What’s the difference between sugar, other natural sweeteners and artificial sweeteners? A food chemist explains sweet science

A quick walk down the drink aisle of any corner store reveals the incredible ingenuity of food scientists in search of sweet flavors. In some drinks you’ll find sugar. A diet soda might have an artificial or natural low-calorie sweetener. And found in nearly everything else is high fructose corn syrup, the king of U.S. sweetness.

This article is a repost which originally appeared on The Conversation
Kristine Nolin (Associate Professor of Chemistry, University of Richmond) - January 5, 2022
Edited for content and readability - Images sourced from Pexels

Our Takeaways:

  • Glucose is the most basic sugar and is mostly made by plants. Fructose is a sugar from fruit. Galactose is a sugar in milk. Table sugar comes from Sugar Cane.
  • High fructose corn syrup is made from corn starch, then treated with a second enzyme to convert some of it into fructose. Generally, high fructose corn syrup is roughly 42%-55% fructose.
  • Natural Non-sugar Sweeteners – These are food additives such as stevia and monk fruit, as well as natural sugar alcohols. These molecules aren’t sugars, but they can still bind to the sweet receptors and therefore taste sweet.
  • Artificial Sweeteners are produced in labs and factories and are not found in nature.

I am a chemist who studies compounds found in nature, and I am also a lover of food. With confusing food labels claiming foods and beverages to be diet, zero-sugar or with “no artificial sweeteners,” it can be confusing to know exactly what you are consuming.

So what are these sweet molecules? How can cane sugar and artificial sweeteners produce such similar flavors? First, it is helpful to understand how taste buds work.

Taste buds and chemistry

The “taste map” – the idea that you taste different flavors on different parts of your tongue – is far from the truth. People are able to taste all flavors anywhere there are taste buds. So what’s a taste bud?

Taste buds are areas on your tongue that contain dozens of taste receptor cells. These cells can detect the five flavors – sweet, sour, salty, bitter and umami. When you eat, food molecules are dissolved in saliva and then washed across the taste buds, where they bind to the different taste receptor cells. Only molecules with certain shapes can bind to certain receptors, and this produces the perception of different flavors.

Molecules that taste sweet bind to specific proteins on the taste receptor cells called G-proteins. When a molecule binds these G-proteins, it triggers a series of signals that are sent to the brain where it is interpreted as sweet.

Natural sugars

Natural sugars are types of carbohydrates known as saccharides that are made of carbon, oxygen and hydrogen. You can imagine sugars as rings of carbon atoms with pairs of oxygen and hydrogen attached to the outside of the rings. The oxygen and hydrogen groups are what make sugar sticky to the touch. They behave like Velcro, sticking to the oxygen and hydrogen pairs on other sugar molecules.

The simplest sugars are single-molecule sugars called monosaccharides. You’ve probably heard of some of these. Glucose is the most basic sugar and is mostly made by plants. Fructose is a sugar from fruit. Galactose is a sugar in milk.

Table sugar – or sucrose, which comes from sugar cane – is an example of a dissacharide, a compound made of two monosaccharides. Sucrose is formed when a glucose molecule and a fructose molecule join together. Other common dissacharides are lactose from milk and maltose, which comes grains.

When these sugars are eaten, the body processes each of them slightly differently. But eventually they are broken down into molecules that your body converts into energy. The amount of energy from sugar – and all food – is measured in calories.

High fructose corn syrup

High fructose corn syrup is a staple of U.S. foods, and this hybrid sugar sweetener needs a category all on its own. High fructose corn syrup is made from corn starch – the main carbohydrate found in corn. Corn starch is made of thousands of glucose molecules bonded together. At an industrial scale, the starch is broken into individual glucose molecules using enzymes. This glucose is then treated with a second enzyme to convert some of it into fructose. Generally, high fructose corn syrup is roughly 42%-55% fructose.

This blend is sweet and cheap to produce but has a high calorie content. As with other natural sugars, too much high fructose corn syrup is bad for your health. And since most processed foods and drinks are packed full of the stuff, it is easy to consume too much.

Natural nonsugar sweeteners

The second category of sweeteners could be defined as natural nonsugar sweeteners. These are food additives such as stevia and monk fruit, as well as natural sugar alcohols. These molecules aren’t sugars, but they can still bind to the sweet receptors and therefore taste sweet.

Stevia is a molecule that comes from the leaves of the Stevia redaudiana plant. It contains “sweet” molecules that are much larger than most sugars and have three glucose molecules attached to them. These molecules are 30 to 150 times sweeter than glucose itself. The sweet molecules from monk fruit are similar to stevia and 250 times sweeter than glucose.

The human body has a really hard time breaking down both stevia and monk fruit. So even though they’re both really sweet, you don’t get any calories from eating them.

Sugar alcohols, like sorbital, for example, are not as sweet as sucrose. They can be found in a variety of foods, including pineapples, mushrooms, carrots and seaweed, and are often added to diet drinks, sugar-free chewing gum and many other foods and drinks. Sugar alcohols are made of chains of carbon atoms instead of circles like normal sugars. While they are composed of the same atoms as the sugars, sugar alcohols are not absorbed well by the body so they are considered low-calorie sweeteners.

Artificial sweeteners

The third way to make something sweet is to add artificial sweeteners. These chemicals are produced in labs and factories and are not found in nature. Like all things that taste sweet, they do so because they can bind to certain receptors in taste buds.

So far, the U.S. Food and Drug Administration has approved six artificial sweeteners. The most well known are probably saccharin, aspartame and sucralose – better known as Splenda. Artificial sweeteners all have different chemical formulas. Some resemble natural sugars while others are radically different. They are usually many times sweeter than sugar – saccharin is an incredible 200 to 700 times sweeter than table sugar – and some of them are hard for the body to break down.

While a sweet dessert may be a simple pleasure for many, the chemistry of how your taste buds perceive sweetness is not so simple. Only molecules with the perfect combination of atoms taste sweet, but bodies deal with each of these molecules differently when it comes to calories.

Sugar and Aging: What You Need to Know

People looking to extend their lives have a particular interest in sugar and aging, but what does the science actually say?

This article is a repost which originally appeared on Longevity Advice
Rachel Burger - September 13, 2021
Edited for content and readability Images sourced from Pexels

In a lot of diets, from the Mediterranean diet to the low-carb diet, all uniformly advocated for removing processed foods and refined sugar.

But mechanistically, why is sugar a problem? Does sugar contribute to aging? Are there nuances to the sugar-is-always-bad narrative?

In this article, I aim to answer all these questions. But first, I want to address a larger question: why is sugar talked so much in relation to health, nutrition, and aging?

Why is sugar a focus?

Humans are hardwired to love sweet foods.

You might meet the occasional adult who claims to hate sugar, but you’ve likely never met a kid who turned their nose up at a sweet. In fact, there’s a general consensus that sugar preferences in children are not a byproduct of advertising or food manufacturing, but of biological desires. A review published in the journal Clinical Nutrition and Metabolic Care explains, “Heightened preference for sweet-tasting foods and beverages during childhood is universal and evident among infants and children around the world.”

While “too sweet” is a concept adults are familiar with (they tend to max out at about what you’d get in a 20 oz Gatorade), there is no known upper limit to how much sweetness—sugar, by extension—kids like.

“Sugar” is shorthand for “simple carbohydrates.” There are two natural categories of sugars:

  • Monosaccharides: Simple carbs with a single sugar molecule. Glucose, fructose, and galactose are monosaccharides.
  • Disaccharides: Simple carbs with two sugar molecules joined together.

There are only three disaccharides that are naturally occurring. Sucrose, which you can find in table sugar, honey, and dates, is a combination of glucose and fructose. Lactose, or the combination of glucose and galactose, is natural milk-derived sugar, found in cream, butter, and human breast milk. Finally, there’s maltose, which has two bonded glucose molecules, which is found in germinating grains. Foods with maltose include beer and bread.

(Other sweeteners, like high fructose corn syrup, are man-made disaccharides [any of a class of sugars whose molecules contain two monosaccharide residues].)

Carbohydrates, regardless of if they’re simple or complex carbs, are used for four functions in the human body. As this is an incredibly dense topic, please use the links provided for further reading if you’re interested.

  • Producing energy: Most human cells prefer or require carbohydrates to produce energy and work as they’re supposed to.
  • Energy storage: Carbohydrates that aren’t immediately used are stored as glycogen.
  • Building macromolecules: Carbohydrates are used to make ribose and deoxyribose, the foundations of macromolecules like DNA and RNA.
  • Preserving fat and protein: Blood glucose spares the body from having to use fat and protein as the body’s main source of energy.

In other words, carbohydrates are an essential part of a functioning human body. Because simple carbs have a shorter chain of molecules, they’re easier to digest in the body. Over email, Julie Olson, BSc., CN, BCHN, CGP, of Fortitude Functional Nutrition, elaborates: “Carbohydrates are a main source of energy, converted by the body to power our cells. We need some sugar for some brain cells, some kidney cells, red blood cells, and testes cells” to function properly.

Simple carbs are a subject of conversation in nutritional circles because humans generally rely on carbohydrates to function, and humans particularly like sugar and its sweetness.

Unfortunately, our preference for sweets has led to an excess of added sugar in the Western diet.

Added sugar versus natural sugars

When I say “added sugar,” I mean simple carbs that have been mixed into foods during food processing. Natural sugars, by contrast, are simple sugars found in whole foods, like sugars found in fruits and vegetables.

Some sugars found in nature, like honey and maple syrup, are also considered added sugar.

The American Heart Association recommends consuming no more than 100 calories, or six teaspoons, of daily added sugars for females and children. Males can consume up to nine teaspoons, or 150 calories, of added sugars daily.

Unfortunately, the average American consumes 17 teaspoons of added sugar every day—that’s a 183% increase and an 89% increase from recommended daily intake for females and males, respectively.

And that excess sugar consumption has huge health consequences.

Sugar and aging

Added sugar increases the rate of biological aging. It does so in several ways. In 2018, the Annual Review of Nutrition published a systematic review of longitudinal studies on the correlation between high sugar consumption and cancer. They produced an infographic that aptly demonstrates just how much of the body added sugar ages and points to mechanisms as to why it does so:

This next section will drill down into three documented ways sugar and aging are intertwined: AGEs, inflammation, and diabetes. I’ll also cover a quick study on sugar’s effect on telomeres at the end.

Sugar and aging: a close look at AGEs

 

Let’s talk a bit about “advanced glycation end products,” or AGEs. AGEs are a diverse group of molecules that build up in human cells, particularly in muscle tissue and plasma. They’re created as a reaction between glucose and the amino acid glycine—when sugar meets fat or protein in the body. AGEs have a particularly resistant structure to degradation.

Emerging research suggests that AGEs form endogenously at an even higher rate with fructose than glucose—sweeteners like high fructose corn syrup, apple juice, honey, molasses, caramel, and agave syrup all contain fructose.

In other words, AGEs make your skin appear dry, saggy, and wrinkled—old. While AGEs age your insides, they also quickly age your exterior as well.

Diet is a major source of AGEs—barbecued meats, in particular, are full of them. They can also form while humans metabolize their food. AGEs formed in vivo tend to particularly affect “long-lived proteins, such as hemoglobinalkaline phosphataselysozymecollagen [and] elastin.”

There’s a general consensus in the scientific community that accumulated AGEs “are an inevitable component of the aging process in all eukaryotic organisms, including humans.” The more you have, the quicker you age.

Here’s why AGEs are a problem in large quantities: they’re linked to diabetes, cardiovascular disease, and renal disease. They’re also connected to Alzheimer’s disease and kidney disease. A whole host of studies demonstrate that AGEs trigger oxidative stress and excessive reactive oxygen species (which also cause oxidative stress).

Sugar and aging: chronic inflammation

Source: “Epigenetic signatures underlying inflammation: an interplay of nutrition, physical activity, metabolic diseases, and environmental factors for personalized nutrition

Inflammation is a biological defensive response to an irritant, like bacteria or viruses. If you skin your knee, the area around the cut will inflame, as a part of your immune system, to combat infection and to promote healing. Concentrations of white blood cells cause inflammation.

Inflammation can be short-term, or “acute.” If you’re like me and allergic to hay, your body will have an acute inflammatory response—an itchy, watery nose, a puffy face—until the irritant goes away. Inflammation can also be long-term, or “chronic,” and you can stay inflamed regardless if the trigger is still present.

There are a lot of age-related diseases connected to chronic inflammation. To name just a handfulthey include:

  • Diabetes
  • Cardiovascular diseases
  • Arthritis and joint diseases
  • Chronic Obstructive Pulmonary Disease (COPD)
  • Certain kinds of cancer

Chronic inflammation can also help form AGEs.

Several studies have established that sugar, in all its forms, correlates with inflammation. Some studies have found that fructose appears to cause the most inflammation out of all of sugar’s forms, but that hasn’t been a consistent finding across all studies.

While it’s a mystery why some inflammation remains acute and other inflammation becomes chronic in some people and not others, sugar consumption is a significant precursor to chronic inflammation in many people.

Sugar and aging: diabetes

If you want to see a complicated cocktail of fact and misinformation, look closely at the relationship between sugar, obesity, and diabetes.

There is no known cure for diabetes, though diabetics can go into remission. Diabetes is the seventh-leading cause of death in the United States as of 2019.

Obesity is also a chronic disease. Obesity is defined as having a BMI, or a person’s weight in kilograms divided by the square of height in meters, of 30.0 or higher. According to Harvard Medical School, there are “genetic, developmental, hormonal, environmental, and behavioral factors” that contribute to who does and doesn’t have obesity.

Like diabetes, there are many treatments for obesity, but no known cure. One study suggests that if trends continue, all American adults will be either overweight or obese by 2048.

I choose to mention obesity and diabetes together because they have a significant causal relationship—obesity is an independent risk factor that can lay the groundwork for diabetes to developAlmost all (89%) of people with diabetes are obese or overweight. I found a massive range of estimates of how many obese individuals develop diabetes, from 2.9% to 30%. Many of the studies cited here look at both obesity and diabetes together as comorbid conditions. For example, hypertrophic obesity—what happens when fat cells enlarge more than normal—directly leads to insulin resistance.

Researchers have formally tied added sugar consumption to obesity and diabetes several times over. Though the relationship is complex and researchers don’t fully understand all mechanisms involved, it’s clear that added sugar consumption, particularly fructose, raises the risk of developing obesity and diabetes.

For example, foods high in fructose stimulate ghrelin while suppressing leptin—hormones responsible for hunger and satiety. Sugar can promote chronic hyperglycemia, which can both lead to weight gain and is another risk for diabetes. And sugary drinks, especially, are tied directly to obesity.

Sugar and aging: a bad combination (so what should we do?)

People looking to stay young for a long time should limit their sugar consumption. While how added sugar works in the body isn’t simple or predictable, there are literally thousands of studies tying added sugar to diseases of aging.

With all that said, it’s natural for humans to crave and eat limited amounts of sugar.

Sugar and aging is a massive topic with a lot of nuance—so much so that I didn’t even get a chance to cover alternative sweeteners.

What are your takes on sugar? What do you do to avoid them or to add them mindfully to your diet?