Additionally, according to "The Merck Index", glucuronolactone is used as a detoxicant. The liver uses glucose to create glucuronolactone, which inhibits the enzyme B-glucuronidase (metabolizes glucuronides), which should cause blood-glucuronide levels to rise. Glucuronides combine with toxic substances, such as morphine and depot medroxyprogesterone acetate, by converting them to water-soluble glucuronide-conjugates which are excreted in the urine. Higher blood-glucuronides help remove toxins from the body, leading to the claim that energy drinks are detoxifying. Free glucuronic acid (or its self-ester glucuronolactone) has less effect on detoxification than glucose, because the body synthesizes UDP-glucuronic acid from glucose. Therefore, sufficient carbohydrate intake provides enough UDP-glucuronic acid for detoxication, and foods rich in glucose are usually abundant in developed nations.