Following a fructose-free diet excludes any food or beverage containing the sugar fructose, as well as any sugar that converts to fructose. Table sugar, high fructose corn syrup, glucose and the sugar substitute sorbitol are included on the list. Understanding the rationale behind the diet and becoming knowledgeable about dietary precautions are vital when adopting a fructose-free eating style.
A fructose-free diet is generally prescribed for individuals who have one of two types of fructose intolerance. Hereditary fructose intolerance (HFI) is a rare genetic disorder involving the absence of the gastrointestinal enzyme aldolase B, which breaks down fructose for absorption into the bloodstream. A buildup of fructose in the blood damages the kidneys and liver. Fructose malabsorption is the second type of intolerance. Although less serious, it produces uncomfortable gastrointestinal symptoms such as gas, bloating and diarrhea. Both conditions require diagnosis by a physician. Dr. Luc Tappy at the University of Lausanne in Switzerland says “no direct evidence for more serious metabolic consequences” exists for healthy individuals who wish to avoid fructose.
Fructose is a simple sugar found naturally in fruit. Because fruit is the primary source, all fruits, juices, extracts and dehydrated fruits are avoided. Honey, maple syrup, agave nectar, jellies, marmalade and other fruit products are also eliminated. Some vegetables have a high natural fructose content. This includes carrots, tomatoes, corn, newly harvested white potatoes and sweet potatoes. According to the Hereditary Fructose Intolerance Laboratory at Boston University, cooking vegetables releases free fructose and may help improve tolerance in some individuals.
Numerous manufactured foods utilize fructose, table sugar and sorbitol as additives. Fifty percent of table sugar, or sucrose, is fructose. When choosing a processed food item, read labels carefully. Fructose hides under other names such as beet sugar, brown rice syrup, baker’s sugar, date sugar, carob powder and cane sugar. A few items on the “avoid” list are luncheon meats, sweetened breakfast cereals, relishes, bottled sauces, flavorings and breads with added sugar. More detailed information is available online (see Resources below).
Most protein foods are permissible. Red meats, pork, poultry, fresh fish, eggs and nuts are good choices as long as there is no breading. Calcium-rich milk, cheese and natural yogurts provide variety when menu planning. A limited number of vegetables are permitted, which include asparagus, cauliflower, spinach, rutabagas, peppers and lettuce. Pasta, rice, barley, and unsweetened breads and cereals are fine starch choices. All fats such as butter, margarine and oil are allowed. Salad dressing should be made from scratch because many commercial dressings contain sugar. Additional lists of allowable food items, recipes and discussion blogs are available online (see Resources below).
Most individuals with a genetic fructose intolerance experience symptom relief when fructose, sucrose, glucose and sorbitol are eliminated from the diet, according to Susan Shepherd, dietitian for the Gastroenterology Department of Box Hill Hospital in Australia. Individuals following a fructose-free eating plan should be aware the diet is limited in vitamin C and antioxidants. In addition, nutritional supplements may contain sugar and sorbitol. Consultation with a physician and registered dietitian is highly recommended.