Fatty Acids Cheat-Sheet:
Saturated:
Long Chain
Palmitic - primary saturated fatty acid in most diets - high in beef or pork fat but low in vegetable oils - increases LDL and HDL, little effect on the ratio of Total Cholesterol to HDL
Stearic - primarily found in beef or pork fat and in small amounts in vegetable oils - does not increase LDL - believed to be rapidly converted to a monounsaturated fatty acid after absorption
Medium Chain (don't require carnitine to cross mitochondrial membrane - more likely to be used as an energy substrate than for storage)
Lauric - greatly increases total cholesterol, moreso increasing HDL than LDL
Myristic - increases serum total cholesterol, both LDL/HDL - not a large % of fatty acid intake - doesn't effect TC:HDL much
Short Chain
butyric, propanoic acid - not generally found in the human diet, except from fermentation of fibers in the gut - potential preventative role in colon cancer
Monounsaturated:
contains 1 cis double bond - shown to lower LDL cholesterol and leaves HDL unchanged
ω−7 (non-essential)
Palmitoleic - minor fatty acid in the diet - major source is macadamia nuts - mixed data for cholesterol effects - depends on current cholesterol status, whether it is ingested in the diet or endogenously produced - of little concern with low intakes
Vaccenic - precursor to conjugated linoleic acid - potential heart health benefits - isomer of oleic acid - trans fatty acid
ω−9 (non-essential)
Oleic - lowers LDL - large constituent of 'Mediterranean diets' (olive oil)- thought to be antiatherogenic -
Polyunsaturated:
ω−3
A-Linolenic (ALA) - essential fatty acid - precursor to EPA and DHA - similar effect on cholesterol levels as monounsaturated fats - also shown to inhibit vascular inflammation - found in plant foods, such as flax/chia/hemp/soy
Stearidonic (SDA) - more efficiently converted to EPA than ALA is - not a large part of the diet, found in fish oils and non common plant sources like echium - current studies show little effect on TC, HDL, LDL or TGs - shown to alter lipogenic gene expression and reduce expression of CRP - soy is currently being genetically modified to produce SDA from its ALA
Eicosapentaenoic (EPA) - precursor to DHA - substantially lowers triglycerides levels when consumed alongside DHA, at least 2g/day - Isolated EPA not shown to increase LDL
Docosahexaenoic (DHA) - increases HDL slightly more than EPA, most isolated trials show increases in LDL cholesterol - significant decreases in serum TGs >2g/day
ω−6
Linoleic - essential fatty acid - precursor to Arachidonic Acid, substrate for prostaglandins and thromboxanes - lowers LDL cholesterol- low, if any effect, on HDL
Gamma-Linolenic - significantly decreases plasma TGs, increases HDL - shown to reduce serum thromboxane and potentially increase vascular prostacyclin production - said to be anti-atherogenic - found in borage and primrose oils
Trans:
produced from the hydrogenation of unsaturated cis fatty acids - most unsat cis fatty acids become saturated but a fraction is converted into trans fatty acids - shown to raise LDL and lower HDL compared to other fatty acids
Some occur naturally, like conjugated linoleic acid, and don't appear to be atherogenic
References:
http://ajcn.nutrition.org/content/77/5/1146.full
http://www.ncbi.nlm.nih.gov/pubmed/7695873
http://ajcn.nutrition.org/content/60/6/986S.abstract
http://www.nrcresearchpress.com/doi/abs/10.1139/H09-079#.UlyX8SSpY7A
http://onlinelibrary.wiley.com/doi/10.1002/ejlt.201100187/pdf
http://www.ncbi.nlm.nih.gov/pubmed/15983523
http://europepmc.org/abstract/MED/10443051
http://ajcn.nutrition.org/content/53/5/1230.abstract
http://jn.nutrition.org/content/134/11/2991
Whelan et al, Effects of Dietary Stearidonic Acid on Biomarkers of Lipid Metabolism, 2012. The Journal of Nutrition
http://ajcn.nutrition.org/content/71/5/1085.full
http://www.lipidjournal.com/article/S1933-2874%2811%2900745-8/abstract
http://ajcn.nutrition.org/content/53/3/660.short
http://www.ncbi.nlm.nih.gov/pubmed/7846101
Saturated:
Long Chain
Palmitic - primary saturated fatty acid in most diets - high in beef or pork fat but low in vegetable oils - increases LDL and HDL, little effect on the ratio of Total Cholesterol to HDL
Stearic - primarily found in beef or pork fat and in small amounts in vegetable oils - does not increase LDL - believed to be rapidly converted to a monounsaturated fatty acid after absorption
Medium Chain (don't require carnitine to cross mitochondrial membrane - more likely to be used as an energy substrate than for storage)
Lauric - greatly increases total cholesterol, moreso increasing HDL than LDL
Myristic - increases serum total cholesterol, both LDL/HDL - not a large % of fatty acid intake - doesn't effect TC:HDL much
Short Chain
butyric, propanoic acid - not generally found in the human diet, except from fermentation of fibers in the gut - potential preventative role in colon cancer
Monounsaturated:
contains 1 cis double bond - shown to lower LDL cholesterol and leaves HDL unchanged
ω−7 (non-essential)
Palmitoleic - minor fatty acid in the diet - major source is macadamia nuts - mixed data for cholesterol effects - depends on current cholesterol status, whether it is ingested in the diet or endogenously produced - of little concern with low intakes
Vaccenic - precursor to conjugated linoleic acid - potential heart health benefits - isomer of oleic acid - trans fatty acid
ω−9 (non-essential)
Oleic - lowers LDL - large constituent of 'Mediterranean diets' (olive oil)- thought to be antiatherogenic -
Polyunsaturated:
ω−3
A-Linolenic (ALA) - essential fatty acid - precursor to EPA and DHA - similar effect on cholesterol levels as monounsaturated fats - also shown to inhibit vascular inflammation - found in plant foods, such as flax/chia/hemp/soy
Stearidonic (SDA) - more efficiently converted to EPA than ALA is - not a large part of the diet, found in fish oils and non common plant sources like echium - current studies show little effect on TC, HDL, LDL or TGs - shown to alter lipogenic gene expression and reduce expression of CRP - soy is currently being genetically modified to produce SDA from its ALA
Eicosapentaenoic (EPA) - precursor to DHA - substantially lowers triglycerides levels when consumed alongside DHA, at least 2g/day - Isolated EPA not shown to increase LDL
Docosahexaenoic (DHA) - increases HDL slightly more than EPA, most isolated trials show increases in LDL cholesterol - significant decreases in serum TGs >2g/day
ω−6
Linoleic - essential fatty acid - precursor to Arachidonic Acid, substrate for prostaglandins and thromboxanes - lowers LDL cholesterol- low, if any effect, on HDL
Gamma-Linolenic - significantly decreases plasma TGs, increases HDL - shown to reduce serum thromboxane and potentially increase vascular prostacyclin production - said to be anti-atherogenic - found in borage and primrose oils
Trans:
produced from the hydrogenation of unsaturated cis fatty acids - most unsat cis fatty acids become saturated but a fraction is converted into trans fatty acids - shown to raise LDL and lower HDL compared to other fatty acids
Some occur naturally, like conjugated linoleic acid, and don't appear to be atherogenic
References:
http://ajcn.nutrition.org/content/77/5/1146.full
http://www.ncbi.nlm.nih.gov/pubmed/7695873
http://ajcn.nutrition.org/content/60/6/986S.abstract
http://www.nrcresearchpress.com/doi/abs/10.1139/H09-079#.UlyX8SSpY7A
http://onlinelibrary.wiley.com/doi/10.1002/ejlt.201100187/pdf
http://www.ncbi.nlm.nih.gov/pubmed/15983523
http://europepmc.org/abstract/MED/10443051
http://ajcn.nutrition.org/content/53/5/1230.abstract
http://jn.nutrition.org/content/134/11/2991
Whelan et al, Effects of Dietary Stearidonic Acid on Biomarkers of Lipid Metabolism, 2012. The Journal of Nutrition
http://ajcn.nutrition.org/content/71/5/1085.full
http://www.lipidjournal.com/article/S1933-2874%2811%2900745-8/abstract
http://ajcn.nutrition.org/content/53/3/660.short
http://www.ncbi.nlm.nih.gov/pubmed/7846101
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