אקו - אטקינס

[אבי כהן]

זכור לי שלא מזמן שאל כאן מישהו לגבי AD וצמחונות...או משהו דומה

להלן לינק ל "כוכב" החדש שמסתמן כרגע - דיאטות אקולוגיות.

http://www.sciencedaily.com/releases/2009/06/090608162426.htm

מבחינתי, השורות הבאות מסכמות לא רע את הכתוב בקישור:

"High-protein, low-carbohydrate diets are advocated by many, predominantly commercial, weight loss programs," write Katherine R. Tuttle, M.D., and Joan E. Milton, M.S., R.D., C.D., of the Providence Medical Research Center at Sacred Heart Medical Center and the University of Washington School of Medicine, Spokane, Wash., in an accompanying editorial.
"Most of these diets have been promoted within popular culture and until recently have been subjected to little scientific scrutiny. Substantial concern has been raised about the potential for adverse effects. Meat is commonly consumed as a major source of dietary protein. However, meat derived from animal muscle also typically contains large amounts of saturated fat and cholesterol."
"The article by Jenkins et al provides insight into debatably more effective and possibly safer tactics for designing higher-protein diets for weight loss and cardiovascular risk reduction. However, it is premature to recommend the 'Eco-Atkins' diet as a weight loss diet of choice without confirmation of its efficacy in larger studies of more diverse and higher-risk individuals. Long-term studies are also essential to ascertain both sustainability and safety."

 

[bentzurm]

איזה התעסקות בקקה, אפילו אני לא מתעסק בזה עד כדי כך 😘

זה המקצוע שלי. אל תקרא לו קקה. 🤪

 

[bentzurm]

🤯 😍

אני לא מבין בזה ברמות שאפילו מתחילות להתקרב לידע שלך...
הדבר היחיד שהנחתי שאני 'קורא' שם, זה על קורלציה חיובית בין צריכה של שומן רווי ובין מה שבשפת העמחה נקרא "הסתיידות עורקים", או יותר ספציפית ויותר מדויק (למחקר הזה) - ירידה בכושר/יכולת ההובלה של כלי הדם.

אני מקבל (בשמחה) את הניתוח שלך

הבעיה היא שרוב האנשים שלא מהתחום קוראים רק את האבסטרקט ולא בטוח שמסוגלים להבין את הדקויות של המחקר המלא או המסקנות. הרבה פעמים גם האבסטקרט קצת "מנפח" את התוצאות. אבל כמובן עדיף לקרוא כמה שיותר וכל הכבוד למי שפותח פאבמד בלי פחד.

 

[Mike Bikov]

מה המקצוע? לנתח מערכות ?

 

[bentzurm]

מה המקצוע? לנתח מערכות ?

מחקר ביוכימי. התואר הראשון שלי היה במדעי הרפואה (סוג של ביולוגיה עם התמחות במחקר רפואי).

 

[Mike Bikov]

מחקר ביוכימי. התואר הראשון שלי היה במדעי הרפואה (סוג של ביולוגיה עם התמחות במחקר רפואי).

למה תמיד חשבתי שאתה עובד הייטק?

 

[bentzurm]

למה תמיד חשבתי שאתה עובד הייטק?

באמת למה? עבדתי שנתיים בתור מתכנת (ובצבא) אבל זה היה במאה הקודמת. 😆

 

[אבי כהן]

מחקר ביוכימי. התואר הראשון שלי היה במדעי הרפואה (סוג של ביולוגיה עם התמחות במחקר רפואי).

למדת בפקולטה ברחובות?

 

[bentzurm]

למדת בפקולטה ברחובות?

לא. תואר ראשון בתל-אביב ותארים מתקדמים (שני ושלישי שעדיין בעיצומו) במכון ויצמן.

 

[אבי כהן]

אני זוכר את וייצמן בזכות כמה מתרגלים שהיו לנו משם. כל מיני 'פריקים' שהיו דוקטורנטים במתמטיקה ולא הבינו מדוע אנחנו מתקשים באינפי שזה משהו שכנראה הם סיימו עוד בבי"ס יסודי.
יש לך כבר דיסרטציה לתואר ווו ?

 

[bentzurm]

אני באמצע התואר כרגע. יש עוד שנתיים לפחות עד שתהיה לי תזה מוגמרת. בינתיים יש חתיכות שצריך להרכיב והמון חיידקים שלא משתפים פעולה.

 

[אבי כהן]

התלבטתי בזמנו בין לימודי תואר 2 בגנטיקה או ביכומיה. בחרתי במנהל עסקים : ))

הרבה בהצלחה לך

 

[Mike Bikov]

באמת למה? עבדתי שנתיים בתור מתכנת (ובצבא) אבל זה היה במאה הקודמת. 😆

אז איפה אתה עובד ביימנו?

 

[bentzurm]

אני דוקטורנט במכון ויצמן. זה עבודה במשרה מלאה עם מלגה (משכורת).

 

[Mike Bikov]

J Nutr. 2006 Jan;136(1):159-65. Related Articles, Links
Click here to read
Dietary Saturated Fat Intake Is Inversely Associated with Bone Density in Humans: Analysis of NHANES III.

Corwin RL, Hartman TJ, Maczuga SA, Graubard BI.

Biostatistics Branch, DCEG, NCI, Bethesda, MD.

Mounting evidence indicates that the amount and type of fat in the diet can have important effects on bone health. Most of this evidence is derived from animal studies. Of the few human studies that have been conducted, relatively small numbers of subjects and/or primarily female subjects were included. The present study assessed the relation of dietary fat to hip bone mineral density (BMD) in men and women using NHANES III data (n = 14,850). Multivariate models using SAS-callable SUDAAN were used to adjust for the sampling scheme. Models were adjusted for age, sex, weight, height, race, total energy and calcium intakes, smoking, and weight-bearing exercise. Data from women were further adjusted for use of hormone replacement therapy. Including dietary protein, vitamin C, and beta-carotene in the model did not influence the outcome. Analysis of covariance was used to generate mean BMD by quintile of total and saturated fat intake for 4 sex/age groups. Saturated fat intake was negatively associated with BMD at several hip sites. The greatest effects were seen among men < 50 y old (linear trend P = 0.004 for the femoral neck). For the femoral neck, adjusted mean BMD was 4.3% less among men with the highest compared with the lowest quintile of saturated fat intake (BMD, 95% CI: highest quintile: 0.922 g/cm(2), 0.909-0.935; lowest quintile: 0.963 g/cm(2), 95% CI: 0.950-0.976). These data indicate that BMD is negatively associated with saturated fat intake, and that men may be particularly vulnerable to these effects.

Am J Clin Nutr. 2004 Sep;80(3):550-9. Related Articles, Links

Saturated fats: what dietary intake?

German JB, Dillard CJ.

Department of Food Science and Technology, University of California, 1 Shields Avenue, Davis, CA 95616, USA. [email protected]

Public health recommendations for the US population in 1977 were to reduce fat intake to as low as 30% of calories to lower the incidence of coronary artery disease. These recommendations resulted in a compositional shift in food materials throughout the agricultural industry, and the fractional content of fats was replaced principally with carbohydrates. Subsequently, high-carbohydrate diets were recognized as contributing to the lipoprotein pattern that characterizes atherogenic dyslipidemia and hypertriacylglycerolemia. The rising incidences of metabolic syndrome and obesity are becoming common themes in the literature. Current recommendations are to keep saturated fatty acid, trans fatty acid, and cholesterol intakes as low as possible while consuming a nutritionally adequate diet. In the face of such recommendations, the agricultural industry is shifting food composition toward lower proportions of all saturated fatty acids. To date, no lower safe limit of specific saturated fatty acid intakes has been identified. This review summarizes research findings and observations on the disparate functions of saturated fatty acids and seeks to bring a more quantitative balance to the debate on dietary saturated fat. Whether a finite quantity of specific dietary saturated fatty acids actually benefits health is not yet known. Because agricultural practices to reduce saturated fat will require a prolonged and concerted effort, and because the world is moving toward more individualized dietary recommendations, should the steps to decrease saturated fatty acids to as low as agriculturally possible not wait until evidence clearly indicates which amounts and types of saturated fatty acids are optimal.

The research is clear: Carbohydrates, not fats, are the foe in America's battle against heart disease and obesity
By: Adam Campbell & Jeff Volek, Ph.D., R.D.

The recent news that the Atkins low-carb diet works well and improves health has some people scratching their heads.

If Atkins means eating lots of meat, eggs and cheese, won't all that saturated fat wreck your cholesterol levels and put you on the road to heart disease?

Well, no. There's no good evidence of that. And there's plenty of evidence that the opposite is true--that eating more saturated fat lowers the risk for heart disease. That's what a recent Harvard University study found: People who had the highest saturated fat intake also had the least plaque buildup on their artery walls. The American Journal of Clinical Nutrition described the findings as an "American Paradox."


In the Stanford University study that made recent headlines, women on the "fatty" Atkins diet ended up with the healthiest cholesterol levels and the best blood pressure readings, compared to those on other diets, notably the famous Ornish low-fat diet.

Here are a few bullet-points summarizing the current research on saturated fats.

--We typically eat more than a dozen kinds of saturated fat. Some have zero effect on cholesterol. Some raise bad (LDL) cholesterol, but all of them raise good (HDL) cholesterol to a greater extent. That?s a net gain in heart health.

--The nation's top health organizations have for decades called saturated fat one of the main culprits for diet-related diseases, including obesity, diabetes, heart disease, and cancer. Problem is, this blame stems from research that is now seen as incomplete. For instance, a famous 1953 study took data from six countries, overlooking 16 countries whose numbers provide contradictory evidence. (Like France, for instance, or native cultures in Africa and Canada where high amounts of fat and saturated fat are eaten but heart disease is practically unknown.)


--Since the 1970s, American men have decreased their saturated fat intake by 14 percent and increased their carbohydrate intake by 23 percent--yet rates of obesity and heart disease are increasing. You might say that carbohydrates make people fat, which leads to heart disease. Or that more carbohydrates you eat, the greater your risk for a heart attack.


--But these simple numbers only suggest a cause. To prove something, you need a controlled experiment. There have been many such clinical trials, and not one has shown has shown that cutting back on saturated fat reduces heart disease risk.

--When you look at the effect of saturated fat on health, you must also look at the intake of carbohydrates. Many studies have shown that if you replace carbs with fat, your triglycerides levels go down and your good cholesterol goes up. And your bad (LDL) cholesterol particles get bigger, which means they're less harmful.


--Here's a paradox for you: A high saturated fat intake decreases blood levels of saturated fat. How can this be? Here's how: The saturated fat in your blood comes from both the food you eat and from your liver, which produces saturated fat. The more carbs you eat, the higher your insulin levels climb, which signals your liver to produce saturated fat. If you go on a low-carb diet, your insulin levels drop, and so does production of saturated fat.

--A bonus: with low insulin levels, your body can burn more fat for energy, decreasing your sat-fat levels even more.

J Lipid Res. 1993 Sep;34(9):1515-26. Links
Differential mobilization of white adipose tissue fatty acids according to chain length, unsaturation, and positional isomerism.Raclot T, Groscolas R.
Centre d'Ecologie et de Physiologie Energetiques, CNRS, Strasbourg, France.

The present study aims at determining whether, and how, the molecular structure of fatty acids influences their mobilization from fat cells. The in vitro mobilization of 52 fatty acids ranging in chain length from 12 to 24 carbon atoms, in unsaturation from 0 to 6 double bonds, and including 23 pairs of positional isomers was examined. Fat cells were isolated from adipose tissue of rats fed a fish-oil diet and treated with norepinephrine to stimulate lipolysis. Fatty acid composition of free fatty acids (FFA) released from these cells was compared to that of the triacylglycerols (TAG) from which they originated. The percentage weight of most fatty acids, and especially that of very long-chain fatty acids, was significantly different between FFA and TAG. The percentage of 20:5n-3 (eicosapentaenoic acid) and of 20:4n-6 (arachidonic acid) was 2.7 and 1.7 times higher in FFA than in TAG, respectively, whereas that of 20:1(n-11, 9 or 7), 22:1(n-11, 9 or 7) and 24:1n-9 was 1.7-2, 2.4, and 3.5 times lower, respectively. The relative mobilization (% in FFA/% in TAG) of the least readily mobilized fatty acid (24:1n-9) was 15-fold lower than that of the most readily mobilized (18:5n-3). For a given chain length, the relative mobilization increased exponentially with unsaturation, e.g., increasing from 0.45 to 2.7 in C 20 fatty acids when the number of double bonds increased from 0 to 5. Amongst the fatty acids with 18 to 22 carbon atoms, the shorter the chain was, the more steeply relative mobilization increased with unsaturation. On the other hand, for a given unsaturation the relative mobilization decreased with increasing chain length, e.g., decreasing from 1.15 to 0.3 in monoenes when the chain length increased from C 14 to C 24. A two-carbon-atom shortening of the chain length was on average equivalent to inserting one double bond for increasing the relative mobilization, i.e., by about 40%. The relative mobilization was also affected by the position of the double bond(s); increasing on average by 10% when there was a two-carbon-atom displacement towards the methyl end of the chain. These results demonstrate that under conditions of stimulated lipolysis individual fatty acids are more readily mobilized from fat cells when they are short and unsaturated, and when their double bonds are closer to the methyl end of the chain.(ABSTRACT TRUNCATED AT 400 WORDS)

***
Diabetes Care. 2002 Aug;25(8):1283-8. Links
Effects of diets enriched in saturated (palmitic), monounsaturated (oleic), or trans (elaidic) fatty acids on insulin sensitivity and substrate oxidation in healthy adults.

* Lovejoy JC,
* Smith SR,
* Champagne CM,
* Most MM,
* Lefevre M,
* DeLany JP,
* Denkins YM,
* Rood JC,
* Veldhuis J,
* Bray GA.

Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, Louisiana 70808, USA.

OBJECTIVE: Diets high in total and saturated fat are associated with insulin resistance. This study examined the effects of feeding monounsaturated, saturated, and trans fatty acids on insulin action in healthy adults. RESEARCH DESIGN AND METHODS: A randomized, double-blind, crossover study was conducted comparing three controlled 4-week diets (57% carbohydrate, 28% fat, and 15% protein) enriched with different fatty acids in 25 healthy men and women. The monounsaturated fat diet (M) had 9% of energy as C18:1cis (oleic acid). The saturated fat diet (S) had 9% of energy as palmitic acid, and the trans fatty acid diet (T) had 9% as C18:1trans. Body weight was kept constant throughout the study. After each diet period, insulin pulsatile secretion, insulin sensitivity index (S(I)) by the minimal model method, serum lipids, and fat oxidation by indirect calorimetry were measured. RESULTS: Mean S(I) for the M, S, and T diets was 3.44 +/- 0.26, 3.20 +/- 0.26, and 3.40 +/- 0.26 x 10(-4) min(-1). microU(-1). ml(-1), respectively (NS). S(I) decreased by 24% on the S versus M diet in overweight subjects but was unchanged in lean subjects (NS). Insulin secretion was unaffected by diet, whereas total and HDL cholesterol increased significantly on the S diet. Subjects oxidized the least fat on the M diet (26.0 +/- 1.5 g/day) and the most fat on the T diet (31.4 +/- 1.5 g/day) (P = 0.02). CONCLUSIONS: Dietary fatty acid composition significantly influenced fat oxidation but did not impact insulin sensitivity or secretion in lean individuals. Overweight individuals were more susceptible to developing insulin resistance on high-saturated fat diets.

***
Int J Obes Relat Metab Disord. 2002 Jun;26(6):814-21. Links
The influence of the type of dietary fat on postprandial fat oxidation rates: monounsaturated (olive oil) vs saturated fat (cream).

* Piers LS,
* Walker KZ,
* Stoney RM,
* Soares MJ,
* O'Dea K.

Menzies School of Health Research, Casuarina, Australia. [email protected]

OBJECTIVE: To compare postprandial whole-body fat oxidation rates in humans, following high-fat (43% of total energy) mixed breakfast meals, of fixed energy and macronutrient composition, rich in either monounsaturated fat (MUFA) from extra virgin olive oil or saturated fat (SFA) from cream. DESIGN: Paired comparison of resting metabolic rate (RMR), thermic effect of a meal and substrate oxidation rates following consumption of isocaloric breakfast meals, differing only in the type of fat, administered in random order 1-2 weeks apart. SUBJECTS: Fourteen male volunteers, body mass index (BMI) in the range 20-32 kg/m(2), aged 24-49 y and resident in Melbourne, Australia, were recruited by advertisement in the local media or by personal contact. MEASUREMENTS: Body size and composition was determined by anthropometry and dual energy X-ray absorptiometry (DEXA). Indirect calorimetry was used to measure RMR, thermic effect of a meal, post-meal total energy expenditure and substrate oxidation rate. Blood pressure and pulse rates were measured with an automated oscillometric system. Fasting and 2 h postprandial glucose and insulin concentrations and the fasting lipid profile were also determined. RESULTS: In the 5 h following the MUFA breakfast, there was a significantly greater postprandial fat oxidation rate (3.08+/-4.58 g/5 h, P=0.017), and lower postprandial carbohydrate oxidation rate (P=0.025), than after the SFA breakfast. Thermic effect of a meal was significantly higher (55 kJ/5 h, P=0.034) after the MUFA breakfast, in subjects with a high waist circumference (HWC > or = 99 cm) than those with a low waist circumference (LWC<99 cm). This difference was not detected following the SFA breakfast (P=0.910). CONCLUSION: If postprandial fat oxidation rates are higher after high MUFA, rather than SFA meals, then a simple change to the type of dietary fat consumed might have beneficial effects in curbing weight gain in men consuming a relatively high-fat diet. This may be particularly evident in men with a large waist circumference.

***
Br J Nutr. 2003 Sep;90(3):717-27. Links
Substitution of saturated with monounsaturated fat in a 4-week diet affects body weight and composition of overweight and obese men.

* Piers LS,
* Walker KZ,
* Stoney RM,
* Soares MJ,
* O'Dea K.

Menzies School of Health Research, Casuarina, Northern Territory, Australia. [email protected]

A randomised crossover study of eight overweight or obese men (aged 24-49 years, BMI 25.5-31.3 kg/m(2)), who followed two diets for 4 weeks each, was performed to determine whether substitution of saturated fat with monounsaturated fat affects body weight and composition. Subjects were provided with all food and beverages as modules (selected ad libitum) of constant macronutrient composition, but differing energy content. The % total energy from saturated fat, monounsaturated fat and polyunsaturated fat was 24, 13 and 3 % respectively on the saturated fatty acid (SFA)-rich diet and 11, 22 and 7 % respectively on the monounsaturated fatty acid (MUFA)-rich diet. MUFA accounted for about 80 % of the unsaturated fats consumed on both diets. Body composition, blood pressure, energy expenditure (resting and postprandial metabolic rates, substrate oxidation rate, physical activity), serum lipids, the fatty acid profile of serum cholesteryl esters and plasma glucose and insulin concentrations were measured before and after each diet period. Significant (P< or =0.05) differences in total cholesterol and the fatty acid composition of serum cholesteryl esters provided evidence of dietary adherence. The men had a lower weight (-2.1 (SE 0.4) kg, P=0.0015) and fat mass (-2.6 (SE 0.6) kg, P=0.0034) at the end of the MUFA-rich diet as compared with values at the end of the SFA-rich diet. No significant differences were detected in energy or fat intake, energy expenditure, substrate oxidation rates or self-reported physical activity. Substituting dietary saturated with unsaturated fat, predominantly MUFA, can induce a small but significant loss of body weight and fat mass without a significant change in total energy or fat intake.

http://articles.mercola.com/sites/articles/archive/2002/02/23/vegetarianism-myths-06.aspx


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[אבי כהן]

שתי הערות משה:
1. אתה חייב לגוון קצת את מה שאתה עושה בשעות האלו של הלילה 😆
2. אני לא קורא ציטוטים ממחקרים שנערכו לפני שנת 2000

אז מה הסוף? Inconclusive ?

 

[Mike Bikov]

בשבילך זה לילה, בשבילי זה בוקר.
בקשר לשנת 2000, יש המון דברים שאתה עושה ביומיום או שעשית עד היום שקושרים במחקרים שנעשו אי שם בשנות ה60 (טיפטון לדוגמא)