The fruits are with
the vegetables, essentials of everything
healthy diet and somewhat balanced. They are often characterized, among other things, by their sweetness – especially when fully ripe. This sweet taste so appreciated comes from their high content of a type of sugar which, we will not be very surprised… is called fructose! They also contain glucose, but in much lower quantities.
We will focus on the first of these two sugars. Because, paradoxically, fructose could well be the more harmful to our health.
Fructose is, along with glucose, a component of white (or table) sugar and corn syrup. These two sweeteners are used as common ingredients in the preparation of processed foods, sauces and condiments, sweets and sweetened carbonated drinks.
This is where the problem begins. Many studies associate increased consumption of these products with a greater incidence of metabolic diseases such as obesity, diabetes, hepatic steatosis (excess fat in the liver) and blood lipids.
Quantity and quality, the two key parameters
Regarding the question of quantity. The increase in consumption of food products rich in sweeteners leads, in parallel, to the absorption of calories. Calories which, if not burned, accumulate in the form of fat in the body and will promote the development of the metabolic diseases indicated above.
Fructose and glucose are used in the preparation of the aptly named “sweets” © PxHere
Unfortunately, this type of high calorie diets, poor in fruits and vegetables and rich in fats and fructose, has become global – hence the epidemic growth of these pathologies.
However, if you consult a dietician or a nutritionist, you will always find the same advice: to be healthy, eat about five servings of fruits and vegetables, spread over the different meals of the day.
The moderate daily consumption of a natural and unprocessed food, such as a fruit, is however healthy. And let’s use common sense: it’s not about eating two kilos of pears and a melon a day!
As for quality, now. Fructose turns very easily into fat in the liver. For the same quantity of fructose and glucose, the first will produce more fat in the liver. This means that excess fructose is more likely to alter our metabolism and facilitate the onset of metabolic diseases than other sugars.
Beware of the slogan “Eat five servings of fruit and vegetables a day” © Peggy Greb / Pixnio CC0
But then… Are these pathologies also favored by the simple consumption of fruits, also rich in fructose?
It’s all in the packaging
A little reminder, already, on the evolution of our species. We are, whatever some may think, monkeys, and chimpanzees are our distant cousins. For millions of years, our ancestors have adapted to a varied diet rich in vegetables, seeds and foraged fruits.
When we take fructose in the traditional way, so to speak, we don’t ingest it alone but together with its natural “packaging”: the fruit as a whole, with all its other components – fibers, minerals, vitamins, etc.
This is why we must conscientiously chew every morsel we eat. In doing so, we mix these different components, including the abundant fibers, with our saliva and digestive juices. This means that the fructose contained in the fruit is slowly incorporated and associated with many other elements in our organism.
This allows our intestinal cells to absorb and consume the vast majority of the fructose that arrives. So that in the end, only a very small part of it reaches the liver via the blood to be transformed into fat.
The problem with fructose taken in processed form, and especially liquid (juice and soda), is that it is absorbed too quickly and in too large quantities © New Africa / Shutterstock (via The Conversation)
This is how processed sugar works in our body
Conversely, when we absorb a large quantity of fructose “taken out of its natural environment”, whether in a candy, a sauce, an ice cream or, worse, in liquid form, in a sweet drink for example, the situation is very different.
We literally flood our fructose digestive tract dissolved in water. The latter is quickly absorbed by the intestinal cells, but they are quickly overwhelmed and a large part therefore continues its way to the liver. Where it will be turned into fat…
The liver is responsible for distributing this excess fat throughout the body. If it happens in isolation, it hardly matters. But heavy and frequent consumption will exceed our ability to regulate and, in the long term, lead to health problems. This excess fat deposited in our body can lead to obesity, diabetes, hypercholesterolemia etc.
Over time, metabolic disorders also increase the risk of suffering a heart attack. or even cancer. For example, a study was recently published showing that
the higher the sugar consumption, the greater the incidence of cancer.
Evolution of obesity in France by sex © Yoqtan / Wikimedia CC BY-SA 4.0
But beware ! This dangerous link between fructose and pathologies applies mainly to the consumption of sugar in liquid form. Moreover, when the association between the onset of cancers and the consumption of fruit juice is specifically studied, it is positive: the higher the consumption of fruit juice, the higher the incidence of cancer.
Fruit sugar: good or bad?
If you have read the above, you guess the answer… Consuming fruits is obviously good because we crunch them, chew them, mix them with other foods to make them easier to digest. In this way, their various components, including fructose, are slowly incorporated into our body.
But when we drink fruit juice, the situation is different. We absorb much more fruit than if we had to peel it, chew it, etc. Also, since we don’t take fructose in its “natural package”, it is absorbed all at once, quickly, hits the liver and once there, we figure out what’s going on.
The fruits are therefore preferably to be consumed as such, and the juices a pleasure to which one can indulge from time to time.
And if you decide to drink a juice, do not remove the pulp! The pulp helps the sugar in the fruit to enter our body more slowly, just as it happens when we eat the fruit directly…
This analysis was written by Gaëlle Chagny, CNRS researcher in mathematics (statistics) and Thierry de la Rue, CNRS researcher in mathematics, both at the University of Rouen Normandy.
The original article was published on the site of The Conversation.
