Phytosterols are plant substances with a structure very similar to human cholesterol. When taken regularly with the diet, they help to effectively lower cholesterol, reduce the risk of atherosclerosis and heart attack, and may even protect against certain types of cancer. The sources of phytosterols are mainly vegetable oils and fortified products such as margarines, yoghurts, cheese and chocolate.

Contents:

  1. Fitosterole and cholesterol
  2. Phytosterols and cancer
  3. Phytosterols - other properties
  4. Phytosterols - sources of occurrence
  5. Phytosterol-enriched foods and supplements
  6. Fiteosterols - side effects of excess

The name "phytosterol" is directly associated with cholesterol. Actually, becausephytosterolsare compounds with very similar structure and functions to cholesterol, but found only in the plant world. Animal and human organisms produce cholesterol, while phytosterols can only be supplied to them through the diet.

They are the building blocks of plant cell membranes and are responsible for hardening their structure. The phytosterols group includessterols , which have an unsaturated bond in the molecule, as well asstanols- with all saturated bonds. Sterols are much more common in plants.

Stanols make up only 10% of all phytosterols. Among this group of compounds, more than 40 different substances have been identified, however the most common are β-sitosterol, campesterol and stigmasterol. Β-sitosterol alone accounts for nearly half of all phytosterols in the human diet.

Fitosterole and cholesterol

Phytosterols are known as a dietary component that, when consumed in adequate amounts, significantly reduces total cholesterol and "bad" LDL cholesterol. How does it happend? Phytosterols are very similar in structure to cholesterol.

Thanks to this, they can take its place in micelles, i.e. particles thanks to which cholesterol is absorbed into the bloodstream in the intestines. Thus, phytosterols inhibit the absorption of cholesterol in the digestive tract and cause its increased excretion from the body. At the same time, they are absorbed into the bloodstream to a very small extent.

Consuming about 1.5 g of phytosterols a day causes a decreasecholesterol absorption by 30-40%, while 2.2 g per day - by 60%.

Although reduced absorption of cholesterol with food causes its greater production in the liver, the concentration of this compound in the blood serum decreases significantly. This beneficial effect on cholesterol levels has been known since the 1950s.

At that time, however, much higher doses of phytosterols were used, even 18 g per day. Currently, 1 g per day is considered the lowest therapeutic dose. The significant influence of phytosterols on cholesterol in the human body is well known and researched.

Studies on the effects of dietary phytosterols on the blood lipid profile usually last about 3 weeks. By using a dose of 1 to 3 g of phytosterols per day, the total cholesterol concentration is reduced by 5-11%, and the LDL fraction by up to 16%.

Based on many studies, it has been found that the intake of more than 3 g of phytosterols per day does not affect a further decrease in lipoprotein concentration and this amount is considered borderline. This is still much more than the average dietary intake.

On average, we consume 20-50 mg of stanols and 100-350 mg of sterols every day. This means that in order to lower cholesterol through diet, we must consume phytosterol-enriched foods.

Studies by Gylling and colleagues have shown that consuming margarine with 3 g of phytosterols lowers total cholesterol by 11% and LDL by 15%. Polagruto found that fortified chocolate reduced cholesterol by 4.7% and LDL by 6%. Similar beneficial results were obtained when the subjects enriched with phytosterols were given: orange juice, cheese and soy milk.

Higher drops in lipoproteins are obtained by taking phytosterols in the diet in one dose a day than by spreading them over several meals.

People with elevated cholesterol are much more likely to develop atherosclerosis and other cardiovascular diseases. The main goals of treatment are to lower total cholesterol, LDL cholesterol and improve the HDL / LDL ratio.

Due to their hypocholesterolemic effects, phytosterols are an obligatory dietary component for a he althy heart. They also contribute to the inhibition of platelet aggregation and reduce the formation of atherosclerotic plaque.

Plant sterols reduce the release of prostaglandins, i.e. a pro-inflammatory factor, slow down the oxidation of LDL cholesterol and increase the viability of endothelial cells in blood vessels. All this has a positive effect on the functioning of the cardiovascular system.

A 10% reduction in LDL levels reduces the risk of coronary heart disease by 20%. By combining a proper rich dietIn fiber, he althy fats, vegetables and fruits with phytosterols, you can reduce LDL levels by up to 24%.

Phytosterols and cancer

Phytosterols have anti-cancer properties. They affect many processes that can lead to cancer development. It has also been observed that they inhibit the formation of free radicals, have a strong antioxidant and anti-inflammatory effect.

A very important feature of neoplastic cells is resistance to signals that program cell death. Phytosterols inhibit tumor proliferation (multiplication of cells) through complex processes and induce apoptosis, i.e. cell death.

They also inhibit the formation of metastases. It has been shown, among others, that β-sitosterol stops the growth and metastasis of breast cancer cells, inhibits the development of colon cancer and prostate cancer. A three-year study in Uruguay found that plant sterols reduce the risk of stomach cancer.

Several epidemiological studies have investigated the relationship between dietary phytosterol consumption and cancer risk. It was noticed that the consumption of phytosterols in people diagnosed with breast cancer, lung cancer or stomach cancer was significantly lower than in the control group of he althy people.

Since phytosterol consumption is associated with a higher proportion of plant products in the diet, it is likely that the protective anti-cancer properties cannot be attributed to the phytosterols themselves, but also to other plant compounds.

Phytosterols - other properties

• Phytosterols can reduce inflammation and reduce an overly strong immune response, which may be useful in the treatment of autoimmune diseases such as rheumatoid arthritis and psoriasis.

• Some phytosterols stimulate insulin secretion. They can be helpful in the prevention of type II diabetes.

• Consuming phytosterols reduces prostatic hypertrophy, relieves difficulty urinating, increases urethral flow and reduces the amount of urine remaining in the bladder after excretion.

Phytosterols - sources of occurrence

Phytosterols are present in all plant cells, and their richest sources are vegetable oils. Sesame seeds, wheat germ, walnuts, peanuts and hazelnuts, almonds, legume seeds and grain products are also rich in these ingredients. Tall oil is used for the production of sterols, which is obtained from the elements of the subcortex of pine.

Phytosterol content in selected plant products

ProductPhytosterol content [mg / 100 g]
Rice bran1190
Corn oil952
Rapeseed oil879
Sesame Oil865
Sunflower oil725
Soybean oil221
olive oil176
Almonds143
Beans76
Corn70
Palm oil49
Lettuce38
Banana16
Tomato7

Phytosterol-enriched foods and supplements

The consumption of phytosterols in European countries does not exceed 300 mg per day, and in Japan, where the share of plant products in the diet is greater - 400 mg. However, the recommended daily dose of phytosterols, which has the effect of lowering blood cholesterol levels, is at least 1 g. Therefore, it was considered necessary to enrich food with plant sterols.

It was quickly discovered that the stanols formed in the process of hydrogenation (saturation of the double bond) were much more stable than sterols and had a stronger cholesterol-reducing effect. Thanks to the technology developed in Finland, it became possible to add stanols to fat products, which are their best carrier.

The most common on the market are margarines with phytosterols, but you can also find yoghurts, milk drinks, mayonnaise, matured cheese, homogenized cheese, meat products, confectionery, muesli, orange juice and chocolate. The first phytosterol margarine was commercialized in Finland in 1995.

According to the regulation of the European Commission from 2004, enriched food should have information on the content of phytosterols in the product on the packaging and a statement on avoiding the consumption of more than 3 g of plant sterols per day.

Due to the fact that plant sterols are recommended as a dietary product, the offer of supplements is not very extensive. We will get phytosterols in pharmacies in the form of tablets and capsules in preparations aimed at people controlling cholesterol levels and men with prostate problems.

Important

Fiteosterols - side effects of excess

Phytosterols consumed in the amount of more than 3 g per day reduce the level of β-carotene, lycopene and fat-soluble vitamins in the human body. They probably reduce not only the absorption of cholesterol, but also fat-soluble substances. Consuming phytosterols can reduce the amount of β-carotene in the blood by up to25% and vitamin E by 8%, therefore it is advisable to enrich margarines with phytosterols with fat-soluble vitamins.

Products rich in phytosterols should not be consumed by children under the age of 5 with normal cholesterol levels, as this may cause disturbances in the absorption of vitamins and too much decrease in the level of cholesterol, which is necessary for young organisms.

References:

1. Kopeć A., Nowacka E., Piątkowska E., Leszczyńska T., Characteristics and he alth-promoting properties of plant sterols, Food. Science. Technology. Quality., 2011, 3 (76), 5-14 2. Nowak A., Phytosterols in the daily diet, Advances in Phytotherapy, 2011, 1, 48-51 3. Półrolniczak A., Rubiś B., Rybczyńska M., Molecular basis dietary supplementation with phytosterols in terms of morbidity and cancer treatment, Współczesna Onkologia, 2008, 10, 447-451 4. Szymańska R., Kruk J., Phytosterols - occurrence and importance for humans, Kosmos. Problems of biological sciences, 2007, 1-2 (56), 107-114 5. Włodarek D., Plant sterols - what is it and how it works, Food for he alth. Bulletin for medical circles, 2008, 8, 12

Category:

Diets