Kevin Klatt, PhD, RD

The American Heart Association (AHA) released it's Presidential Advisory on Dietary Fats and Cardiovascular Disease this week and the responses have been all over the place (see medscape ,  science-based medicine , HNR , Gary Taubes , Cardiobrief ). Here's my summary/take: There's nothing terribly new about this advisory; it's relatively the same line of thinking/evidence that the AHA has used to support it's recommendations in the past, so regular followers of the field will not read this report and be too shocked. The most novel aspect of it is an updated meta-analysis of 4 diet-heart trials which the AHA generated. The new meta analysis comes about because there have been multiple meta-analyses which have attempted to address this issue over the past several years, and they don't all align nicely - see here , here , here . Why? Because the study inclusion criterion that are used are often not the same. Shorter term trials have consistently shown that satu...

Credit: Hindawi.com               When it comes to Omega 3's, form and source are quite important, both from a health and evolutionary perspective. There are three kinds of these fatty acids: alpha linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). ALA is the shorter plant form, and currently the only form considered essential; ALA can be elongated into the longer chain EPA/DHA, found in fish and phytoplankton, via fatty acid desaturases (enzymes your liver produces).               Referring to ALA as the only essential omega 3 fatty acid has been an issue of contention in the field of nutritional sciences. EPA/DHA, at low doses, are thought to be potent anti-inflammatory agents, lower triglycerides , and help maintain cholesterol homeostasis, via decreasing lipogenic gene expression in the liver (2), all having prof...

I really applaud anyone who is trying to make positive changes to their lifestyle, especially by improving their nutrition but, few things annoy me more than massively disseminated misinformation. The most virulent case of this is linoleic acid, an omega 6 (n-6) fatty acid. Do one google search of "Omega 6's and Inflammation" and you'll find articles on every internet health site, written by MDs/RDs/etc etc, telling you that Omega 6's, like those found in vegetable oils, are virtually the cause of every modern day ailment, from heart disease, to acne and arthritis. They'll cite you information stating that the n-6:n-3 fatty acid ratio is all out of whack. There seem to be 2 reasons that people claim linoleic acid is pro-inflammatory. 1, because it is a precursor to inflammatory molecules in the body. 2, because it is subject to oxidation, and these oxidative endproducts (reactive carbonyl compounds, ketones, aldehydes) incite an immune response . 1. Lino...

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 ci...