One
of the consistent nutrition messages in the last 50 years is that saturated
fats found in dairy and meat raise blood cholesterol and therefore increase the
risk of heart disease. However, this
time honored recommendation is now being called into question. A recent editorial arguing limiting saturated
fat does not curb heart disease risk by cardiovascular disease researcher Dr.
DiNicolantonio and a review of the
current research by Dr. Siri-Tarino and colleagues have been generating a reexamination
of the evidence on this subject.
Dr. DiNicolantonio points out that the
original findings that linked saturated fat and heart disease were based on
epidemiologic (population) studies in which researchers cherry-picked the
evidence for groups that matched their hypothesis while excluding populations
for which there was contrary evidence.
And, the 2010 Siri-Tarino review of existing epidemiologic studies on
the relationship between saturated fat and heart disease found no significant
evidence saturated fat intake increases cardiovascular disease rates. Another reason saturated fat has been linked
to heart disease is the evidence that it raises LDL cholesterol levels but,
increasingly, it is being recognized that LDL cholesterol is made up of a
combination of artery damaging small dense LDL particles and comparatively
benign light large LDL particles and it appears that saturated fat mostly
increases the light large LDL rather than the dangerous small LDL in the
blood. Dr. DiNicolantonio argues the
real drivers of increases in the small damaging LDL particles is
over-consumption of carbohydrates especially in the form of sugars and refined
grains.
Additionally,
one of the chief reasons saturated fat has been linked to heart disease is the
finding that diets high in red meat, which is generally high in saturated fat,
are linked with higher heart disease rates.
This is especially true for processed meat. In the past few years researchers have been uncovering
other ways that meat may be contributing to heart disease. It appears that the nitrites in processed
meat can damage arteries and increase metabolic problems linked to diabetes. Also, it has been found carnitine which is
especially rich in meat may be metabolized into a substance that increases
arterial damage by small LDL particles.
What to do: While new questions are being raised about
the role of saturated fat in heart disease risk, it is too early to make a
definitive conclusion. Stay tuned. In the meantime, there is stellar
epidemiologic evidence that a traditional Mediterranean diet rich in olive oil,
nuts, fish, beans, fruits, and vegetables does help to prevent and improve
cardiovascular disease. At the same time
there is also good evidence diets high in processed carbohydrates such as refined
flour and sugar do increase the risk of cardiovascular disease.
Adapted from articles available at:
http://www.sciencedaily.com/releases/2014/03/140305191429.htm
http://www.medicalnewstoday.com/articles/273528.php
Sources:
DiNicolantonio
JJ. The cardiometabolic consequences of replacing saturated fats with
carbohydrates or omega-6 polyunsaturated fats: do the dietary guidelines have
it wrong? Open Heart. 2014;1. doi:10.1136/openhrt-2013-000032.
Micha
R, Wallace SK, Mozaffarian D. Red and processed meat consumption and risk of
incident coronary heart disease, stroke and diabetes mellitus: a systematic
review and meta analysis. Circulation2010;121:2271-83. Available at: http://ajcn.nutrition.org/content/91/3/535?ijkey=2755fae85a1e0c716ad5d4419af2cd89c40e3388&keytype2=tf_ipsecsha&linkType=ABST&journalCode=ajcn&resid=91/3/535&atom=/bmj/347/bmj.f6340.atom
Siri-Tarino
P, Sun Q, Hu FB, Krauss RM. Meta-analysis
of prospective cohort studies evaluating the association of saturated fat with
cardiovascular disease. Am J Clin Nutr
2010; 91: 535-46. Available at: http://circ.ahajournals.org/content/121/21/2271.full.pdf+html
No comments:
Post a Comment