Is cholesterol the forgotten anabolic?
Cholesterol is a small, fat-like molecule that supposedly clogs our arteries and kills us. But is cholesterol really the bad guy? Or maybe it’s the opposite: a lifter’s best friend?
Cholesterol & your gains: the research
Riechman et al. (2007) found that cholesterol may be good for your gains. In their study, 49 elderly individuals completed a 12-week strength training program with nutritional guidelines. Retrospective analysis of participants’ nutritional logs showed a linear dose-response relationship between dietary cholesterol intake and lean body mass increases (per DEXA). The more cholesterol they consumed, the more muscle they gained. This relationship held up when protein and fat intake were controlled for. See the figure below.
Lee et al. (2011) compared a high (~800 mg/d) and a low (< 200 mg/d) cholesterol diet in young, healthy adults. The high cholesterol group had a nearly 3 times higher myofibrillar protein synthesis rate 22 hours after intense resistance exercise than the low cholesterol group. Myofibrillar protein synthesis is a measure of muscle growth, specifically how quickly your muscles are creating new proteins, so these findings again suggest a high cholesterol diet is beneficial for muscle growth.
Van Vliet et al. (2017) also found that whole eggs stimulate more myofibrillar protein synthesis than the same amount of protein from egg whites. The yolk is very rich in cholesterol, so knowing that cholesterol stimulates myofibrillar protein synthesis, it’s likely that it’s the cholesterol in whole eggs that makes them great muscle building food.
Most other research on the relationship between cholesterol and muscle growth hasn’t been published yet. Below is a recap of the data we currently have.
- In a similar design as the first study from Riechman et al., Riechman & Gasier (2007) again found beneficial effects of a high cholesterol intake for muscle growth and strength development, though the effects were more modest than in their previous study and it’s unclear if protein intake was controlled for.
- Riechman et al. (2008) performed another replication study and found a dose-response relationship between cholesterol intake and strength development but not lean body mass. Again, it’s unclear if protein intake was controlled for.
- In yet another replication study, Iglay et al. (2009) found no relationship between cholesterol intake and muscle growth or strength development. However, they also did not find any effect of 0.9 vs. 1.2 g/kg/d of protein, which suggests their study was statistically underpowered to research this topic.
Research on statins also hints at a beneficial role of cholesterol for your muscles. Statins are a type of medicine used in the treatment of various cardiovascular (heart-related) problems. Statins lower your cholesterol and a common side-effect is myopathy. Statin therapy can reduce muscle strength and functionality, induce inflammation in your muscles (myositis) and even complete muscle fiber death (rhabdomyolysis).
A low cholesterol intake may also be the reason why lacto-ovo-vegetarian diets tend to result in less muscle growth than omnivorous diets in strength trainees, even with the same protein intake. Cholesterol content in plant lipids is about 100-times lower than in animals. However, many other factors, like protein quality, could also explain the lesser muscle mass of vegetarians.
All in all, the available research suggests a high-cholesterol diet is good for muscle growth and strength development.
How can cholesterol increase muscle growth?
The main-stream media demonize cholesterol based on its potential effects in your blood. If you’ve been basing your perception of cholesterol around that message, you may be surprised to find that cholesterol has several potential mechanisms of action to increase muscle growth.
- Cholesterol increases membrane viscosity, which may influence membrane stability. This may have an influence on the extent to which muscle cells are damaged during exercise and the magnitude of the inflammatory response.
- Cholesterol seems to play a role in the muscle repair process by controlling inflammation. Muscle damage creates inflammation, which leads to the recruitment of immune cells to assist with the recovery process. See our article on why inflammation like cholesterol is wrongly demonized for more information.
- Cholesterol is essential for lipid raft formation. Lipid rafts assemble the components for signalling pathways and enhance signalling between pathways that play an important role for muscle hypertrophy, such as the growth factors IGF-I and mTOR. Cholesterol depletion can lead to protein missorting, which reduces the signal transduction. Activation of mTOR corresponds with the found increase in myofibrillar protein synthesis after cholesterol consumption.
Simply put, cholesterol can help your muscle cells resist damage and can improve their ability to repair themselves after your workouts, which is crucial for muscle growth.
Cholesterol can also improve your gains indirectly.
- Cholesterol is the precursor for anabolic hormones and is crucial for their production.
However, simply having a high serum cholesterol level or eating a ton of dietary cholesterol doesn’t necessarily lead to increased testosterone or more lean body mass gain by itself. The limiting factor of anabolic hormone production is often the transport of cholesterol into mitochondria, where its turnover takes place, not necessarily the amount of cholesterol available in the blood stream. So increased dietary cholesterol intake doesn’t lead to increases in the testosterone level in all studies.
However, we do have indirect evidence from the literature on saturated fat that a typical high cholesterol diet increases testosterone production. Saturated fat is a building block for cholesterol, which in turn is used for testosterone production.
A low saturated fat intake is associated with reduced testosterone production. For example, men going from a 40% fat diet with a high saturated fat intake to a 25% fat diet with a low saturated fat intake experienced a decrease in total and free testosterone levels; going back to their original diet caused testosterone levels to increase again (see graph below if you’re interested in the details). Several other studies have also found that diets low in saturated fat reduce circulating testosterone levels.
In fact, in the first study of cholesterol’s effect on lean body mass, the authors also found a significant correlation between saturated fat intake and lean body mass growth. Many diets with a high cholesterol content are also rich in saturated fat, so this is not too surprising, but it leaves open the possibility that cholesterol is actually irrelevant and it’s all about saturated fat instead. To find out, the Bayesian research team contacted Dr. Riechman, the principal investigator of the above study on cholesterol. He confirmed that they controlled for the total fat intake (and protein and energy intake) in the analysis on cholesterol, strongly suggesting cholesterol plays an independent role for muscle growth.
The cholesterol conspiracy theory
Before everyone starts eating 10 eggs a day, we feel the research is a bit suspect: only about 1 in 3 studies on the relation between cholesterol and muscle growth have been published, even though the research was conducted several years ago already. And most of the published research mentioned above was performed by the same principle investigator, Dr. Riechman, who received research grants totaling roughly $2.7 million (that we could find) from sources including the U.S. Poultry & Egg Association.
However, it’s just a fact that scientific research is expensive, so people willing to put a lot money into it, often have something to gain from it. Individuals like Bret Contreras and Menno Henselmans that pay for scientific research out of their own pocket are very rare. The scientific industry is set up so that the integrity of the researchers should prevent the sponsors’ conflict of interest from deceiving the public. And this generally works. Food industry funded nutrition research does not have significantly different outcomes than research with other funding. Plus, Dr. Riechman also received funding from the American Heart Association and the US Army. Not to mention, it’s pretty damn far fetched to pour millions of dollars and risk your career and reputation to promote – of all things you could sell – cholesterol specifically for – of all possible markets – individuals interested in muscle growth. Us meatheads are a tiny part of the population. Us meatheads interested in scientific research tinier still.
Ok, let’s take the tinfoil helmets off and assume there’s no major conspiracy theory going on. That begs the question…
But isn’t cholesterol bad for your heart?
Nope. The mainstream media portrayal of cholesterol’s health effects is about as accurate as the claim of most Olympians that they’re natural. The media will have you believe all that cholesterol you consume ends up clogging your arteries, but the reality is, for most people how much cholesterol you consume in your diet does not even influence how much cholesterol is in your blood. Cholesterol is so important for the body that it is highly regulated. If your diet does not contain much cholesterol, your intestines will increase their absorption to compensate. If that’s not enough, your body will produce its own cholesterol.
Some people, around 20%, have a genetic variation that makes them absorb or synthesize so much cholesterol that their diet does influence their blood cholesterol level. Even in these hypperresonders, however, a high cholesterol diet does not generally negatively influence their cholesterol profile. If total blood cholesterol increases at all during a high cholesterol diet, both ‘good’ HDL and ‘bad’ LDL cholesterol generally increase in the same proportion.
A review paper on the heart-related health effects of cholesterol concluded: “Epidemiological data do not support a link between dietary cholesterol and cardiovascular disease.”
A review on egg consumption concluded that “the evidence suggests that a diet including more eggs than is recommended (at least in some countries) may be used safely as part a healthy diet in both the general population and for those at high risk of cardiovascular disease, those with established coronary heart disease, and those with type 2 diabetes mellitus.”
- The available research indicates a high cholesterol diet may be advantageous for muscle growth and strength development by increasing muscle cell integrity and signalling for muscle growth. The beneficial cholesterol intake seems to be at least 7.2 mg dietary cholesterol per kg of lean body mass and more than 400 mg in men.
- Since your body autoregulates your blood cholesterol level, a high cholesterol intake generally does not increase your serum cholesterol level. Even in hypperresonders, cholesterol intake does not generally change the ratio of ‘good’ HDL to ‘bad’ LDL cholesterol or cause heart-related problems.
Here’s how much cholesterol is in various foods according to the USDA.
|Food||Serving size||Cholesterol content|
|Egg yolk||1 egg yolk (18 g)||195 mg|
|Whole egg||1 large (60 g)||222 mg|
|Butter||1 tbsp. (14 g)||30 mg|
|Cheese||1 slice (17 g)
|Whole milk||1 cup (230 ml)
|Whole milk yoghurt||100 g||13 mg|
|Red meat||100 g||72 mg|
|Poultry||100 g||58 – 84 g (lower end for lean protein)|
|Giblets (kidney, liver)||100 g||275 – 515 mg|
|Fish||100 g||43 – 65 g (higher end for fatty fish)|
Since only animal foods contain significant amounts of bioavailable cholesterol, vegans may want to compensate for their low cholesterol intake by consuming more (saturated) fat so the body can produce enough of its own cholesterol.
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2020 update: See this post for a new study on this topic.
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