These are the only animal foods that have significant amounts of carbohydrate. Most of our carbohydrates come from plant foods. Complex carbohydrates are also called polysaccharides, because they contain many sugars. The prefix "poly-" means "many.
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. 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. 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! 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. 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.
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 cellulose, 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. Although potatoes only contain a small amount of vitamin C, we generally eat a lot of them. They're good value for money and can be a healthy choice. Although potatoes are a vegetable, in the UK we mostly eat them as the starchy food part of a meal, and they're a good source of carbohydrate in our diet.
Because of this, potatoes do not count towards your five portions of fruit and vegetables a day , but they can have an important role in your diet.
Potatoes are a healthy choice when boiled, baked, mashed or roasted with only a small amount of fat or oil and no added salt. When cooking or serving potatoes, go for lower-fat or polyunsaturated spreads, or small amounts of unsaturated oils, such as olive or sunflower oil.
Leave potato skins on where possible, to keep more of the fibre and vitamins. For example, eat the skin when you have boiled or baked potatoes. If you boil potatoes, some nutrients will leak out into the water, especially if you have peeled them. To stop this happening, only use enough water to cover them and cook them only for as long as they need. Storing potatoes in a cool, dark and dry place will help stop them sprouting. Do not eat any green, damaged or sprouting bits of potatoes, as these can contain toxins that can be harmful.
Bread, especially wholemeal, granary, brown and seeded varieties, is a healthy choice to eat as part of a balanced diet. Wholegrain, wholemeal and brown breads give us energy and contain B vitamins, vitamin E, fibre and a wide range of minerals. White bread also contains a range of vitamins and minerals , but it has less fibre than wholegrain, wholemeal or brown bread. If you prefer white bread, look for higher-fibre options. Some people avoid bread because they're concerned about having a food intolerance or allergy to wheat, or they think bread is fattening.
However, completely cutting out any type of food from your diet could mean you miss out on a range of nutrients that you need to stay healthy. Bread can be stored at room temperature. Follow the "best before" date to make sure you eat it fresh.
What are the different types of carbohydrates? There are three main types of carbohydrates: Sugars. They are also called simple carbohydrates because they are in the most basic form. They can be added to foods, such as the sugar in candy, desserts, processed foods, and regular soda. They also include the kinds of sugar that are found naturally in fruits, vegetables, and milk.
They are complex carbohydrates, which are made of lots of simple sugars strung together. Your body needs to break starches down into sugars to use them for energy.
Starches include bread, cereal, and pasta. They also include certain vegetables, like potatoes, peas, and corn. It is also a complex carbohydrate. Your body cannot break down most fibers, so eating foods with fiber can help you feel full and make you less likely to overeat. Diets high in fiber have other health benefits. They may help prevent stomach or intestinal problems, such as constipation.
They may also help lower cholesterol and blood sugar. Fiber is found in many foods that come from plants, including fruits, vegetables, nuts, seeds, beans, and whole grains. Which foods have carbohydrates?
When you consume dietary fiber, most of it passes through the intestines and is not digested. For good health, adults need to try to eat 25 to 30 grams of fiber each day. Most Americans do not consume nearly enough fiber in their diet, so while it is wise to aim for this goal, any increase in fiber in your diet can be beneficial. Most of us only get about half of what is recommended. Fiber contributes to digestive health, helps to keep you regular, and helps to make you feel full and satisfied after eating.
Beans and legumes. Think black beans, kidney beans, pintos, chickpeas garbanzos , white beans, and lentils. Fruits and vegetables, especially those with edible skin for example, apples, corn and beans and those with edible seeds for example, berries. Whole grain cereals Look for those with three grams of dietary fiber or more per serving, including those made from whole wheat, wheat bran, and oats. Whole grain breads To be a good source of fiber, one slice of bread should have at least three grams of fiber.
Another good indication: look for breads where the first ingredient is a whole grain. For example, whole wheat or oats.
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