Pterostilbene for Antioxidant Protection

Caveats

In vitro antioxidant potency has repeatedly failed to predict human benefit - large trials of beta-carotene, vitamin E and vitamin C found no benefit and in some cases harm, with beta-carotene increasing lung cancer risk in smokers. Reactive oxygen species also serve necessary signalling functions, including in exercise adaptation and immune defence, so suppression is not automatically good. Safety of pterostilbene: the key flag is that 250 mg/day raised LDL cholesterol in the Riche randomised trial, an effect attenuated by co-administered grape extract - relevant because people taking it for antioxidant purposes are usually pursuing cardiovascular health. Human safety data cover roughly 8 weeks only, so long-term safety is unknown and no upper intake level has been set; do not exceed the studied range. Pterostilbene inhibits cytochrome P450 enzymes in vitro and may have antiplatelet activity, so use caution with anticoagulants such as warfarin and direct oral anticoagulants, antiplatelet drugs, and medications with narrow therapeutic windows, and stop before surgery. Avoid in pregnancy and breastfeeding, as no safety data exist. For oxidative stress, a diet high in vegetables, fruit, legumes, nuts and whole grains has the evidence that isolated compounds lack.