What Are the Causes of High Cholesterol?

Factors that may increase bad cholesterol in the body

Below are few common factors that may increase bad cholesterol in the body:

• Hereditary: Cholesterol or heart diseases may run in the family and is usually inherited.
• Comorbid diseases: Diabetes, liver diseases, and kidney and thyroid diseases
• Smoking cigarettes or passive smoking: Cigarette smoking damages the walls of your blood vessels, making them more prone to accumulate fatty deposits. Smoking might also lower your level of high-density lipoprotein (HDL) or "good" cholesterol.
• Age: The risk of high cholesterol increases with age as functioning of the liver may reduce and may become less able to remove low-density lipoprotein (LDL) cholesterol.
• Diet: Eating an excessively unhealthy diet that includes saturated fat, found in animal products, and trans fats, found in some commercially baked cookies and crackers and microwave popcorn, can increase the cholesterol level. Foods that are high in cholesterol, such as red meat and full-fat dairy products, will also increase your cholesterol.
• Excessive weight: Having a body mass index (BMI) of 30 or higher puts you at risk of high cholesterol. Obesity is directly related to high cholesterol and bad health. 
• Physical activity: Lack of physical activity and exercise may increase bad cholesterol deposits in the arteries. Exercise helps boost our body's HDL or good cholesterol. 

Cholesterol is an important substance required by the body to build healthy cells. It is waxy and sticky in nature. Excess cholesterol is harmful for the body. Cholesterol usually comes from the below sources:

• Liver: It is the main site for cholesterol synthesis in the body.
• Food: The remainder of cholesterol in the body comes from foods derived from animals (meat, poultry, and full-fat dairy products). Foods that are usually high in saturated and trans fats cause the liver to make more cholesterol. This added production means excess cholesterol production, which is harmful for the body.
• Some tropical oils: Oils such as palm oil, palm kernel oil, and coconut oil if consumed in high quantity may lead to high cholesterol levels. These oils are often found in baked goods.

There are two types of cholesterol: 

• Bad cholesterol or low-density lipoprotein (LDL) cholesterol: It transports cholesterol particles throughout the body. LDL cholesterol builds up in the walls of the arteries, making them hard and narrow.
• Good cholesterol or high-density lipoprotein (HDL) cholesterol: It picks up excess cholesterol from the blood vessels and takes it back to your liver.

Too much of the bad kind, or not enough of the good kind, increases the risk of plaque buildup in the inner walls of the arteries that feed the heart and brain. A plaque is found on the inner side of the large blood vessels. It is made of cholesterol, calcium, and blood products. It makes the lumen of these blood vessels narrow.

Usually, cholesterol circulates in the blood, making the blood more viscous. As the amount of cholesterol in the blood increases, so does the risk to the health. Cholesterol can combine with other substances to form a thick, hard deposit on the inside of the arteries. This can narrow the arterial openings and also make them less flexible (a condition known as atherosclerosis). If a blood clot forms and blocks one of these narrowed arteries, it may result in a heart attack or stroke. With high cholesterol, one can develop fatty deposits in the blood vessels. Eventually, these deposits increase, making it difficult for enough blood to flow through your arteries. Sometimes, those deposits can break suddenly and form a clot that may cause a heart attack or stroke.

Healthy levels of cholesterol don’t vary much for typical adults. Variation of recommended levels tends to change due to other health conditions and considerations.

Total cholesterol:

• Adults who have total cholesterol levels less than 200 mg/dL are considered healthy.
• If total cholesterol is between 200 and 239 mg/dL, it is borderline high.
• If total cholesterol is 240 mg/dL and above, it is considered high and harmful.

Bad cholesterol or low-density lipoprotein (LDL):

• LDL cholesterol levels should be less than 100 mg/dL.
• 100-129 mg/dL is acceptable for people with no health problems but may be a concern for anyone with heart diseases or heart disease risk factors.
• 130-159 mg/dL is borderline high.
• 160 mg/dL and above is considered high and harmful.

Good cholesterol or high-density lipoprotein (HDL):

• HDL levels should be kept higher. The optimal reading for HDL levels is 60 mg/dL or higher.
• If HDL is less than 40 mg/dL, it can be a major risk factor for heart diseases.