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CARBS – The Often-Confused Macronutrient Broken Down, Part I : Focus on Fiber

on May 6, 2013

84781462[1]I was in the supermarket the other day when I overheard a mom tell her toddler that he couldn’t have a snack that he saw because “it has carbs and we are not eating carbs anymore so Mommy and Daddy can lose weight.”  Meanwhile, this same mom was drinking a rather large iced tea that I am guessing had a decent amount of sugar in it.  While this mother’s statement to her child made me cringe for so many reasons, what struck me was how unaware she was of the basic facts of what carbohydrates are…. And how important healthy forms are for growing bodies and brains.  Yes, you heard me correctly – the human body needs carbohydrates to function properly.  With so many health claims out there touting carbs to be a weight gain promoter, I think it’s fair to say that too much, or the wrong kind of any form of food we take into our body can pose health risks.  I am not saying shove your face with a loaf of bread each time you get hungry (and I use this example because that is what I did as a youngster growing up on Long Island – from world-famous delicious bagels to killer Italian food, I pretty much ate enough carbs during the day to fuel a space mission to Mars and back), but keep plenty of healthy carbohydrates stocked in your home for energy levels to stay stable and healthy.  Too many times, I find people totally baffled as to what carbohydrates are exactly – the types that exist and what kinds and how much you should be getting.  Rather than try to avoid all carbohydrates out of fear that they will lead to weight gain and an unhealthy diet, stay away particularly from carbohydrates in the form of concentrated sugars (like soft drinks, candies, sweet snacks, cookies, etc.).  Carbohydrates in the form of whole grains, vegetables, and legumes/beans are healthy options that can fuel the body well.  Over the next few articles, I’ll try and break a major carbohydrate lesson  down into the most easy-to-understand terms so you don’t have to feel like you’re committing a dietary sin each time you or your family eats a “carb.”  I want to pay particular attention to dietary fibers in this article, as we cannot get enough of this healthy carb.

Lets’ start with the basics.  One of the most important carbohydrates is glucose (otherwise known as blood sugar or dextrose) – this simple carbohydrate provides nearly all of the energy the human brain uses daily.  Glycogen is a more complex sugar (called a polysaccharide, meaning “many sugars”) that is made up out of several glucose molecules.  Glycogen is manufactured and stored in the liver and muscles as a storage form of glucose.  Both glucose and glycogen provide about half of all the energy muscles and other body tissues use.  The other half of the body’s energy comes from mostly fat.  So what does all of this technical jargon about glucose and glycogen mean?  In actuality, people don’t eat glucose and glycogen directly.  Rather, when foods rich in carbohydrates are eaten, the human body receives glucose for immediate energy and converts some glucose into glycogen for reserve energy.  All plant foods (i.e. whole grains, vegetables, legumes/beans, and fruits) provide ample carbohydrates.  Some people may not realize this, but even dairy foods like milk contain carbohydrates due to their sugar content (yes, milk naturally has sugar!).

  • Here are two quick tips to remember:
  • Monosaccharides and disaccharides are known as the “sugars” and referred to as simple carbohydrates
  • Polysaccharides are known as starches and fibers and referred to as complex carbohydrates

Chemically, the dietary carbohydrate “family” includes:

  • Monosaccharides (“simple sugars”)
    • The most important dietary sugars get paired together to make other forms of sugars.  These simple sugars that are the backbone of other sugar compounds are:
      • Glucose– serves as the essential energy source for all of the body’s activities.  Its significance to nutrition is huge – glucose is usually the one sugar found in every other form of sugar.
      • Fructose – is the sweetest of sugars.  This sugar has the same chemical formula as glucose, but its structure is different, which allows the atoms to stimulate the taste buds on the tongue to produce a sweet sensation.  This sugar naturally occurs in fruits and honey.  Unfortunately, this is also the sugar that has been chemically and physically mutated into HFCS (high fructose corn syrup) that now floods the food industry’s supply, ranging from breads to soda.
      • Galactose – this occurs naturally in only a few foods and is found more as parts of other, more complex sugars.
  • Disaccharides (sugars made of pairs of monosaccharides/simple sugars) – glucose occurs in all three dietary forms of this type of sugar:
    • Maltose – is sometimes known as “malt sugar” and is produced whenever starch is broken down (which ultimately begins in the mouth with the enzyme salivary amylase…which is why too many starchy foods can lead to cavities because the sugars coat the teeth).  This form of sugar also occurs during the fermentation process that yields alcohol.  Maltose is not a common sugar in foods – it’s most notably found in barley.
    • Sucrose – fructose and glucose form sucrose, and actually tastes sweet due to the fructose.  This occurs naturally in many fruits and some vegetables and grains.  Table sugar is made by the refinement of juices from sugarcane and sugar beets, which are rich in sucrose.
    • Lactose – is the primary sugar found in milk (it’s known as “milk sugar”) and is made from the combination of galactose and glucose.  Lactose contributes half of the energy provided by fat-free milk.
  • Polysaccharides (large molecules composed of chains of monosaccharides) – these complex sugars are made up of many glucose units and are very important for energy production in the body.  There are three major types:
    • Glycogen – as mentioned earlier, this is the stored form of sugar (glucose) to be released for energy in the body.  It is found only to a limited extent in meats and not at all in plants.  This is why food is not a considerable source of this carbohydrate.  Hormones are released in the body to signal the release of energy; these hormones trigger glycogen storage sites in the liver or in muscle cells and then the stored sugar (glucose) is released.  Without proper stores of glycogen, the body cannot produce energy on demand when needed.
    • Starches – while the human body stores glucose as glycogen, plant cells store glucose as starches.  These sugars are long, branched or unbranched chains of hundreds or thousands of glucose molecules linked together.  These giant starch molecules are packed side-by-side in grains such as wheat or rice, in root crops and tubers such as yams and potatoes, and in legumes such as peas and beans.  When eaten, the human body breaks down the starch to glucose and uses the glucose for its own energy purposes.
      • All starchy foods come from plants.  à Grains are the richest food source of starch, providing much of the food energy for people all over the world (rice, wheat, corn, millet, rye, barley, legumes, tubers, and oats).
    • Fibers – Dietary fibers are the structural parts of plants, therefore found in all plant-derived foods (vegetables, fruits, whole grains, and legumes).  Most dietary fibers are polysaccharides and very similar to starches except that the bonds that hold fiber together cannot be broken down by the digestive enzymes in the body.  This means that the body cannot utilize them for energy and passes them out of the body.  Just because the body cannot use fibers for much energy does not mean that they serve no purpose.  Fibers are broken down into two main types:
      • Soluble fibers – this means these fibers can be dissolved in water.  These fibers can even form gels (think chia seeds) and are easily digested  by bacteria in the colon (this means they are “fermentable” = gas!).  Oats, barley, legumes, and citrus fruits all are considered soluble fibers and are most often associated with protecting against heart disease and diabetes by lowering blood sugar and cholesterol (these fibers bind to cholesterol and sugars and remove them from the body).  Oatmeal and chia seeds are great forms of fiber.
      • Insoluble fibers – these fibers do not dissolve in water or form gels and are less readily fermented.  Whole grains (i.e. bran) and vegetables are the most common types and promote bowel movements (which can also help constipation).  Hemp seeds and flax seeds are a great source of fiber.

Many times, I see processed foods touting the label as “high fiber” or “low carb” and I look at the nutrition label and gasp…. Sometimes the fiber content is so ridiculously unnatural that I wonder what chemicals were used to create this ratio of fiber.  While eating high-fiber foods are great for your health, make sure they come from natural sources and not from manufactured “functional fibers” that are nothing but factory created foods.  Eating too many of these functional fibers is dangerous, especially to children because it can cause a lack of nutrient and mineral absorption.  It can also lead to dehydration if it causes too many bowel movements.  It is not advised for parents to give their children supplements like dissolving fiber granules or foods that are full of functional fibers.  Rather, natural forms of soluble and insoluble fiber are what the human body needs to safely support health.

This is just the tip of the iceberg when delving into the whole realm of carbohydrates.  Now that you hopefully have a clearer understanding of what carbohydrates are and the different forms of food they can be found in, I will continue next article more on how carbohydrates are digested and absorbed in the body, which is important to know so you can better understand how your children (and yourself) utilize the foods taken in.  Knowing the balance of nutrients is imperative to maintaining a healthy diet.


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