On this page, we’ll get acquainted with the chemical structure of different types of carbohydrates and learn where we find them in foods.
First, all carbohydrates are made up of the same chemical elements:
- carbon (that’s the “carbo-” part)
- hydrogen and oxygen, in about a two-to-one proportion, just like in H2O (that’s the “-hydrate” part)
For this reason, you may see carbohydrates abbreviated as “CHO” in our class.
Carbohydrates can be divided into two main types: simple and complex. Simple carbohydrates are made up of just one or two sugar units, whereas complex carbohydrates are made up of many sugar units. We’ll look at each of these in turn. This figure gives you an overview of the types of carbohydrates that we’ll cover.
Figure 4.4. Carbohydrates can be divided into two main types: simple (including monosaccharides and disaccharides) and complex.
are sometimes called “sugars” or “simple sugars.” There are 2 types of simple carbohydrates: monosaccharides and disaccharides.
contain just one sugar unit, so they’re the smallest of the carbohydrates. (The prefix “mono-” means “one.”) The small size of monosaccharides gives them a special role in digestion and metabolism. Food carbohydrates have to be broken down to monosaccharides before they can be absorbed in the gastrointestinal tract, and they also circulate in blood in monosaccharide form.
There are 3 monosaccharides:
Note that all three have the same chemical formula (C6H12O6); the atoms are just arranged a bit differently.
1 – Glucose
Here’s the chemical structure of :
In this class, we’ll sometimes use a simpler green hexagon to represent glucose:
You’re already familiar with glucose, because it’s the main product of photosynthesis. Plants make glucose as a way of storing the sun’s energy in a form that it can use for growth and reproduction.
In humans, glucose is one of the most important nutrients for fueling the body. It’s especially important for the brain and nervous system, which aren’t very good at using other fuel sources. Muscles, on the other hand, can use fat as an energy source. (In practice, your muscles are usually using some combination of fat and glucose for energy, which we’ll learn more about later.)
Food sources of glucose: Glucose is found in fruits and vegetables, as well as honey, corn syrup, and high fructose corn syrup. (All plants make glucose, but much of the glucose is used to make starch, fiber, and other nutrients. The foods listed here have glucose in its monosaccharide form.)
2 – Fructose
Here’s the chemical structure of :
In this class, we’ll sometimes use a simpler purple pentagon to represent fructose:
Fructose is special because it is the sweetest carbohydrate. Plants make a lot of fructose as a way of attracting insects and animals, which help plants to reproduce. For example, plants make nectar, which is high in fructose and very sweet, to attract insects that will pollinate it. Plants also put fructose into fruit to make it tastier. Animals eat the fruit, wander away, and later poop out the seeds from the fruit, thereby sowing the seeds of the next generation. Animal gets a meal, and the plant gets to reproduce: win-win!
Figure 4.5. Fructose in nature: A bee collects sweet nectar from a flower, in the process spreading pollen from flower to flower and helping plants to reproduce. Bees use nectar to make honey, which humans harvest for use as a sweetener. (Honey contains a mix of sucrose, fructose, and glucose). A kiwi is sweetened in part by fructose. Animals enjoy the sweet fruit and then later poop out the seeds, sowing them for a new generation of kiwi trees.
Food sources of fructose: Fruits, vegetables, honey, high fructose corn syrup
3 – Galactose
Here is the chemical structure of :
In this class, we’ll sometimes use a blue hexagon to represent galactose:
Food sources of galactose: Galactose is found in milk (and dairy products made from milk), but it’s almost always linked to glucose to form a disaccharide (more on that in a minute). We rarely find it in our food supply in monosaccharide form.
The second type of simple carbohydrates is . They contain two sugar units bonded together.
There are 3 disaccharides:
- Maltose (glucose + glucose)
- Sucrose (glucose + fructose)
- Lactose (glucose + galactose)
1 – Maltose
Here is the chemical structure of :
Maltose is made of two glucose molecules bonded together. It doesn’t occur naturally in any appreciable amount in foods, with one exception: sprouted grains. Grains contain a lot of starch, which is made of long chains of glucose (more on this in a minute), and when the seed of a grain starts to sprout, it begins to break down that starch, creating maltose. If bread is made from those sprouted grains, that bread will have some maltose. Sprouted grain bread is usually a little heavier and sweeter than bread made from regular flour.
Maltose also plays a role in the production of beer and liquor, because this process involves the fermentation of grains or other carbohydrate sources. Maltose is formed during the breakdown of those carbohydrates, but there is very little remaining once the fermentation process is complete.
You can taste the sweetness of maltose if you hold a starchy food in your mouth for a minute or so. Try this with a simple food like a soda cracker. Starch is not sweet, but as the starch in the cracker begins to break down with the action of salivary amylase, maltose will form, and you’ll taste the sweetness!
2 – Sucrose
Here is the chemical structure of :
Sucrose is made of a glucose molecule bonded to a fructose molecule. It’s made by plants for the same reason as fructose — to attract animals to eat it and thereby spread the seeds.
Sucrose is naturally-occurring in fruits and vegetables. (Most fruits and vegetables contain a mixture of glucose, fructose, and sucrose.) But humans have also figured out how to concentrate the sucrose in plants (usually sugar cane or sugar beets) to make refined table sugar. We also find sucrose in maple syrup and honey.
The sucrose found in a sweet potato is chemically identical to the sucrose found in table sugar. Likewise, the fructose found in a fig is chemically identical to the fructose found in high fructose corn syrup. As we’ll discuss more later, what’s different is the package the sugars come in. When you eat a sweet potato or a fig, you also get lots of fiber, vitamins, and minerals in that package, whereas sugar and high fructose corn syrup only provide sugar, nothing else. It’s not a bad thing to eat sugar. After all, it’s a vital fuel for our brain and nervous system. But paying attention to the package it comes in can help us make good overall choices for health.
3 – Lactose
Here is the chemical structure of :
Lactose is made of a glucose molecule bonded to a galactose molecule. It is sometimes called “milk sugar” as it is found in dairy products like milk, yogurt, and cheese. These are the only animal foods that have significant amounts of carbohydrate. Most of our carbohydrates come from plant foods.
are also called polysaccharides, because they contain many sugars. (The prefix “poly-” means “many.”) There are 3 main polysaccharides:
All three of these polysaccharides are made up of many glucose molecules bonded together, but they differ in their structure and the type of bonds.
1 – Starch
is made up of long chains of glucose. If these chains are straight, they’re called amylose; if they’re branched, they’re called amylopectin.
Here is an amylose segment containing 3 glucose units.
The next figure shows an amylopectin segment containing 4 glucose units. The chemical structure is represented differently, but can you spot the place where it branches?
Using our green hexagon to represent glucose, you can picture starch as something like this:
Humans have digestive enzymes to break down both types of starch, which we’ll discuss on the next page.
Starch is the storage form of carbohydrate in plants. Plants make starch in order to store glucose. For example, starch is in seeds to give the seedling energy to sprout, and we eat those seeds in the form of grains, legumes (soybeans, lentils, pinto and kidney beans, for example), nuts, and seeds. Starch is also stored in roots and tubers to provide stored energy for the plant to grow and reproduce, and we eat these in the form of potatoes, sweet potatoes, carrots, beets, and turnips.
When we eat plant foods with starch, we can break it down into glucose to provide fuel for our body’s cells. In addition, starch from whole plant foods comes packaged with other valuable nutrients. We also find refined starch—such as corn starch—as an ingredient in many processed foods, because it serves as a good thickener.
2 – Glycogen
is structurally similar to amylopectin, but it’s the storage form of carbohydrate in animals, humans included. It’s made up of highly branched chains of glucose, and it’s stored in the liver and skeletal muscle. The branched structure of glycogen makes it easier to break down quickly to release glucose to serve as fuel when needed on short notice.
Liver glycogen is broken down to glucose, which is released into the bloodstream and can be used by cells around the body. Muscle glycogen provides energy only for muscle, to fuel activity. That can come in handy if you’re being chased by a lion, or sprinting to make your bus! Both liver and muscle glycogen serve as relatively short-term forms of energy storage; together, they can only provide enough glucose to last for about 24 hours in a person fasting or eating a very low carbohydrate diet.
Even though glycogen is stored in the liver and muscles of animals, we don’t find it in meat, because it’s broken down soon after slaughter. Thus, glycogen is not found in our food. Instead, we have to make it in our liver and muscle from glucose.
Here’s a beautiful depiction of glycogen.
Figure 4.6. Glycogen is made from long, branching chains of glucose, radiating around a central protein.
3 – Fiber
includes carbohydrates and other structural substances in plants that are indigestible to human enzymes. Fiber is made by plants to provide protection and structural support. Think about thick stems that help a plant stand upright, tough seed husks, and fruit skin that protect what’s growing inside. These are full of fiber.
Figure 4.7. Examples of food plants high in fiber, including wheat, broccoli, and apples.
In our food, we find fiber in whole plant foods like whole grains, seeds, nuts, fruits, vegetables, and legumes.
One of the most common types of fiber is , the main component in plant cell walls. The chemical structure of cellulose is shown in the figure below, with our simplified depiction next to it. You can see that cellulose has long chains of glucose, similar to starch, but they’re stacked up, and there are hydrogen bonds linking the stacks.
When we eat fiber, it passes through the small intestine intact, because we don’t have digestive enzymes to break it down. Then, in the large intestine, our friendly microbiota—the bacteria that live in our colons—go to work on the fiber. Some fiber can be fermented by those bacteria. We’ll discuss fiber more later in the unit.
- Levin, R. J. (1999). Carbohydrates. In Modern Nutrition in Health and Disease (9th ed.). Baltimore: Lippincott Williams and Wilkins.
- U.S. Department of Agriculture. (n.d.). FoodData Central. Retrieved November 15, 2019, from https://fdc.nal.usda.gov/
- Figure 4.4. “Types of carbohydrates diagram” by Alice Callahan made with Microsoft SmartArt is licensed underCC BY-SA 4.0
- “Structure of alpha-D-glucopyranose (Haworth projection)”, “Structure of beta-D-fructofuranose (Haworth projection)”, and “Structure of beta-D-galactopyranose (Haworth projection)” by NEUROtiker is in the Public Domain
- “Simple carbohydrate diagrams” (with hexagons, pentagon) by Alice Callahan is licensed under CC BY-SA 4.0
- Maltose structure is cropped from “Amylase reaction consisting of hydrolyzing amylose, producing maltose” by BQmUB2012134 is in the Public Domain, CC0
- “Skeletal formula of sucrose” by NEUROtiker is in the Public Domain, CC0
- ” Lactose (simplified structure)” by NEUROtiker is in the Public Domain, CC0
- Figure 4.5. “Flower with bee” by pontla; “Honey” by sunny mama; “Kiwi” by ereta ekarafi;all licensed underCC BY-NC-ND 2.0
- Figure 4.6. “Glycogen” by Häggström, Mikael (2014). “Medical gallery of Mikael Häggström 2014“. WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.008. ISSN 2002-4436. Public Domain.
- Figure 4.7. “Wheat” by Bernat Caser; “Broccoli” by albedo20; “Apple” by Fiona Shields;all licensed under CC BY-NC-ND 2.0
- “Chemical structure of cellulose” by laghi.l is licensed underCC BY-SA 3.0
Nutrition: Science and Everyday Application, v. 1.0 by Alice Callahan, PhD; Heather Leonard, MEd, RDN; and Tamberly Powell, MS, RDN is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.
Which of the following are guidelines to keep in mind when choosing a dietary supplement? Look for third-party testing, for example a USP label, on the dietary supplement. Check with your healthcare provider about the supplement. Be mindful of product claims.
Nutritional supplements enhance your regular diet to ensure a healthy supply of nutrients. They contain vitamins and minerals that help you feel better, look better, and even sleep better. Nutritional imbalances can cause symptoms you didn't even realize were because of a vitamin or mineral deficiency.
- Magnesium and calcium/multivitamin. ...
- Vitamins D, E and K. ...
- Fish Oil & Gingko Biloba. ...
- Copper and zinc. ...
- Iron and Green tea. ...
- Vitamin C and B12.
The researchers concluded that multivitamins don't reduce the risk for heart disease, cancer, cognitive decline (such as memory loss and slowed-down thinking) or an early death. They also noted that in prior studies, vitamin E and beta-carotene supplements appear to be harmful, especially at high doses.
When your body gets an adequate amount of vitamins, you may feel more alert. As a part of the role vitamins play in boosting energy production, they also can help to diminish mental fatigue. These symptoms aren't very common, but for those who live with them, they can have noticeable effects.
People with diabetes, intestinal disease, heart disease or kidney disease should not take magnesium before speaking with their health care provider. Overdose. Signs of a magnesium overdose can include nausea, diarrhea, low blood pressure, muscle weakness, and fatigue. At very high doses, magnesium can be fatal.
Evidence. Research on the use of fish oil for specific conditions shows: Heart disease. While research shows that people who eat dietary sources of fish oil at least twice a week have a lower risk of dying of heart disease, taking fish oil supplements seems to have little to no benefits to heart health.
Fish oil is an excellent source of omega-3 fatty acids. Omega-3 fatty acids are essential for the proper development of the eyes, brain, and reproductive cells. They are also vital for heart and lung health, in addition to optimal functioning of the immune and endocrine systems.
- Magnesium. Experts believe consuming magnesium before sleep can aid your REM cycle. ...
- Calcium. Calcium is a natural muscle relaxant, and it's a fantastic before-bedtime substance. ...
- Vitamin B. ...
- Vitamin C. ...
- Vitamin K. ...
Combining supplements will not normally interfere with the way they work and in some cases may be beneficial, for example vitamin C helps iron absorption. However, certain supplements may interact with each other.
The most important steps are to fit vitamin D into your routine and take it consistently to ensure maximum effectiveness. Try taking it alongside breakfast or with a bedtime snack — as long as it doesn't interfere with your sleep.
The most popular nutrient supplements are multivitamins, calcium and vitamins B, C and D. Calcium supports bone health, and vitamin D helps the body absorb calcium. Vitamins C and E are antioxidants—molecules that prevent cell damage and help to maintain health.
Tailored Vitamins Better than Multivitamins There's no real rationale behind multivitamins, say nutrition experts. A better strategy is to take just the vitamins a person needs based on age and diet.
High-dose vitamins can turn your pee a bright, almost neon yellow color. The most common culprit is vitamin B2, also known as riboflavin, which is found in most multivitamins. The neon color in pee is just a harmless sign that you're taking more than your body needs, and the excess is mixing with your pee.
Ask your doctor to perform blood tests to determine what vitamin and mineral deficiencies you may have, and to establish a baseline by which you can measure the benefits of your multivitamin. Be sure to schedule follow-up lab tests 30 days after you begin a new multivitamin regimen.
- Best Overall - MuscleBlaze MB-Vite Multivitamin. ...
- Best Budget - HealthKart HK Vitals Multivitamin. ...
- Best For Women - Rainbow Light Women's One Multivitamin. ...
- Best For Men - One A Day Men's Multivitamin.
High doses of magnesium from supplements or medications can cause nausea, abdominal cramping and diarrhea. In addition, the magnesium in supplements can interact with some types of antibiotics and other medicines.
- Abnormal eye movements (nystagmus)
- Muscle spasms or cramps.
- Muscle weakness.
Yes! You can and should take magnesium and vitamin D together. In fact, the bioavailability of vitamin D largely relies on magnesium. Also, many nutrients wouldn't work efficiently without magnesium, further highlighting the importance of this mineral!
So, people using blood thinners, such as warfarin, should not take fish oil or other omega-3 fatty acid supplements because of the increased risk of dangerous bleeding.
According to new research, those fish oil pills may actually be a waste of money. A new study conducted by scientists at the University of Georgia suggests that taking fish oil daily could only be effective if you have the right genetic makeup.
Taking more than 3 grams daily might increase the chance of bleeding. Fish oil side effects include heartburn, loose stools, and nosebleeds. Taking fish oil supplements with meals or freezing them can reduce these issues. Consuming high amounts of fish oil from DIETARY sources is possibly unsafe.
These results prompted the American Heart Association to recommend fish oil supplements to patients with heart disease, and many cardiologists followed suit. It wasn't long before the benefits of fish oil were being touted even for people without heart disease.
A previous study was conducted on hyperlipidemic mice, which showed that fish oil intake in the morning was more effective in decreasing blood and liver triglyceride levels, than an evening intake. This chrononutrition study was conducted in Japan in 2017 and published in the Nutrition journal.
Older adults and the elderly typically shouldn't take more than 250 milligrams of EPA and DHA daily. However, when treating high triglycerides, your doctor may recommend up to 15 grams if you have high blood pressure and as much as 10 grams if you have rheumatoid arthritis.
- Exercise often: Studies prove that people with high activity levels are more likely to maintain their weight loss than others who are not as active. ...
- Eat a healthy breakfast daily. ...
- Stay hydrated. ...
- Eat whole foods. ...
- Eat responsibly and mindfully. ...
- Plan your meals ahead of time.
|electrolytes||minerals that help maintain the body's fluid balance|
|herbal supplement||a chemical substance from plants that may be sold as a dietary supplement|
|dietary supplement||a non-food form of one or more nutrients|
|megadose||a very large amount of a dietary supplement|
Foods like fruits, vegetables, whole grains, fish, lean meat, beans, nuts and seeds are all great examples of nutrient dense foods. By choosing more nutrient-dense foods, you'll get the beneficial nutrients your body needs without consuming too many calories.
The Dietary Guidelines for Americans recommend that carbohydrates make up 45% to 65% of total daily calories. So if you get 2,000 calories a day, between 900 and 1,300 calories should be from carbohydrates. That translates to between 225 and 325 grams of carbs a day.
Vitamins are meant to be a support to weight loss, not the only cause. Vitamin B, D, iron, and magnesium are 4 popular supplements for weight loss.
- Green Tea. Share on Pinterest. ...
- Coffee. Coffee is used by people around the world to boost energy levels and lift mood. ...
- Black Tea. Like green tea, black tea contains compounds that may stimulate weight loss. ...
- Water. ...
- Apple Cider Vinegar Drinks. ...
- Ginger Tea. ...
- High-Protein Drinks. ...
- Vegetable Juice.
- Eat a healthy diet. Focus on plant-based foods, such as fruits, vegetables and whole grains, and choose lean sources of protein and low-fat dairy products. ...
- Replace sugary beverages. ...
- Keep portion sizes in check. ...
- Include physical activity in your daily routine.
In general, FDA is limited to postmarket enforcement because, unlike drugs that must be proven safe and effective for their intended use before marketing, there are no provisions in the law for FDA to approve dietary supplements for safety before they reach the consumer.
The amygdala is the primary brain area regulating appetite with response to emotions. Indeed, the amygdala activates to food cues [124, 125], and this response is increased in childhood, adolescent, and adult obesity [126-129].
- Bisphenol A and similar compounds. ...
- Artificial trans fats. ...
- Polycyclic aromatic hydrocarbons. ...
- Coumarin in cinnamon. ...
- Added sugars. ...
- Mercury in fish.
Kelp, alaria and laver (kombu, wakame and nori in Japanese cuisine) are among the most common. Almost all kinds are edible. Seaweed is loaded with vitamins and minerals. Once dried it will keep of months, too.
1. SPINACH. This nutrient-dense green superfood is readily available - fresh, frozen or even canned. One of the healthiest foods on the planet, spinach is packed with energy while low in calories, and provides Vitamin A, Vitamin K, and essential folate.
Recommended Consumption. The 2010 Dietary Guidelines for Americans recommends consuming 45 to 65 percent of your calories as carbohydrates and 10 to 35 percent of your calories as protein. For someone who eats 2,000 calories a day, this translates into 225 to 325 grams of carbohydrates and 50 to 175 grams of protein.
When you don't get enough carbohydrates, the level of sugar in your blood may drop to below the normal range (70-99 mg/dL), causing hypoglycemia. Your body then starts to burn fat for energy, leading to ketosis. Symptoms of hypoglycemia include: Hunger.
Protein is a nutrient used to make and repair our body cells (like blood and muscle cells).