All about cholesterol
Thought you knew the deal with cholesterol?
If you've had a cholesterol reading, and wonder what to make of it, read on!
Cholesterol is a yellow waxy substance that's made by our liver - did you know that while cholesterol is needed by our body, we don't ACTUALLY need to eat it?!
This is because our liver can make all we need - pretty cool huh!
Cholesterol is also ONLY found in animal products, explaining why people on plant based diets tend to have much lower levels of cholesterol overall, as well as lower rates of the health issues caused by cholesterol.
Cholesterol is a type of fat, and it's measured on blood tests as a way to assess your cardiovascular risk.
Decades of research shows us that's there's a very strong link between too much cholesterol, and higher rates of heart attacks, strokes, and blocked arteries in other parts of the BODY - and despite what you may have seen on social media, the science is incredibly clear on this 😉
Yet while we often think of cholesterol as always being a bad thing, on the flip side it's also important for our health
Cholesterol is used as part of our cell walls, nerve sheaths, and is needed to make sex hormones (ie oestrogen, testosterone), vitamin D, and bile acids (for digesting fat).
So we need some, but not too much!
The other key with cholesterol, is where it goes to in our body - we want it in the right place (for these functions), and not blocking our blood vessels…
When you get a cholesterol reading, it will report different types of cholesterol.
These are the target numbers for cholesterol readings in new zealand (ie what healthy cholesterol readings should look like) :
✔️Total cholesterol <4 mmol/L
✔️LDL cholesterol <2 mmol/L
✔️Triglycerides <1.7 mmol/L
✔️HDL cholesterol >1 mmol/L
✔️Total:HDL cholesterol ratio <4
(note LDL targets are lower for people at high risk of heart disease, or existing heart disease - so it's best to discuss this with your doctor for personalised advice)
Let's take a look at each of these next.
Total cholesterol - this is all the types of cholesterol added together. As it includes both good and bad cholesterol, it's less important than the seperate readings, unless it's very high (ie above 8)
LDL cholesterol - this is 'bad' cholesterol. It's the one that goes out to our blood vessels, and causes atherosclerosis (the blocked arteries that can lead to heart attacks and strokes, as well as some types of dementia, and peripheral vascular disease).
This means higher levels of LDL = more cholesterol going where we don't want it to go
Did you know, that every 1% you reduce your LDL cholesterol, you decrease your risk of heart disease by 2%?!!
LDL comes mostly from fat in our diet, namely saturated fat, and also trans fats. The less we eat of these, the lower our LDL (and heart disease risk) is likely to be.
With the exception of coconut oil and palm oil, saturated fat is found solely in animal products - so the less of these you eat, the less LDL you will produce.
In reality it's more complex than this (genetics also plays a role), but it's a good general rule.
Trans fats also elevate LDL, they are artificial fats made by food processing - they are harmful to health and best avoided (they're labelled as 'partially hydrogenated vegetable oil' on food labels, and are found in ultraprocessed foods)
Triglycerides - these are also a type of fat, and are the bodies storage system for excess energy
When we eat more calories than we need immediately, our liver turns these into triglycerides and stores them in fat cells
We need some triglycerides for backup energy supplies - but if your blood levels are high, it indicates that the storage 'units' are too full and are spilling over into your bloodstream ie that your body is struggling to cope
This is usually caused by eating excess calories (in particular from added sugar, refined carbohydrates, and too much food in relation to activity levels, as well as alcohol.)
High triglycerides are often an early sign of insulin resistance (prediabetes), and can also indicate fatty liver disease.
If you have high fasting triglycerides, this is a very strong signal that your body is having trouble dealing with the amount of calories you are eating - which is why high triglycerides are also a sign of insulin resistance (the precursor to type 2 diabetes). Even high non fasting triglycerides are not a good sign.
High triglycerides can also be a marker of fatty liver disease, due to excess fat being stored in the liver (ie when our fat cells get too full). With this, liver function tests are slightly abnormal as well.
The main message here is - high triglycerides are not normal, so don’t ignore them!!
HDL cholesterol - this is the good one, it transports cholesterol molecules from our blood stream back to our liver, where it is used up. HDL is highly protective against heart disease.
In general we want HDL levels to be higher, and LDL levels and triglycerides to be lower.
So how can we improve cholesterol readings with lifestyle?
1) Plant foods are naturally cholesterol free (so the more you eat, the better 🌱)
Plants also contain fibre and other nutrients, which actually lower bad cholesterol (LDL).
There is even a cholesterol lowering diet called the portfolio diet, that's been shown to reduce LDL cholesterol as much as some statin medication!
It contains a variety of whole plant foods proven to help cholesterol levels :
✔️ Soy protein: 50 grams per day (ideally unprocessed soy, ie tofu, edamame beans, miso)
✔️Plant sterols: 2 grams per day
✔️Nuts: 45 grams per day ie 1 handful, or about 23 almonds
✔️Soluble fiber: 18 grams per day (ie from oats, barley and other whole grains)
2) Saturated fat and trans fats have the biggest effect on LDL levels, as these are what LDL is made from. So try to limit these as much as possible.
Saturated fat is the fat found in fatty meats (ie red meat), full fat dairy, and eggs
Plants do not contain saturated fat (apart from some tropical oils, such as coconut and palm oil), so as a general rule, the more plants and the less animal products you eat, the lower your LDL will be.
Research shows that for every 1% of energy in our diet that comes from saturated fat, our LDL cholesterol will increase by 0.02–0.04 mmol/L.
Note some people have genetic cholesterol disease where their LDL will be high regardless of diet - there are specific guidelines for managing this, that are best discussed with your doctor.
3) Cholesterol (from foods) actually doesn't affect blood cholesterol readings as much as saturated fat! It's mostly found in animal foods, in particular in egg yolk, shrimp, beef, pork and poultry, as well as cheese and butter.
Remember our body makes all the cholesterol we need - we don’t really need to eat it.
4) Exercising regularly, not smoking, aiming for a healthy weight, increasing omega 3 in your diet (via plant based sources such as chia seeds, linseed, walnuts, and hemp hearts, or via oily fish) can also help increase your HDL levels and protect your heart and blood vessels
5) To reduce your triglycerides, the key is ensuring your body isn't getting more sugar, energy, and refined carbs that it can cope with.
Simple dietary and lifestyle changes can be incredibly effective at reducing triglycerides, these also help reverse insulin resistance and fatty liver disease.
✔️reducing added sugar
✔️swapping out processed carbs for whole grains (ie white flour/rice/pasta for brown)
✔️reducing carbohydrate portion sizes (aim for 1/4 of your plate or less)
✔️cutting back on alcohol
✔️getting more active
Like with everything in lifestyle medicine, every little change counts - and it's never too late to start!!
If you'd like to read about cholesterol in more detail please check out our blog post on this.