Are beverages healthy if they use sugar substitutes?

When it comes to sweet things, the first thing that comes to our mind is definitely sugar. Humans consume sugar to replenish energy on the one hand, and to enjoy the pleasure brought by sweetness on the other. However, gradually, "sugar" and "tooth decay", "obesity", "high blood sugar" and so on have established clear connections, and excessive intake of sugar will cause various diseases. Sugar substitute sweeteners came into being. As early as the 1950s, sugar substitute diet drinks were launched. Now supermarkets are full of sugar substitute foods and drinks labeled "zero sugar", "zero calories" and "zero energy".

So, what exactly are sugar substitutes? Are they really as healthy as the merchants claim?

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01

Sweeteners and sugar substitutes

If you want to understand what sugar substitutes are, you have to start with the classification of sweeteners. Sweeteners refer to substances that can give food a sweet taste. Depending on whether they can generate calories to provide energy to the human body, sweeteners can be divided into nutritive sweeteners and non-nutritive sweeteners.

As the name implies, nutritive sweeteners can provide energy to the human body, mainly including sugars and sugar alcohols. Sugars are the main source of energy for our body. Each gram of sugar can produce about 4kcal of calories. Common sugar sweeteners in life include glucose, fructose, lactose, sucrose, maltose, etc. Another type of nutritive sweetener - sugar alcohols, including xylitol, sorbitol, maltitol, etc., can also provide energy for the human body, releasing about half the calories of sugars, and each gram of sugar alcohol can produce 2.1kcal of calories.

Non-nutritive sweeteners also include two categories. One is natural sweeteners such as stevioside, mogroside and other sweeteners extracted from plants; the other is artificially synthesized sweeteners. Common sweeteners of this type include aspartame, sucralose (sucralose), saccharin, acesulfame potassium, neotame, etc. The characteristics of this type of sweetener are that it contains almost no calories but is extremely sweet.

02

The sweetest substance Luguname

How sweet can it be?

Saccharin is the earliest artificial sweetener, which was created in 1878. It is 350 times sweeter than sucrose. During the First World War when supplies were scarce, saccharin sales were astonishing, but it was later considered to have a risk of cancer and was banned in 1977. It was not until 1991 that researchers found that saccharin did not cause cancer, so it was used as a sweet ingredient for fat-reducing meals or for diabetic patients.

There is also a very sweet sweetener called neotame , which is composed of N-[N-(3,3-dimethylbutyl)-L-α-aspartyl]-L-phenylalanine-1-methyl ester, and its sweetness can reach more than 8,000 times that of sucrose. How sweet is 8,000 times that of sucrose? The author bought a can of neotame out of curiosity. When he opened the can of sweetener, he just smelled it at the mouth of the can, and he felt the sweetness in his mouth, and this sweetness lasted for a full 10 minutes. It is said that the sweetness of a small spoonful of neotame can cover the sweetness of the sucrose you consume in a year!

Neotame bought by the author (Source: Photographed by the author)

Of course, Neotame is not the sweetest substance in the world. The sweetest substance in the world is a substance called Lugduname, which was developed at the University of Lyon, France in 1996. The sweetness of Lugduname is about 220,000 to 300,000 times that of sucrose, but it is not currently used as a sweetener in food.

The structure of Luguname (Source: wikimedia)

03

Will sugar substitutes also affect blood sugar?

Traditionally, synthetic sweeteners are not absorbed and degraded by the human body. They are excreted the same way they are taken in, and will not affect blood sugar levels. However, as early as 2014, researchers found a link between changes in the microbiome and blood sugar response in mice after they ingested sugar substitutes. A recent academic paper published in the journal Cell shows that non-nutritive sweeteners can affect human blood sugar levels.

Effects of artificial sweeteners on blood sugar (Source: Reference 1)

Israeli researchers found that artificial sweeteners affect the body's metabolism of glucose, leading to changes in blood sugar. They recruited 120 volunteers and divided them into six groups, four of which were experimental groups. While taking glucose, they were asked to eat four common sugar substitutes, namely saccharin, aspartame, sucralose, and stevia. The intake of each volunteer was lower than the FDA's permitted standard. The fifth group of volunteers only ate the same amount of glucose, and the sixth group ate nothing. The trial lasted for two weeks, and the researchers tracked the blood sugar levels of the volunteers every day using a blood glucose meter.

What were the results of the experiment? The researchers analyzed the data collected continuously and found that compared with the fifth group of volunteers who only ate glucose, the blood sugar of the volunteers who took saccharin and sucralose increased significantly, but when they stopped taking the above two sweeteners, the blood sugar of the volunteers returned to normal levels.

How do synthetic sweeteners affect blood sugar levels in the human body? Mice, like humans, have the ability to digest food and extract energy from it, not only because of our genes, but also because of the activities of the trillions of microorganisms that live in our digestive tracts, collectively known as the gut flora or gut microbiome.

The researchers transplanted the feces of volunteers into germ-free mice in order to give the mice the intestinal flora of the volunteers. The researchers monitored the increase in blood sugar in the mice and found that these non-nutritive sugar substitutes would change the types and numbers of intestinal flora. The changed bacteria are responsible for guiding the metabolism of sugars, converting sugars into energy or storing them in the body. If the flora changes, the body's ability to "process" glucose will be affected, causing blood sugar fluctuations to increase, thereby increasing blood sugar.

Of course, the study found that not everyone's blood sugar levels will be affected by sugar substitutes. Seven volunteers were selected in the experimental group, and only four of them had increased blood sugar after taking non-nutritive sweeteners. The test results on mice were similar.

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It seems that sugar substitutes are not as people initially thought, replacing the sweetness of sugar without causing any impact on the human body. However, using sugar substitutes instead of sugar does not necessarily mean health. There are endless beverage "assassins" on the market with labels such as "sugar-free", "zero fat" and "zero calories". For food safety, what we need to do is to carefully read the ingredient list before purchasing food.

However, if you really can't give up "fat house happy water" and have to choose between "real sugar" drinks and sugar substitute drinks, then compared with the harm caused by diseases such as tooth decay and obesity, it is better to choose sugar substitute drinks.

References:

【1】 Suez J, Cohen Y, Valdés-Mas R, et al. Personalized microbiome-driven effects of non-nutritive sweeteners on human glucose tolerance[J]. Cell, 2022, 185(18): 3307-3328. e19.

【2】Brown A. Artificial Sweeteners: Friend or Foe to Your Microbiome[J]. Microreviews in Cell and Molecular Biology, 2018, 4(1).

【3】 SWEETENERS COFA, BANE BO R. International Journal of Pharmacy[J].

【4】 https://en.wikipedia.org/wiki/Lugduname

Author | denovo

Review | Zhang Na, Associate Researcher, Doctoral Supervisor, Peking University School of Public Health

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