A six-carbon sugar.
Found in sucrose and high fructose corn syrup.
More than twice as sweet as its isomer glucose.
Most calorie sweeteners contain approximately equal amounts of fructose and glucose, either linked covalently as in sucrose (table sugar) or as monosaccharide mixtures in high fructose corn syrup and honey.
Fructose containing sugars has been implicated as a driver of the epidemic of obesity, diabetes, and cardiovascular diseases.
Fructose products are preferred by consumers and cooks over products containing only glucose due to the intrinsic greater sweetness over products containing only glucose.
Has the ability to improve the appearance and texture of baked goods.
Increase ingestion and use as a sweetener may be playing a role in the current obesity epidemic.
In contrast with glucose, fructose ingestion only weakly stimulates insulin secretion.
Fructose, as found in many industrial sweeteners, has four calories per gram but has a very low glycemic index and does not cause insulin production, probably because β cells have low levels of GLUT5.
Compared with glucose, fructose ingestion attenuates increase in circulating levels of glucagon-like polypeptide 1(GLP-1) a satiety hormone, and does not attenuate levels of gherlin, an appetite stimulating hormone.
The above suggests that fructose increases food seeking behavior and increases food intake (Bray GA et al).
Fructose is a sugar that has found its way into our diets at higher levels via food and drink containing table sugar, which is half fructose, or high-fructose corn syrup.
This increase over the last few decades has been associated with several metabolic diseases including obesity, fatty liver disease, hypertension, insulin resistance and Type 2 diabetes.
In the early 20th century, the average American ate around 15 grams of fructose a day, while today, the average is more than 55 grams.
Fructose containing sugars (sucrose, fructose), have been implicated as drivers of the epidemic of obesity, diabetes, and cardiovascular disease.
Fructose, or fruit sugar, occurs naturally in fruits, some root vegetables, cane sugar and honey and is the sweetest of the sugars.
It is one of the components of sucrose or table sugar.
Fructose can cause liver inflammation and addiction similarly to ethanol by using similar metabolic pathways, unlike glucose.
It is used as a high-fructose syrup, which is manufactured from hydrolyzed corn starch that has been processed to yield corn syrup, with enzymes then added to convert part of the glucose into fructose.
High fructose consumption promotes fat accumulation in the liver by stimulating lipogenesis in the liver and reducing the beta-oxidation of fat.
Fructose can cause liver inflammation and addiction similarly to ethanol.
The enzyme fructokinase rapidly metabolizes fructose that leads to a decreased level of intracellular adenosine triphosphate (ATP).
When ATP decreases it leads to increases oxidative stress and impairments in proper protein synthesis and mitochondrial function in the liver.
There is no evidence that fructose from unprocessed fruit is a health risk.
Pure fructose intake may cause malabsorption in some individuals.
Does not elicit insulin secretion directly and is taken up almost exclusively by the liver.
The metabolism of fructose is not tightly regulated, like glucose, by the liver cell energy state.
Fructose rapidly undergoes glycolysis fueling lipogenesis under certain conditions.
Absorbed in the small intestine without help of digestive enzymes.
Only about 25–50g of fructose per sitting can be properly absorbed.
In individuals with fructose malabsorption absorption is less than 25g per sitting.
Fructose malabsorption, is a digestive disorder in which absorption of fructose is impaired by deficient fructose carriers in the small intestine’s enterocytes, resulting in an increased concentration of fructose in the entire intestine.
Fructose malabsorption is found in up to 30% of the population of Western countries and Africa.
Common in patients suffering symptoms of irritable bowel syndrome.
The occurrence in patients with IBS is not higher than in the normal population.
A small proportion of patients with both fructose malabsorption and lactose intolerance also have celiac disease.
Fructose that has not been adequately absorbed in the large intestine reduces the absorption of water osmotically and is metabolized by colonic bacteria into short chain fatty acids, producing hydrogen, carbon dioxide and methane gases.
This increase in hydrogen is detectable with the hydrogen breath test.
The consequences of fructose malabsorption include: an increased osmotic load, rapid bacterial fermentation, altered gastrointestinal motility, the formation of mucosal biofilm and altered profile of bacteria.
Fructose malabsorption symptoms are enhanced with other short-chain poorly absorbed carbohydrates such as sorbitol.
Fructose malabsorption has a higher chance of inducing symptoms in patients with functional gut disorders than asymptomatic subjects.
Fructose malabsorption associated with decreased tryptophan, folic acid and zinc levels.
Fructose malabsorption causes improper absorption of tryptophan in the intestine, reduced levels of tryptophan in the blood, and depression.
By restricting dietary intake of free fructose symptom relief can be achieved in a high proportion of patients with functional gut disorders.
Fructose malabsorption associated symptoms include: bloating, diarrhea, and/or constipation, flatulence, abdominal pain, nausea and vomiting.
The diagnostic test is the hydrogen breath test.
No known cure.
Appropriate diet helps control symptoms.
Foods that should be avoided with fructose malabsorption include those foods and beverages containing greater than 0.5g fructose.
Foods with >3g of fructose per serving presents a high fructose load and a risk of inducing symptoms.
Glucose enhances absorption of fructose, so fructose from foods with fructose-to-glucose ratio <1, like white potatoes, are readily absorbed.
Foods with fructose-to-glucose ratio >1, like apples and pears, are often associated with symptoms regardless of the total amount of fructose in the food.
Foods to be avoided include those rich in fructans and other fermentable oligo-, di-and mono-saccharides and polyols, including artichokes, asparagus, leeks, onions, and wheat-containing products.
Foods to be avoided include those containing sorbitol, present in some diet drinks and foods.
Stone fruits, or xylitol, and other polyols such as erythritol, mannitol, and other added artificial sweeteners in commercial foods should be avoided.
Foods with a high glucose content ingested with foods containing excess fructose may help absorb the excess fructose.
Fructan intake for fructose malabsorbers should be kept to less than 0.5 grams/serving,
Foods with more fructose than glucose include: Sucrose, apples, pears, fruit juice, watermelon, raisins, honey, high fructose corn syrup and mango.
Fruits that contain nearly equal amounts of the fructose and glucose do not present problems for patients with fructose malabsorption.
Apples, pears and watermelon contain more than twice as much fructose as glucose.
Fructose levels in grapes varies depending on ripeness with unripe grapes containing more glucose.
Foods which are unfavorable that contain more fructose than glucose include the fruits: apple, pear, guava, honeydew melon, papaya, quince, star fruit, and watermelon, and dried fruits: apple, currant, date, fig, pear, and raisin, fortified wines, and foods containing added sugars, such as agave nectar, some corn syrups, and fruit juice concentrates.
Favorable foods in which fructose is equal or less than glucose include: Stone fruits: apricot, nectarine, peach, plum, Berry fruit: blueberry, blackberry, boysenberry, cranberry, raspberry, strawberry, loganberry, and Citrus fruit: kumquat, grapefruit, lemon, lime, mandarin, orange, tangelo, and other fruits: ripe banana, jackfruit, kiwi fruit, passion fruit, pineapple, rhubarb, tamarillo.
Foods, such as bread, that are gluten-free are suitable for fructose malabsorbers.
Fructose malabsorbers do not need to avoid gluten, and many can eat breads made from rye and corn flour.
Fructose and fructans which are polymers of fructose cause GI discomfort in susceptible individuals.