Tuesday, January 5, 2010

sorry for going MIA {again}

I promise I’m still alive. I really didn’t intend to go this long between posts, but it just sort of happened. I hope that you’ll bear with the sporadic posting due to the craziness of my dietetic internship.
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Thanks for all of the positive feedback on my first post on fat. This topic is not easy for me to write about, especially because it goes against mainstream nutrition principles. Just a forewarning: usually I hate writing super wordy posts, but this one is a doozy {kudos if you get all the way through..}
Basically, there are 2 sides to this story. One side, supported by the American Dietetic Association and the American Heart Association, is the basis for our current dietary recommendations on fat and holds that saturated fat is the main cause of increased cholesterol levels and heart disease.
Lipid Hypothesis
hamburger
There have been numerous studies that have examined the link between saturated fat intake and heart disease:
  • Ancel Keys conducted research in the 1950’s which concluded that high saturated fat intake was associated with high cholesterol which was associated with heart disease. However, many studies have questioned both the methodology and conclusions from his studies.
  • The Framington Heart Study (1948) compared subjects who consumed large amounts of saturated fat and cholesterol with those who consumed little. Recent results showed that subjects with high cholesterol or blood pressure were at increased risk for CHD, but high cholesterol was not related to dietary fat or cholesterol intake.
  • The Lipid Research Clinics Coronary Primary Prevention Trial (LRC-CPPT), is often used to justify low fat diets due to the finding that every 1% reduction in serum cholesterol levels led to a 2% reduction in the risk for CHD. However, all subjects consumed a low-cholesterol, low-saturated-fat diet, and the experimental group was also given a cholesterol-lowering drug. Independent researchers who tabulated the results of this study found no significant statistical difference in coronary heart disease death rates between the two groups.
The other side of the story…
avocado
In addition to the flaws in the studies discussed above, there have been numerous studies which support the conclusion that saturated fat does not cause heart disease.
  • The incidence of heart disease has increased since 1920, but the consumption of animal fat in the American diet has decreased.
  • The Mediterranean diet contains a high percentage of saturated fat, yet incidence of heart disease is quite low in this area.
  • Studies have shown that when overweight persons with high cholesterol and triglycerides were put on high fat and low carbohydrate diets, their lipid profiles improved significantly (Volek, 2008).
  • The American Journal of Clinical Nutrition just published a study this month evaluating the association of saturated fat with heart disease and found that the intake of saturated fat was not associated with an increased risk of coronary heart disease, stroke, or cardiovascular disease.
Bottom line: I’m uncertain of the link between dietary intake of saturated fat and cholesterol and heart disease. I don’t think an extremely low fat diet is beneficial or maintainable, but I also don’t think that severely limiting carbs is a good idea either. So that leaves us back where we started…moderation.
Stay tuned for part 3…answers to your questions and what other researchers say causes heart disease.
Feel free to comment with any additional questions, and I’ll try to include them in the next post.
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16 comments:

  1. great post thats why as dietitians we have to stay up to date on all the latest research as its constantly changing!

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  2. you are learning soo much! i loved reading this! thanks for the info girl! miss youuu!

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  3. Great post - I agree with you, I think moderation is key as the studies don't provide a scientific conclusion either way.

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  4. Such a great post- I love reading stuff like this! Really interesting that saturated fat isn't necessarily linked to cardiovascular disease...hmmm... It's hard to keep up with all the research beine done. Every week seems to bring new studies proving something different.

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  5. I agree, extremely low fat intake diet is really bad for women specially. Now when I check labels, I make sure that's high in "good" fat and low in sugar.
    Do you know what's the recommended daily fat intake per weight?

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  6. so interesting em! I'm stumped by that recent study not finding any relationship between sat fat and heart disease. Balance and exercise has to be key and reducing simple carbs. I want to look into more about coconut oil/fat and I'm sure you have a post on this too. Thanks! Good luck with your internship, looking forward to the next installment!

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  7. Yes, I heard about this new information too. I guess we will just wait to see what comes of this and what further research indicates. I think that even though saturated fat has decreased in American diets, there are other factors that can't be controlled for, like the decrease in labor intensive jobs to desk jobs, and with the mediterannean diet, they tend to eat more fruits and vegetables than Americans and are not AS obese (yet), and have higher intakes of antioxidants, so are there other things out there with protective factors in diets that contain high amounts of saturated fat. I guess we'll see in time what the final verdict is here.

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  8. thanks emily! I read the whole thing, yup! very interesting, and I need to learn to be more critical about reserach, and base my opinions on evidence. hmm, can't wait for the next one. Where did you learn about the Weston A Price Foundation? thanks again!

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  9. Welcome back Em! I've missed your posts, but I and everyone understand your busy schedule. It is interesting to see both sides, and more than ever I conclude balance is important.

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  10. Don't worry about not posting - life just happens, you know?! I love these posts! I always try to have the 'moderation' view even though there are a lot of vocal people on both sides of the spectrum. Thanks for the facts!

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  11. i can run faster than you. hehe.

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  12. You always write such informative posts.

    I never can get the fat-thing right. I'll just continue to pretend that I'm eating a moderate amount and wonder why my thighs are growing larger...

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  13. Moderation and variety is the key to health and happiness. It's all about finding a happy balance and staying in tune with your body-- it knows what it needs!

    have a wonderful evening <3

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  14. Great post! I guess everything in life is about balance.

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  15. I'm definitely happier on more fat, although I don't think my saturated fat intake is very high (except from chocolate!) Mainly, I eat a lot of nuts and EVOO. And I have way more energy than when I restricted fats. It is strange to go against what I've heard for so long (and still hear constantly) that low fat is best. It just doesn't work for me.

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  16. very well put! and it wasn't super wordy...i actually think its pretty concise! i'm glad that there are upcoming RD's like you who are not afraid to challenge "mainstream" nutrition. it seems that there was a lot of not-so-good science used to come up with the original saturated fat recommendations, and these recommendations need to be challenged! good luck with the rest of your internship!!

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