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Fructose

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[[File:Soft drink shelf.JPG|right|thumb|500px|One of the greatest sources of Fructose is one of the two common single molecule sugarssoft drinks.]]Fructose can be good or bad for an athlete depending on when it's consumed. Fructose can help athletic performance when taken as a fuel source during exercise, the but at other being glucosetimes excessive fructose can create health issues. Fructose is found in sugar (sucrose), High Fructose Corn Syrup, Honey and [http://en.wikipedia.org/wiki/Agave_nectar Agave]. The combination of a Excessive fructose intake has been described as "an environmental toxin with major health implications"<ref name="FructoseMajorHealth"/>. High Fructose Corn Syrup may be slightly worse for health than sugar, and may be a source of toxic mercury.  =What is Fructose?=Fructose is a common simple sugar that along with glucose molecule is makes up ordinary table sugar (sucrose), or common and High Fructose Corn Syrup (HFCS). In table sugar, one molecule of fructose is combined with one molecule of glucose. In High Fructose Corn Syrup the fructose and glucose are not linked together, but mixed in various ratios, generally close to 50:50 (55% and 42% is a common <ref name="FructoseExerciseHealth"/>, with 55% being used in drinks and 42% being used in foods<ref name="FructoseHFCS2"/>). Fructose is sometimes called "fruit sugar substitute that contains both " because it is commonly found in fruit. Some fruit, such as apples and pears contain twice as much fructose and as glucose<ref name="FructoseNutrientDatabase"/>. While glucose  =Health risks of Fructose=The effect of fructose is absorbed very different from glucose, with different pathways in the digestive system body being used<ref name="FructoseFructolysis"/>. Fructose tends to result in the production of fat, influences hormones that control appetite, energy balance, and can be used directly by the storage of bodyfat, as well as tending to create insulin resistance<ref name="FructoseHavel"/><ref name="FructoseFatOxidation"/>. It has been proposed that intakes of >50g per day of fructose must go may be a cause of type II diabetes<ref name="FructoseUricT2Diabetes"/>. Fructose is also believed to the be a risk factor for hypertension, elevated triglycerides, obesity, preeclampsia, chronic kidney disease, stroke, cardiovascular disease, and mortality<ref name="FructoseEpiRole"/><ref name="FructoseSSB"/>, as well as causing [http://en.wikipedia.org/wiki/Non-alcoholic_fatty_liver_disease liver disease] similar to that seen in alcoholics<ref name="FructoseLiverAssy"/><ref name="FructoseLiverOuyang"/><ref name="FructoseLiverCollison"/><ref name="FructoseSDNAFLD"/>. Also, there may be converted a link between fructose and dementia<ref name="FructoseDementia"/>. Both Fructose and Glucose tend to result in increased body fat, Fructose can produce a useable formgreater increase in visceral (internal) fat<ref name="FructoseVisceralFat"/><ref name="FructoseAbdominal"/>, which is a risk factor for heart disease<ref name="FructoseVisceralFatHeart"/> and diabetes<ref name="FructoseVisceralDiabetes"/>. This conversion process slows Between 1977 and 2001 Americans increased the effective digestion percentage of their daily calories from soft drinks from 2.8% to 7.0% and from fruit juice from 1.1% to 2.2%<ref name="FructoseIntake"/>. ==Fructose and Fruit==The health risks of high fructose consumption and not generally seen with high intakes of whole fruit<ref name="FructoseExerciseHealth"/>. While fruit does contain fructose, giving it 's not easy to consume significant quantities of fructose from whole fruit. For instance, an Apple contains about 10g of fructose, and a 16 ounce soft drink contains about 26g of fructose. The Apple is generally much slower to consume than a soft drink, and in addition, the Apple contains fiber couple slow absorption. However, the health benefits of whole fruit do not seem to apply to fruit juice<ref name="FructoseJuiceKids"/>. There does not appear to be any evidence that fruit juice has a lower [[Glycemic Index]]health risk than soft drinks. ==Sugar and High Fructose Corn Syrup==Corn syrup does not naturally contain any fructose, but it can be processed so that some of the glucose is converted to fructose, hence the term High Fructose Corn Syrup. Typically high fructose corn syrup has a similar amount of fructose as ordinary table sugar (sucrose) which is 50:50 fructose and glucose. With table sugar, the fructose and glucose are linked together, but they are separate in High Fructose Corn Syrup, as well as honey<ref name="FructoseHoney"/>, and cooking sugar with and an acid (such as jam making) separates the fructose and glucose<ref name="FructoseInvertedSugar"/>. The consensus of research indicates that High Fructose Corn Syrup has a similar effect to ordinary table sugar<ref name="FructoseHFCSMeta1"/><ref name="FructoseHFCS2"/><ref name="FructoseHFCS3"/><ref name="FructoseHFCS4"/><ref name="FructoseHFCS5"/><ref name="FructoseHFCS6"/><ref name="FructoseHFCS7"/><ref name="FructoseHFCS8"/><ref name="FructoseTappy"/><ref name="FructoseHFCSJacn"/>. There are a number few studies which indicate differences between the separate fructose/glucose which is found in High Fructose Corn Syrup or honey and table sugar. Rats fed 40% of calories from fructose/glucose had impaired fasting glucose and were less active than with equivalent amounts of health concernssugar<ref name="FructoseGFDiffRat"/>, and higher triglycerides (60% of calories)<ref name="FructoseDiffTG"/>. Fructose metabolism is different for different species so animal studies, especially concerning triglycerides, may not be applicable to humans<ref name="FructoseHFCSSpecies"/>. I found two studies that showed a difference in humans. Carbohydrate sensitive men had a greater insulin response to a large dose of separate fructose/glucose after a 9 hour fast compared with table sugar, though not a greater blood sugar level<ref name="FructoseHFCSCarbSens"/>. Another study<ref name="FructoseHFCSHumanTG"/> showed higher triglyceride levels from separate fructose/glucose than table sugar in 8 healthy men. A more significant concern is mercury contamination of HFCS which a study found in half of the samples analyzed<ref name="FructoseHFCSMercury"/>. Overall, I would conclude that high fructose corn syrup is slightly worse than sugar, which combined with the risk of mercury contamination indicates it may be worth avoiding.  =Fructose and Obesity=Studies have shown that drinking soft drinks results in an increase in energy intake and body weight in both overweight<ref name="FructoseWeight1"/> and normal weight<ref name="FructoseWeight2"/> subjects. This weight gain has also been shown in animal studies<ref name="FructoseWeightAnimal1"/><ref name="FructoseWeightAnimal2"/>, and a study of diabetics<ref name="FructoseWeightDiabetics"/>. One mechanism may be that fructosedoes not stimulate the hormone leptin that reduces appetite<ref name="FructoseWeightLeptin"/> . One study showed that drinking artificially sweetened (aspartame) soda actually caused a reduction in energy intake compared with no soda and some also lost body weight<ref name="FructoseWeight2"/>. =Fructosefor Athletes=As noted in [[Nutrient Timing]], the human body responds to nutrition differently when exercising. This is also true for fructose, including liver damage similar which can be a beneficial addition to alcoholism a sports drink. Combined carbohydrate types, such as fructose, glucose or [[Maltodextrin]] are absorbed more easily than when taken in isolation<ref name="FructoseExCombMix"/>, and the creation combination of unhealthy fats as part fructose and glucose provides more carbohydrate fuel than glucose alone<ref name="FructoseExCombRoy"/><ref name="FructoseExCombRowlands"/>. While fructose alone does not improve performance in the way that glucose does<ref name="FructoseExFrucOrGluc1"/>, the combination of fructose and glucose improves performance more than glucose alone<ref name="FructoseExFrucAndGlucBoys"/>. The combination of fructose metabolismand glucose also results in better fluid absorption than either alone<ref name="FructoseExerciseHealth"/>. Larger quantities Also, some of the health issues of fructose are mitigated by exercise<ref name="FructoseFLDExcRat"/>. Fructose on its own can also cause digestive gasupsets, but the combining glucose with fructose either as sugar (sucrose) or separately dramatically improves fructose absorption<ref name="FructoseAbsorbtion"/>. Therefore a good sports drink should contain some fructose along with glucose and/or [[Maltodextrin]]. See [[Fellrnr's Go Juice]]. ==References==
<references>
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