High levels of cholesterol are a danger to the kidneys and CKD (Chronic Kidney Disease) patients. A study by the Physicians’ Health Study followed about 4,500 healthy men and collected blood samples for over 10 years. The researchers used a creatinine test to check how well the men’s kidneys were functioning. A creatinine test measures how well the kidneys filter waste from the blood. The study also looked at the cholesterol levels of men. After looking at the kidney function and cholesterol, the researchers discovered that high total cholesterol and high low-density lipoprotein (LDL) or “bad” cholesterol, appeared more often in participants whose kidneys weren’t functioning well.

Men whose kidneys weren’t functioning well also had lower levels of good cholesterol. High-density lipoprotein (HDL) or “good cholesterol” helps keep cholesterol from building up inside blood vessels. A separate study revealed that high levels of “bad” cholesterol or low levels of “good” cholesterol along with high levels of other unhealthy blood lipids can cause kidney problems. Hence, people with high cholesterol levels were about twice as likely to develop chronic kidney disease. Generally,  women have higher levels of HDL cholesterol than men due to their female sex hormone called estrogen.

When the kidneys aren’t functioning well, it also affects the way the body handles cholesterol and other lipids. This is why kidney disease and high cholesterol go hand in hand. Managing a person’s cholesterol level may be one way to slow down the progression or the onset of chronic kidney disease. 

What is Cholesterol?

Cholesterol is a fatty substance found in the blood. The body produces cholesterol as well as gets it from animal-based food sources. Cholesterol plays different functions, including helping in the production of sex hormones and assisting bile production.

It is also a building block for human tissues. Too much cholesterol can build up in the blood vessels that can narrow the vessels and lead to a blockage. As a result, it prevents the blood from getting to a certain area of the body. Coronary heart disease happens when your heart vessels are blocked, which could lead to a heart attack or stroke.

It is very common for people with CKD to have heart and blood vessel disease (cardiovascular). This is the reason why it is necessary to have an annual lab test to check your cholesterol level. If there are changes with your health, your primary health care provider may advise a more frequent lab test to be done.

Different kinds of Cholesterol

Cholesterol is made of different parts which are LDL and HDL. Both are lipoproteins that carry cholesterol through the bloodstream. LDL or low-density lipoprotein is considered bad cholesterol, while HDL or high-density lipoprotein is the “good” cholesterol.

Cholesterol testing

A complete cholesterol test, also known as a lipid panel or lipid profile, will measure the amount of HDL and LDL. As this test is affected by food, it is recommended to fast at least nine hours before the lab test. This test measures your HDL level, LDL level, Total Cholesterol, Triglycerides, and VLDL or very-low-density lipoprotein (VLDL).

Triglycerides are a type of fat found in the blood, where high levels of it can potentially increase your risk of heart disease, especially in women. VLDL is another type of "bad" cholesterol, wherein high VLDL levels are linked to the development of plaque on the arteries. Measuring VLDL isn’t easy and is typically estimated based on triglyceride.

Cholesterol is commonly measured in milligrams (mg) of cholesterol per deciliter (dL) of blood.

A healthy range of cholesterol depends on different factors such as age, family history, lifestyle, etc. Nevertheless, generally speaking, low LDL and high HDL levels are good indicators for heart health.

CKD and Cholesterol

If you have CKD, the Renal Association in the UK and the Association of Clinical Diabetologists have recommended that CKD patients who are at risk of disease in their blood vessels should have a total cholesterol level of less than 4.0 mmol/l. A higher level of HDL is considered good, whereas LDL level should be less than 2.0 mmol/l as per The Renal Association guideline.

Note that these target levels vary depending on different factors. It is best to talk to your primary healthcare provider to know what is a healthy range for you.

What causes a high cholesterol level?

Your cholesterol level depends on different factors including family history, age, and certain conditions such as CKD. Research suggests that people with CKD are at an increased risk of CVD (cardiovascular disease), especially if their age is above 50 years. They are also more prone to have issues with narrowing of blood vessels over time, compared to their healthier counterparts. 

People with kidney disease have unique blood vessels issues, as abnormalities with minerals and vitamins may worsen blood vessel disease. Diet and exercise also play a great role in cholesterol levels. A diet rich in saturated fat and cholesterol may contribute to high levels of cholesterol. On the other hand, those who are malnourished or suffering from other illnesses may have unusually low cholesterol levels.

How to manage your cholesterol levels when you have CKD

There are medications prescribed to lower the levels of cholesterol in your body. However, these medications work best when paired with healthy lifestyle changes. Studies suggest that certain medicines called statins can help slow the progression of CKD and heart disease. Statins are used to lower high cholesterol levels in the blood.

Quitting smoking and working out or exercise can also help keep your cholesterol level within a healthy range.

Moreover, following a kidney-friendly diet can have a great impact on your blood cholesterol levels.

The main goal is to reduce the intake of animal-based food sources and other foods that are high in cholesterol. Among these food sources include dairy products, eggs, red meat, and processed foods. Saturated fats can increase blood cholesterol levels, whereas unsaturated fats such as Olive, peanut, and canola oils, Avocados, nuts and seeds may be less harmful.

Minimize your use of trans-fatty acids since they can increase LDL cholesterol. Trans fat can be found in a range of food products including commercial baked goods such as pies, cookies, cakes, and Microwave popcorn.

Choosing plant-based food sources may help manage your cholesterol. Talk to your dietitian for a customized kidney-friendly diet.