Too much fruit hurts?
How many times have you been told that consuming lots of fruit and vegetables is a good habit? The general indications indicate the canonical 5/6 portions a day, but this is not enough to define a healthy diet. After all, as you know very well, in a truly balanced diet the benefits are also conditioned by the quantities.
Eating fruit and vegetables is good, but what side effects can be linked to excessive consumption?
In the opinion of the nutritionist and science writer Derry Procaccini, generic indications without specifics on quality and quantity, I can only increase the confusion and the risk of problems related to obesity. For this reason, in this article, we will talk about fructose to investigate the issue of fruit consumption in terms of quality and quantity.
Types of fruit: oily & sugary dry
First of all, it is good to know that the fruit should be divided into at least two categories:
Oily dried fruit: rich in good fats, minerals and low in sugars such as almonds, cashews, pine nuts, peanuts and walnuts;
Sugary fruit: low in good fats and rich in simple sugars such as dates, mangoes, grapes, apples, pears, peaches, plums, apricots, bananas, etc.
In the first case, given the relationship between good fats and sugar poverty, these are not particularly dangerous foods for raising insulin. Instead, sugary fruit contains about 50% fructose and 50% glucose. In this case, the presence of two simple sugars, called monosaccharides, would require us to limit their consumption. This is because the two types of elements are also ingested through other sources throughout the day. But how do sugars work with our body?
What are glucose and fructose?
Glucose is a sugar (aldehyde monosaccharide) whose concentration in the blood is called glycemia. The blood sugar level in the blood depends on: the intake of glucose through food, the hepatic reserve of glycogen and hormonal regulation.
Glucose is the most present sugar in nature, and it is very important because it is used both by animals and plants as the main energy source. The most important property of glucose is its reduced reaction to the amino groups of proteins that gives rise to glycation. The latter reduces, or completely eliminates, the activity of many enzymes and is responsible for many long-term effects of diabetes such as blindness or poor renal function.
Also fructose (known as levulosio) belongs to the family of so-called simple sugars and is found in the vast majority of sugary fruits, in honey and also in some vegetables. Many of you know that fructose is a particular sugar, mainly because it is metabolized in the body through specific pathways that differ from those of glucose. But what effects can fruit trigger at metabolic level after a high- index meal?
Fructose: how it works in our body
Fructose metabolism typically generates uric acid within minutes of ingestion. Uric acid is a waste product found in the blood and high levels of this element are normally associated with gout. This relationship has long been recognized, especially for overweight people, who suffer from high blood pressure and kidney disease. What is striking, however, is that the functions of uric acid in cells are classified both as an antioxidant and as a pro-oxidant. Therefore, if uric acid is excessively reduced, its antioxidant benefits are lost, while its role as a pro-oxidant tends to increase with excessively high levels.
According to research, ideal uric acid levels lie between 3 – 5.5 mg / dl. Previously, it was thought that uric acid was secondary in stimulating disorders and pathologies but, researchers have identified a central role of this element. When uric acid levels reach or exceed 5.5 mg / dl the risk is to develop hypertension, as well as diabetes, obesity and other kidney disorders.
Fructose and glycemic index
Until recently, it seemed that the only monosaccharide (simple sugar) we had to pay attention to was glucose. However, more and more studies show that fructose with its direct effect on raising blood sugar is one of the most dangerous sugars. Consequently, an attempt was made to define a maximum recommended daily intake.
We must not forget that sugar intake stimulates the production of natural opioids, a key factor in addiction. The brain becomes essentially dependent on opioids not unlike addiction to morphine or heroin. So the more you eat it, the more you need it creating a vicious circle in consumption.
To clarify the issue and give you the tools
Those who have conducted extensive fructose research and its effects are Dr. Richard Johnson, a professor of medicine at the University of Colorado and director of the kidney division who also deals with transplants and research on blood pressure. In his books: The Fix Sugar and The Switch Fat he meticulously described the dangers of fructose.
In particular, it focused on the study of the effects of this element on the metabolic system both at the level of cell cultures and in animals and through clinical studies. In his research he has thus deepened the relationship between fructose and obesity, high blood pressure, kidney disease, hypertension, fatty liver and other health problems. The results led him to identify the effects that uric acid has on blood pressure, insulin production and renal function.
Indeed, the Professor has shown that 90% of obese adolescents with newly diagnosed hypertension had elevated levels of uric acid. The cure for normalizing blood pressure in 87% of these adolescents would have been achieved simply by lowering uric acid levels.
Another personality that has made the difference in this field is Dr.
Robert Lustig, academician of pediatric medicine of the Division of medical specialty at the University of CA at point of entry.
The professor recounts his findings on the dangers of fructose and other sugars at a conference that you can find online and which we recommend you take a look at.
How to take fructose?
Since 55% of the recommended daily fructose quota is found in a can of soft drink it is necessary to pay attention to the doses introduced with the fruit. As we had anticipated at the beginning of this article it is commonly thought to be able to eat fruit at will, instead we must remember that fruit, especially the best, and therefore the sweetest is rich in fructose and glucose.
As a standard recommendation, our nutritionist Derry Procaccini strongly recommends keeping the total fructose consumption below 25 grams a day. However, for most people it would also be wiser to limit fruit fructose to 15 grams or less, as it is virtually guaranteed to consume hidden sources through most beverages and through almost all processed foods. Below, for completeness, find a table in which we reported the ratio between fruit, dose size (1 fruit or cup) recommended and grams of fructose content. And remember that a healthy diet is first of all varied and balanced!
Fructose and Agave
Finally, another consideration is to be made on Agave syrup. This food is often described as a valid alternative to common sugar (sucrose). According to research by another specialist; Dr. Ingrid Kohlstadt, a colleague from the America College of Nutrition and associate professor at the Johns Hopkins School of Public Health; however, the sap is chemically processed by the agave plant producing a compound known as high fructose hydrolyzate or inulin syrup. This alternative to the common sugar (sucrose) has nothing to do with the original Agave plant and has no nutritional value.
In conclusion, with this article, we do not want to discredit the nutritional value of fruit. On the contrary, we would like to pay attention to the possible side effects of excessive consumption and disseminate information on specific characteristics, sometimes very different, among fruit varieties.