The Truth About Dietary Cholesterol | Dr. Peter Attia & Dr. Andrew Huberman
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00:00:02.160 | Most people are operating under the assumption
00:00:08.260 | that eating saturated fat is bad
00:00:10.580 | and you only do it insofar as you want to taste it.
00:00:14.100 | And then of course there's a small group of people
00:00:16.260 | that love to eat organs and meats
00:00:18.720 | and really pack cholesterol
00:00:21.060 | and would argue that it doesn't matter
00:00:23.100 | if your LDL is 870, it's not gonna impact your health.
00:00:27.580 | What's the reality around LDL, HDL, dietary cholesterol,
00:00:32.220 | saturated fat, at least in your view?
00:00:34.940 | - So first let's differentiate between cholesterol and fat
00:00:38.860 | just for the listener, 'cause we use them,
00:00:42.060 | I don't wanna make sure people understand.
00:00:43.420 | So cholesterol is a really complicated molecule.
00:00:46.740 | So it's a ringed molecule.
00:00:48.740 | God, I used to know exactly what its structure was,
00:00:52.320 | but it could have 36 carbons for all I remember.
00:00:56.180 | It is a lipid, so it is a hydrophobic molecule
00:00:59.860 | that is synthesized by every cell in the human body.
00:01:04.140 | It is so important that without it,
00:01:07.180 | if you look at sort of genetic conditions
00:01:10.860 | that impair cholesterol synthesis,
00:01:13.700 | depending on their severity, they can be fatal in utero.
00:01:17.420 | So in other words, anything that really interferes
00:01:19.900 | with our ability to produce cholesterol
00:01:23.500 | is a threat to us as a species.
00:01:26.100 | And the reason for that is cholesterol makes up
00:01:29.540 | the cell membrane of every cell in our body.
00:01:32.580 | So as you know, but maybe the listeners don't,
00:01:36.120 | even though a cell is a spherical thing,
00:01:38.340 | it has to be fluid, right?
00:01:40.060 | It's not just a rigid sphere, like a blow up ball, right?
00:01:44.460 | It's gotta be able to kind of move in this way
00:01:48.060 | to mesh with other cells.
00:01:50.540 | It also has to accommodate having porous structures
00:01:53.780 | that traverse its membrane to allow ions
00:01:57.500 | and things like that to go across.
00:01:59.820 | And it's cholesterol that gives the fluidity
00:02:02.540 | to that membrane.
00:02:04.280 | It's also, as you're alluding to,
00:02:06.020 | the backbone of some of the most important hormones
00:02:09.300 | in our body, estrogen, progesterone, testosterone, cortisol.
00:02:14.300 | So we have this thing, super important, okay.
00:02:19.060 | Then let's talk about, can you get cholesterol in your diet?
00:02:23.340 | Yes, you can eat foods that are rich in cholesterol.
00:02:26.480 | What was known in 1960,
00:02:31.580 | but somehow escaped everybody's imagination
00:02:34.960 | until finally the American Heart Association
00:02:36.900 | acknowledged this a few years ago,
00:02:38.940 | is that the cholesterol you eat
00:02:41.060 | does not really make it into your body.
00:02:43.340 | And the reason for that is it's hysterified.
00:02:45.780 | So we have, and not to get too nerdy,
00:02:48.140 | but I think people, I think if,
00:02:49.700 | I really think it's important people understand
00:02:51.100 | how this thing works.
00:02:51.940 | So we have cells in our gut, and enterocytes,
00:02:54.900 | they're the endothelial cells of our gut.
00:02:57.500 | They have, each one of them has basically
00:03:00.620 | two transporters on them.
00:03:01.820 | So the first is called
00:03:02.980 | the Niemann-Pick C1-Like-1 Transporter.
00:03:06.140 | The second is called the ATP Binding Cassette G5/G8.
00:03:10.180 | Okay, the Niemann-Pick C1-Like-1 Transporter
00:03:14.560 | will bring in any sterol, cholesterol,
00:03:17.960 | zoosterol, phytosterol, any sterol
00:03:20.680 | that fits through the door will come in.
00:03:22.680 | Virtually all of that is the cholesterol we produce
00:03:28.380 | that gets taken back to the liver,
00:03:30.600 | that the liver packages in bile and secretes.
00:03:34.100 | So that's what aids in our digestion,
00:03:35.940 | which is another thing I should have mentioned earlier.
00:03:37.560 | In addition to using cholesterol
00:03:39.920 | for cell membranes and hormones,
00:03:41.920 | we wouldn't be able to digest our food without cholesterol
00:03:44.340 | because it's what makes up the bile salts.
00:03:47.240 | So our own cholesterol is basically recirculated
00:03:50.320 | in a pool throughout our body,
00:03:52.020 | and this is the way it gets back into the body.
00:03:54.720 | It's through this Niemann-Pick C1-Like-1 Transporter.
00:03:57.840 | When it gets in there, the body,
00:03:59.780 | this is the checkpoint of regulation.
00:04:01.680 | This is where the body says,
00:04:02.600 | "Do you have enough cholesterol in the body, yes or no?"
00:04:05.480 | If yes, I will let that cholesterol
00:04:08.280 | make its way into the circulation.
00:04:10.500 | So it'll go off the basolateral side of the cell,
00:04:13.200 | not the luminal side, into the body.
00:04:15.220 | Alternatively, the body says,
00:04:16.740 | "You know what, we have enough cholesterol.
00:04:19.160 | "I'm gonna let you poop this out."
00:04:20.580 | And now the ATP binding cassette will shoot it out.
00:04:23.180 | It'll go back into the luminal side, and away it goes.
00:04:25.880 | So all of the cholesterol in our body is not esterified,
00:04:31.040 | meaning it doesn't have that big,
00:04:32.260 | bulky side chain attached to it.
00:04:34.980 | The cholesterol you eat is esterified,
00:04:37.580 | and an esterified cholesterol molecule
00:04:40.320 | simply can't physically pass
00:04:42.080 | through that Neiman-Pixey 1-like-1 Transporter.
00:04:44.340 | Now, we probably manage to de-esterify
00:04:49.340 | 10 to 15% of our dietary cholesterol.
00:04:53.380 | So in other words, there are small amounts
00:04:55.480 | of dietary cholesterol that do make their way
00:04:58.020 | into our circulation, but it represents a small fraction
00:05:02.920 | of our total body's pool of cholesterol.
00:05:05.300 | Again, this was known, even by Ancel Keys,
00:05:08.580 | the guy who turned fat
00:05:10.660 | into the biggest boogeyman of all time.
00:05:12.700 | Ancel Keys acknowledged this in the 1960s.
00:05:15.880 | Dietary cholesterol plays no role in serum cholesterol.
00:05:19.160 | Again, it took the American Heart Association
00:05:22.240 | another 60 years to figure that out,
00:05:24.520 | but even now they acknowledge that.
00:05:26.700 | Dietary cholesterol has no bearing.
00:05:28.680 | - So why is it that it's pretty easy to find studies,
00:05:33.160 | or at least people who are highly credentialed
00:05:36.120 | from good institutions,
00:05:37.180 | claiming that eating saturated fat, cheese-
00:05:40.560 | - Saturated fat's different.
00:05:41.520 | - Saturated fat, red meat,
00:05:42.760 | things that are rich in cholesterol,
00:05:45.160 | to be more specific, is bad for us
00:05:49.080 | in terms of our eventual LDL.
00:05:51.080 | - So this is two different things.
00:05:52.280 | So saturated fat consumption in many people
00:05:55.800 | will raise LDL cholesterol.
00:05:58.000 | So it's important to differentiate
00:06:00.080 | between the, what is saturated fat?
00:06:02.040 | So saturated fat, of course, is a fatty acid,
00:06:04.000 | just so people understand,
00:06:05.080 | totally different molecule from cholesterol.
00:06:06.720 | Cholesterol has this very complicated ring structure,
00:06:09.080 | multiple rings stuck together.
00:06:11.240 | SFA, saturated fat, is just a long-chain fatty acid
00:06:14.440 | that is fully saturated, meaning it has no double bonds,
00:06:17.300 | and it can exist in isolation,
00:06:19.240 | it can exist in a triglyceride, triacylglyceride,
00:06:22.400 | or a phospholipid, or all sorts of things like that.
00:06:26.280 | So when we eat foods that contain fat,
00:06:30.880 | basically there are three distinctions for that fat.
00:06:33.480 | Is it saturated?
00:06:34.560 | Is it monounsaturated, one double bond?
00:06:36.360 | Or is it polyunsaturated, two or more double bonds?
00:06:38.920 | The observation that eating saturated fat
00:06:43.800 | raises cholesterol is generally correct.
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