symposium Flashcards
how much of our diet is fat
diet and exercise modify risk of arterial disease (endothelium dysfunction)
95% dietary fat is triacylglycerol
Fatty acids (saturated, monounsaturated or polyunsaturated) and glycerol
Dietary fat and formation of lipid profile
Consists of a range of fatty acids
how does fat interact with the liver
liver>VLDL>LPL>IDL(back to liver)or>LPL>LDL>LIVER
Adipose tissue and muscle>FFA>LPL(SI>Chylomicron>LPL)>Chylomicron remnant>LIVER
what is saturated fatty acid intake associated with
with increased CHD risk
Dietary fats and fatty acids are complex – not one answer as to their CHD risk
Meta analysis reaffirms guidance to reduce
how do fatty acids vary
Different individual fatty acids, such as odd or even saturated or short, medium, long saturated fatty acids have different metabolic pathways.
Eg Extra virgin coconut oil promoted to healthy oil, main saturated fatty acid is lauric acid
Butter, palm oil and animal fat, main saturated fatty acids are palmitic acid
what are polyunsaturated fatty acids
omega 3
ALA-EPA-DHA>minimally inflammatory and inflammation resolving
omega 6
LA-AA>pro inflammatory
what is omega 3
Long chain PUFA, EPA and DHA acid derived from oily fish
Shorter chain PUFA can act as a EPA precursor
Health benefits of omega 3 are associated with anti inflammatory responses ans decreased expression of genes involved in inflammatory and atherogenesis related pathways
Recent review = increasing DHA/EPA had little effect on cardiovascular death, coronary death or events, stroke or heart irregularities.
what is omega 6
Linoleic acid
Main dietary sources include corn oil, intakes of omega 6 have exceeded saturated fats in recent years
Metabolised to form AA which is considered pro inflammatory
LA in adipose tissue, but also in platelets, is positively associated with CAD
what is the CVD risk of LA
Opposing views Arguments for reduction Reduced TC and LDL Argument for increased risk Increases susceptibility of LDL and other lipoproteins to oxidation Increases small dense LDL Reduce HDL Increase TGs
what are dietary carbs
Dietary carbs include non starch polysaccharides, starch polysaccharides, disaccharides and monosaccharides
From these only three sugars are absorbed glucose, galactose and fructose
how do carbs link to lipid profile
Low carb fashionable – type 2 diabetes remissions
Short term impact on reducing wight, insulin resistance, HbA1c and TG profile
But long term, heterogenous in nature with no definition for low carbs
how do carbs affect diet
Reduction in dietary intake of fat = inc intake of carbs,
decreases total LDL (but increases small dense LDL so greater atherogenesis)
A down reg of insulin response due to continued stimulation from higher carbs = lipolysis
Increases a greater delivery of fatty acids and an increase in hepatic esterification over production of VLDL, particularly TG-rich VLDL1
Carbs hepatic synthesis of VLDL and reduction in HDL
how do fruits and veg affect diet
Diets higher in vegetables and fruits commonly associated with a reduction in CVD risk
Soluble fibre in plants shown to decrease serum cholesterol by inhibiting reabsorption in GI tract
Consumption improves antioxidant status by improving plasma total antioxidant capacity and glutathione peroxidase activity in healthy young adults
Primary emphasis on improving lipid profile
Increase low calorie fruit and vegetable intake to at least 5 portions a day
what are dietary patterns
Increased interest in pattern as opposed to single nutrients of food groups
Study on Mediterranean diet without energy restriction on CVD risk
USA DASH eating plan with no special foods just nutritional goals (fruit, veg, whole grains including fat-free/low fat dairy, fish, poultry, beans, nuts and veg oils and limiting food in high saturated fat like meats, full fat dairy and tropical oils, also limiting sugar)
what did the PREDIMED and DASH studies find about diet
PREDIMED (Mediterranean)
1 year randomised control trial of those at high CVD risk
Reduced ambulatory bp, fasting blood glucose and total cholesterol
DASH
Compared to control diet
Lowered BP, total cholesterol (LDL and HDL)
what is obesity
Weight gain associated with energy intake being greater than energy expenditure
Excess energy intake leads to obesity
Reducing energy intake and increasing exercise can lessen
Fat tissue provides a source of FFA in circulation providing fatty acids for metabolism
Visceral adipose tissue is less responsive to insulin and delivers FFA to circulation (inc ROS, inhibit NO, activate RAS, induce adiposis)
