Whenever we hear the word Cholesterol, the first thought that comes to our minds is “bad substance”. But have you ever considered it an essential nutrient in our diet? Do you know this natural fat present in the human body serves many major functions? Let’s jump in to know about the role of cholesterol – a major component of the cell membrane in the human body.
Before digging deep into the role of cholesterol, we first need to know about its composition, types, and the amount required in the human body for its proper functioning. Let us discuss what is cholesterol.
What is Cholesterol?
Made up of alcohol and fats, ‘Cholesterol’ has a Greek origin and is made up of three smaller words. Where ‘chole’ means bile, ‘stereos’ means solid, and ‘ol’ means alcohol.
Types of Cholesterol
Divided into two main groups, Cholesterol may come from plants and/ or animals.
Plant Cholesterol – Phytosterol
Plants produce a substance like cholesterol called phytosterol. When we have phytosterol in our food it will absorb more quickly in blood than cholesterol. This causes a small amount of cholesterol to enter the blood. The digestive track excretes excess (absorbed) phytosterol and released it out of the body without any change in feces. Hence, it becomes a protective process.
In addition to lowering the risk of Cardio Vascular Diseases, preliminary research on Phytosterol shows its potential to inhibit lung, breast, prostate, and colon cancer. However, there is considerable debate on whether plant-based cholesterol is enough for keeping us healthy or not. It is here that we move on to discuss the role of animal cholesterol, i.e., the role of Lipoproteins.
Animal Cholesterol- Lipoproteins
Animals make cholesterol for their need on their own. Though, it is also naturally present in scarce quantities. Cholesterol moves in the form of small bundles in human blood called lipoproteins. These are fat on the inside but proteins on the outside. This makes it easy for cholesterol to move in form of small bundles in the blood.
Types of Lipoproteins
Following are the two types of Lipoproteins
LDL is the abbreviated form of Low-Density Lipoprotein and HDL- High-Density Lipoprotein. Both types of lipoproteins carry cholesterol and circulate in the blood.
HDL (High-Density Lipoprotein)
Known as ‘good cholesterol, HDL carries cholesterol from all parts of the body back to the liver. Linked directly to heart health, HDL intake is a good way of maintaining cardiovascular (add some medical terminology here). Expelled from the body along with the waste from the liver, the higher the level of HDL in the body, the higher the heart.
LDL (Low-Density Lipoprotein)
Known as ‘bad cholesterol, LDL is highly unhealthy. If the amount in the blood is too high, it starts to clot in the walls of the arteries, which means that too much of it causes heart disease.
Composition of Cholesterol in animal cells
Animal fat is a complex mixture of triglycerides, which holds low amounts of both phospholipids and cholesterol molecules that make all animal (and human) cells. All animal cells produce cholesterol, however, all animal-based foods have different amounts of cholesterol.
Animal Sources of Cholesterol
All sources contain different amounts of cholesterol based on their composition. Major sources of cholesterol include red meat, egg yolks, whole eggs, liver, kidneys, goblets, fish oil, and butter. Human breast milk also has a lot of cholesterol.
Plant sources of Cholesterol
Plant-based fatty acids are ‘heart-healthy’ fats because they are high in HDL. They are present in olives and olive oil, whole grains, including bran, cereals, and brown or wild rice. Ground flaxseeds and flaxseed oil also contain omega-3 fatty acids. Many vegetarians use flaxseed as a source of omega-3 fatty acids because they’re one of the better plant-based sources of this heart-healthy fat. Nuts, including Brazil nuts, almonds, pistachios, and others, as well as peanuts, which are technically legumes, are filled with heart. Moreover, they also contain plant sterols in high densities. Chia seeds are a good source of plant-based omega-3 fatty acids, fiber, and other healthy nutrients. Avocados contain folate and monounsaturated fat.
How human body uses Cholesterol from the diet?
The body makes its cholesterol according to its needs, but cholesterol is also present in our food. A human man weighs 68 kg. His body normally makes about 1 gram (1,000 mg) of cholesterol daily and the body has about 35 grams of cholesterol which is mostly inside the cell membranes. Cholesterol in the diet has an insignificant effect on the concentration of cholesterol in the blood. However, during the first seven hours after eating a high cholesterol diet, the amount of cholesterol in the blood is significantly high. The liver collects cholesterol and releases it into the digestive tract of which 50% is reabsorbed into the bloodstream by the small intestine. At the same time, when the cholesterol in the blood is absorbed from the food, the body reduces its cholesterol production.
Maximum specified amount of Cholesterol in the body
The amount of cholesterol in human blood should not exceed 200 mg per 100 ml of blood because if this amount reaches 240 then the possibility of heart disease increases. If it exceeds 240 then the risk doubles. Therefore, keep in mind that the amount of cholesterol in the blood should not be too high. To keep cholesterol levels in check, there are ways to lower them.
Role of Cholesterol in the Human Body
There are various roles of cholesterol in the human body. From supporting the immune system to keeping us warm in winters, to protecting vital organs such as kidneys, and heart from shock and external damage – the role of cholesterol is significant and profound.
1. Support Cell Membrane
Cholesterol is essential for the life of all animals. One of the prime functions is to build and support cell membranes. Cholesterol makes up about 30% of all animal cell membranes. The function of cholesterol is to help the cell membrane for maintaining its form and survival. It also prevents ions from being absorbed.
2. Helps in the Production of Different Hormones
In the presence of cholesterol, the human body produces critical hormones, including the stress hormone cortisol. The role of cholesterol is also to help in the production of the sex hormones, testosterone, progesterone, and estrogen.
3. Vital Role in the Digestion Role of Cholesterol in the Human Body
The liver also uses cholesterol to make bile, a fluid that plays a vital role in the processing and digestion of fats.
4. Protection of Nerves in the Brain
Cholesterol is used by nerve cells for insulation. Myelin Sheath acts as a protective layer. Most of the body’s cholesterol resides in the brain in the form of myelin which contains almost 80% of the cholesterol found in the adult brain. Cholesterol is also important for nerve impulses. Research on cognitive decline and the levels of cholesterol (and Vitamin B12) shows a significant correlation.
5. Aids in the Absorption of Vitamin D
The human body needs cholesterol as it helps in the digestion of vitamin D and other fat-soluble substances. Most dietitians and nutritionists suggest taking oral Vitamin D supplements with fat-based meals. Not only does this ensure efficient absorption of Vitamin D, but it also keeps the cholesterol levels in check, as well. However, there is a catch here. While no research has established the exact amount of fats needed for optimal Vitamin D absorption, they recommend a low-to-moderate level of fat in food.
