Pterostilbene - A beneficial supplement with high bioavailability
Pterostilbene is a natural compound that can be found in blueberries, grapes as well as processed foods and beverages made from these fruits (i.e., wine or grape juice). A variety of clinical, randomized, double-blind studies indicate that supplemental pterostilbene intake may provide several health benefits. Its molecular structure is similar to resveratrol, and both fall under the category of phytoalexins (compounds that are produced by plants to fend off parasites and insects). One may argue pterostilbene is the better supplement of the two, as it is more potent and more bioavailable:
Absorption
In contrast, to resveratrol, pterostilbene was shown to have increased hydrophobicity and oral absorption. Compared to the estimated 20% of oral bioavailability of resveratrol, pterostilbene has close to 80% oral bioavailability at doses between 56 and 168mg/kg. Pterostilbene’s clearance rate indicates that it efficiently bioaccumulates in the body, and its twin methoxy groups enable it to diffuse into cells more readily than supplemented resveratrol.
Health benefits of pterostilbene
Reducing Blood Pressure
This study suggests that pterostilbene lower blood pressure in adults with high cholesterol levels (hypercholesterolemia). While pterostilbene had some adverse effects on cholesterol, these effects were mitigated by grape seed extract. These findings support the theory, that grape seed extract and pterostilbene are meant to be supplemented together (just like one does when munching on grapes)
Reducing Neuroinflammation (Inflammation of the nervous system)
In this study, 10-30 μM of pterostilbene was shown to lower microglial nitric oxide production without scavenging directly from nitric oxide radicals. It does so by inhibiting IκBα phosphorylation. These effects were shown to be slightly more potent than those of resveratrol.
Blood Glucose & Diabetes
Several studies indicate that pterostilbene can improve blood glucose levels:
- By supplementing a hypercholesterolemic hamster’s diet with 25 micrograms/kg of pterostilbene, blood glucose levels dropped by 14%.
- In diabetic rats, 40mg/kg for six weeks resulted not only in reduced blood glucose levels but also a concomitant increase in insulin.
- To a lesser degree, these benefits even extended to healthy rats, reducing blood glucose by 6.3%.
- In Hyperglycemic rats, the effects of 40mg/kg pterostilbene supplementation can be compared to a 500mg/kg intake of metformin.
Cognitive function
Pterostilbene has even been shown to improve cognition in aged rats when supplemented over 12-13 weeks. The cognitive improvements were shown to have a correlation with pterostilbene concentrations in the hippocampus,
Is pterostilbene safe to supplement?
A study subjected mice to 3000mg/kg doses of pterostilbene every day. (Which is 500 times the estimated human intake.) These doses did not exert and significant clinical toxicity.
But what about humans?
In a human clinical trial, test subjects supplemented 250mg of pterostilbene taken in 125mg doses, twice a day, over the course of 6-8 weeks. They did not show clinical or biochemical signs of toxicity.
Why combine with Grape Seed Extract?
As mentioned above, there were some cases where pterostilbene taken by itself caused a slight increase in LDL. This side effect was negated when grape seed extract was supplemented alongside pterostilbene. Fundamentally speaking, in nature, grape seeds and pterostilbene are found together within the same piece of fruit and have been consumed together by humans for millennia.
Besides the benefit the combination of the two can offer, grape seed extract itself also provides various health benefits, such as:
- Suppresses bone destruction in autoimmune arthritis
- Improves blood flow, reducing the risk of blood clots