty acid; medium-chain fatty acid; long-chain saturated fatty acid; coconut oil; palm oil; blood lipids; cholesterol; cardiovascular disease
- Identifier
- http://hdl.handle.net/1959.13/1406167
- Identifier
- uon:35600
- Rights
- Copyright 2019 Nisha Panth
- Language
- eng
- Full Text
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| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | ATTACHMENT01 | Thesis | 1 MB | Adobe Acrobat PDF | View Details Download | ||
| View Details Download | ATTACHMENT02 | Abstract | 264 KB | Adobe Acrobat PDF | View Details Download |