Gamma oryzanol is a compound found in rice bran oil. It lowers cholesterol and decreases inflammation. Due to its antioxidant activity, it combats wrinkles and skin aging. In addition, this supplement may also help with diabetes, insulin sensitivity, obesity, and allergies. Although gamma oryzanol has been used in Japan for decades, studies are still uncovering its many potential health benefits. Read on to find out why this supplement is gaining in popularity.
What Is Gamma Oryzanol?
Apart from rice, it is also found in wheat, maize, rye, triticale, and barley, but at much lower levels .
It has been used as a supplement in Japan since the early 70s.
- lowers bad cholesterol. Phytosterols (plant sterols) found in this supplement have a structure similar to cholesterol and are well known for their LDL-cholesterol-lowering effect .
- is anti-inflammatory [5, 6].
- lowers blood glucose .
- is an antioxidant. This is due to ferulic acid, a strong antioxidant that protects cells from reactive oxygen species (ROS) [8, 9].
Gamma oryzanol is commonly used as an exercise supplement as well as to build muscles. However, the results regarding muscle strength are controversial.
It is much more promising as a supplement that decreases cholesterol and helps with inflammation.
Mechanisms of Action
Gamma oryzanol decreases cholesterol by:
- Decreasing the uptake of cholesterol by gut cells .
- Decreasing HMG-CoA reductase activity. HMG-CoA reductase is an enzyme that promotes cholesterol production [10, 11].
- Blocking the formation of micelles, which are small aggregates of molecules that often contain cholesterol [10, 12].
This supplement lowers inflammation by:
- Decreasing NF-kB – the master-regulator of inflammation .
- Decreasing inflammatory molecules PGE2, COX-2, TNF-alpha, and IL-6 [5, 6].
- Lowering CRP – a marker of chronic low-grade inflammation .
Gamma oryzanol is an antioxidant. It removes organic radicals .
It lowers blood glucose levels by increasing PPAR-γ and C/EBPα, which increase the uptake of glucose by cells .
This compound combats cancer by:
- Increasing the activity of natural killer cells, which combats tumor cell growth [16, 17].
- Reducing caveolin-1 and PCGEM1 expression. These genes are involved in the development and progression of prostate cancer .
- Suppressing blood vessel formation to inhibit tumor growth .
Health Benefits of Gamma Oryzanol
1) Decreases Cholesterol
Gamma oryzanol blocks the uptake of cholesterol by gut cells, as it decreases HMG-CoA reductase, an enzyme that promotes cholesterol production. This supplement also increases cholesterol removal by bile acids [10, 19].
In 30 men with high cholesterol, rice bran oil, with varying amounts of gamma oryzanol, was able to lower total and LDL cholesterol levels. However, there was little difference between the cholesterol-lowering effects of the high and low gamma oryzanol-containing rice bran oil .
Gamma oryzanol decreased total cholesterol and LDL cholesterol levels in 20 schizophrenia patients with high cholesterol .
In another study, this supplement lowered cholesterol and improved fat metabolism in rats fed a high-cholesterol diet .
Gamma oryzanol decreased cholesterol levels in hamsters with high cholesterol .
It also lowered cholesterol absorption by 20% and increased cholesterol removal by bile acids in rats .
2) May Prevent Hardening of the Arteries (Atherosclerosis)
This compound decreased cholesterol and reduced “aortic fatty streaks” in hamsters. Fatty streaks are the first visible damage in the hardening of the arteries .
However, it was ineffective in treating hardening of the arteries (atherosclerosis) in rabbits .
3) May Improve Muscle Strength
A study of 30 healthy participants found that gamma oryzanol improved bench press and leg curl results, showing that the supplement may have improved muscle strength during resistance training .
However, another study on 22 weight-trained men showed that nine weeks of gamma oryzanol supplementation did not influence performance .
4) May Be Beneficial in Diabetes
This compound directly acts on pancreatic cells to enhance glucose-stimulated insulin release .
Also, it directly enhances glucose uptake by fat cells (adipocytes) .
5)May Improve Insulin Sensitivity
6) May Combat Obesity
A study performed on rats suggests that gamma oryzanol can combat obesity by blocking dopamine receptors (D2R) in the brain (striatum). These receptors are part of the brain reward system. They are increased by a high-fat diet, resulting in hedonic overeating .
It also decreased the production of fat cells (adipocytes) .
7) Gamma Oryzanol and Cancer
Gamma oryzanol inhibited colon tumor growth in mice by :
- Increasing natural killer (NK) cell activity
- Increasing cytokines TNF-alpha, IL-1beta, and IL-6
- Reducing blood supply to the tumor
Cycloartenol ferulate, a component of gamma oryzanol, reduced the growth of skin tumors in mice .
However, a study on rats reported a rare side effect of gamma oryzanol – promoting lung cancer. But its effect is weak and occurs only at a very high dosage .
8) Improves Your Skin
When delivered under the skin via an injection, gamma oryzanol protected against skin-aging and improved wrinkles in 15 people and UV radiation-exposed rats .
Also, when it was incorporated into a cream and applied to the skin, it hydrated and lightened the skin .
9) May Combat Osteoporosis
10) Is Anti-Inflammatory
This supplement reduced lung inflammation in rats with sepsis .
11) May Prevent Anaphylaxis
Anaphylaxis is an extreme allergic reaction characterized by swelling and difficulty breathing.
A component of gamma oryzanol called cycloartenol ferulate was able to reduce mast cell degranulation (mast cells release histamine and other inflammatory agents), which decreased the anaphylaxis reaction in rats .
12) May Promote Hair Growth
A rice bran extract containing gamma oryzanol promoted hair growth and the formation of new hair follicles in mice .
13) May Improve the Immune Response
14) May Protect from Heavy Metal Toxicity
15) May Prevent Ulcers
Limitations and Caveats
Since most of the studies mentioned here were on animals, caution should be taken when using gamma oryzanol for its health benefits in humans.
Despite the frequent use of gamma oryzanol by athletes as a strength supplement, there is limited evidence available to support the effects of this compound on muscle strength during resistance training .
The testosterone-lowering effects of gamma oryzanol are only theoretical and haven’t yet been proven .
Further studies are needed to confirm that gamma oryzanol reduces HMG-CoA reductase activity in humans .
Gamma Oryzanol and Hormones
Gamma oryzanol and its source rice bran oil are generally considered to be safe, with little to no side effects reported in studies.
Gamma oryzanol is a promoter of lung cancer in rats, but its effect is weak and occurs only at a very high dosage .
Gamma oryzanol is generally administered orally at a variety of doses.
One study (referenced in a review) administered gamma oryzanol thrice daily at 20 mg .
- “This got rid of my ulcer. It took a while, but it works.”
- “I would not recommend this as a workout-related antioxidant. Gamma Oryzanol is not very effective.”
- “I was surprised to feel a difference. My muscles are less sore, I lost weight and my sexual performance improved. No apparent side effects. This is one of the few products I’ve used that is effective even after a few weeks of use.”
- “As an integrative medicine doctor, I have used this a lot in my patients and they’ve had great results. It has almost no side effects and it is cheap.”