Cholesterol is an essential waxy substance used by the body to build cells and make vitamins as well as other hormones. The majority of cholesterol is known as blood, or serum cholesterol and is produced by the liver, whereas the rest comes through the consumption of food and animal products, which is referred to dietary cholesterol1,2.
Good and Bad Cholesterol
There are two main types of cholesterol: the high-density lipoprotein (HDL) which is commonly referred to as the good cholesterol, and the low-density lipoprotein (LDL), known also as the bad cholesterol. The role of HDL is to carry the cholesterol from your cells back to the liver and to clean the build-up of plaque in your arteries via the liver3,4.
LDL carries cholesterol toward the cells that require it, and when there is too much, it can cause the build-up within the artery walls. There is also ongoing research that suggests that abnormally high levels of LDL can lead to heart attacks, strokes, peripheral atrial disease and transient ischaemic attacks (mini-strokes)3.
It is however important to understand the role that cholesterol plays within the body. The terms “good” and “bad” give rise to a lot of confusion, when in fact both forms of cholesterol are necessary for proper cell function and maintenance. They both serve as a key building blocks, created by the liver to aid in the repair of cells and muscular tissue, as well as ensuring proper development of essential hormones.
In addition to dietary cholesterol, the consumption of foods and animal products also raise your triglyceride levels. If you consume extra calories, namely carbohydrates, your liver increases the production of triglycerides to store in your fat cells for later use as energy. When necessary, your body releases them as fatty acids for heat and metabolism. A sustained high triglyceride level, can also be a cause of concern as it shares the same health risks as cholesterol4. Your triglycerides level will rise naturally as your metabolism breaks down the food and funnels it into your fat cells.
Reducing Cholesterol Levels
There are a number of ways to reduce dietary cholesterol, here are a few adjustments you could consider4,5:
- Consuming less saturated fat (lean meats, low-fat animal products)
- Limit calories from fat to be less than 30% of your total calorific intake
- Limit processed and simple carbohydrates (sugar, white flour, baked/deep fried foods)
- Eat foods rich in Omega-3 fatty acids (fish or supplementation)
- Eat more fibrous foods, 25-30g per day (fruit, vegetables, whole grains)
- Limit alcohol consumption
- Quit smoking
- Increase aerobic exercise
Healthy Cholesterol Ranges
The classifications of cholesterol is measured in milligrams per decilitre (mg/dL) or millimole per litre (mmol/L) and can be viewed on your measurement device. For help in choosing the right cholesterol meter, you can read more here. The guidance ranges for cholesterol and triglycerides are as follows2,4,6:
Total Cholesterol (TC)
- Normal: values less than 200mg/dL (5.17mmol/L)
- Borderline high: between 200 – 239mg/dL (5.17 – 6.18mmol/L)
- High: values greater than 240mg/dL (6.21mmol/L)
- Desirable: value less than 100mg/dL (2.58mmol/L)
- Borderline high: between 100 – 159mg/dL (2.58 – 4.11mmol/L)
- High: between 160 – 189mg/dL (4.14 – 4.89mmol/L)
- Very high: value greater than 190mg/dL (4.91mmol/L)
- Low: value less than 40mg/dL (1.03mmol/L)
- Desirable: value greater than 60mg/dL (1.55mmol/L)
- Normal: value less than 150mg/dL (1.69mmol/L)
- Borderline High: value between 150 – 199mg/dL (1.69 – 2.25mmol/L)
- High: value between 200 – 499mg/dL (2.26 – 5.63mmol/L)
The ranges for cholesterol and triglycerides work well as an indication to potential health related issues, however, they should not be considered as absolute or a panic point. Consider for example, you have a high total cholesterol reading. It’s a good point to reflect on your lifestyle: Do you have a healthy diet, did you recently engage in strenuous physical activity, have you consumed a lot of alcohol? Each of these factor in to causing a heightened total cholesterol reading.
You can also calculate your total-cholesterol-to-HDL ratio by dividing TC by HDL value (in mg/dL) as this will give you more insight. A total cholesterol ratio of 3.5:1 is considered very good with anything below 5.1:1 being healthy and acceptable7.
Cholesterol and Diabetes
Type 2 diabetes is associated with a number of lipoprotein abnormalities, including a reduction in HDL, as well as an elevation in LDL and triglycerides. This condition is referred to as diabetic dyslipidaemia and occurs even when the diabetic individual has normal LDL levels. Insulin resistance, another underlying symptom of type 2 diabetes also affects the particle concentrations and lipoprotein sizes of both LDL and HDL. The combination of insulin resistance and diabetic dyslipidaemia puts people at risk for developing premature atherosclerosis and coronary heart disease8,9.
Medical Disclaimer: The information reflected in this article is intended for educational purposes only. Please consult your physician or medical specialist before making any major adjustments to your diet.
- American Heart Association (2020) – Cholesterol 101: An Introduction
- Bellows, L and Moore, R (2012) – Dietary Fat and Cholesterol Fact Sheet No.9319, published to Colorado State University Extension
- NHS Inform (2021) – High Cholesterol
- University of Rochester Medical Center (2021) – Health Encyclopaedia, The Truth About Triglycerides
- Bhatt, A (2018) – Cholesterol: Understanding HDL vs. LDL, published to Harvard Health Publishing
- Rosenson, R (2021) – Patient Education: High Cholesterol and Lipids (Beyond the Basics), published to uptodate.com
- University of Rochester Medical Center (2021) – Lipid Panel with Total Cholesterol: HDL Ratio
- American Heart Association (2021) – Cholesterol and Diabetes
- Krauss, R (2004) – Lipids and Lipoproteins in Patients With Type 2 Diabetes