Caffeine and Pomegranate Juice
The Latest Research

Caffeine: Exercise In A Pill?
If you have been keeping up with the latest 'MD Research' reports in every issue of Muscular Development, you may have noticed several studies reporting that caffeine can reduce the incidence of diabetes. Interestingly, caffeine acts on the same biochemical pathway as exercise. Caffeine has been implicated in the regulation of glucose and lipid metabolism, including actions such as insulin-independent glucose transport, glucose transporter 4 expression (stimulates glucose uptake independent of insulin), and fatty acid utilization in skeletal muscle. To make things simple, caffeine works independently of insulin for glucose uptake in muscle. Exercise has similar mechanisms of actions, as it can decrease blood glucose without changes in insulin; glucose can be taken up from muscle independently of insulin. Caffeine stimulates muscle glucose transport in the absence of insulin, increases GLUT4 messenger RNA or protein expression in cell cultures, and enhances fatty acid metabolism in muscle. These effects are similar to the exercise-induced changes in skeletal muscle. Researchers examined the biochemical pathway in which caffeine decreases glucose uptake in muscle by exposing isolated muscle fibers to caffeine. The researchers found that caffeine activated the chemical messenger AMPK, which is a fuel sensor for the cell. AMPK has been found to be activated after exercise, yet in the study, caffeine stimulated AMPK activation similar to muscle contraction. Thus, it is likely that AMPK is a signaling-intermediary leading to caffeine-stimulated glucose transport in skeletal muscle. Considering that caffeine and exercise exert similar effects in stimulating AMPK, caffeine may be the active ingredient responsible for the preventive effect of coffee and green tea on the development of type 2 diabetes mellitus. In this context, further studies are needed to clarify whether oral administration of caffeine at a physiologic dose results in AMPK activation and induces AMPK-related metabolic events, including glucose transport, in skeletal muscle.

Egawa T, Hamada T, Kameda N, Karaike K, Ma X, Masuda S, Iwanaka N, Hayashi T. Caffeine acutely activates 5'adenosine monophosphate-activated protein kinase and increases insulin-independent glucose transport in rat skeletal muscles. Metabolism, 2009 Nov;58(11):1609-17.

Pomegranate Juice Reduces Muscle Soreness and Improves Strength
Ellagitannins are bioactive polyphenols abundant in some fruits and nuts, such as pomegranates, black raspberries, raspberries, strawberries, walnuts and almonds. Pomegranate (Punica granatum L.) fruits are widely consumed fresh and as a beverage, such as juice. If you have been reading the news lately, pomegranate juice has been found to have a protective role in preventing heart disease, high blood pressure and prostate cancer— and now it can even protect skeletal muscle!
A previous study reported that tart cherry juice prevents muscle soreness via potent antioxidant effects; pomegranate juice seems to also provide protective effects from muscle damage. The mechanisms mediating polyphenol supplementation from fruit are not clear, but may be linked to a reduction of oxidative stress and inflammation, which is caused by intense exercise. Subjects consumed pomegranate juice twice daily and then performed a bout of maximal eccentric exercise— the most muscle-damaging form of exercise you can perform. After the intense workout session, the group that consumed pomegranate juice recovered from exercise faster than the group that did not consume pomegranate juice, and had less muscle soreness. In conclusion, this study demonstrates that twice-daily pomegranate juice consumption rich in ellagitannin supplementation over a nine-day period improves strength recovery 48-72 hours following a damaging bout of eccentric exercise.

Trombold JR, Barnes JN, Critchley L, Coyle EF. Ellagitannin Consumption Improves Strength Recovery 2-3 Days after Eccentric Exercise. Med Sci Sports Exerc, 2009 Nov 23.