Fructose is one of the fundamental carbohydrates in our diet. It is found in most sugary fruits and honey, and is absorbed in the intestines due to protein transport placed on the membrane of the intestinal cells.
However, some people have more difficulty than others in the digestion of fructose, and this can cause a variety of problems (gas, diarrhea, constipation). It is very often a genetic deficiency. Still very little is known, pending an in-depth investigation.
Fructose malabsorption is defined as a kind of digestive problem in which the absorption is compromised by a deficiency of fructose carriers in the enterocytes of the small intestine. This means that it is impossible to decompose the fructose, which allows its molecules to reach the colon “undigested” with consequent unpleasant effects.
Very often with fruit, the blood sugar crashes and ingesting certain fruits or honey cause harmful effects. Including..
- Muscle cramps
- Sugar cravings
Bloating, when from the result of fermentation, is caused by an imbalance of the intestinal flora and an excess of pathogenic bacteria. While most of the cells in our body cannot use fructose as an energy source, the bacteria in our gut can, which would explain those difficulties in the digestive tract.
With the moderate consumption of fruit and choice of fruits with a low glycemic index (blueberries, raspberries, blackberries, strawberries), things usually get better, but some symptoms can persist.
Without an elimination diet or aid of any test, suspending the ingestion of fruit (except avocados) for a few days (2-3), you’ll see whether the last remaining symptoms disappear altogether.
Mark Sisson on Fructose
Some experts claim that fructose is the best choice for diabetics for its lower glycemic index than glucose and sucrose. In fact, fructose produces a smaller increase in insulin compared to glucose. However, fructose is higher than in the levels of ghrelin, which increases – rather than suppress – the appetite, as does insulin. Finally, fructose is “worked” almost exclusively by the liver. And there is some evidence that the load on the liver over time can help to produce non-alcoholic fatty liver disease. The metabolism of fructose in the liver produces finally uric acid, a precursor of cardiovascular disease.
The recommendations of Paul Jaminet
In this video by Dr. Robert Lustig, held at the University of California, expresses the following verdict:
Fructose is a poison. It has nothing to do with the calories. It’s just poison.
Many scientists would not be so drastic, but many would agree in saying: “fructose is a poison if taken in large doses or accompanied with omega-6 fatty acids”.
In rodents, the high consumption of fructose leads to insulin resistance, obesity, type 2 diabetes, and high pressure. In people, the effects are similar, but less pronounced, with the exception of overweight individuals who eat a lot of fatty acids.
According to Paul Jaminet, consumption of fructose (25 grams per day, up to 10 per meal) from vegetables such as berries, carrots, and beets is healthy (for diabetics). Higher doses may be “dangerous”.
Fructose Breath Test
The symptoms of malabsorption (abdominal pain, bloating, flatulence, and diarrhea) in 50% of people who suffer from it appear 1 to 3 hours after ingestion of fructose. The breath test can measure the amount of hydrogen present after ingestion of fructose in order to evaluate the presence of malabsorption.
Procedures for the implementation of the test
The patient blows into a bag specially designed to capture the alveolar air and a second for dead space air.
The first air sample is taken when the patient is fasting, and after administering a fixed dose of fructose, samples of air are taken every half hour for four hours. After the ingestion of fructose in normal conditions, the concentration of hydrogen will not be much different from the baseline. In case of fructose malabsorption, concentration of hydrogen will be greater than the baseline value of at least 20ppm.