This month, in between my packing and moving and waiting on hold for
change of address calls, I still managed to compile some of my favorite headlines in
health for February 2015. You can read them all here.
One topic that deserved a special highlight was the un-vilifying of
saturated fat.
Below are some excerpts on the latest findings of saturated fat, the
conflicting science, and the updated guidelines from the American Heart
Association embracing more healthy
saturated fats in the diet. (This means processed meat is still not advised).
Background Summary
Dietary guidelines for the prevention or
treatment of coronary artery disease (CAD) have emphasized a reduction in the
consumption of saturated fat since the 1960s.[1] Dietary saturated fat
increases blood levels of low-density lipoprotein cholesterol (LDL-C) and
subsequent risk for CAD, or so goes the conventional wisdom. Indeed, there are
studies showing such associations,[2,3] but other data challenge the
hypothesis, including meta-analyses showing no link between saturated fat
consumption and risk for CAD or cardiovascular disease (CVD).[4,5] The
disparate findings have led to calls to stop demonizing saturated fat[6,7] and
equally vocal cries to proceed with caution before we let lard back on the
menu.[8] Meanwhile, the 2013 American College of Cardiology (ACC)/American
Heart Association (AHA) guidelines on lifestyle management to reduce CVD risk
omitted a target for total dietary fat but did recommend a goal of 5%-6% of
calories from saturated fat.[9]
…
In a meta-analysis of over 60 trials, higher
intakes of saturated fat were associated with increases in both LDL-C and
high-density lipoprotein cholesterol (HDL-C) and decreases in triglyceride
levels, for a net neutral effect on the ratio of total cholesterol to HDL
cholesterol.[11] Although saturated fats increase LDL-C, they reduce the LDL
particle number. Total LDL particle number quantifies the concentration of LDL
particles in various lipid subfractions and is considered a stronger indicator
of CV risk than traditional lipoprotein measures.[12] As for stearic acid, the
allegedly non-cholesterol-raising fat, while it appears to lower LDL-C relative
to other SFAs, one analysis concluded that it raised LDL-C, lowered HDL-C, and
increased the ratio of total to HDL cholesterol in comparison with unsaturated
fatty acids.[13] And this is one of the confounders of much nutrition
research–observations about a given nutrient are highly dependent on what you
compare it to.
…
The MESA trial showed that meat SFA was
associated with greater CVD risk (hazard ratio = 1.26 for +5 g/d and 1.48 for
+5% of energy, respectively), but before the vegetarians break out the
champagne, the EPIC trial conducted in almost half a million middle-aged adults
from 10 countries found that processed meats but not red meat per se were linked
to CV mortality.[19] Processed meat included ham, bacon, sausages, and minced
meat in ready-made products. Similarly, in a study in over 37,000 Swedish men,
the risk for new heart failure and death from heart failure increased by 8% and
38%, respectively, for every 50-g rise in daily processed-meat intake.[20] (1)
The AHA Recommendations
Speaking with heartwire , Dr Alice Lichtenstein (Tufts University, Boston, MA),
a spokesperson for the AHA, said its recommendations, as well as others, such
as the 2010 Dietary Guidelines for Americans, no longer recommend individuals
consume a low-fat diet. Instead, they recommend a moderate amount of fat
intake, with approximately 25% to 35% of calories coming from fat. The 2010
Dietary Guidelines for Americans recommends individuals consume less than 10
percent of calories from saturated fatty acids (and to replace these fats with
monounsaturated and polyunsaturated fatty acids).
As the researchers point out, Lichtenstein said
the reason for the change was that people were substituting simple, refined
carbohydrates for fat, which in turn led to dyslipidemia, an increase in
triglyceride levels, and a reduction in HDL cholesterol. “One of the
reasons the guidelines are reviewed on a regular basis is because as new science
emerges you’ll need to modify the recommendations,” she told heartwire . “No one is
recommending low-fat diets anymore that I’m aware of.”
The connection between lower levels of saturated
fat and reduced cardiovascular disease was also recently challenged in a
meta-analysis conducted by Dr Rajiv Chowdhury (University of Cambridge, UK),
noted Lichtenstein. The issue again, however, is one of substitution. (2)
Below are some
other sources on how the “Big Fat Surprise” of fat not being the villain is hitting
mainstream.
1. An interview
with The Big Fat Surprise author Nina
Teicholz was done with Medscape Cardiology. Nina was an investigator reporter
and made a huge wave when she wrote her book about the health benefits of
saturated fats.
Ms Teicholz:I am an
investigative journalist. I worked for NPR for many years as their South
American correspondent, among other roles. When I got into print journalism, I
started doing a series of investigative food stories for Gourmet magazine. They assigned me a
story on trans fats. That story, which came out in 2004, broke the issue wide
open, and I got a book contract from it. In the course of writing that story
and as I was researching the book, I spoke to a number of scientists who had
been marginalized. These people told me an alternative story about dietary
fats, about how basically everything that we had come to believe about fat was
untrue. It wasn’t just trans fats; there was a whole story about vegetable oils
and saturated fats that seemed to turn everything that we thought we knew on
its head. Once I realized that this was much bigger than trans fats, I
reoriented my book to be about all fats. That led me down this exhaustive compulsive
path because there’s such a huge body of scientific literature about dietary
fat and cholesterol, heart disease, and the history of it all. (3)
2. A study on how
dairy saturated fats may be beneficial for diabetes type 2:
The odds of incident type 2 diabetes is lower
in people who have high plasma levels of odd-chain saturated fatty acids that
come primarily from dairy fats, compared with people who did not have these
biomarkers, a large, prospective multicenter study finds. (4)
Make sure not to miss out on more news from February by reading my Top Reads!
Sources:
(1) Ward, T.
Saturated Fat and CAD: It’s Complicated. theheart.org on Medscape. February 9,
2015.
http://www.medscape.com/viewarticle/839360?src=wnl_edit_specol&uac=146852BY#vp_4
(2) O’Riordan. No
Evidence to Support Dietary Fat Recommendations, Meta-Analysis Finds. Heartwire.
February 12, 2015. http://www.medscape.com/viewarticle/839708?src=wnl_edit_specol&uac=146852BY#vp_2
(3) An Interview
With The Big Fat Surprise Author Nina Teicholz. Medscape Cardiology. February
9, 2015. http://www.medscape.com/viewarticle/839061?src=wnl_edit_specol&uac=146852BY
(4) Dairy
Saturated Fats Lower Type 2 Diabetes Risk. Medscape Medical News. April 14,
2014. http://www.medscape.com/viewarticle/829920?src=wnl_edit_specol&uac=146852BY#vp_2
