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When people think of sugar, they are most likely thinking of the granulated white sugar we use in baking or in our morning coffees. This type of sugar, also called table sugar, is sucrose. Even though this form of sugar is what a lot of people most commonly associate the word “sugar” with, there are actually four different types that we can find in commonly consumed foods. These four types include: glucose, fructose, lactose, and sucrose. You may be thinking there can’t be much of a difference between all these sugars, but it turns out, sugar is such a broad umbrella term, and there are different health effects within these four different categories of sugar. So, what exactly are these sugars, and what are their health effects?
You may recognize this sugar as the one produced in the process of photosynthesis. Plants use glucose to provide energy for themselves, and, coincidentally, glucose is our most significant source of energy, too! A lot of the carbohydrates we consume actually turn into glucose when processed by our bodies. It is extremely important for us to have glucose because we need it for our bodily functions. Aside from providing the body energy, glucose has other beneficial health effects for us.
One benefit glucose provides our bodies is helping us build up our endurance for whatever activities we participate in. The glucose your body doesn’t use is actually stored as glycogen, and the more glucose you consume, the more energy you will have reserved throughout the day. With this short-term stored energy, you will get the endurance you need to perform activities that require it, such as running a mile or even moving heavy items at work. Another benefit glucose provides, because it provides energy to the body, is the regulation of body temperature. Lastly, glucose is also important in the rebuilding of muscle. Since glycogen is stored in muscle, when you expend most of your energy, that glycogen supplied in the muscle will have depleted. Consuming glucose, along with protein, after a workout provides your body the nutrients it needs in order to promote muscle growth.[1]
To help guide your glucose consumption, here is a list of some delicious foods that contain glucose:
● Blueberries (high in antioxidants)
● Tamarind fruit or juice (source of antioxidants and anti-inflammatory properties)
● Orange juice (great source of vitamin c)
● Cherries (source of antioxidants and anti-inflammatory properties)
● Pears (source of fiber)[1]
Fructose
Fructose is a sugar that is found naturally in fruits, some vegetables and honey. Even though this type of sugar is found in such a wide variety of produce, “most fructose is consumed in sweet beverages, desserts, and other foods sweetened with high-fructose corn syrup (HFCS) or other added sugars.”[2] Due to this, fructose is considered to have more negative health effects connected to it than beneficial ones. However, there is one health benefit to consuming fructose, specifically for diabetic individuals who still have a sweet tooth.
The National Library of Medicine states, “Because of the low glycemic index of fructose, fructose may be an alternative as a sweetener for those diabetic patients who like sweet foods but are liable to high postprandial glucose concentrations.”[3] So, fructose may be a better alternative to glucose when it comes to the diets of diabetic individuals who want to consume something sweet sometimes. The National Library of Medicine continues, “In clinical studies, fructose has either improved metabolic control of diabetic patients or caused no significant changes.”[3] More long-term studies have to be done, but some clinical studies have shown that some diabetic individuals who consume moderate amounts of fructose have not been affected negatively. However, it is, of course, advised for diabetic individuals (and probably everyone, considering the information to come) to stay away from consuming high amounts of fructose. It is also preferable for individuals to get most of their fructose where it occurs naturally because the fruits, vegetables and honey in which it is naturally found definitely have more nutrients and benefits than the processed foods it is added to.
These processed foods and drinks containing fructose are to blame for the negative health effects associated with this sugar. Since HFCS is used to sweeten a lot of beverages and sweets like different pastries, desserts, and candies, it is clear why consuming high amounts of fructose wouldn’t be much of a challenge in America. “High fructose corn syrup accounts [for] 40 percent of sweeteners which are added to food or other beverages.”[2] An article published under the Harvard Medical School continues on this topic stating, “The increase in fructose intake is worrisome [...] because it suspiciously parallels increases in obesity, diabetes, and a new condition called nonalcoholic fatty liver disease that now affects up to one-third of Americans.”[4] All of these negative health effects linked to HFCS consumption in America give fructose a really bad reputation. If you are going to consume HFCS, keep it to an absolute minimum to avoid any adverse health effects that may be brought on due to HFCS overconsumption. However, don’t let this information make you stray away from the healthy fruits, vegetables and honey that contain fructose and the vitamins and minerals these foods provide you.
Lactose
Lactose is a different class of sugar than glucose or fructose. It is a disaccharide, which means it is composed of two monosaccharide residues. The two monosaccharides that make up lactose are glucose and galactose. In nature, galactose is mostly found combined with other sugars, but “it is found as the monosaccharide in peas.”[5] According to the International Dairy Federation, “In normal conditions, galactose is quickly and almost completely metabolized to glucose in the liver,” which makes it “a key source of energy.”[6]
Now, back to lactose.
Clearly, since galactose and glucose make up lactose, it has the health benefit of being an energy source. However, it also has other health benefits including being low calorie and having a lower glycemic index than glucose. Like fructose, this makes lactose a better sugar alternative for diabetic individuals.[7] Lactose also acts as a prebiotic, which “enhances the growth of microflora in [the] intestinal tract to maintain [a] healthy digestive tract.”[7]
Some things you can consume that contain lactose are milk, ice cream, cheese, yogurt, and many other dairy products. However, if you know or suspect you have a lactose intolerance, it would be in your best interest to limit your lactose consumption to a minimum in order to avoid any unnecessary discomfort caused by your intolerance.
Sucrose
Sucrose, like we went over at the beginning of this article, is the most common sugar, and the most commonly used in households, hence its nickname “table sugar.” “Table sugar is usually extracted from sugar cane or sugar beets. It consists of 50% glucose and 50% fructose, bound together.”[8] This makes sucrose, similar to lactose, a disaccharide since it is made up of two monosaccharides. “Sucrose is found in several fruits and vegetables and is present in large quantities in sugar beet and sugar cane – from which it is extracted and purified on a vast industrial scale.”[9] The varying purification processes of sucrose is what creates different forms of common sugar, such as white sugar and brown sugar. Brown sugar goes through less of a purification process, so the retained molasses causes that brown color. However, that is only if the brown sugar is unrefined. Refined brown sugar is made by adding molasses back into white sugar.
Even though it is a common sugar to use and consume, “high sucrose consumption has frequently been blamed for many of the illnesses that afflict affluent populations.”[9] Some of these negative health effects include:
● Mood swings
● Insulin sensitivity
“When blood sugar suddenly rises in the case of [a] sucrose rich meal, high insulin is formed to shuttle glucose to muscle cells where it could be burned. Overtime, high insulin leads to [the] wearing out of insulin receptors, which causes high blood glucose, chronically.”[9]
● Tooth decay
“Bacteria [in the mouth] feed on sugar, and acid is formed as a waste. Eventually, acid erodes tooth enamel, resulting [in] tooth loss or decay.”[9] In order to prevent any tooth decay caused by high sucrose consumption, it is important to remember to brush your teeth at least twice a day and to even rinse your mouth with mouthwash after every meal.
● Change in cholesterol
No, not a good change. “Large contents of sucrose promote triglyceride levels, [...] [so] sucrose affects the level of cholesterol by lowering [the] level of high density lipoproteins, which [...] [are] known to be good cholesterol.”[9]
Some foods that contain sucrose naturally (which is the preferred way to consume any sugar) include sweet potatoes, mangos, pineapples, tangerines, bananas, and many other foods that have great vitamins and minerals that are important to nutrition.
Even though some of these sugars do have negative health effects, it is important to note that these negative health effects are caused by high consumption of these sugars through processed foods. It is perfectly fine to consume these sugars through the foods in which they occur naturally because these foods have so many positive attributes that are important for your health. It is most beneficial and less harmful to consume these sugars through whole foods and to keep the consumption of processed foods to a minimum.
References:
1. Glucose Facts and health benefits: Nutrition. Nutrition | Benefits and Facts. (2019, May 3). https://www.healthbenefitstimes.com/nutrition/glucose/.
2. Fructose facts and health benefits: Nutrition. Nutrition | Benefits and Facts. (2019, May 3). https://www.healthbenefitstimes.com/nutrition/fructose/.
3.Uusitupa, M. (n.d.). Fructose in the diabetic diet. The American journal of clinical nutrition. https://pubmed.ncbi.nlm.nih.gov/8116561/.
4. Skerrett, P. J. (2011, April 26). Is fructose bad for you? Harvard Health. https://www.health.harvard.edu/blog/is-fructose-bad-for-you-200705012507.
5. Libretexts. (2020, August 11). Galactose. Chemistry LibreTexts. https://chem.libretexts.org/Bookshelves/Biological_Chemistry/Supplemental_Modules_(Biological_Chemistry)/Carbohydrates/Monosaccharides/Galactose.
6. International Dairy Federation. (2017, March). Factsheet 002 - 2017 reasons why galactose is good for you. Scribd. https://www.scribd.com/document/486487934/Factsheet-002-2017-Reasons-why-galactose-is-good-for-you.
7. Lactose facts and health benefits: Nutrition. Nutrition | Benefits and Facts. (2019, April 28). https://www.healthbenefitstimes.com/nutrition/lactose/.
8. Bjarnadottir, A. (2020, June 26). The 56 most common names for sugar. Healthline. https://www.healthline.com/nutrition/56-different-names-for-sugar#1.-Sugar/sucrose.
9. Sucrose facts and health effects: Nutrition. Nutrition | Benefits and Facts. (2019, May 5). https://www.healthbenefitstimes.com/nutrition/sucrose/.
Contributors:
Author: Lauryn Agron
Editor: Anum Khan
Health scientist: Rayven Hall