Nutrition is the process of nourishing the body through the foods you eat; eating nutritious foods is necessary for good health and growth. Adequate nutrition is important to maintain a healthy body that enables to fighting off disease and operating at its best.

We get the nourishment mainly from the macronutrients, which includes the major dietary groups, but micronutrients are also essential. Having a balanced diet with both types is ideal for a good nutrition.

One thing to keep in mind is that there’s no one-size-fits-all in eating for health and happiness. Everybody has their own levels of nutrients that enhance the food choices to work uniquely for their bodies based on various factors such as age, gender, genetics, metabolism, physical activity level, and personal preferences. It’s important to listen to your body and how you feel in response to your diet.

Let’s go deeper to understand the role for each of them.

Macronutrients

Macronutrients provide the energy that your body needs to function, and its 3 main groups are carbohydrates, proteins, and fats. Each of the macronutrients is required in fairly large amounts daily to support many of your body’s vital functions such as breathing, temperature regulation, digestion, cell repair, and movement.

Carbohydrates

Carbohydrates are sugar molecules that are breaking down and used as energy in the body. There are 2 kinds of carbohydrates that are based on their chemical structure: simple and complex. Simple carbohydrates give a fast burst of energy, while complex carbohydrates give a slow energy release due to their fiber content. Carbohydrates should make up of about 50% of your daily diet.

Proteins

Proteins are needed for growth and repair and exist in every cell in the body. They are made of amino acids, both essential and nonessential. The body is unable to make the 9 essential amino acids on its own, so they need to come from the foods. Some food sources, called complete proteins, have all of these essential amino acids found mostly in animal products and some plant sources such quinoa, soy, and hemp. Other plant foods are incomplete proteins have some of the amino acids needed daily. It is possible that you can get all of the amino acids you need with the plant-based diet.

Fats

Fats store energy in the form of triglycerides and can be breaking down for energy when needed. The 2 main types of fats are unsaturated and saturated. It is best to eat more of the unsaturated fats than saturated fats for the health benefits.

Saturated fats are solid at room temperature. They are found mostly in animal sources such as meat, poultry, butter, and cheese; they are also in some plant foods like coconut oil and palm oil.

Unsaturated fats are split in 2 types: monounsaturated and polyunsaturated. Monounsaturated fats have 1 double bond in its chemical structure that can be found in olive oil and nuts, whereas polyunsaturated fats have more than 1 double bonds and can be found in flaxseeds and chia seeds. Different from saturated fats, they are liquid at room temperature and mainly found in plant sources.

Trans fats are naturally found in some dairy and meats as well as in processed and hardened vegetable oils. Industrial trans fat or hydrogenated fat is made by adding hydrogen to oil. Many processed foods incorporated them to extend its shelf life. Trans fats are harmful to your health in a high intake because they can increase levels of “bad” cholesterol or LDL (low-density lipoprotein) in the blood, which leads to a greater risk of heart disease. Many countries have taken measures to remove trans fats in the food manufacturing process; it is best to avoid it altogether if possible.

Micronutrients

Micronutrients, which are vitamins and minerals, are important for the body to perform its functions and are needed in smaller amounts than macronutrients; thus, micronutrients are easily underrated. However, the lack of micronutrients can make a negative impact on your health. According to the World Health Organization, the micronutrient deficiency causes some of the most common health problems such as anemia (iron), rickets, and osteoporosis (vitamin D), all have deabilitating effects on the body’s well-being and performance.

Vitamins and minerals can be found in plants. Plant foods come in various colors, and each color is connected to the nutrients they contain. For example, red contains lots of vitamin C; orange has vitamin A; green has vitamin K and iron; and purples has antioxidants. Therefore, a colorful diet will provide a full range of nutrients to nourish your body.

The daily requirement for each micronutrient is different per individual based on their needs. If your diet is healthy and balanced with plant and animal food sources, then you are likely to get all of the micronutrients your body needs without supplements. For anyone who doesn’t eat animal sources, a well-plan diet with right supplements cover the essential nutrients you need. If you need help with figuring which diet works best for you, consult a registered dietitian or certified nutritionist.

Vitamins

Vitamins are separated into 2 types: water-soluble and fat-soluble. Water-soluble vitamins are not stored in the body and its excess would be excreted in the urine. Fat-soluble vitamins can be stored in the body and are soluble in dietary fats.

Water-Soluble Vitamins

Vitamin B produces red blood cells; supports the cardiovascular, nervous, and immune systems; and lowers fatigue by releasing energy from food. There are 8 types of B vitamins that play important roles in physiological functions. They must be consume daily to stay healthy since they are not stored in the body.

• B1 – Thiamine – Enriched noodles, sunflower seeds, fortified cereals, whole grains, lentils
• B2 – Riboflavin – Spinach, peas, fortified cereals, mushrooms, almonds
• B3 – Niacin – Peanuts, fortified wheat flour, whole grains, legumes
• B5 – Pantothenic Acid – Mushrooms, oats, potatoes, avocados, brown rice, black beans
• B6 – Pyridoxine – Avocados, bananas, green vegetables, soybeans, quinoa, sunflower seeds
• B7 – Biotin – Found in most foods, including sweet potatoes
• B9 – Folic Acid – Broccoli, cabbage, kale, sprouts, chickpeas, kidney beans
• B12 – Cobalamin – Eggs, milk, fish, cheese, fortified yeast extract, cereals

Vitamin C is an antioxidant that protects cells from oxidative damage and supports immune system function. In addition, it promotes collagen production that improves skin elasticity and maintains healthy skin, blood vessels, and cartilage.

Fat-Soluble Vitamins

Vitamin A supports the vision, cell renewal, and immune system function.

Vitamin D is a hormone made in the kidneys through sunlight exposure; it is essential for the growth, development, and maintenance of strong teeth, bones, and muscles.

Vitamin E is a strong antioxidant that protects cells from oxidative damage, maintains healthy skin and eyes, and boosts the immune system.

Vitamin K is necessary for blood clot.

Minerals

Minerals offer more vital nutrients for our health and body.

Calcium maintains bones and teeth health. It plays a crucial role in muscle contraction for the heart and for normal blood clot.

Iodine is necessary for thyroid hormone production, brain development, and bone maintenance.

Iron promotes red blood cell production and supports brain and immune function.

Magnesium supports the nervous system function and releases energy from foods.

Phosphorus releases energy from foods and develops strong teeth and bones.

Potassium balances water content, maintains blood pressure, and supports the heart function.

Selenium protects cells from oxidative damage, supports immune function, and helps normal male fertility

Sodium balances water content.

Zinc supports immune system function; promotes hormone and cell production; maintains skin, hair, and nails

Fiber

Fiber supports the digestive system health by slowing down digestion, which regulates blood sugar levels. This helps you feel full longer that reduce the chance of weight gain. Sadly, most people don’t get enough of it, despite the positive benefits of consuming it. For every 8 g more to the daily diet, you can lower the risk of type 2 diabetes by 15%, heart disease by 19%, and colon cancer by 80%.

Soluble Fiber

It is the type of fiber that dissolves in water to make a gel-like substance, which helps softens the stool. This facilitates through the gut, which relieves constipation. It slows down digestion and regulates blood sugar levels. In addition, it lowers the cholesterol absorption into the bloodstream, which has the positive effect to reduce the LDL cholesterol level in the blood circulation. Soluble fiber is mainly in flesh and pulp of many fruits and vegetables, grains, seeds, and legumes.

Insoluble Fiber

It does not dissolve in water that it can somewhat break down by digestion. This helps to push food particles through your digestive tract, which prevents digestive problems. Consuming sufficient amount of it supports regular bowel movements and maintains blood sugar levels. Insoluble fiber appears in the skins and seeds of many fruits and vegetables, nuts, seeds, whole grains, rice, and wheat bran.

Resistant Starch

Carbohydrates are composed of large amounts of beta-glucose monomers, which also referred to as resistant starch because they are unable to break down by the small intestine. When they got into the large intestine, they are fermented by gut bacteria.

This fermentation process makes short-chain fatty acids (SCFAs), which activate the immune system and support mental health.

Examples of foods containing resistant starch are potatoes, rice, whole grains (i.e., barley, oats, and sorghum), green bananas, and beans and legumes.

Cooked and cooled

Cooled cooked white rice, potatoes, sweet potatoes, or pasta have more resistant starch than if consumed hot. Even if you reheat them later, the amount of resistant starch is still increasing. Thus, enjoy these foods and make extra batches to refrigerate and reheat for the upcoming meals.

Store the cooked rice properly since it is prone to have bacterial spores that cause food poisoning. These spores are growing when the rice is out at room temperature. Cool and refrigerate it within an hour of cooking. Refrigerate for no longer than a day and reheat it before consuming.

Get Ample Fiber

The average daily fiber intake is 10-15 g; it’s best to go for 28 g. A high fiber food has 5 g fiber per serving.

Try your best to include a mix of different sources of fiber by eating lots of whole grains, vegetables, fruits, beans, lentils, nuts, and seeds in your diet as much as possible.

Foods may have a combination of types of fibers. For example, whole grains are good sources of both insoluble fiber and resistant starch. Eating these foods may decrease your risk of heart disease, diabetes, and several types of cancers.

Keep in mind that a sudden increase fiber intake can cause digestive issues like bloating and loose bowel movements. It is best to increase levels of fiber gradually and under the supervision of a doctor, dietician, or nutritionist, if needed.

Starch and Fiber

They are confusing because both are included in the same foods and are carbohydrates. Let’s go over the difference between them.

Starch

Polysaccharides like amylopectin are composed of alpha-glucose monomers. When they are linked, the bond angles formed and build a branched and/or spiral structure. These bonds can be broken down by enzymes in the digestive system. They are found in rice, potato, white bread and pasta, wheat, and barley.

Fiber

Polysaccharides like cellulose are composed of beta-glucose monomers and can be found in plants. These units of glucose are connected and formed bond angles to build stable parallel, interlinked chains. In contrast with starch, there are no enzymes that break down these bonds in the small intestine.

Digestion

Digestion is the process that the body absorbs necessary nutrients from the foods for an optimal function. Nutrients are transferred into the bloodstream that bring to areas in the body where they are needed, and waste matter is made and excreted. The digestive system is about 30 ft (9 m) long in adults. Let’s go over each part and their role is.

Mouth

Food goes into the mouth and is breaking down into smaller pieces by teeth through chewing. Digestive enzymes in saliva start the process of chemically breaking down the food. The ball of chewing food (bolus) is swallowed and enters to the esophagus.

Esophagus

It is the large muscular tube that extends from the epiglottis (locates at the back of the throat and behind the tongue) to the stomach. Its muscle moves the bolus through the tube downwards to the stomach. The lower esophageal sphincter is a muscular ring that act as the stomach’s gateway. Acid reflux occurs if it doesn’t close properly.

Stomach

The stomach releases digestive enzymes and acid that breaks down the food that enters. Gut muscles contract to mix the food with the chemicals to break it further and the acid kills off unfavorable microbes in it. This process releases the satiety hormone, leptin when full, while the hunger hormone, ghrelin when hungry. The stomach turns the food into chyme, which is a liquid consistency that makes it easier for the small intestine to process.

Small Intestine

The majority of nutrient absorption occurs in 23 ft (7 m) long section of the digestive tract. It is covered with multiple tiny villi and microvilli that absorb the nutrients from chyme (called diffusion) and pass them into the bloodstream

Food spends 2-6 hours in the small intestine to be breaking down by digestive enzymes to facilitate diffusion. Some enzymes are from the pancreas, which releases hormones to regulate blood sugar levels as they increase in response to eating a meal. Also, the gallbladder secretes bile into the small intestine to further aid in digestion.

What’s left is mainly water, bacteria, dead cells from the gut lining, and indigestible fiber. These move along the small intestine to the ileocecal valve – the gateway to the large intestine.

Large Intestine

Its main role is finishing the job and making feces. During the 12-30 hours in here, the water content of the liquid mixture is slowly absorbed and turns into stools.

Most of the microbes in trillions are living in the large intestine. These gut bacteria play an essential role in the synthesis of key nutrients. They interact with immune cells that can prevent inflammation. They ferment the indigestible fiber in the large intestine, which releases the short-chain fatty acids. Another product of these bacteria is gas. Giving various types of fiber to feed the gut microbes helps the digestive processes and support beneficial gut bacteria.

Rectum and Anus

The end product is semi-solid waste material called the feces. They are gathered together in the rectum, which is at the further end of the large intestine and before the 2 anal sphincters at the exit. Contraction and relaxation of the anal muscles pushes the stool through the sphincters and exit from the anus.

The Process of Nutrient Absorption within the Body During Digestion

Diffusion is the process of absorbing nutrients by the body. The inner wall of the small intestine has many tiny projections called villi, and they can expand the surface area that facilitates absorption. On average, the small intestine has 2,690 square feet (250 square meters) of surface area.

Villi are covered in microscopic projections called microvilli, which are responsible for diffusion. When the nutrient particles go in the small intestine, they pass through microvilli into the villi. Each villi connects to blood and lymphatic vessels that link the intestine to the body’s circulatory and lymphatic systems. Proteins and carbohydrates pass into the blood vessels, while fats pass into the lymphatic vessels.

Both blood and lymphatic vessels bring these nutrients to various areas of the body to be used as needed or stored for later use.

Metabolism

Metabolism is a collective of chemical reactions occur in your body to maintain its function; it goes hand in hand with nutrition since the food we eat provides the energy required to fuel metabolism.

Typically, a person utilizes about 10% of energy intake on digestion, 20% on physical activity, and 70% by organs and tissues to maintain the body’s function. Every process, such as breathing and thinking, uses energy. The basal metabolic rate (BMR) is the amount of calories needed to continue a person’s life while they are sitting still.

The body metabolizes the energy it consumes is performed between 2 states – fed and fasted.

Fed (Absorptive) State

In the midst of or after eating a meal, the food is broken down and the glucose goes into the blood for cells to absorb and use as fuel. When the body gets more glucose from the food than necessary by cells, they stop absorbing it. The rising in blood glucose levels causes the release of insulin, which activates liver and muscle cells absorb the excess glucose in the bloodstream, convert it to glycogen, and store it for future use. In addition, insulin stimulates the conversion of glucose to triglycerides (fats) in adipose tissue. Excess fatty acids from the food are also stored in adipose tissue.

The amount of energy stored in the body depends on the BMR, which affects in various factors like genetics, age, sex, and body composition. In order to keep a stable and healthy weight, you must intake the energy in the body that aligns with the energy release out to stay functional, including the energy used in physical activity. If you put in more calories consistently than you burn, the extra will store as fat.

Fasted (Postabsorptive) State

Several hours after eating, blood glucose levels decrease, which activates the pancreas to release glucagon. This causes the liver and adipose tissue to metabolize glycogen stores, which releases glucose into the bloodstream that are available to use as energy for the body.

After long fasting, the stored fat from the adipose tissue are broken down into glycerol and fatty acids in the liver; ketone bodies are the by-product. Protein is the last resort for fuel.

Calories

It is the measurement used to estimate the amount of energy is stored in the chemical bonds of the foods you eat. The guidelines said a man needs ~2,500 kcal a day and a woman ~2,000 kcal to maintain a healthy weight, but they should be adjusted based on factors like age, size, and level of physical activity.

The body may not get full amount of released energy from foods. For instance, fiber foods, like nuts, take more energy to digest and you absorb the remaining energy. Another thing is 2 people may absorb different levels of nutrients from the same quantity of the same foods. The amount of energy your body is able to absorb nutrients are based on the gut health and the length of the intestines.

Keep in mind that calories are not everything! A number does not indicate how healthy you are or the quality of nutrition you eat.