Early in my career as a dietitian, I faced a common problem. I was working in medical centres and seeing clients who would be bulk billed, so their session was free of charge.
When I would ask “what are we looking to do today?” I would often get a response along the lines of “I have high cholesterol and my doctor said I should come see you. I don’t really think I’ll get much out of this, but they told me to come anyway.”
Obviously giving standard nutrition advice to reduce cholesterol would not really cut it. Advice that is commonly given or would take a lot of effort to implement would likely not be received overly well due to the lack of buy-in and trust.
This is where plant sterols come in. They are a simple way to reduce cholesterol by a significant degree with minimal effort.
This was my way in to provide a recommendation that could be an easy win, encouraging them to be more open to future recommendations.
Plant sterols should not be used as the ONLY strategy to help manage cholesterol of course. But if we can get an easy win that requires minimal effort, then it is worth exploring that option.
What Are Plant Sterols?
Plant sterols are a naturally occurring part of all plants. They are substances that are similar to cholesterol, except in plant form.
They are mainly found in vegetables, nuts, legumes, seeds, fruits and grains.
The mechanism through which they can help reduce cholesterol levels in the blood is by reducing the absorption of cholesterol in the first place and increasing the excretion of it.
Benefits
Plant sterols consistently reduce cholesterol levels, particularly LDL cholesterol.
On average, research has shown consistent consumption of 1.5-3g of plant sterols per day reduces LDL cholesterol by 7.5-12%.
These studies all differ in length, but there is one study that identified a 14% reduction in those who took plant sterols for a full year.
If you have high cholesterol, this can be something that makes a significant difference.
For context, the average person appears to get around 400mg through food, while those who follow plant-based diets consume around 600mg on average.
To get to that 1.5-3g dosage, supplementation or consuming foods fortified with plant sterols is likely necessary.
Is There Any Controversy?
Plant sterols seem to be too good to be true. It is rare that a supplement (not medication) has a clinically meaningful improvement that translates to significantly improved health outcomes.
I think whenever something seems too good to be true, people naturally want to identify if there is a catch.
The first piece of controversy that is often highlighted is that there is no actual evidence that plant sterols reduce the risk of cardiovascular events from occurring.
Typically reducing cholesterol reduces the risk of cardiovascular disease. It is intuitive to assume that plant sterols should help reduce that as well.
To be clear though, the reason there is no evidence on this topic is that it has not been directly studied. I have seen other practitioners highlight that there is no evidence, almost as if they are suggesting that there is evidence that it does NOT reduce the risk. But at this stage, it is just unclear.
Other people have proposed that because there are high levels of plant sterols identified in those with sitosterolaemia (a rare condition), which is associated with cardiovascular issues, maybe plant sterols can be actively harmful.
I think this is a line of thinking worth keeping an eye on, but at this stage, it is not something I see as overly concerning.
Something that dramatically reduces the concern I would have over stuff like that is that even in one of the two main papers highlighting this controversy, this line is present:
“Since the introduction on the market of the first phytosterol enriched margarine, no cases with negative health effects have been reported.”
My interpretation is that plant sterols when used in normal dosages, do not appear harmful. The worst-case scenario is that they reduce cholesterol without impacting cardiovascular disease risk. The best-case scenario is they help reduce BOTH cholesterol and cardiovascular disease risk.
Dosage and How to Take
The standard dosage is 2-3g of plant sterols per day.
Going a bit above 3g does not appear harmful but does not provide any additional benefit.
This can be consumed in either supplement form or by choosing foods that have been fortified with plant sterols.
In Australia common products include:
While some have proposed that consuming it within food could improve the effectiveness of plant sterols, research has shown that capsule form works just as effectively.
Splitting the dosage 3x per day, alongside breakfast lunch and dinner might be slightly superior to having just 1x per day at any time. At this stage my recommendation is to do that if it is feasible and easy to do so.
Consistency is a lot more important though. Having it 1x per day at any time (ideally alongside food) appears to work quite well still.
Is It Possible to Get Enough Through Food Instead of Supplementing?
I understand the appeal of trying to limit supplementation where possible. A food-first approach makes a lot of sense.
My philosophy on supplements is that they can be beneficial if we are consistently going to be getting a sub-optimal amount through food.
With plant sterols, that likely is to be the case.
As mentioned, the average person gets around 400mg per day through food. This is 13-20% of the optimal amount.
Even if you were to eat triple the amount most people get, it would still fall short of the target.
Unfortunately, the other issue is that it is hard to measure your intake through food. I have previously looked into this and could not easily find the average plant sterol content of different foods to make a plan that could reach these targets.
I would say it is possible to achieve these targets, it is just highly unlikely to happen for most people.
Side Effects
Outside of the potential controversy stuff that was addressed earlier, side effects seem to be minimal.
There is potential that plant-sterol supplementation might reduce the absorption of certain fat-soluble vitamins a little bit. The impact appears to be relatively mild if it occurs and can be comfortably offset by consuming a slightly more nutrient rich diet.
When consumed in large amounts they may increase the risk of GI upset. This outcome seems very rare when consumed in the recommended amounts though.
Another area people are often curious about is whether they can be used alongside statins. They work through different mechanisms and appear to be fine to take alongside each other. You would want to consult with your doctor about it though, since it might reduce the dosage of the statins required to achieve the desired outcome.
Summary
Plant sterols were identified in the 1950s but have really gained momentum since the 1990s when they were first effectively integrated into food products for fortification.
They have been quite well studied and consistently reduce LDL cholesterol with minimal identifiable downsides.
It is not guaranteed that they reduce the risk of cardiovascular disease complications, although theoretically, it makes sense to assume that they likely could.
For now, while I would not suggest that it should be a first-line recommendation for everybody with high cholesterol, it is definitely an option worth exploring.
Since it is a relatively easy thing to add with an average improvement of ~10% in terms of reducing cholesterol, it makes sense for a lot of people to consider in addition to other options that can help manage cholesterol.
