I searched to see if this was posted before but nothing came up. My apologies in advance if this has been posted before.
So I came across this study Changes in atherogenic dyslipidemia induced by carbohydrate restriction in men are dependent on dietary protein source which I thought was pretty interesting. Atherogenic dyslipidemia is a cholesterol pattern which leads to hardening of the arteries.
They are basically contrasting the levels of cholesterol between saturated fat from butter vs saturated fat from plant source in conjunction to beef consumption. The exerpt does not specify whether it is grass-fed beef or conventional beef; but my assumption would be that it's conventional beef since that is the most applicable source to the average beef-consumer.
What's interesting to note is that they found a correlation between higher saturated fat consumption interacting with a micronutrient in beef on lipoprotein metabolism.
I don't think this is anything to get your panties in a knot over. But it might be something to take into consideration.
Personally, I would love to see this study done with grass-fed beef to see if maybe the hormones and preservatives in conventional beef have any impact on saturated fat interaction with beef. But it certainly won't
asked byuser95438 (66)
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on June 24, 2012
at 06:29 AM
For one, it was a randomized cross-over study looking at differences of 2 low-carb diets (compared to baseline), one contained a higher amount of saturated fat (vs MUFA) than the other. Both diets contained lean beef and the different types of fat were added in addition to the beef, so I fail to see how the source of the beef effects the results.
From this interview it looks like the study authors think the saturated fat is increasing absorption of the iron in the beef which is causing the adverse lipid profile, but he emphasizes that they don't know yet at this point why there is a difference. Also, Krauss has this to say about serum ferritin levels in case people jump the gun on this and go get their blood levels tested:
We have tested a standard lab marker for iron status, serum ferritin, but have not found it to correlate with lipid responses to a high beef diet. There are other analyses that could be more informative but not yet in the standard repertoire, and we plan to test these in our current study.
Also, in the comments, Jane points out that in rats SAFA inhibit the absorption of copper and manganese which may affect the antioxidant superoxide dismutase.
Looks like a study to throw into the follow-up pile! Thanks.
on June 24, 2012
at 02:16 AM
I didn't read your link (not yet but I will when I have time to concentrate) but I think that you have to look at what else you are eating in addition to the fat. Is the person eating sugar and carbs along with the fat? I am of the opinion that the sugar and carbs are what make destroy the epithelial lining of the blood vessels making it easy for the cholesterol to stick and cause problems.