Found in all living organisms, purines are necessary to build genetic material or DNA. Protein foods are the richest sources of purines, but some fruits and vegetables have higher amounts as well. When they are metabolized, purines are broken down into uric acid. In some individuals, high amounts of uric acid can cause gout or kidney stones. Eating a low-purine diet can help to reduce uric acid levels.
A low-purine diet is restricted to 100 to 150 milligrams of uric acid each day. Most vegetables are considered low-purine foods, with less than 100 milligrams of uric acid per 100-gram serving. Vegetables that have the highest amount of purines include artichokes, bean sprouts, broccoli, brussels sprouts, leeks, mushrooms, peas and peapods. These vegetables contain between 60 and 100 milligrams of uric acid per 100 grams. They should be eaten in small amounts, so choose only one high-purine vegetable per day when following a low-purine diet.
Vegetables with moderate amounts of purines can be eaten in larger portions on a low-purine diet. Good choices, which have about 20 to 50 milligrams of uric acid per 100-gram serving, include asparagus, bamboo shoots, cabbage, cauliflower, corn, green or string beans, green peppers, kale, kohlrabi, spinach and summer squash. Most individuals on a low-purine diet can safely have at least two servings of these vegetables each day.
The vegetables with the lowest purine amount include carrots, chicory, eggplant, lettuce, onions, radishes and tomatoes. Any of these can be eaten in larger portions and throughout the day. Eating a large salad made with several of these is a good way to get more vegetables and still follow a low-purine diet.
It's important to note that even the highest-purine vegetables are significantly lower than protein foods and organ meats, like meat, seafood and liver, which have several hundred to 1,000 milligrams per serving. If you have been advised to restrict high-purine foods, it's also helpful to drink at least eight to 12 glasses of water or fluid each day because it helps to dilute urinary uric acid and avoid rapid weight loss, which can increase uric acid levels.