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colette_heimowitz's Blog

Nutritionist

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Nutritionist's Blog

Monounsaturated fats

October 2

The Role of Dietary Saturated Fat on Cardiovascular Risk

 

Jeff S. Volek, PhD, RD presented his most recent abstract at our science advisory board meeting this month. Since you have asked me to blog on the subject of saturated fat , here is a description of his presentation and abstract which covers this subject very well.
 
The current rationale for decreasing saturated intake is to reduce LDL concentration in the blood. Recommendations that reduce saturated fatty acids (SFA) to levels of 10% of calories or less must take into account the likelihood of changes in dietary habits that will increase carbohydrate consumption to levels above which data no longer shows beneficial effect. Such recommendations should consider the NHANES data showing the lack of effect of reductions in saturated fat on obesity and diabetes and should consider large trials like the Women’s Health Initiative showing limited effects of recommendations to reduce dietary fat in general. Dietary carbohydrate is key element in understanding the relation of dietary SFA to risk for cardiovascular disease.
 
Carbohydrate-restricted diets, although relatively high in SFA, show effects on the fatty acid blood profile  that are very different from those seen in studies conducted in the presence of moderate to high dietary carbohydrate. A high carbohydrate diet prolongs circulatory exposure to dietary SFA, and conversely, dietary restriction of carbohydrate, via reduced secretion of insulin, allows for greater rates of fat management of the incoming fat mix. High dietary fat is thus expected to be bad for you only if there is sufficient carbohydrate to provide the hormonal state in which the fat will be stored rather than burned. 
 
The known metabolic effects of carbohydrate provide a mechanism for explaining the seemingly paradoxical finding that a low carbohydrate diet leads to significant decreases in blood levels of SFA despite increased saturated fat intake. Recent work from controlled feeding studies in the laboratory of Dr. Jeff Volek at the University of Connecticut,  indicate that altering fat quality of a very low carbohydrate diet by emphasizing monounsaturated fats( MUFA) and omega -3 fatty acids significantly decreases the plasma SFA pool and has other beneficial effects. More generally, Dr Volek has discovered that low carbohydrate diets are a preferred approach to treating metabolic syndrome. Metabolic syndrome (insulin resistance syndrome) represents a group of seemingly disparate physiologic signs that indicate a predisposition to obesity, diabetes, and cardiovascular disease.
 
 From a clinical standpoint, there are numerous pharmacologic agents that target individual markers but none treat all. Consistent with the idea that an intolerance to carbohydrate is an underlying feature of metabolic syndrome, Dr Volek’s study has shown that reduction in dietary carbohydrate results in global improvement in traditional and emerging markers associated with metabolic syndrome, particularly the cardio metabolic profile (HDL is raised, postprandial vascular function improved; small dense LDL-C, triglycerides and apoB/apoA-1 are reduced).   Control diets, restricted in fat, are shown to be less effective. 
 
The ability to target multiple markers with a single intervention provides support for the notion of a unique metabolic state that conforms to the idea of a syndrome.   The experimental results point to carbohydrate restriction as an alternative or adjunct to other approaches that generally require multiple pharmacologic interventions, and that have had only limited success. Future recommendations on dietary fat should consider underlying mechanisms and interactions of fat with other macronutrients. All points of view should be considered. The heterogeneity of the population suggests that only very broad guidelines may be possible.

(11) Comments Post comment

Oct 4, 2009
I should print this out and tape it to the refrigerator at work for all those ladies on the "Slim Fast" diet. ;-)
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Oct 6, 2009
Thank you. This info was very helpful. All of the "health shows" on tv scare people about high protein, saturated fats, and low carb diets. Dr. OZ show recently told audience that high protein diets are bad for their kidneys. Thank you for providing more information about these issues on your website.
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Colette Heimowitz
Nutritionist
Oct 6, 2009
A common misconception about Atkins is that it is high in protein. The amount of protein consumed on Atkins is well within the limits of safety.

People just don't get the fact that when carbs are low enough the body is simply running on a different metabolism. Fats are burned for energy.

You can understand their concern when your only reference is high carbohydrate consumption. The worst combination is high carb high fat.
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Oct 8, 2009
Thank you SO much for this article!

I am printing it out right now.. and then copying it to an email and sending it to my mom.

Heidi :)
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Oct 8, 2009
"You can understand their concern when your only reference is high carbohydrate consumption. The worst combination is high carb high fat."

What percentage of saturated fat is SAFE for someone not in ketosis and eating 100g net carbs from healthy whole foods daily?
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Oct 8, 2009
Yo Pattycakebaker, do you by chance have any recipe's for gluten/soy powder bread that can be used with yeast for rising? What I've been trying lately is rather heavy and will not rise very well. Thanx !
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Oct 17, 2009
Hi Buzzy,

Sorry I don't have a gluten/soy powder bread recipe. I'm gluten intolerant and have not made a bread with soy flour.
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Oct 19, 2009
Buzzy, when you make bread with soy (or other alternative flours), they don't rise well, because there's "no" gluten, which is the elasticky high-protein component of wheat flour which gives the yeast-gasses something to grab onto -- to describe it simply! :-) add 2-4 tablespoons of vital wheat gluten to the soy, and it'll help without adding a lot of carbs. if you use too much gluten your bread will resemble play-dough ... again, very heavy, but for a different reason.

tess
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Oct 19, 2009
Thanx Ladies, I shall continue to experiment. If I find the magic solution I will let you know.
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Oct 23, 2009
Why do the heart doctors say low fat diets are the best and of course, NO eggs, or very limited to one a week? My husband is afraid to do Atkins because he has had an ICD implanted due to tachycardia arythmia.
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Oct 23, 2009
Probably because if they cured people they'd be out of business.
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