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Introduction

Gamma oryzanol are a group of compounds which are components of rice bran oil – which has been previously extracted from the hard-outer brown layer of rice.

The compounds commonly referred to as gamma-oryzanol include cycloartenol, cycloartenyl ferulate, beta-sitosterol, 24-methylenecycloartanol, and campesterol.

Due to the beneficial properties within these compounds, they are now being extracted out and made into supplemental form.

The main uses of this supplement are to prevent and treat high cholesterol levels, symptoms of menopause, and aging.

This supplement is now also becoming more integrated within gym communities as there is a theory that it can boost hormone levels, especially testosterone and human growth hormone levels that are closely linked to strength and muscle growth.

Gamma Oryzanol Health Benefits

May Reduce LDL Cholesterol Levels

Although cholesterol is needed for a wide variety of metabolic functions, excess LDL (“bad”) cholesterol can result in cholesterol deposits in blood vessel walls, which can lead to clogged arteries and cardiovascular disease.

6 weeks of high gamma-oryzanol rice bran oil has been reported to reduce LDL cholesterol levels by ~10% more than low gamma-oryzanol rice bran oil, in males with high cholesterol levels [1].

It is thought to lower cholesterol levels by aiding in the reduction of dietary cholesterol absorption, thus making it less bioavailable.

This inhibited absorption of dietary cholesterol is seen mainly within the intestines, with limited evidence that there is impaired uptake of cholesterol into the cells lining the intestine [2].

This effect is speculated to be due to the policosanol and tocotrienols content of gamma-oryzanol as these have been previously linked to possessing cholesterol-reducing properties [3] [4].

In addition, other evidence shows that gamma-oryzanol can increase the excretion of bile acids by 100-250%. As cholesterol needs to be used to synthesize new bile acids to replace excreted ones, this mechanism can reduce free cholesterol levels in the blood [5].

May Lower Inflammation

Inflammation is a natural response by the immune system to help your body heal and defend itself, however chronic inflammation is where this response is prolonged and begins to attack healthy cells.

Limited amounts of evidence have shown that gamma-oryzanol may have anti-inflammatory effects. This effect, combined with its effects on lowering LDL cholesterol, could be crucial for preventing cardiovascular disease. This is important because LDL cholesterol only becomes a real issue when there is an increase in inflammation which oxidizes the LDL and causes it to become unstable.

Importantly, gamma-oryzanol has shown to suppress proinflammatory biomarkers such as NF-kB by ~10% , particularly in the lining of arterial walls where plaque development is most common [6].

Lab studies suggest this effect is due to the saponin content of gamma-oryzanol [7]. Saponins are toxic plant compounds which help decrease blood lipids and blood glucose responses [8].

What About Hormone Levels?

Gamma-oryzanol does not appear to significantly effect hormonal levels, despite many people taking the supplement purely for this reason.

The only study available which assesses this relationship analyses males athletes undergoing a weight training program, where 500mg of gamma-oryzanol failed to influence testosterone and estrogen concentrations [9].

Based on the nutritional profile of gamma-oryzanol, it is also highly unlikely for future research to see different results. It is not advised to take this supplement for performance enhancing reasons.

How to Take Gamma Oryzanol?

If you are looking to use gamma-oryzanol it is best to use a supplement, as rice bran is only 0.1% gamma-oryzanol by weight (unless you really love eating a tonne of rice bran!).

If you really want to avoid supplementation, rice bran oil is a superior option to rice bran. 6 grams of oil has the same content of gamma-oryzanol than 300mg of a supplemental form.

Regarding the dosage, it is recommended to take 300mg of gamma oryzanol per day for cholesterol-lowering purposes. Some researchers suggest this should be split into three 100mg doses, distributed evenly throughout the day, to increase the bioavailability.

However, this dosage is more of a logical estimation as opposed to a validated recommendation, with the research using highly variable amounts of gamma-oryzanol; 50-800mg daily.

Gamma Oryzanol Safety And Side Effects

Provided the recommended doses are not exceeded, gamma oryzanol is likely safe for most adults when taken by mouth, however the potential side effects of this supplement are not fully known.

It is currently advised to avoid supplementation if you are pregnancy, breast-feeding, or if you have an underactive thyroid (hypothyroidism).

Conclusion

Gamma oryzanol are a group of compounds which are components of rice bran oil that are used to prevent and treat high cholesterol levels, menopause, and aging.

Based on the current scientific data, supplementing with gamma oryzanol may help to lower LDL cholesterol levels and inflammation.

This being said, it is far too soon for any conclusive statements to be made on this compound and its effects on human health.

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This article has been reviewed and fact-checked by a certified nutritionist, and only uses information from credible academic sources.