Athletes looking to extend their endurance capacity may achieve better results by taking high doses of curcumin. And curcumin supplementation may also help people who are trying to lose weight by doing intensive cardio training. We, the ignorant compilers of this webzine, came up with these ideas after reading an animal study that physiologists at Kanazawa University in Japan published in Metabolism.
The researchers injected the curcumin directly into the rats’ small intestine. The doses used were 50 and 100 mg curcumin per kg bodyweight per day. The human equivalent of these doses would be about 600-1200 mg per day. Because intraperitoneal administration of curcumin is about twice as efficient as oral administration, you’d have to double these high doses. Ugh.
Not easily absorbable
Curcumin [structural formula shown below] is not easily absorbable, hence the high doses. Supplements manufacturers have devised methods to increase the absorbability of curcumin so that such high doses are no longer necessary. You can read more about this here and here.
If we are to believe the threads on some bodybuilding forums [professionalmuscle.com 12-06-2015], some adventurous bodybuilders have found another way of getting round the low bioavailability of curcumin. They use injectable preparations containing the stuff. Doses of several hundred milligrams a day are believed to enhance the effects of steroids on body composition, and offer protection against side effects. Users report that their muscles work harder, as well as a decrease in fat mass and increase in endurance capacity.
The Japanese weren’t interested in bodybuilding however. They wanted to know whether curcumin supplementation would boost the effects of endurance training, and if so, how. They attempted to answer this question by analysing the animals’ muscle cells at the end of the experiment.
The researchers found more mitochondria in the muscle cells of the animals that had not trained but had received curcumin [CD50] [CD110] than they did in the muscle cells of the rats that had not trained and had also not been given curcumin [DMSO], as the figure below shows.
Endurance training [eTR] led to a bigger increase in the number of mitochondria than curcumin supplementation did. But the increase in mitochondria as a result of endurance training was even bigger when combined with curcumin. The more mitochondria muscle cells have, the more nutrients they can convert into energy. Endurance capacity increases, as does calorie expenditure.
The researchers discovered that curcumin boosts the concentration of cAMP in the muscle cells. cAMP is a messenger molecule that’s needed for internal communication within cells. In addition curcumin boosts the concentration of SIRT1 and active AMPK. The Japanese produced the figure below to summarise how curcumin probably works.
The study was not financed by a curcumin manufacturer, but by the Japanese and Indonesian governments.
Curcumin treatment enhances the effect of exercise on mitochondrial biogenesis in skeletal muscle by increasing cAMP levels
In response to physiologic stressors, skeletal muscle has the potential to elicit wide variety of adaptive responses, such as biogenesis of mitochondria and clearance of damaged mitochondria to promote healthy muscle. The polyphenol curcumin, derived from the rhizome Curcuma longa L., is a natural antioxidant that exhibits various pharmacological activities and therapeutic properties. However, the effect of curcumin on the regulation of mitochondrial biogenesis in skeletal muscle remains unknown. The present study aimed to examine the effects of combination of endurance training (eTR) and curcumin treatment on the expression of AMPK, SIRT1, PGC-1?, and OXPHOS subunits, mitochondrial DNA copy number, and CS activity in rat skeletal muscle. Furthermore, the present study also examined the effect of exercise and curcumin treatment on the levels of cAMP and downstream targets of PKA including phosphorylated CREB and LKB-1.
Ten-week-old male Wistar rats were randomly divided into non-eTR and eTR groups. Low doses (50 mg/kg-BW/day) or high doses (100 mg/kg-BW/day) of curcumin dissolved in dimethyl sulfoxide (DMSO) were injected intraperitoneally in all animals for 28 days to investigate the effect of curcumin alone and the combined effect of curcumin with eTR. Western blotting (WB) and immunoprecipitation (IP) were performed to detect the presence of proteins.
Our results demonstrated that combination of curcumin treatment and eTR increased the expression of COX-IV, OXPHOS subunits, mitochondrial DNA copy number and CS activity in the gastrocnemius (Gas) and soleus (Sol) muscles. In addition, this combination increased AMPK phosphorylation, NAD+/NADH ratio, SIRT1 expression, and PGC-1? deacetylation. Furthermore, curcumin treatment as well as exercise also increased levels of cAMP and downstream target of PKA including phosphorylation CREB and LKB-1 which are involved in the regulation of mitochondrial biogenesis.
Taken together, these results suggest that the combination of curcumin treatment and eTR has the potential to accelerate mitochondrial biogenesis in skeletal muscle by increasing cAMP levels.