Fructose

Hello,

I know we have covered fructose and its effects on the liver, but could you please explain once more what happens in the liver after consuming fructose? And I've heard that glucose-fructose syrup is even worse.

Thank you.

Excessive fructose intake is associated with the overgrowth of certain gut bacteria and subsequently increased intestinal permeability. Bacteria contain endotoxins, which promote increased production of inflammatory substances (cytokines) in some liver cells. Simultaneously, during fructose metabolism in the liver, substances are formed (glyceraldehyde-3-phosphate, dihydroxyacetone phosphate, pyruvate) that are transported into mitochondria at high concentrations, leading to the stimulation of a process called de novo lipogenesis (excess carbohydrates are converted into fat because this metabolic state prevents fatty acids from entering the mitochondria). The resulting fat particles are then deposited in the liver and support the development of steatosis. High-fructose corn syrup is a source of fructose, and it should be avoided just like all other "artificial" sources of this sugar.

Hello.
We know that fructose is metabolized differently (in the liver without the involvement of insulin). So why is it generally recommended to consume fruit after finishing physical activity? Does fruit also contain other simple sugars?
Thank you for your response.

Fruit is also a source of sucrose. The recommendation to consume fruit after exertion is a topic for discussion - the advantage lies in the rapid initial satiation, satisfaction of sweet taste, providing fiber, carbohydrates, and micronutrients, thus initiating processes leading to the replenishment of depleted glycogen. Another perspective (opinion) suggests that the increased activity of insulin related to carbohydrate metabolism, which you supply immediately post-exertion, suppresses the production of growth hormone, which is (especially in strength sports) important for the regeneration of muscle tissue. The intake of fruit after exertion is, therefore, a matter of personal consideration based on the requirements for metabolism.

Do you happen to know of any other foods, like fructose, that would support the production of the hormone ghrelin?

Fructose is commonly cited as the dietary component that most promotes the production of the hormone ghrelin. However, there is a difference between concentrated sources of fructose used as a sweetener and fructose commonly consumed from sources like fruit, where ghrelin levels increase significantly more after the ingestion of sweeteners. Furthermore, it is generally accepted that proteins in the diet suppress the production of this hormone the most. That is, ghrelin is produced more in the stomach after the consumption of typically low-protein foods/dishes (= high-carbohydrate and high-fat).

Hello,
For children aged 1-3 years, do you recommend avoiding dried fruit as a source of high fructose concentration?
Thank you.

Due to the fructose content, certainly not, although some types are relatively concentrated sources (raisins, dates, figs...), it is more reasonable to monitor their total amount. A high proportion of dried fruit in the diet provides an above-average amount of fiber, and in children of this age, there is a risk of multiple times exceeding the recommended daily allowance, which results in increased stress on the intestinal tract. Dried fruit is a beneficial part of the diet, but it is prudent to regulate the total consumed quantity in this age group.

Hello,

According to certain sources (e.g., David Perlmutter, MD, Drop Acid - https://www.amazon.com/Drop-Acid-Surprising-Controlling-Extraordinary/dp/0316315397), nutrition for diabetes should focus on reducing uric acid levels to ideally 4 – 4.5mg/dl, which can be quite challenging when reducing carbohydrates. His opinion can be summarized as that inflammation increases uric acid, and particularly fructose, which is directly metabolized into uric acid, and foods with a high content of nucleic acids (such as meat, yeast-based products) are the main culprits for rising uric acid levels. For example, he cites beer (even non-alcoholic, which has a high carbohydrate content and is made with yeast) as an example. He suggests getting home uric acid testing in capillary blood and measuring it on an empty stomach (in our country, for instance, easytouch - https://www.lekarna.cz/vyrobce/easytouch/). Just like with sugar, it’s probably an individual journey for everyone with common principles, where uric acid is a signaling molecule that increases glucose, raises blood pressure, and triggers insulin production, which as a storage hormone aims to store fat in the body. According to him, this is a signal for our ancestors that after eating ripe fruit in the autumn (fructose), it's necessary to raise blood pressure, increase glucose (to supply the brain with sugar so we wouldn’t get eaten by something), and accumulate some fat because winter is coming, and we want to survive it. However, he argues that we signal our bodies all year round that winter is coming, but it never really does (perhaps also because we live in heated apartments).

Would you suggest which principles to adhere to for lowering uric acid levels?

All these principles are incorporated into individual steps in modifying dietary regimes, which you aim to translate into practice through the ZOF application onto the plate. The principle involves understanding that while we have mapped individual metabolic pathways through biochemical reactions, they do not function in living systems the same way as we are accustomed to with software, i.e., on the principle of zeros and ones. We are the result of an evolutionary development that has lasted several hundred million years, and it has programmed the body's systems not only in a complex manner but also in a comprehensive way, with the goal of maintaining a healthy balance, which has a different range of flexibility in each individual. We know that increased fructose intake leads to the formation of uric acid, which is part of a spectrum of indicators signaling pro-inflammatory processes. We have population-defined reference values for sugar intake, including fructose, but adhering to them is not a guarantee of success with metabolic disorders because the organism behaves unexpectedly here. It is not possible to predict optimal nutrient intake values, but on the other hand, we should know how to apply them to the plate while simultaneously acting responsibly by diligently monitoring available metabolic indicators, among which uric acid in diabetes mellitus (DM) certainly belongs. Additionally, it is necessary to consider that metabolism will behave differently in DM1 and DM2. Because DM2 is a problem always accompanied by inflammation, dietary modifications should invariably aim to support anti-inflammatory factors. There are many of these, starting with monitoring the quality of food, the amount of proteins, sugars, trans fatty acids, the ratios of fatty acids led by O3:O6, fiber content, the share of alkaline elements, sufficient vitamins, and a higher intake of antioxidants. The whole "trick" lies in the fact that you will never know in advance which of the mentioned factors had a greater or even crucial influence on suppressing the pro-inflammatory environment and establishing potential metabolic balance. It thus pays to respect the entire spectrum of rules, with fructose intake control being just a needle in a haystack. In the process of body care with DM, it is necessary first to understand these holistic behavioral rules of biological systems (which involves coming to terms with the fact that they are such), subsequently start translating them onto the plate, and ultimately possess sufficient patience while waiting for results, which will moreover differ in scope for each individual.

Hello, Mr. Jelínek.

I am curious about the differences in the digestion of fructose and beet sugar. Why can fructose ferment in the intestines for some people while sugar does not?

Thank you for your response.

In the given situation, several factors can influence digestive manifestations. It is important to distinguish between:

- the amount of sugar ingested,
- its form - pure (e.g., in beverages) vs. bound to other components (in food),
- the composition of the diet,
- the activity (diversity) of the intestinal microbiota.

The process of absorbing fructose is more complex than that of glucose (sugars are absorbed through different enzymatic reactions). Beet sugar (sucrose) is composed of glucose and fructose; therefore, when consuming the same amount of this sugar compared to pure fructose as a sweetener, the digestive tract receives a halved portion of fructose. This can lead to different digestive tract reactions in specific situations.

Furthermore, the question arises as to what exactly you mean by the term "ferment." Fructose (fruit sugar) is typically found in fruit, which is rich in soluble fiber. This fiber absorbs water in the intestines, and consuming larger amounts of fruit can lead to feelings of fullness or bloating (however, this is not "fermentation in the intestines").