What Are Macronutrients and Micronutrients and Why Are They Important for Your Body?

Macronutrients are the main nutrients found in food. Macronutrients maintain your

body’s essential functions. Macronutrients come from proteins, fats, and carbohydrates,

which give your body energy in the form of calories. Macronutrients are typically

measured in grams (g) and can be a useful way to track the food that you are consuming.

Overall, counting macros is a way to focus on the variety of foods that you are eating –

and how much of each – instead of counting calories.

Examples of macronutrients include:

• Protein

• Fat

• Carbohydrates

Protein

• Protein contains 4 kcal/gram.

• Protein contains amino acids and serves as the major structural building blocks of the human body: bone, muscle, skin, brain, nucleic acids.

• Essential amino acids are those which cannot be made by the human body and must be consumed in the diet.

• Some amino acids can be used as an energy source (converted to glucose or ketones when needed).

• Protein deficiency can lead to a disease state (Kwashiorkor is sufficient calories but insufficient protein).

• USDA Daily Recommended Intake (DRI) for protein is 0.8 to 2.0 grams/kg/day depending upon age, gender, physical activity.

Fat

• Fat contains 9 kcal/gram.

• Fats or lipids are a diverse group of compounds used as an energy source and for many metabolic processes:

1. Immune response (omega-3 fatty acids)

2. Cell membrane structure (phospholipids)

3. Brain tissue (cerebrosides)

4. Synthesis of bile acid, cholesterol, vitamin D, steroid hormones

5. Insulation

• Two fatty acids cannot be made by the body and these “essential” fatty acids must be consumed in the diet [i.e., omega-3 alpha linolenic acid (ALA) and omega-6 linoleic acid (LA)].

• Omega-3 fatty acids eicosapentaenoic acid (EPA)and docosahexaenoic acid (DHA) and gamma linolenic acid (an omega-6 fatty acid) are sometimes considered “conditionally essential,” meaning they can be endogenously derived on the condition of no lack of intake of essential fatty acids. Given humans are only able to produce small amounts of EPA and DHA, oral intake of EPA and DHA is often recommended from cold water marine fish.

• USDA Daily Recommended Intake (DRI) for fat is at least 30 grams/day.

Carbohydrates

• Carbohydrates contain 4 kcal/gram.

• Carbohydrates can serve as a source of energy as well as cellular structural elements such as hyaluronic acid and proteoglycans; carbohydrates may contain sugars, starch and/or fiber.

• The intestinal digestion of carbohydrates results in breakdown products of monosaccharides such as glucose, galactose, and fructose. Glucose and galactose are actively transported into intestinal cells by sodium glucose cotransporter-1 (SGLT-1). Fructose is absorbed across intestinal cells by facilitated diffusion via glucose transporter 5 (GLUT-5).

• The satiation from carbohydrates in foods (e.g., fruits) is substantially dependent upon the presence of fiber. Fiber-free juice can be consumed 11 times faster than intact apples, with apples more satiating than puree, and puree more satiating than fruit juice. Especially in susceptible individuals (e.g., insulin resistance), fruit juice consumption may result in higher insulin levels compared to whole fruit consumption.

• Carbohydrates are generally not considered an essential macronutrient, as liver, kidney, and possibly small intestine can synthesize glucose (i.e., gluconeogenesis). However, with genetic defects affecting glucose metabolism and/or storage (e.g., glycogen storage disease), carbohydrates may be considered conditionally essential.

• Calorie deficiency can lead to marasmus (insufficient calories), but there is no known carbohydrate deficiency.

• USDA Daily Recommended Intake (DRI) for carbohydrate is 130 grams/day.

Micronutrients consist of vitamins and minerals and are measured in either milligrams

(mg), micrograms (mcg), or International Units (IU). Your body needs a smaller amount of

micronutrients for optimal performance. Though micronutrients do not provide energy,

they are essential for functions like digestion, hormone production, and brain function.

Micronutrients can be found in fruits and vegetables. Some vitamins that are examples of micronutrients include:

• Vitamin B1. Also known as thiamine, vitamin B1 aids in converting nutrients into energy. Foods include white rice, fortified breakfast cereals, and black beans.

• Vitamin B2. Also known as riboflavin, this vitamin is good for energy production, cell function and fat metabolism. Foods include instant oats, fat-free yogurt and milk.

• Vitamin B3. Also known as niacin, vitamin B3 drives the production of energy from food. Foods include chicken breast, turkey breast, salmon, and tuna.

• Vitamin B5. Also called pantothenic acid, this vitamin helps with fatty acid synthesis. Foods include shitake mushrooms, sunflower seeds and avocados.

• Vitamin B6. Also called pyridoxine, vitamin B6 helps your body release sugar from stored carbohydrates for energy, and creates red blood cells. Foods include chickpeas, tuna and potatoes.

• Vitamin B7. Also known as biotin, it aids the metabolism of fatty acids, amino acids and glucose. Foods include eggs, salmon, pork chops and sweet potatoes.

• Vitamin B9. Also known as folate. Vitamin B9 is important for proper cell division. Foods include spinach, white rice, and asparagus.

• Vitamin B12. Also called cobalamin, vitamin B12 helps with red blood cell formation and proper nervous system and brain function. Foods include beef liver, salmon, milk, and yogurt.

• Vitamin C. Also known as ascorbic acid, vitamin C is required for the creation of neurotransmitters and collagen. Foods include red peppers, oranges, grapefruits, and kiwis.

Minerals that are good examples of micronutrients include:

• Calcium. This mineral helps build strong bones and teeth and helps with muscle function. Foods include yogurt, orange juice, cheese and milk.

• Magnesium. Found in foods like pumpkin seeds, almonds and spinach, this mineral aids in the regulation of blood pressure.

• Sodium. You need sodium for optimal fluid balance and to maintain your blood pressure.

• Potassium. Potassium helps with muscle function and nerve transmission. You can find potassium in foods like apricots, lentils, prunes, and raisins.