Marilyn:
> Sent: Sunday, March 11, 2007 8:14 AM
> Fat, though, is a factor in some cancers and should be looked at
> carefully.....
Ron Hoggan:
> Hi Marilyn,
> Can you give me a source for that claim?
Hi Ron,
I'm trying to better understand the saturated fat debate myself, which tends
to be rather emotional. I don't have a dog in the hunt, but some time ago I
saw claims by Michael Eades and Anthony Colpo that there are no studies
demonstrating a link between saturated fatty acids (SFAs) and coronary heart
disease (CHD). I find Dr. Eades to be a credible source and the remarkably
contrarian and clear-cut nature of the claim piqued my interest, so I made
note of any study reports I came across that seemed to indicate a link
between SFAs and CHD or risk factors for CHD. I tried to eliminate the most
suspect reports, such as reports that were merely reviews of past studies or
reports that made dubious extrapolations based on comparisons of nations.
Below is what I have collected. The last report is from a clearly biased
source (a USDA research center) but the others seem to be from fairly
independent sources. Are you familiar with any of these reports? I included
my summary of the conclusions of each report in brackets.
Some of the studies could be clouded with SF from dairy foods.
Unfortunately, the source of SF in such studies is not always specified.
------
[Replacing saturated fat with either n-6 polyunsaturated or monounsaturated
fat is equally effective at reducing LDL.]
The effect of replacing dietary saturated fat with polyunsaturated or
monounsaturated fat on plasma lipids in free-living young adults. Eur J Clin
Nutr. 2001; 55(10):908-15.
Hodson L ; Skeaff CM ; Chisholm WA
Department of Human Nutrition, University of Otago, Dunedin, New Zealand
http://www.nature.com/ejcn/journal/v55/n10/abs/1601234a.html
Two randomized controlled trials showing that when saturated fat foods were
restricted in favor of vegetable polyunsaturated or monounsaturated fats,
lowered blood cholesterol by about 20 percent (LDL by 22 percent).
Authors' conclusion: Replacing saturated fat with either n-6 polyunsaturated
or monounsaturated fat is equally efficacious at reducing the total to high
density lipoprotein cholesterol ratio.
[SF is a strong predictor of CHD mortality in middle aged American Indians.]
Dietary fat intake and risk of coronary heart disease: the Strong Heart
Study. Am J Clin Nutr. 2006; 84(4):894-902. Xu J ; Eilat-Adar S ; Loria C ;
Goldbourt U ; Howard BV ; Fabsitz RR ; Zephier EM ; Mattil C ; Lee ET.
Center for American Indian Health Research
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Ab
stract&list_uids=17023718
"Total fat, saturated fatty acid, and monounsaturated fatty acid intake were
strong predictors of CHD mortality in American Indians aged 47-59 y,
independent of other established CHD risk factors."
[SFAs were found to be positively associated with the inflammatory markers
C-reactive protein and circulating interleukin [IL]-6 in overweight men, but
not lean men]
Fernandez-Real JM, Broch M, Vendrell J, and Ricart W. 2003. Insulin
resistance, inflammation, and serum fatty acid composition. Diabetes Care
26:1362–1368.
1 Unitat de Diabetologia, Endocrinologia i Nutrició, University Hospital of
Girona "Dr. Josep Trueta," Girona, Spain
2 University Hospital of Tarragona "Joan XXIII," Tarragona, Spain
http://care.diabetesjournals.org/cgi/content/abstract/26/5/1362
RESULTS—The percentage of saturated FAs (r = 0.30, P = 0.01) and -6 FAs (r =
-0.32, P = 0.001) were significantly associated with circulating IL-6,
whereas the percentage of -3 FAs correlated negatively with C-reactive
protein in overweight subjects (P = 0.04). Saturated-to--3 and
saturated-to--6 FA ratios were significantly and positively associated with
C-reactive protein (P < 0.0001) and IL-6 (P < 0.001), respectively. In
contrast, none of these associations reached statistical significance in
lean subjects. ...
CONCLUSIONS—Dietary FAs (as inferred from plasma FA concentration) seem to
be linked to inflammatory activity in overweight subjects and in subjects
with insulin resistance. Being overweight modulates the relation of FAs to
inflammatory markers.
[Harvey Diamond claimed this study showed that saturated fat raises blood
pressure]
Puska, P., J.M. Iacono, A. Nissinen, H.J. Korhonen, E. Vartianinen, P.
Pietinen, R. Dougherty, U. Leino, M. Mutanen, S. Moisio, and J. Huttunen.
1983. Controlled, randomized trial of the effect of dietary fat on blood
pressure. Lancet 1:1-5. [Cited by former vegetarian Harvey Diamond in Fit
for Life II: Living Health--The Complete Health Program]
[Beef Fat Increased LDL; subjects were restricted to nonfat dairy to avoid
confounding data with SF from dairy foods]
Am J Clin Nutr. 1990 Sep;52(3):491-4.
Cholesterol-lowering effect of a low-fat diet containing lean beef is
reversed by the addition of beef fat.
* O'Dea K,
* Traianedes K,
* Chisholm K,
* Leyden H,
* Sinclair AJ.
Department of Human Nutrition, Deakin University.
http://www.ajcn.org/cgi/content/abstract/52/3/491
The aim of this study was to differentiate between lean beef and beef
fat as risk factors for elevated plasma cholesterol concentrations. Ten
healthy weight-stable subjects (five men, five women) participated. Energy
intake was kept constant over the 5-wk study. Total cholesterol
concentrations fell significantly within 1 wk of commencing the very-low fat
(9%) energy from fat) lean-beef (500 g/d) diet (5.91 +/- 0.47 to 4.72 +/-
0.42 mmol/L, p less than 0.001) and rose as beef drippings were added in a
stepwise manner in weeks 4 and 5 (5.45 +/- 0.56 mmol/L in week 5). The
changes in total cholesterol concentrations were due almost entirely to
changes in the concentration of low-density lipoprotein cholesterol levels.
These results indicate that it is the beef fat, not lean beef itself, that
is associated with elevations in cholesterol concentrations and that lean
beef can be included in cholesterol-lowering diets provided it is free of
all visible fat and the saturated fatty acid content of the diet is low.
[SFAs increase both LDL and HDL; palm oil has better effects than coconut
oil]
Proc Soc Exp Biol Med. 1990 Nov;195(2):261-9.
Dietary palmitic acid (16:0) enhances high density lipoprotein cholesterol
and low density lipoprotein receptor mRNA abundance in hamsters. Lindsey S,
Benattar J, Pronczuk A, Hayes KC.
Foster Biomedical Research Laboratory, Brandeis University, Waltham,
Massachusetts 02254.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?itool=abstractplus&db=pubmed&c
md=Retrieve&dopt=abstractplus&list_uids=2236108
In order to examine the qualitative effect of different fats and specific
fatty acids on plasma lipids and lipoprotein metabolism, six low fat,
cholesterol-free diets were fed to young male hamsters (10/group) for a
4-week period. Fat blends were formulated with coconut oil, palm oil,
soybean oil, high oleic acid safflower oil, butter, corn oil, and canola
oil. Diets contained 13% energy as fat and dietary polyunsaturate/saturate
ratios ranged from 0.12 to 1.04, one of which incorporated the American
Heart Association-recommended concentrations of saturates, monoenes, and
polyenes and another reflected the current American Fat Blend. In three
diets the polyunsaturate/monounsaturate/saturate ratio was held constant
while only the 12:0, 14:0, and 16:0 were varied. Plasma lipoproteins and
apoproteins were assessed in conjunction with the abundance of specific
hepatic and intestinal mRNA for the low density lipoproteins (LDL) receptor
and various apolipoproteins associated with cholesterol metabolism. The
plasma cholesterol response was lowest with the American Heart Association
blend and equally elevated by the more saturated, low polyene diets
(polyunsaturate/saturate, 0.12-0.38). Replacing 12:0 plus 14:0 from coconut
oil with 16:0 as palm oil induced a significant increase in high density
lipoprotein (HDL) cholesterol with a trend toward decreased LDL. These
shifts in lipoprotein cholesterol were corroborated by measures of the
LDL/HDL ratio, the plasma apolipoprotein B/apolipoprotein A1 ratio, and
differences in the synthesis of apolipoproteins and the LDL receptor based
on estimates of the mRNA for these proteins in the liver and gut, using
specific cDNA probes for apolipoprotein A1, apolipoprotein B, apolipoprotein
E, and the LDL receptor. Although it has been suggested that dietary
polyenes lower total plasma cholesterol, including HDL, and that saturated
fat increases both these pools of cholesterol, the current data represents
the first evidence that a specific saturated fatty acid, i.e., palmitic
acid, may enhance HDL production.
[SFAs are associated with CHD mortality; an analysis of past study data from
the Baltimore Longitudinal Study of Aging (BLSA). This report is somewhat
suspect since it is by a USDA research center, which is a suspect source,
and it is merely an analysis of past data, which could be manipulated to
give the picture that the researchers want, but I included it because it
makes a direct link between SF and CHD and the researchers theoretically
might not have manipulated the data.]
The Combination of High Fruit and Vegetable and Low Saturated Fat Intakes Is
More Protective against Mortality in Aging Men than Is Either Alone: The
Baltimore Longitudinal Study of Aging1 Katherine L. Tucker2, Judith
Hallfrisch*, Ning Qiao, Denis Muller*, Reubin
Andres* and Jerome L. Fleg*
Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on
Aging at Tufts University, Boston, MA and * National Institute on Aging
Intramural Program, National Institutes of Health, Bethesda, MD
http://jn.nutrition.org/cgi/content/full/135/3/556
"the results of this study support earlier observations that dietary intakes
low in SF or high in FV [fruit and vegetable] each offer protection against
CHD mortality"
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