What is Red Yeast Rice?
Red yeast rice is produced when a mold called Monascus purpureus colonizes and ferments rice. The mold turns the rice dark red and produces a medicinal compound called monacolin K. Red yeast rice has been a part of traditional Chinese medicine for over a thousand years; today, it is sold as a health food and supplement across the world [1, 2].
This fascinating foodstuff may also reduce methane production by livestock. Methane, a potent greenhouse gas, might be the most dangerous byproduct of raising animals for food. When goats ate a diet containing 8.2% red yeast rice, the methane-producing bacteria in their guts was suppressed, and the goats released less methane [4, 5].
- Decreases cholesterol
- Lowers blood pressure
- Fights cancer
- Improves metabolic syndrome
- Prevents complications of obesity
- Reduces inflammation
- Improves bone health
- Amount of monacolin K not usually stated
- Active ingredient controlled in the USA
- May contain a kidney toxin
- Potentially dangerous drug interactions
- Some supplements may be spiked with lovastatin
Red yeast rice contains, on average, 73.4% starch, 0.8% fiber, and 5.8% protein by weight. Its health effects are caused by a compound called monacolin K, the natural form of the cholesterol-lowering drug lovastatin [6, 4].
Monacolin K, which is chemically indistinguishable from lovastatin, is the main active component of red yeast rice. It is produced by Monascus purpureus, the red mold that ferments the rice and gives it its distinctive color .
The FDA regulates lovastatin, so commercial red yeast rice cannot be sold in the United States if it has more than a trace amount of monacolin K. However, many red yeast rice supplements do not have information about monacolin K on the label; multiple studies suggest that these supplements may contain significant amounts of this compound. It is currently impossible to know how much monacolin K a particular red yeast rice supplement contains without testing it in a lab [7, 8, 9].
Other Beneficial Compounds
Monascus purpureus produces several bioactive compounds which may be beneficial to our health. The most important of these are the monacolins and pigments. Red yeast rice contains at least 13 monacolins and several pigments [10, 11].
If red yeast rice is incorrectly fermented, it may contain a yeast toxin called citrinin. This poisonous compound causes kidney failure in animals and may cause mutations or damage in the DNA of cells [10, 14, 15].
Mechanism of Action
HMG-CoA reductase is an enzyme that converts a compound called HMG-CoA to mevalonate. Mevalonate is an essential building block for thousands of other molecules, including cholesterol. Monacolin K, like lovastatin, binds to HMG-CoA reductase and prevents the production of cholesterol .
Mevalonate can also be converted into important compounds like coenzyme Q10. Coenzyme Q10 is an antioxidant found in the mitochondria, the energy-making machinery of the cell. It may be responsible for the muscle-wasting side effects of lovastatin .
Red yeast rice doesn’t just contain monacolin K and its complete mechanism is more complex than lovastatin’s. According to some researchers, the other compounds in red yeast rice may, in fact, reduce the risk of side effects like muscle weakness .
Health Benefits (Likely Effective)
Multiple clinical trials have produced the following benefits of red yeast rice. Red yeast rice has not been approved by the FDA for any medical purpose or health claim; the FDA has further warned that monacolin K is an unapproved new drug. Talk to your doctor before supplementing with red yeast rice.
High cholesterol is a serious health problem linked to obesity, insulin resistance, high blood pressure, heart attack, stroke, and diabetes. The most effective way to control cholesterol levels and prevent these conditions is to make healthy diet and lifestyle choices; however, some people are prone to high cholesterol regardless of these choices [20, 21].
Red yeast rice lowers bad cholesterol (LDL) and triglycerides and raises good cholesterol (HDL) in the blood. It may also prevent weight gain and maintain normal levels of liver enzymes and leptin [22, 23, 24].
In multiple studies with almost 8,000 participants between them, people supplementing with red yeast rice had decreased LDL and total cholesterol, with no damage to liver or kidney function .
2) Heart Disease
Triglycerides, like cholesterol, are a type of fatty compound found in the blood. Recent studies have found that triglycerides are more likely than cholesterol to cause heart disease and stroke [26, 27].
Red yeast rice lowers both cholesterol and triglycerides and measurably reduces the rate of heart attacks. In nearly 5,000 patients who had already suffered a heart attack, long-term red yeast rice supplementation lowered mortality rates by a third and cut the likelihood of a future heart attack in half, from 10.5% to 5.7% .
In combination with coenzyme Q10, red yeast rice also makes blood vessels more flexible. Stiff blood vessels, especially arteries, increase the risk of plaques forming in the vessels; these blockages can eventually lead to heart attack, stroke, and other complications [29, 30, 31].
Chinese researchers have extensively studied xuezhikang, a red yeast rice extract, for its anti-inflammatory effects. In 50 patients with coronary heart disease, 1200 mg of xuezhikang per day produced decreased markers of inflammation and triglycerides [32, 33].
In rats with high cholesterol, red yeast rice decreased the expression of genes that cause inflammation. The rats that ate the supplement had decreased levels of TNF-α and IL-6, two compounds that increase inflammation .
Monascustin, one of the active compounds of red yeast rice, may inhibit a gene called HDAC1. We do not yet fully understand how HDAC1 controls inflammation, but this relationship may be responsible for the anti-inflammatory effect of RYR [35, 36].
Potential Benefits with Insufficient Evidence
At least one clinical trial has produced the following benefits of red yeast rice, but these studies have either not been repeated or produced contradictory results. Red yeast rice has not been approved by the FDA for any medical purpose or health claim; the FDA has further warned that monacolin K is an unapproved new drug. Talk to your doctor before supplementing with red yeast rice.
4) Metabolic Syndrome & Blood Sugar
Metabolic syndrome is a collection of conditions including obesity, high blood pressure, high blood sugar, insulin resistance, high levels of triglycerides, and low levels of good cholesterol (HDL). People with metabolic syndrome also have increased inflammation and are prone to inflammatory conditions [37, 38].
Red yeast rice can lower cholesterol, blood pressure, and blood sugar; it also has anti-inflammatory and bone–strengthening effects. More research is required before doctors actively prescribe red yeast rice for metabolic syndrome; however, most of their hesitation has to do with citrinin toxicity and an inconsistent chemical profile. Red yeast rice is a useful nutraceutical for managing metabolic syndrome and obesity [39, 23].
Animal Research (Lacking Evidence)
No clinical evidence supports the use of red yeast rice for any of the conditions listed in this section. Below is a summary of the existing animal and cell-based research, which should guide further investigational efforts. However, the studies listed below should not be interpreted as supportive of any health benefit.
5) Kidney Function
High cholesterol and triglycerides can cause serious kidney damage if left untreated. Through its effect on these fats, red yeast rice protected the kidneys from injury in a rat study .
The effect of red yeast rice on healthy kidneys is currently unknown. Furthermore, some red yeast rice may be contaminated with citrinin, which can cause kidney damage. We do not recommend red yeast rice as a supplement for kidney health .
6) Bone Health
In one rat study, red yeast rice reduced bone loss in rats with osteoporosis. Animals given red yeast rice supplements had higher bone mineral density and healthier bone cells than those without the supplement .
A study of white rabbits demonstrated a similar effect. In this study, however, the researchers added a red yeast rice extract to grafts and applied these grafts to a rabbit’s skull. The grafts that included red yeast rice extract showed improved bone growth compared to grafts without the extract .
Monascuspiloin, a yellow pigment in red yeast rice, can cause the death of prostate cancer cells by inhibiting mTOR and increasing AMPK. Through this same pathway, monascuspiloin makes cancer cells more sensitive to radiation and enhances the effectiveness of radiation therapies [42, 43].
Another pair of compounds found in red yeast rice, rubropunctatin and monacolin L, are of interest to cancer researchers. Rubropunctatin may block telomerase, an enzyme that allows cancers to metastasize and move to different parts of the body. Meanwhile, monacolin L seems to increase the rate of apoptosis, or cell death, in the tumor [44, 45].
These effects have not yet been studied in animal models, let alone in humans.
Some research suggests that combining red yeast rice with other supplements could further improve its benefits and prevent adverse side effects. Talk to your doctor before adding any new supplements to your regimen, let alone combinations of supplements.
Red yeast rice, like lovastatin, decreases levels of a compound called coenzyme Q10, or CoQ10. CoQ10 is important for maintaining muscle mass and strength: this is why the most common side effect of statins is muscle disease. According to some practitioners, supplementing CoQ10 alongside red yeast rice may reduce the incidence of these side effects [19, 46, 29].
Healthy fats like rice bran oil (rather than coconut or sunflower) may further reduce cholesterol buildup while supplementing with red yeast rice. In one study, rats ate a very high cholesterol diet and supplemented with red yeast rice; the group of rats fed with rice bran oil had far lower cholesterol and oxidative stress when compared with rats fed other oils .
Berberine is a compound found in several different medicinal plants. This compound has been a part of Chinese and Indian traditional medicine for thousands of years. Berberine is reported to increase LDL cholesterol receptors in the liver, thereby reducing LDL in the blood. In one human study, a combination of berberine and red yeast rice reduced LDL as much as statin therapy, with a much lower rate of muscle damage .
Labeling and Regulation
There is currently no way to tell how much monacolin K, citrinin, or any other active compound is in a given red yeast rice supplement. Some red yeast rice supplements have been found to contain pure lovastatin, probably added during production. Almost all commercial supplements have different chemical profiles than the standardized red yeast rice that is used in clinical studies [49, 50].
Lack of regulation is perhaps the biggest safety concern associated with red yeast rice supplements. If you are not confident in the safety of your supplement, we recommend switching or discontinuing it.
Pregnant women should not use red yeast rice. Lovastatin has been associated with birth defects after exposure in the womb. The data is not conclusive, but most researchers caution against using any statin during pregnancy; this includes monacolin K [51, 52, 53].
Citrinin is produced by molds and fungi and is often found in poorly stored food. Long-term exposure to citrinin can cause damage to the heart, liver, kidney, and reproductive system. High-quality red yeast rice does not contain enough citrinin to be dangerous; however, supplement bottles are unlikely to admit to citrinin content. Use caution and always buy high-quality supplements to avoid this toxin [14, 10].
Since monacolin K is the same chemical as lovastatin, people taking red yeast rice and lovastatin may have similar side effects. Known side effects of lovastatin include muscle pain and weakness, nausea, heartburn, headache, and memory loss .
Muscle problems are among the most commonly reported side effects of all statins, ranging from slight pain to severe muscle breakdown. People with existing muscular conditions like myasthenia gravis should avoid red yeast rice: monacolin K may worsen their symptoms .
Other compounds found in red yeast rice may compensate for some of the negative side effects of monacolin K. People taking red yeast rice as a supplement usually have fewer side effects than those taking lovastatin .
Some people may have a very rare allergy to Monascus purpureus. In one case, a young and otherwise healthy butcher developed a severe anaphylactic reaction just from handling red yeast rice as an ingredient for sausage [58, 59].
Limitations and Caveats
Most, but not all, of the above health effects and safety considerations refer to studies on red yeast rice: some refer to studies on lovastatin. The FDA considers lovastatin and monacolin K from red yeast rice to be chemically identical; the other bioactive compounds in red yeast rice may change the effect of monacolin K on the human body. The effects of lovastatin and red yeast rice will, therefore, be very similar, but not exactly the same.
Most red yeast rice supplements do not contain a standardized amount of monacolin K and other bioactive compounds. The effects of different supplements may vary, and researchers using different extracts may reach different conclusions.
Few drugs have been specifically tested for interactions with red yeast rice. However, because monacolin K is identical to lovastatin, drugs that interact with lovastatin should not be combined with red yeast rice.
Verapamil treats high blood pressure, angina, and irregular heartbeat. Red yeast rice and lovastatin both increase the availability and effect of verapamil. If you are taking verapamil for any reason, consult your doctor before supplementing with red yeast rice [60, 61].
Many drugs have demonstrated interactions with statins. These include:
- Erythromycin 
- Clarithromycin 
- Antifungals that end with -azole (such as itraconazole) 
- Antiviral drugs 
- Warfarin 
- Cholesterol-lowering drugs like gemfibrozil 
- Colchicine 
- Heart medication like amiodarone [69, 70, 71, 72]
- Danazol 
- Immunosuppressants like cyclosporine 
- Cimetidine 
Talk to your doctor before using red yeast rice supplements if you are currently taking any of these medications.
Like some of the drugs above, grapefruit blocks an enzyme called CYP3A4 and prevents statins from being broken down. These statins can then build up to dangerously high levels and cause serious muscle problems. Even a single glass of grapefruit juice with lovastatin could be dangerous; we recommend avoiding grapefruit if you are supplementing with red yeast rice .
Other foods that increase or decrease CYP3A4 activity will also decrease or increase the effect of red yeast rice.
Familial hypercholesterolemia is a genetic condition that causes very high levels of bad cholesterol (LDL) to build up and remain in the blood, regardless of diet and lifestyle. This condition is under-diagnosed and under-treated; genetic testing is not offered in all countries .
Familial hypercholesterolemia is often treated with statins such as lovastatin. Red yeast rice lowers LDL cholesterol and may be especially beneficial to people with this disease .
Mutations at any one of four genes cause familial hypercholesterolemia. These genes are :
- LDLR, which normally produces the LDL receptor. A mutation here reduces the body’s ability to get rid of LDL. This type of mutation accounts for 85 – 90% of all cases of familial hypercholesterolemia.
- ApoB, which normally allows LDL to bind to its receptor. This type of mutation accounts for 5 – 10% of all cases.
- PCSK9, which normally degrades LDL receptors. When PCSK9 is too active, it has a similar effect to an LDLR mutation. This type of mutation is rare.
- LDLRAP1, which normally allows LDL receptors to cross the cell membrane and enter the cell. This type of mutation is rare; two copies are required to cause familial hypercholesterolemia.
SNPs associated with hypercholesterolemia include: rs693, rs7575840, rs4420638, rs12654264, rs1529729, rs688, and rs11591147. Certain variations in these SNPs have been associated with heart disease; people who carry them may benefit the most from red yeast rice .
CYP3A4 is an enzyme that breaks down many drugs and other substances, including lovastatin. Variations in the CYP3A4 gene may cause different people to respond differently to red yeast rice .
Variations in some SNPs are associated with decreased CYP3A4 activity, including rs2740574, rs67666821, rs35599367, and rs4987161. People with certain variations in these SNPs may have a stronger response to red yeast rice because CYP3A4 will take longer to break down monacolin K [79, 80, 81, 82].
Variations in other SNPs are associated with increased CYP3A4 activity, including rs4986910 and rs2737418. People with specific variations in these SNPs may have a weaker response to red yeast rice because CYP3A4 will clear monacolin K more quickly [83, 84].
Women also have higher CYP3A4 activity than men and may have a weaker response to red yeast rice .
Red yeast rice can be eaten as is, ground up into a powder, or purified into an extract. Xuezhikang is a partially purified extract found primarily in China. Clinical studies should use standardized red yeast rice with known quantities of active compounds [86, 87].
If you choose to supplement with red yeast rice, keep in mind that there is currently no way to tell how much monacolin K, citrinin, or other compounds are in each supplement without lab testing. Companies are not required to give this information on the label .
Before it was outlawed by the FDA, red yeast rice extract was sold in the USA as a supplement called Cholestin. You or someone you know may have used Cholestin before the turn of the century. People who responded well to Cholestin may likewise respond well to red yeast rice; talk to your doctor to see whether this is an appropriate option for you .
There is no safe and effective dose of red yeast rice because no sufficiently powered study has been conducted to find one.
Clinical studies use a purified extract of red yeast rice that is guaranteed to contain a certain percentage of monacolins. In one such study, 10 mg of monacolins per day, from purified extract, safely reduced cholesterol and prevented harmful changes to blood vessels. It also lowered hs-CRP, a protein that increases during inflammation .
In another study, 2.4 g of red yeast rice per day reduced cholesterol and blood triglycerides. The correct dosage depends on the purity and form of the supplement .
Red yeast rice is produced when the red mold Monascus purpureus grows on white rice. This health food is a staple of Chinese traditional medicine; it contains a group of bioactive compounds called monacolins and several pigments.
Monacolin K is chemically identical to lovastatin, a drug prescribed to lower cholesterol. As a result, the FDA controls red yeast rice supplements; it may be difficult to find a high-quality supplement that contains enough monacolins to be effective.
Monacolin K, like lovastatin, blocks the production mevalonate, which is later converted to cholesterol. This decreases total cholesterol and bad cholesterol (LDL), but it also decreases coenzyme Q10 and other important compounds.
Like many nutraceuticals, red yeast rice carries some risk. Lovastatin has been linked to birth defects; pregnant women should therefore not supplement with red yeast rice. Red yeast rice may also interact with several drugs; always consult your doctor before choosing to supplement. If you are taking red yeast rice, avoid eating grapefruit or drinking grapefruit juice.
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