Eating eggs might up your cholesterol. So what?

Thursday, September 24, 2009 16:18
Comments Off on Eating eggs might up your cholesterol. So what?

Q. One of my friends still insists that dietary cholesterol contributes to body cholesterol. Since I wasn't able to convince him that this isn't true, I tried to look for actual studies and research to prove my point.  Could you direct me to a few studies that show that that dietary cholesterol does not affect our cholesterol levels? Thanks?!

A. First, let me get this out of the way: Many experts strongly doubt that blood cholesterol levels have anything to do with heart disease and that worrying about cholesterol (in your food or your body) is a waste of time.

But you didn't ask me to help convince your friend that he doesn't need to worry about his cholesterol levels; you asked me to supply some evidence that dietary cholesterol does not effect blood cholesterol levels.

Maybe it's more accurate to say that, for most of us, dietary cholesterol doesn't affect blood cholesterol levels in any way that matters–even if you accept the cholesterol/heart disease hypothesis.

A review of 167 studies finds that increasing dietary cholesterol does increase blood cholesterol levels, but only minimally.  On average, every 100mg of cholesterol translates into a 2.2mg/dL increase in total cholesterol.

However, dietary cholesterol increases both "good" and "bad" cholesterol. In fact, even though total cholesterol levels may go up a bit, the HDL/LDL ratio (which many consider to be a better predictor of risk) does not appear to change in response to increased dietary cholesterol. You can read the entire article here: The Impact of Egg Limitations on Coronary Heart Disease

Could limiting dietary cholesterol lower your good cholesterol?

It's interesting to consider that people who limit dietary cholesterol may be reducing their "good" cholesterol as fast as they're reducing their "bad" cholesterol. Not to worry, because the impact of dietary cholesterol on blood cholesterol is fairly minimal. 

The one exception
would be people who have a genetic abnormality that make them extremely
sensitive to the effects of dietary cholesterol. These people usually
know who they are because they have very high cholesterol levels very early in life.

Here's another review article that might be of interest: Cholesterol intake and plasma cholesterol: an update

From the abstract:

Reports from
the Lipid Research Clinics Research Prevalence Study and the Framingham
Heart Study have shown that dietary cholesterol is not related to
either blood cholesterol or heart disease deaths. In a similar manner,
10 clinical trials (1994 to 1996) of the effects of dietary cholesterol
on blood lipids and lipoproteins indicate that addition of an egg or
two a day to a low-fat diet has little if any effect on blood
cholesterol levels. This observation was noted in young men and women
with normal cholesterol levels as well as older subjects with elevated
plasma cholesterol concentrations. 

Unfortunately, this one isn't available on-line in full-text. But if you have access to a medical library the full article will include citations for all the individual studies that the author cites to support his conclusions.

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