Sterols in Plant System

Plant foods were most likely consumed in large quantities throughout human evolution. In addition to being high in fibre and plant protein, our ancestors’ diets were also high in phytosterols, which are plant-derived compounds with structural similarity to cholesterol. There’s mounting evidence that reintroducing phytosterol-rich plant foods into the modern diet can help improve serum lipid (cholesterol) profiles and lower the risk of cardiovascular disease.

Dietary cholesterol and endogenous cholesterol synthesis are both sources of cholesterol in human blood and tissues. Because humans cannot synthesise phytosterols, all phytosterols in human blood and tissues come from the diet.

Sterols in Plants

Plant sterols are cholesterol-like compounds that plants produce. Vegetable oils, nuts, and seeds have the highest concentrations. Plant sterols may lower cholesterol levels by controlling the amount of cholesterol that enters the body. Some plant sterols may also help reduce the amount of cholesterol produced in the body. Plant sterols are commonly used to reduce cholesterol levels. Plant sterols are often used to treat heart disease, colon cancer, stomach cancer, obesity, heart attacks, and various other ailments, but many of these claims lack scientific backing. Plant sterols are not to be confused with beta-sitosterol or sitostanol. Plant sterols of this type are unique. 

Types of phytosterols

Phytosterols are divided into two categories by nutritionists:

(1) The sterol ring in plant sterols has a double bond. -sitosterol, campesterol, and stigmasterol are the most abundant sterols in plants and the human diet. 

(2) The sterol ring in plant stanols lacks a double bond. Only 10% of dietary phytosterols are stanols, particularly sitostanol and campestanol (Figure 2).

Plant sterols and cholesterol

Modifying your eating habits is the first step in lowering cholesterol. Substitute healthy fats (monounsaturated and polyunsaturated) for unhealthy fats (trans and saturated), and raise dietary fibre by focusing on whole grains, fruits, vegetables, and legumes. If all these methods have just not worked as well as you’d hoped, or if you just want to work even harder to decrease your bad cholesterol, try including phytosterols in your diet.

Phytosterols (also known as plant sterols and stanol esters) are a class of naturally occurring compounds found in the membranes of plants. Because phytosterols have a structural similarity to cholesterol, they compete with cholesterol for absorption in the digestive system when consumed. As a result, cholesterol absorption is inhibited, and blood cholesterol levels fall.

Consuming phytosterols in recommended amounts as part of a heart-healthy diet plan has been shown to lower total cholesterol by 10% and LDL or “bad” cholesterol by 14%. This reduction is already in addition to any other cholesterol-lowering measures you may have taken, such as eating a heart-healthy diet or taking a statin. Phytosterols are so effective that the National Cholesterol Education Program recommends that individuals with decent cholesterol take two grammes of phytosterols per day.

The FDA has even endorsed a phytosterol health claim that indicates: “Foods comprising at least 0.65 gramme per serving of vegetable oil plant sterol esters, eaten twice daily with foods for a total daily ingestion of at least 1.3 grammes.”As part of a low-saturated-fat, low-cholesterol diet, it may lower the risk of heart disease.”

Dietary cholesterol absorption and metabolism

Dietary cholesterol must be incorporated into mixed micelles to absorb the cells that line the intestine (enterocytes). After eating a fat-containing meal, the small intestine produces mixed micelles, a mixture of bile salts, lipids, and sterols. The intestinal cholesterol transporter Niemann Pick C1-Like 1 (NPC1L1), which is also involved in phytosterol uptake, is responsible for transport across the apical membrane of enterocytes. Cholesterol is esterified inside the enterocyte by intestinal acyl-coenzyme A (CoA) cholesterol acyltransferases (ACATs; also found in the liver) and incorporated into triglyceride-rich lipoproteins called chylomicrons, which are secreted into the intestinal lymphatics. The lymphatic duct in the thoracic cavity gathers the majority of the lymph before emptying into the systemic circulation. When circulating chylomicrons lose their triglyceride content, they become chylomicron remnants, which the liver absorbs. Cholesterol from chylomicron remnants can either be repackaged into other lipoproteins for transit throughout the body or secreted into bile, which is then discharged into the small intestine.

Plant phytosterols

Phytosterols, also renowned as plant sterols, are a type of cholesterol-like molecule. They can be found in a wide range of plants. They’re a crucial structural component of cell membranes, just like cholesterol.

The most popular phytosterols derived from plants are campesterol, beta-sitosterol, and stigmasterol. They’re naturally found in nuts, seeds, and vegetable oils, and they’re also added to processed foods like margarine.

Because phytosterols can prevent cholesterol from being absorbed, they’re frequently promoted to improve heart health and lower LDL (bad) cholesterol levels in the blood.

However, only about 2% of phytosterols in food are absorbed by the body, compared to about 50% of cholesterol.

Conclusion:

They compete with cholesterol for absorption in the intestine when consumed in foods. This has the potential to lower your blood cholesterol levels, particularly the “bad” low-density lipoprotein (LDL) cholesterol, which can clutter your arteries.  The intestinal cholesterol transporter Niemann Pick C1-Like 1 (NPC1L1), which is also involved in phytosterol uptake, is responsible for transport across the apical membrane of enterocytes. I hope this article finds helpful for you as we tried our best to give you detailed information about Sterols in Plant, types of Phytosterols, plant sterols and cholesterol, plant phytosterols