What is cholesterol?
Cholesterol is an essential lipid that plays a role in the production of cells and hormones. The liver produces cholesterol, which we also obtain from dietary sources such as meat, milk, eggs, and butter.
Cholesterol is transported in the blood while attached to compounds called lipoproteins. The two main lipoproteins are:
- Low-Density Lipoprotein cholesterol (LDL-C) also referred to as ‘bad cholesterol’ because when in excess, it is responsible for transporting cholesterol to our arteries where it builds up and increases our risk of heart diseases.
- High-Density Lipoprotein Cholesterol (HDL-C) also referred to as ‘good cholesterol’ because it is responsible for carrying cholesterol from the arteries back to the liver thus reducing our risk of heart diseases.
- Triglycerides are Fats that are transported by other lipoproteins and they also increase our risk of heart diseases and pancreatitis if in excess.
Any imbalance in the levels of these lipoproteins and/or fats(triglycerides) in blood is termed as a lipid disorder (dyslipidemia) and it increases our risk of developing heart diseases.
Attaining Normal Cholesterol and Triglyceride Levels
Adopting a healthy lifestyle is important for prevention or management of dyslipidemia. People can suffer from the condition by consuming an energy dense diet with little of the required nutrients and being physically inactive. Improving your diet is extremely important in prevention and management of dyslipidemia.
A healthy diet is important for reducing the risk of cardiovascular diseases through dyslipidemia. The following sections contain some of roles played by macronutrients, micronutrients, and foods.
Glycemic Index (GI) and Glycemic Load (GL) are important when it comes to carbohydrates. Refined and processed carbohydrates have a high glycemic index. Consuming carbohydrates with a high GL lowers the level of HDL-C and raises the concentration of triacylglycerols. Increased consumption of carbohydrates especially simple sugar and starch that have a high glycemic index results in smaller LDL-C particles that can then move to sites where they are oxidized by free radicals. Oxidized LDL-C is responsible for the destruction of blood vessels and eventual development of atherosclerosis.
Dietary fiber is a type of non-digestible carbohydrate which suppresses the levels of total and LDL cholesterol while increasing the blood levels of HDL-C.
Substituting animal proteins with plant-based proteins such as soy products has a positive impact on the lipid profile. legumes are beneficial because they are rich in fiber, starch, and complex carbohydrates. In addition, they are low in fats and sodium. Generally, increasing the intake of legumes reduces the concentration of serum cholesterol. It is thought that the soluble fiber, polyphenols, and the proteins that are found in legumes are responsible for the positive effect that they have on the lipid profile.
Eating plant proteins results in a feeling of fullness and they can contribute towards weight loss, reduced blood pressure, altered body composition, and a reduction of plasma triglycerides.
Excess fat intake is generally associated with increased intakes of both saturated fat and calories. Conversely, a low intake of fats and oils increases the risk of inadequate intakes of vitamin E and of essential fatty acids, and may contribute to unfavourable changes in HDL.
One should therefore aim for adequate fat intake recommended for their health condition and ensure that the type of fat one takes is predominantly from sources of MUFAs-Monounsaturated Fatty acids (diet rich in nuts and seeds) and PUFAs-Polyunsaturated Fatty Acids (diet rich in fish, nuts and seeds) with very little saturated and trans fats
Some of the processed foods that you should avoid because of saturated and trans-fats include potato chips, crackers, fried foods, cookies, doughnuts, and pastries. Foods that contain animal fat such as butter, fatty meat, poultry skin, and cream should also be avoided.
Phytosterols and Polyphenols
Phytosterols can only be found in plants and have a similar structure to cholesterol. They improve the lipid profile by inhibiting the absorption of cholesterol in the intestines. People who consume adequate amounts experience reduced LDL levels. Sources include vegetable oils, cereals, and oil seeds. Vegetables, such as cabbage and cauliflower, can also provide phytosterols.
Fruits and vegetables contain compounds such as flavonoids and polyphenols, which reduce the blood levels of LDL-C. They have antioxidant and anti-inflammatory properties and can prevent the synthesis of oxidized LDL-C. Other sources of polyphenols include cocoa, grapes, onions, tomatoes, strawberries, and cinnamon.
Animal protein and Eggs
It is advisable to consume cholesterol rich foods in moderation. For example, egg yolks and red meat.
Green tea reduces the concentration of total cholesterol, LDL-C, and triglycerides while increasing the amount of HDL-C. These effects are mainly attributed to the antioxidant properties and presence of polyphenols in green tea.
Moderate and high amounts of fructose in the diet introduces metabolic changes that raise the amount of plasma triglycerides and promote fat storage. Besides, the added sugars suppress the concentration HDL-C and can lead to the deposition of visceral fat and for this reason, its intake should be limited. Processed foods such as sugar sweetened beverages contain high amounts of these sugars.
Therefore, having a healthy diet requires that you replace unhealthy foods with healthy varieties. Besides, it is advisable to engage in exercise to maintain or slowly move towards a healthy BMI.