Micro Vs. Macronutrients

Macronutrients and MicroNutrients: The Need To Know Basics

Well, we have all heard the saying before, but not until recently did we fully understand the meaning behind the phrase you are what you eat! With poor diet habits now known to lead to so many debilitating illnesses and diseases there is no better time to begin understanding the in and outs and ups and downs of nutrition.

Your Body's Macronutrient Needs

Macronutrients generally refer to the caloric nutrients commonly known as proteins, fats and carbohydrates but has been also known to extend its meaning to minerals we require in larger amounts as well, amino acids, fiber and water. Macro nutrients are the caloric components of food that provide the body with energy, means of growth and repair, hydration and metabolic functionality and are exactly why we need them in large quantities, especially during vigorous exercise or any type of muscular strain on the body. 

Macronutrients:

• Proteins - found in sources such as chicken, fish, pork, eggs, dairy, beans and nuts/seeds
• Fats - found in sources such as almonds, cashews, peanuts, salmon, trout and walnuts
• Carbohydrates - found in sources such as vegetables, fruits, whole grains, and beans

As mentioned prior the quality of the nutrients you eat is very important, so do not let the terms carbohydrates or fats lead you down the path of a dirty diet but remember the calories that you get from a greasy burger are not the same as a grilled chicken sandwich on a whole wheat bun. The point simply being be careful what you choose. You will not gain healthy weight from baked goods that have virtually zero nutritional value. You may, however, want to reach for some brown rice, whole-grain bread and almond butter or peanut that are rich in good fats, proteins, and carbohydrates. 

Macronutrient Spotlight: Proteins

Protein is a large molecular glob made up of little molecules known as amino acids. Protein digestion works by first each protein into amino acids through the stomachs acidic environment. The stomach serves several purposes in the digestion of protein denaturing the proteins in order for digestive enzymes to break them apart even further into smaller molecules known as peptides while providing a safeguard against any potentially harmful microorganisms that may have been digested along with your food. The peptides from the stomach, as well as acidic food particles can move through the digestive track. 

In order to neutralize the acidic food particles as it enters the small intestine, the pancreas secretes a bicarbonate that encourages even more digestion of protein from digestive enzymes found in the pancreas and small intestine. These enzymes act upon the food peptides within the small intestine, breaking them down to even smaller peptides and stripping them of their amino acid properties one at a time so that the absorptive cells of the small intestine may begin transporting the single amino acids through the bloodstream and eventually to the cells throughout the body. 

During protein metabolism, some protein is converted into glucose through a process known as gluconeogenesis - the formation of glucose from a non-carbohydrate source. The main difference being that carbohydrates are composed of simple sugars while protein is comprised of amino acids. So while amino acids are absorbed into the bloodstream, their constituent parts (those stripped of their nitrogen and amino properties) go through a process known as deamination. Deamination will take the amino group and break it down into ammonia to be secreted as urine after being converted to urea and filtered through the kidney. The carbon skeleton (the carbon. hydrogen and oxygen properties) however, can be utilized for protein synthesis, energy, or converted into glucose. 

Macronutrient Spotlight: Fats

Dietary fat has many critical roles in the body. Fats are an energy reserve as the body can only store small amounts of glucose but fat can be stored in an unlimited amount. The energy provided from fat will be used when we sleep, during times of low energy intake, and during physically demanding activities. Fat also provides essential fatty acids and carry fat-soluble nutrients such as certain vitamins. 

Fats require additional digestive action before absorption. This is mainly due to the fact that fat is not soluble or transportable in water mediums (blood and lymph) until undergoing changes. Once fats leave the stomach, they enter the small intestine which signals the gallbladder to release bile that then emulsifies the fats within the intestine. The emulsified fats are then split by enzymes into fatty acids and glycerol. The fatty acids are converted to the liver to be used as an energy source for cells. The fat which does not need to be utilized immediately for energy needs is stored throughout the body in adipose tissue (primarily found in the stomach, thighs, and buttocks) and will provide the body with a continued energy source as it releases new fat as needed. 

Macronutrient Spotlight: Carbohydrates 

The carbohydrates found in the food we eat are found in the form of simple sugars, starches, and fiber. They serve "as a chief source of energy for all body functions and muscular exertion" (Clark,  Lucett & Corn, 2008). The first of these, is very easily digestible and can be found in food sources such as fruits or honey. Double sugars, on the other hand, can be found in things like table salt and require some digestive action, but not nearly as much as starches that can be found in food sources such as whole grain products. Starches need enzymatic action in order to be broken down and thus require prolonged digestive periods. Dietary fiber (cellulose) is most commonly found in the skins of fruits and vegetables and is largely considered indigestible by the human body. It does, however, aid in intestinal mobility and elimination.

During the process of digestion and absorption, complex sugars are broken down into simple sugars such as glucose or fructose by enzymes found within the mouth and the small intestine. As these digested sugars and starches begin passing through the small intestine they are able to be absorbed. Once in their simplest form, carbohydrates are quickly absorbed by the upper and lower parts of the small intestine by villi and are then transferred to the blood stream and carried to the muscles and liver. Fructose however does need to be converted into glucose in the liver before it can be used for energy. From there glucose can be utilized as fuel for the brain, nervous system, and muscles. Due to the fact that we as humans do not consistently eat, some of the glucose is converted to glycogen and stored within the liver and muscles. Furthermore, any excess would then be stored as fat throughout the body as a energy reserve until energy expenditure once again exceeds energy input. Any undigested carbohydrates, such as dietary fiber, will move from the small intestine where absorption occurs to the large intestine and the colon, where elimination occurs.

Your Body's Micronutrient Needs

Micronutrients are the vitamins, minerals, trace elements, and antioxidants that are found in the food we consume. They are essential to ones personal health and are most commonly found in natural foods such as fruits and vegetables but also come from grains, nuts and seeds, dairy foods and meats - the basis of our entire diet. Incorporating a variety of fruits and vegetables into a diet will certainly provide most, if not all, your daily micronutrient needs and while multivitamins can serve as an alternative to meet any deficiencies that may be presents, there is no substitute to eating a healthy and balanced diet. 

Micronutrients cover a wide array of vitamins and minerals from vitamins B1, B2, B12, C, A, D, E and K to minerals such as sodium, chloride, calcium, magnesium, iron, zinc and copper to name a few. Each serves its purpose from energy and metabolism, red blood cell production, supporting vision, bone density, regulating blood calcium to maintaining electrolyte balance, formation of cells, protein building, forming bones and teeth and many more cell processes. Though they may be called micronutrients, do not let their title undermine their large role in overall health.

References

Clark, M., Lucett, S., Corn, R. J., & National Academy of Sports Medicine. (2008). Nutrition. In NASM essentials of personal fitness training (4th ed., p. 477). Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins.