Vitamin E tocotrienols show bone health benefits: Rat data

Annatto tocotrienol – mainly composed of delta-tocotrienol – was found to completely prevent erosion of the bone surface and decreased bone formation associated with testosterone deficiency, report researchers from Universiti Kebangsaan Malaysia in Nutrients​.​

“The current study found that testosterone deficiency caused an increase in osteoclast surface and a reduction in osteoblast surface at the trabecular bone,”​ wrote the researchers. “This caused an imbalance in bone remodeling, which resulted in increased erosion, indicated by elevated eroded surface, and a decrease in matrix synthesis, indicated by reduced osteoid surface and volume. This would weaken the bone and subsequently causing osteoporosis.​

“Annatto tocotrienol supplementation was as effective as testosterone enanthate intervention [one of the standard therapies used to treat osteoporosis in men] in suppressing the adverse effects of testosterone deficiency on bone.”​

Clinical trials​

The study is said to be the first to evaluate the effects of vitamin E tocotrienols in testosterone deficient rats, and the researchers called for clinical trials to validate if the same bone health benefits are observable in humans.

The new study used American River Nutrition’s DeltaGold product – a naturally tocopherol-free mix containing ~90% delta- and 10% gamma-tocotrienol.

Commenting on the research, Dr Barrie Tan, president of American River Nutrition said that the role of tocotrienol is an important one in bone health and reversal of bone loss.

“The effect of tocotrienol in bone health is an emergent science champion by Prof. Soelaiman, who has taken on to study this critical path ‘less traveled’. Two clinical studies are currently underway,”​ said Dr Tan.

The vitamin E family​

Tocotrienols are forms of vitamin E that have traditionally been in the shadow of the more popular vitamin E form – tocopherols.

Overall, there are eight forms of vitamin E: Four tocopherols (alpha, beta, gamma, delta) and four tocotrienols (alpha, beta, gamma, delta). Alpha-tocopherol (alpha-Toc) is the main source found in supplements and in the European diet, while gamma-tocopherol (gamma-Toc) is the most common form in the American diet.

Tocotrienols are only minor components in plants, although several sources with relatively high levels include palm oil, annatto, cereal grains and rice bran.

Study details​

Osteoporosis is a condition of decreasing bone density accompanied by high bone turn-over. While women are four times more likely to develop the disease, approximately two million American men have osteoporosis, and an estimated 12 million more are at risk.

On the other hand, men have a greater mortality and morbidity risk associated with the disease due to complications with hip fractures. Testosterone deficiency is the most common cause of osteoporosis in men, and elicits an imbalance in bone remodeling manifested by decreased bone-forming cells or osteoblasts, as well as increased levels of osteoclasts that are responsible for erosion of the bone surface.

For the new study, Prof Soelaiman and her collaborators compared the effects of annatto tocotrienol (60 mg/kg body weight for eight weeks) with testosterone enanthate (7 mg/kg body weight one per week via injection) in a testosterone-deficient rat model.

Results showed that both compounds were equally effective in attenuating the imbalance in bone remodeling associated with testosterone deficiency. Possible mechanisms may include tocotrienol’s strong antioxidant capabilities, down-regulation of the mevalonate pathway, and suppression of proinflammatory cytokines known to promote osteoclastogenesis, said the researchers.

In previous studies, annatto tocotrienol was shown to improve bone structural and dynamic indices at the femur of castrated male rats, they added. The supplement was also effective in increasing bone formation and preventing bone resorption in a postmenopausal rat model for osteoporosis.

“The current findings suggested that the ability of tocotrienol to halt the decrease in osteoblast number and the increase in osteoclast number due to testosterone deficiency accounted for the improvements in bone health shown in previous studies,”​ they wrote.

Source: Nutrients​​
6(11), 4974-4983; doi:10.3390/nu6114974
“Annatto tocotrienol improves indices of bone static histomorphometry in osteoporosis due to testosterone deficiency in rats”​
Authors: Chin KY, Abdul-Majeed S, Mohd. Fozi NF, Soelaiman IN