What is nutrition?
Nutrition in layman’s language is the process of providing or obtaining food necessary for human health and growth. Medical fraternity defines nutrition as the process of taking food through ingestion and using it for growth, metabolism & repair through digestion, absorption and excretion. So, nutrition is all about intake of healthy food and drinks that provide energy to your body.
A healthy and balanced diet will provide your body with nutrients for overall health and wellness. Human life and health are dependent on essential nutrients found in food through our diet. Nutrition has a direct link to health and diseases for humans of all ages. We need balanced diet to stay fit and healthy, as both under nutrition and over nutrition is harmful to humans.
Undernutrition is particularly harmful to children in the early years of as it results in stunted growth and delay in reaching cognitive milestones. Over nutrition without adequate physical exercise results in obesity and affects all age groups. Under nutrition causes health conditions like anemia due to insufficient intake of iron; thyroid deficiency due to low iodine diet; and impaired vision due to vitamin A deficiency.
What are nutrients?
Human diet must have the right balance of nutrients to provide adequate nourishment for good health and to avoid risks of developing certain health conditions. Our body needs different nutrients and in certain proportion for optimum health and wellness. These nutrients are broadly divided into – Macronutrients and Micronutrients.
Macronutrients are the nutrients that human body needs in relatively large quantities. These include carbohydrates, proteins, fats and water. These nutrients provide energy (measured in calories) to the body. This calorie is used by the body for growth, repair and development of new tissues, carry nerve impulses and to regulate life processes.
Carbohydrates provide energy to the body. In fact, it’s the main source of energy to human body. Food stored in the body, as reserve for future use, is mainly in the form of carbohydrate. It’s stored in our body in three forms – sugar, starch and fiber. Human brain works completely and only on glucose. Excess glucose in human body is stored as Glycogen in the liver. Additionally, carbohydrate serves as fuel during high intensity physical exercise and also spares protein to preserve muscle mass.
Food Sources of Carbohydrate includes grains, dairy products and fruits.
Carbohydrate deficiency in the body can result in the following health conditions:
- Energy loss and fatigue
- Weight loss,
Proteins are the building blocks of life. They are amino acids and essential for humans to function properly. In human body, every cell contains proteins. Your diet must include protein as it helps the body to repair cells as well as to make new cells. Protein is especially important for children, teens and pregnant women as it supports growth and development. Among macronutrients, they are the last to be used for generating energy. But it only happens when the body is depleted of carbohydrates and fats – in case of starvation.
Food sources of protein includes meat, poultry, fish, lentils, soy products, nuts, whole grains and seeds.
Protein deficiency in the body can result in health problems like:
- Loss of muscle mass
- Bone fracture risks
- Infection risks
- Stunted growth in children
Fats are essential components of our diet and contribute to our health and wellness. Fat performs important roles, like serving as an energy reserve, protecting vital organs, insulation, and transporting fat soluble vitamins. In addition, fats have important role in making steroids & hormones, and serve as solvents for hormones.
Fats provide the highest caloric content and synthesizes the largest amount of energy when burnt (1 gram of fat = 9 calories). The body stores extra fat in adipose tissues, and it is burnt only when carbohydrate is depleted in the body.
Food sources of fat includes meat, fish, dairy, oils, nuts and seeds.
Fat deficiency in the body can result in health problems like:
- Heart disease
- Kidney problems
- Pediatric & childhood obesity
- Metabolic syndrome
Our body is made up of 60% water and it’s the main component of bodily fluids. Water is a medium for important functions like carrying nutrients to every cell in the body and removing waste through urine, sweat and tears. It is needed for regulating body temperature and maintaining the ionic balance in blood. Water lubricates joints and works as a shock absorber for body organs and tissues. In addition, water keeps the mouth, eyes and nose moisturized, and also prevents constipation. Human body needs water more than any other nutrient and it’s replenished through food and drinks.
Food sources of water includes drinking water and fluids that come from fruits and vegetables.
Water deficiency in the body can result in health problems like:
- Kidney failure
Micronutrients – also referred to as vitamins and minerals – are the nutrients that human body needs in trace amounts. They are required in tiny amounts, but their absence can have severe consequences. These substances help the body to produce enzymes, hormones and other substances that are essential for development, disease prevention and overall wellbeing.
The body cannot manufacture these substances in sufficient amounts, so it has to be taken through a balanced diet consisting of lots of fruits, vegetables, legumes, whole grains, lean protein, as well as healthy fats like nuts and olive oil. Consuming less than optimal amounts of vitamins, minerals, and other substances can result in health conditions, like type 2 diabetes, heart disease, cancer and osteoporosis.
Vitamins are compounds needed by the body to grow and develop normally. The body needs 13 essential vitamins – A, C, D, E, K and the B vitamins – thiamine (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyroxidine (B6), biotin (B7), folate (B9) and cobalamin (B12). These vitamins can be grouped as fat soluble and water soluble. Vitamins – A, D, E and K – are fat-soluble and stored in fatty tissues of the body. While, vitamin C and the B vitamins are water-soluble and need to be consumed regularly in diet as the excess amount is removed from the body as urine.
The food you eat usually provides all the vitamins your body needs. However, people who follow a vegetarian diet may have to take vitamin B12 supplements. Some amount of Vitamin D and K is produced by the body, and the deficient amount must be provided through the diet or supplements.
Vitamin A: Vitamin A is an antioxidant and vital to human life. It’s essential for eye health and its deficiency may cause night blindness. The main role of vitamin A in the body includes:
- Bone growth
- Cell functions
- Immune system
People who follow a vegetarian diet, children and alcoholics may need extra vitamin A. You may need more vitamin A, if you have certain health conditions, like liver diseases, cystic fibrosis and Crohn’s disease.
We get Vitamin A from both plant and animal sources. Colorful fruits and vegetables are the plant sources, while liver and whole milk are the animal sources of this vitamin.
Vitamin C: Vitamin C is an antioxidant and a vital nutrient. It has a significant role in maintaining the health of your skin, bones and connective tissues. It even helps in the healing process. Vitamin C helps in the absorption of iron. Pregnant & breastfeeding women, burn victims, smokers and people recovering from surgery need more vitamin C than the others.
Food sources of Vitamin C are fruits and vegetables, like citrus fruits, red and green peppers, broccoli, tomatoes and green vegetables.
Vitamin D: Main function of vitamin D is to absorb calcium, a major component of bones. Vitamin D deficiency results in bone diseases like rickets and osteoporosis. This nutrient has a vital role in the functioning of the nerves, muscles and the immune system. Breastfed infants, older adults, dark-skinned people, and people who had gastric bypass surgery or who are obese need more vitamin D. Also, people with health conditions, like liver diseases, cystic fibrosis and Crohn’s disease may require additional vitamin D.
There are three ways of getting vitamin D – by exposing your skin to the sun, diet and supplements. But exposure to the sun may lead to problems like skin cancer and ageing skin. So, most people rely on supplements to fulfill their vitamin D needs.
Food sources of Vitamin D includes egg yolks, liver and sea fish.
Vitamin E: Vitamin E is important for the immune system and metabolic processes in the body. This nutrient is an antioxidant. Dietary source of vitamin E is adequate for most people. But some people with specific health conditions, like liver diseases, cystic fibrosis and Crohn’s disease may need more vitamin E than others. Low amount of vitamin E may result in peripheral neuropathy, retinopathy and reduced immune response.
Food sources of vitamin E include nuts & seeds, vegetable oils, margarine and leafy green vegetables. In case you plan to take vitamin E supplements, its best to consult your doctor as the supplements may interfere with the function of blood thinners and other medicines.
Vitamin K: Vitamin K is vital in the process of growth and development. This nutrient helps the body to make proteins for healthy bones and tissues. It’s also needed for making proteins that facilitate blood clotting. People with low vitamin K suffer from bleeding and haemorrhaging in severe cases.
Food sources of vitamin K includes green vegetables and dark berries. The bacteria present in your intestines also produces vitamin K, though in small amounts. Always consult your doctor before taking vitamin K supplements, especially if you take blood thinners.
B Vitamins: The B vitaminshelp the body to process the food you eat to make energy. They also help in formation of red blood cells. Deficiency of the B vitamins may cause diseases. Low levels of vitamins B6 and B12 may cause anemia.
Main food sources of B vitamins are proteins like meat, poultry, eggs, fish, poultry and dairy products. Green leafy vegetables, beans and peas also have B vitamins.
Each of the 13 vitamins have specific function. People who are deficient in certain vitamins may get health problems. The best way to get enough vitamins is to eat a balanced diet with a variety of foods. In cases, you decide to take vitamin supplements, it’s good to consult your doctor as the vitamins need to be taken in the right dose to avoid health problems arising out of high dose.
Human body needs dietary minerals like iron, sodium, potassium, etc. to function properly. Minerals are classified as macrominerals and microminerals. Macrominerals including iron, calcium, potassium, sodium and magnesium are needed more in amount by the body. Microminerals include copper, zinc, fluoride, cobalt and chromium are needed in very small quantity. They work as co-factors for enzymes to function properly in the body.
Some of the vital minerals needed for the body includes:
Iron is needed to form red blood cells, which carries oxygen to the entire body. It is important in creating hormones and forming connective tissues. Low levels of iron in the body can result in health conditions like weakness, digestive issues and difficulty in thinking. But excess of iron may lead to digestive problems, and if level of iron is very high it can be fatal. Females need more iron during their reproductive years.
Food sources of iron includes beef liver, spinach, tofu, lentils and fortified cereals.
Potassium is a vital mineral for the body. It is an electrolyte and helps in proper functioning of the kidneys, heart, muscles and the nerves. Deficiency of potassium results into stroke, high blood pressure and kidney stones. High levels of this mineral are injurious to people with kidney disease.
Food sources of potassium are bananas, avocados, dried fruits, coconut water, squash, beans and lentils.
Sodium is an electrolyte that helps in proper functioning of the nerves and muscles. It also regulates the fluid levels in the body. Low levels of sodium may lead to hyponatremia. While excess sodium may result in high blood pressure, increasing health risks like cardiovascular disease and stroke.
Main source of sodium is table salt, but it is also present naturally in most foods.
Calcium is important for formation of bones and teeth. This vital mineral is needed for proper functioning of the nervous system, heart health, and other bodily functions. Deficiency can lead to weak bones or teeth loss. Excess calcium results in health conditions like kidney stones, constipation and reduced absorption of other minerals.
Food sources include dairy products, legumes, tofu and green leafy vegetables.
Phosphorus is a vital component of all body cells and is essential for healthy bones and teeth. Deficiency of phosphorus results in bone diseases, impacted appetite, reduced muscle strength and coordination. Anemia, infection risk, burning/prickling sensations in skin and confusion are some other outcomes of low phosphorus in the body.
Food sources include dairy products, salmon, cashews and lentils.
Magnesium plays an important role in muscle and nerve function. This vital mineral regulates blood pressure and blood sugar levels, and also helps the body in making proteins, bone and DNA. Deficiency of magnesium can lead to problems like nausea, weakness, tiredness, restless legs, sleep disorder and other health issues. Excess of this mineral in the body can result in digestive and heart problems.
Food sources include nuts, spinach, and beans.
Zinc has an important role in the health of cells, immune system, wound healing, and in formation of proteins. Low levels of zinc can lead to skin sores, hair loss, altered taste or smell and in rare cases, diarrhea. Excess zinc in the body leads to headaches and digestive problems.
Food sources include beef, oysters and fortified breakfast cereals.
Manganese is used by the body to produce energy. It has an important role in blood clotting and supports the immune system. Deficiency of manganese causes weak bones in children, skin rashes in men, and women are known to experience mood changes. Excess manganese leads to health problems like muscle spasms, tremors and other issues.
Food sources of manganese are hazelnuts, mussels, brown rice, spinach and chickpeas.
Copper enables the body to produce energy, create connective tissues and form blood vessels. Low levels of copper results into high cholesterol, tiredness, patchy skin, and connective tissue disorders in rare cases. Excess copper in the body leads to health conditions like liver damage, diarrhea, abdominal pain and nausea. It may also hamper the absorption of zinc.
Food sources include beef liver, oysters, mushrooms, potatoes and sunflower & sesame seeds.
Selenium has an important role in reproductive and thyroid health of the body. It’s an antioxidant that can prevent cell damage. Too low quantity of this mineral may lead to heart disease, arthritis or infertility in men. Excess selenium results into health problems like diarrhea, skin rashes, irritability, garlic breath, brittle hair or nails, and other issues.
Food sources include Tuna, ham, Brazil nuts, spinach, oatmeal and baked beans.
A balanced diet, comprising of a variety of food, is sufficient to provide the mineral requirements of the body. In case of deficiency, supplements can be taken after consulting a doctor.
Balanced diet comprising of a variety of food products is the best way to stay healthy and fit.