(to mods: not asking for medical advice, but about the science of food intake and how it affects cholesterol level in the blood)
Today I was told by my GP that my latest blood work shows a slightly high (not sure about the actual value) reading wrt cholesterol. GP summoned me for an appointment next week, and in the meanwhile asked me to take pictures of what I eat.
I believe that I have a very healthy diet, lot’s of veggies and no processed food. Regardless, I was a bit surprised by this request, as I remember reading in a book that seemed to be quite well researched ( I believe it was “good sugar, bad sugar” by Allen Carr) that the evidence linking cholesterol intake to the amount of cholesterol in the blood is at best sketchy. IIRC, the author concluded that there seemed to be supporting evidence that a drastic reduction of cholesterol intake showed only marginal improvements for the cases in which the level of Chol in the blood is extremely high, and virtually no improvement for less extreme cases.
I asked to the GP on the phone, and they say that “the science that they know is very different”. I read that book maybe ten years ago, so it is very possible that I remember it wrong and/or that new evidence has emerged.
What do the SDMBers have to say about this topic? Both scientific and anecdotal evidence are welcome, the former to fight ignorance and the latter because I am nosy.
Was in the same boat as you, would eat what I thought was a reasonably healthy diet, tried to get my daily dose of veggies and fruits, watch labels like a hawk, etc. I rarely (maybe once a month if not less) eat any fried foods, avoided all red meats (poultry & fish only), yogurt is my staple snack food.
My blood test from 18 months ago made it seemed like I was wolfing down steaks, eggs, & fried chicken every day. Last test from 3 weeks ago did get it close to normal (107), and I have tried to reduce my intake of foods w/ shortening in them (mainly oatmeal cookies & granola bars), so something went right somewhere. Other than that I remain out of clues.
Note I am almost 59 but with a primo circulatory/respiratory system, my estimated max heart rate is ~ 20 BPM above what all of the charts & formulas say it should be, resting is 58-60.
Many years back my cholesterol was quite high, and I cut down on bad foods. That helped somewhat, but didn’t get me down into the recommended range. What I believe did eventually lower my bad cholesterol was losing weight. My cholesterol tends to track my weight; my diet doesn’t seem to have a big impact on it.
People like me I come by my high cholesterol honestly… I inherited it from my parents. How do I know? 35 years ago my GP noticed my cholesterol was high and put me on a strict no-fat diet for a month. Not a low-fat diet mind you, a no-fat diet, and as a result my cholesterol dropped a few points. It was still way above the 200 total cholesterol number that doctors often use as a red line. Even though I lost weight during that month it didn’t help because my cholesterol was endogenous/internal, and not exogenous/external. My body just happens to produce more cholesterol than most other people.
After trying a variety of things, including Niacin that caused me to have daily hot flashes, my GP put me on a Statin and it dropped immediately from 239 to a comfortable 159. If nothing really helps, and someone wants to get their cholesterol down below a certain number, a Statin may be their best course of action.
I was also researching about this a few months because of what my GP has also mentioned to me on my last checkup. It seems like dietary cholesterol (the ones we get from food intake) is not that really relevant to blood cholesterol levels. You may want to check out this article from Healthline to learn more.
You seem to be assuming that “dietary cholesterol” is the same thing as “diet”. The level of cholesterol specifically in foods you eat has very slight effect, if that, on your own cholesterol levels. But the level of fats, especially saturated fats, in the foods that you eat has a significant effect. It’s not the only thing that affects your cholesterol levels (heredity is a big one), but it’s enough to be significant.
To expand a little.
Yes, the vast majority of cholesterol in you is manufactured inside you by the liver.
The liver runs (as does most of the body) as a form of equilibrium system, regulating production and degradation of cholesterol and the balance of HDL and LDL forms. The basic unit of cholesterol is a pretty fundamental building block of your body. It turns up everywhere. Assembly of it into lumps of HDL and LDL and the balance of these is another part of the system. That is what matter here.
The metabolic pathways in the liver managing cholesterol can be affected by other compounds, in particular things like saturated fats, and worse, trans-fats, compete with HDL and LDL degradation pathways and also affect regulation, thus affecting these levels.
So, what you eat can have a significant effect on your cholesterol levels, but it isn’t the cholesterol you eat that has the important effects. It is stuff that affects the regulation pathways.
Actual HDL and LDL levels significantly beyond norms has a good correlation with bad outcomes. Although there is much unjustified hand wringing and prescription of statins in the face of only slightly elevated levels that is probably not justified.
There is a fallacy that if a lot is bad, a little is still bad. IMHO medical science has a habit of being unduly swung by this.
There’s also the issue that correlations aren’t commutative. The research is quite clear that high cholesterol levels are significantly correlated with early death from heart disease and strokes, that eating high amounts of saturated fat increases cholesterol, and that statin drugs decrease cholesterol. Now, one might conclude from this that eating saturated fats will decrease your lifespan, and statins will increase it… but the research on those two questions is far less conclusive. And of course, that’s what you really care about, not the cholesterol itself.
Thank you @Chronos and @Francis_Vaughan, this is very useful. Do you happen to have some references to divulgative meta-research on this topic so that I can develop a slightly more quantitative understanding of the factors at play? Like, expected effect on SDH/LDH levels for different dietary adjustments and starting points. My values are just slightly off from the norm and I have a pretty healthy diet. I suspect that my headroom is pretty limited.
Exactly my concern. I want to understand better so that I can be prepared to challenge GP’s recommendations, should they appear unreasonable.