Alpha lipoic acid is a natural protective antioxidant. Many foods contain alpha lipoic acid but in very low amounts. They include spinach, broccoli, yams, potatoes, yeast, tomatoes, Brussels sprouts, carrots, beets, and red meat — particularly organ meat.  The antioxidant properties of alpha-lipoic acid have been linked to several benefits, including lower blood sugar levels, slowed skin ageing, improved nerve function and reduced inflammation.