[Rhonda]: You mentioned earlier that we produce cholesterol in our cells, we're making cholesterol
ourselves.
And I think that most people think about cholesterol in their body as originating from the food
they eat.
They think, for example, if they eat an egg, a yolk, which is high in cholesterol, if they
eat six of those eggs, then their blood cholesterol is going to go up, but that's not necessarily
true.
Can you explain?
[Ron]: So one of my multiple lives has been in the world of nutrition, and, early on,
I've been interested in nutrition virtually all my life and really came into lipoprotein
research because I had felt that diet had a very important role in heart disease, and
the lipoprotein effects of diet, I thought, were really important.
And I've been studying that now for a long time.
And so I became involved, not just on the research side of things, but also more on
the public health side through my work with the American Heart Association, I became chairman
of the nutrition committee quite a few years ago now.
And I remember that committee, which has now morphed into a larger organization that I
helped to establish within the AHA, so I've been an important part of the American Heart
Association's messaging to the public.
[Rhonda]: You're involved in the dietary guidelines, right?
[Ron]: Yeah, from the American Heart Association, I've actually did that twice.
And so I was forced to sort of deal with translating the science, such as it is, about diet and
heart disease risk into something that could be actionable.
And that's tough because the data linking diet to heart disease risk through any mechanism,
lipids or otherwise, really doesn't necessarily establish a causal role because there's so
many features in diet.
You can't just easily pick one thing or another.
But cholesterol was on the radar screen.
So, when I became chairman of the nutrition committee on my first cycle, there was a lot
of media.
I spent a lot of my time dealing with the media, and I was just astonished by the questions
I would get about dietary cholesterol, blood cholesterol, and, as we say, people just conflated
those two terms.
And I've spent a considerable portion of my time trying to educate, like, the so-called
science...well, the science writers who are often not trained in science at all, actually,
I'm sorry if I offended anyone.
But they are trying to understand this and they just simplify this right to the point
where it becomes totally meaningless.
The body makes cholesterol.
It regulates the absorption of cholesterol from foods.
And the contribution of dietary cholesterol on blood cholesterol, I was actually forced
to address this in a very rigorous way through a committee that I was on for the Institute
of Medicine of the National Academy of Sciences, which established dietary recommendations
for macronutrients, which it was the first time that anybody really did that seriously.
So we produced this enormous volume.
We had a committee looking at every aspect of macronutrients and health.
And my topic, which I had to take on, was cholesterol, dietary cholesterol.
And when I went through the literature, I was just astonished that how small the effect
is, and it's very difficult to even imagine how an effect of excess dietary cholesterol
couldn't influence heart disease risk unless when you either had a mutation that caused
the cholesterol to build up, or when receiving an enormous amount of dietary cholesterol.
But for the most part, the effect was so small that it was almost unmeasurable.
So we wrote that report and I'd sort of made that point.
And then 15 years later, the current dietary guidelines come out saying, "After all these
years of recommending keeping cholesterol less than 300 milligrams per day, we realized
that we no had data to support that."
And so it took a long time for the U.S. dietary guidelines to catch up, and I was really in
a bind because there was this historical precedent of limiting dietary cholesterol because of
its potential role in blood cholesterol levels.
And it's really not even worth talking about.
[Rhonda]: But the idea is still out there, and physicians still even recommend not eating
eggs.
[Ron]: I know.
Yeah.
So eggs is in a whole, another story.
And so, again, when it moves from dietary components to the food that those components
are contained in, which was really one of the messages that I've tried to emphasize
in all the work that we've done, trying to reach the public, which is, again, a nice
opportunity here for me to do this with you, is that we should be thinking about the overall
context in which those nutrients are adjusted, foods and dietary patterns.
And finally, the U.S. dietary guidelines are beginning to think about dietary patterns
rather than just individual nutrients.
However, they still have not abandoned focus on measuring this or that fatty-acid.
We should be thinking more about the overall food context.
And the important regulators of heart disease risk from a dietary standpoint go way beyond
the effects on blood cholesterol.
And we have to think of a lot more complexity in the role of diet, not that cholesterol
and lipoprotein effects aren't important.
In here, we can point to saturated fatty acids, for example, we can have a discussion about
that if you wish, raising blood LDL levels.
Does that translate into higher heart disease risk?
Well, it's very hard to show that.
In fact, there's almost no evidence to support that relationship.
And parenthetically and maybe importantly, we've shown that the form of LDL that increases
with saturated fat is not the small LDL, but the large LDL.
And in fact, that led me to question whether or not saturated fat was really an important
factor in heart disease risk because our studies did not show that it was increasing small
LDL in the majority of the population.
Maybe there are individuals who are hyper-responders who probably ought to stay away from saturated
fat, but for the general population, I began to suspect that this relationship was not
as strong as people thought because it was the less dangerous form of LDL that was increased
by saturated fat.
In fact, that's what we showed.
And I have gotten involved now in a lot of...
I've taken a lot of heat for that.
But as time has gone on, we first published this with Dr. Siri-Tarino, in my group, about
five years ago now, and we were really hit hard when we published that first paper questioning
the relationship between saturated fat to heart disease risk.
I'm glad to say that, over the last year or two, there have been a number of reports that
have supported that absence of the strong relationship.
And the LDL part of the story, I think, may be part of the reason for that, but there
may be other factors, as well.
Again, it may not be the saturated fat itself that should be incriminated here, it should
be the foods in which that is consumed.
And there may be, for example, in fact, there is evidence from epidemiology that red meat,
particularly processed red meat, which contains saturated fat, may have adverse effects on
heart disease as well as life itself, life expectancy, and other diseases, and it may
not be the saturated fat that's the most important factor there.
We don't know.