Saturated Fat

 The villainization of saturated fat is an appalling one that marks (in my opinion) the ultimate failure in nutrition as a science, and is a main marker of how nutrition is no longer a science (if it ever was) but a game of politics and money. It is stupid at best and dangerous at worst. I've tried rationalizing how saturated fat became the victim and I've figured it out...

How Saturated Fat Became The Enemy In One Act:

Some guy: "I wonder what people should less of/more of to stay healthy?"

Ancel Keys: "I've wondered the same thing but my data from my recent study is rather inconclusive."

Some guy: "Well that's a bummer..."

Ancel Keys: "Hey I know! Let's close our eyes and point at a list of suspects and whatever we point at will be the one that is detrimental to health and  I'll spin my analysis, review, data set, and conclusion to show this."

Some guy: "OK!!"

Ancel closes his eyes and plummets his finder down. It lands right in between saturated fat and sugar.

Ancel Keys: "Hmmmm..."

Enter John Yudkin. Audience applauds

John Yudkin: "Well the answer is obvious isn't it Ancel? It is sugar. All prior evidence shows this and your study also shows this if we look at all countries that you have data for."

Ancel Keys: "Yeah... but it can't be sugar, I mean veggies and fruit have sugar and they are the healthiest thing for you... besides saturated fat looks nasty."

John Yudkin: "Is fruit really that good for you though?"

Ancel Keys: "HERETIC!!! SPAWN OF SATAN!!! GET OUT OF HERE THIS INSTANT!!! I'LL BE SURE TO RUIN YOU FOR THAT!!!

John Yudkin is escorted out.

Ancel Keys: "Well it's settled eat less saturated fat and you will live longer, be thinner, and have less heart problems."

Some guy: "Alright!!"

Flash forward 10 years... Some guy is now 57 years old and having a heart attack because all his arteries are clogged. His final thought was how could this happen... I never at saturated fat. 

What is it?: Saturated fat is fat in which the triglycerides contain only saturated fatty acids, which are fatty acids that have no double bonds between the carbon atoms of the fatty acid chains (hence the name). The carbon chain of the fatty acid is fully saturated with hydrogen atoms. The difference between the many kinds of saturated fatty acids is the number of carbon atoms, which can range from just a few to over 30.


Most Likely:
1) Saturated fat is relatively benign when it comes to heart disease (1) (6) (7)
2) An increase of saturated fat increases LDL (mostly the large, puffy one) and HDL (2) (6) (8)
3) Replacing saturated fat with polyunsaturated fat, monounsaturated fat, and carbohydrates lowers total cholesterol, LDL, and HDL. Replacing with carbohydrates also increases fasting triglycerides. (3) (4) (5) (8) (9) (10)


Maybe:
1) Increasing saturated fat lowers V-LDL cholesterol (11) (12) 


Theory:
1) Increased saturated fat may increase heart disease in women (13)
2) Increasing consumption of lauric acid boosts HDL (14)
3) If suffering from heart disease lower saturated fat intake can prolong life (15)
4) Replacing saturated fat with polyunsaturated fat allows HDL to carry out its anti-inflammatory properties more effectively. (16)







Studies that contributed:


1) Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease
http://www.ajcn.org/content/early/2010/01/13/ajcn.2009.27725.full.pdf

2) Lowering Dietary Saturated Fat and Total Fat Reduces the Oxidative Susceptibility of LDL in Healthy Men and Women
http://jn.nutrition.org/content/130/9/2228.full

3) Effects of dietary fatty acids and carbohydrates on the ratio of serum total to HDL cholesterol and on serum lipids and apolipoproteins: a meta-analysis of 60 controlled trials
http://www.ajcn.org/content/77/5/1146.full

4) Dietary Fat and Risk of Coronary Heart Disease: Possible Effect Modification by Gender and Age
http://aje.oxfordjournals.org/content/160/2/141.full

5) Dietary fat intake and risk of coronary heart disease: the Strong Heart Study
http://www.ajcn.org/content/84/4/894.full.pdf

6) Effect of hydrogenated and saturated, relative to polyunsaturated, fat on immune and inflammatory
responses of adults with moderate hypercholesterolemia
http://www.jlr.org/content/43/3/445.full

7) Plasma C-reactive protein concentration is not affected by isocaloric dietary fat reduction
http://www.sciencedirect.com/science/article/pii/S0899900705003102

8) Randomized clinical trials on the effects of dietary fat and carbohydrate on plasma lipoproteins and cardiovascular disease
http://www.sciencedirect.com/science/article/pii/S0002934301009871

9) Are refined carbohydrates worse than saturated fat?
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2869506/

10) The effect of replacing dietary saturated fat with polyunsaturated or monounsaturated fat on plasma lipids in free-living young adults
http://www.nature.com/ejcn/journal/v55/n10/abs/1601234a.html

11) Dietary Carbohydrate Modifies the Inverse Association Between Saturated Fat Intake and Cholesterol on Very Low-Density Lipoproteins
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3170517/

12) Effect of hydrogenated and saturated, relative to polyunsaturated, fat on immune and inflammatory
responses of adults with moderate hypercholesterolemia
http://www.jlr.org/content/43/3/445.full

13) Dietary fats and 16-year coronary heart disease mortality in a cohort of men and women in Great Britain
http://www.nature.com/ejcn/journal/v56/n8/full/1601509a.html#tbl3

14) Effects of dietary fatty acids and carbohydrates on the ratio of serum total to HDL cholesterol and on serum lipids and apolipoproteins: a meta-analysis of 60 controlled trials
http://www.ajcn.org/content/77/5/1146.full

15) Dietary fat intake and risk of coronary heart disease: the Strong Heart Study
http://www.ajcn.org/content/84/4/894.full.pdf

16) Consumption of Saturated Fat Impairs the Anti-Inflammatory Properties of High-Density Lipoproteins and Endothelial Function
http://www.sciencedirect.com/science/article/pii/S0735109706013386


Studies that didn't contribute (but are still good to read):

--Saturated fat–rich diet enhances selective uptake of LDL cholesteryl esters in the arterial wall
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1177997/?tool=pubmed

--Effect of dietary cholesterol, trans and saturated fatty acids on serum lipoproteins in non-human primate
http://apjcn.nhri.org.tw/server/apjcn/Volume11/vol11sup5/S408.pdf

--Coconut oil as a protective carrier of dietary vitamin A fed to ruminants
http://www.ncbi.nlm.nih.gov/pubmed/9433672

--Dietary Saturated Fatty Acids Down-Regulate Cyclooxygenase-2 and Tumor Necrosis Factor Alfa and Reverse Fibrosis in Alcohol-Induced Liver Disease in the Rat
http://onlinelibrary.wiley.com/doi/10.1002/hep.510260622/pdf