Monacolin K from red yeast rice: Properties and use in keeping cholesterol levels within normal limits
Monacolin K, aka the “natural statin”, is the substance principally responsible for the hypocholesterolemic effect of red yeast rice.
The story of red yeast rice goes back a long, long way. A food source for Asian populations, red yeast rice is also used in traditional Chinese medicine.
Today, its effects have been amply documented in the scientific literature, and it is approved by the European Food Safety Authority (EFSA) and included in the principal European guidelines.
But what is it?
By taking normal cooking rice (Oryza sativa) and adding some yeast, we obtain a product of plant origin, red yeast rice, which contains several nutritive substances, including pigments (which give it its characteristic red color), sugar (especially starch), protein, sterols, fatty acids and monacolins, whose action lowers cholesterol levels.
Products made with red yeast rice vary depending on the strain of yeast added and the fermentation conditions, and they are used both in products to be eaten or drunk, containing fish, meat or sake (rice wine) and as natural dietary supplements.
Monacolin K: what it is and what its properties are
Monacolins are produced by the action of a yeast, Monascus purpureus, which is also responsible for the red color and typical aroma of red yeast rice.
Among the monacolins, the subtype K has a chemical structure identical to that of a molecule, lovastatin, which is the active principle in medicinals used to reduce cholesterol levels, one of the statins.
Like statins, monacolin K acts by inhibiting the enzyme hydroxymethylglutaryl-coenzyme A (HMG-CoA) which is responsible for synthesis of cholesterol.
In this way, monacolin K, contributes to controlling cholesterol levels, reducing the amount of cholesterol synthesized by the body.
The use of monacolin K to fight cholesterol
Cholesterol is a fatty substance produced by the body or introduced by eating some kinds of food (especially egg yolks, meat, poultry, fish and dairy products).
The body uses this substance to build cell membranes and to produce other substances that help metabolize fats.
However, when present in excess, cholesterol, especially “bad” cholesterol (LDL cholesterol), increases the risk of developing cardiovascular disease.
It is therefore fundamental to reduce the quantity of bad cholesterol and increase that of “good” cholesterol (HDL).
Primary prevention calls for a fundamental change in lifestyle.
Nutrition is basic to any strategy designed to keep cholesterol levels within the recommended limits: a diet based on the consumption of foods that are specifically indicated and/or nutritional supplements, along with physical exercise, helps lower cholesterol levels.
An initial treatment approach for managing high cholesterol normally involves “non-pharmacological” measures: a diet low in saturated and trans fats and a greater amount of dietary fiber, along with an exercise program tailored to your physical condition, all of which contribute to reducing LDL cholesterol.
The EFSA has confirmed that monacolin K, assumed in the form of red yeast rice, contributes to keeping circulating cholesterol levels within normal limits.
If taken on a daily basis, monacolin K:
- contributes to reducing LDL cholesterol by 15-25% after only 6-8 weeks;
- reduces levels of triglycerides.
This in addition to reducing levels of total cholesterol, non-HDL cholesterol and C-reactive protein (produced under stress induced by inflammatory agents).
Red yeast rice also contains plant sterols (phytosterols) that block the absorption of cholesterol in the intestine and regulate levels of total cholesterol.
Supplements containing monacolin K
The group of experts on dietetic, nutritional and anti-allergy products (NDA) of the European Authority for Food Safety (EFSA) has issued a scientific opinion on the validity of an indication on health associated with monacolin K from red rice yeast and its effect in maintaining normal levels of HDL cholesterol.
Recommended daily dosages of monacolin K vary from 2 to 48 mg, (although many dietary supplements – about 25% – adhere to the daily dosage set by the EFSA (10 mg/day).
Despite their benefits, dietary supplements of red yeast rice containing monacolin K are not without side effects.
Unsolicited reports of suspect adverse reactions associated with the consumption of products containing red yeast rice mention undesired effects similar to those observed with the use of statins (lovastatin).
It is thus important not to downplay the possible adverse effects associated with monacolin K, specifically:
- myopathy (a condition characterized by symptoms of muscle pain and weakness);
- habdomyolysis (a condition involving the breakdown of muscle tissue and the release of substances into the bloodstream that can damage the kidneys);
- toxicity at the hepatic level (hepatotoxicity).
However, compared to statins, products containing red yeast rice have shown a better tolerability profile, probably due to the limited quantities of monacolin K present in them (max 10 mg) and a psychological component associated with the perception of taking a more “natural” remedy.
Another aspect to take into consideration are the possible interactions with other pharmaceuticals: in fact, compared to lovastatin, the active principle contained in red yeast rice seems to have a greater inhibitory effect on the activity of the enzymes of the cytochrome P450 family (particularly CYP1A2 and CYP2C19) and of glycoprotein P.
Dietary supplements do not require a doctor’s prescription, being classified as food. However, before taking a dietary supplement containing monacolin K, it is recommended that you check with your physician.
If the cultivation process of red yeast rice is not carefully monitored, some strains of Monascus purpureus could produce a toxic substance called citrinin, which can cause kidney failure.
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