Nutrition

What is nutrition?

Nutrition is the process of eating and absorbing food that your body needs for nourishment. It involves breaking down food into nutrients. Nutrients are chemical substances your body needs to function. But this essential process does much more than that. For example:

• Research shows proper nutrition can reduce your risk for diabetes, heart disease and stroke
• It supports the healing process whether you’re recovering from surgery, a cold or a case of stomach flu
• Experts are exploring the influence that nutrition may have on mental health

In other words, there’s more to nutrition than may meet the eye. Taking a closer look at nutrition may help you understand how it works. That may make you feel confident that you’re making the most of what you eat.

What are nutrients?

There are six major classes of nutrients. Eating well is a balancing act that combines all six. The nutrients in the food you eat benefit your body in different ways.

Macronutrients provide energy and keep your body working. Micronutrients are vitamins and minerals. They support your metabolism, among other functions. Water rounds out the list of essential nutrients. It supports nutrition in many ways, like carrying nutrients and oxygen to your cells.

Macronutrients

If your body was a building, macronutrients would be the foundation. Macronutrients are your main source of energy. Macronutrients are:

• Carbohydrates like sugars, starches and fiber, which are the main source of energy powering your body
• Lipids — which are in fats, oils, meat, dairy and other foods — do many things like storing energy and digesting fat
• Proteins, which help to build and repair muscle, as well as regulate hormones

Micronutrients

Micronutrients include essential vitamins and minerals. You need fewer micronutrients than macronutrients, but they’re still very important.

Vitamins are substances that animals and plants make. The food you eat is your main source of most vitamins. Many people take a multivitamin to make sure they’re getting all the vitamins they need. You may recognize some vitamin names, like vitamin A, vitamin C or vitamin D. Others may not be so familiar. But they all contribute to your health. The following are essential vitamins:

• Vitamin A supports your immune system, metabolism and vision.
• Vitamins B1 – 12 all help your body turn food into energy. They also support your blood vessels, brain, immune system and nervous system.
• Vitamin C supports your body in many ways. It helps your body grow tissue. It can also heal wounds and strengthen your immune system.
• Vitamin D partners with calcium to build and maintain healthy bones. Vitamin D also supports brain health and your immune system.
• Vitamin E helps to protect your cells. It also helps to maintain the health of your red blood cells, white blood cells and platelets. This vitamin also supports your brain, eyes and skin.
• Vitamin K helps your blood to clot and prevents excessive bleeding.

Minerals make their way into food via the animals that eat them and the plants that absorb them. Animals and plants provide minerals. These substances support your health in many ways. The following minerals are micronutrients:

• Calcium builds strong bones. It also supports your heart, muscles and nervous system.
• Chromium helps your body metabolize (process) carbohydrates and fats.
• Copper supports brain development, your immune system and your nervous system.
• Fluoride helps to keep your bones strong and to prevent tooth decay.
• Iodine promotes brain development, thyroid health and more.
• Iron helps your body make hemoglobin, a protein in red blood cells.
• Magnesium makes new proteins and helps to convert food into energy.
• Manganese protects your cells from damage and helps your body make energy.
• Phosphorus builds and maintains strong bones and teeth, produces energy and repairs cells.
• Potassium helps to prevent high blood pressure. It also supports muscle health.
• Selenium supports thyroid health and reproductive health.
• Sodium helps cells absorb nutrients. It helps muscle and nerve functions.
• Zinc boosts your immune system and protects your vision.

Food Groups

The long list of macronutrients and micronutrients come together in the five food groups that make up the balanced meals you need to have good nutrition:

• Dairy
• Fruit
• Grains
• Protein
• Vegetables

How nutrition needs change

Getting nutrition right is a balancing act that changes throughout your lifetime. Babies, kids, adults and older adults have very different nutritional needs. For example, breast milk or formula meets most babies’ nutritional needs until they’re six months old. But adults and older adults typically need a different combination of nutrients.

Nutrition for kids of all ages

Breast milk or formula meets most babies’ nutritional needs for the first six months. At six months, you can start adding solid food to the mix. It can be challenging to figure out which mix of solid food gives your baby the best possible nutritional boost. Ask your baby’s pediatrician for suggestions for your baby’s introduction to solid food.

The nutritional balancing act continues as your baby grows. In general, meals that include the five food groups give toddlers and children the right combination of macronutrients and micronutrients.

Nutrition for adults

Building meals from the five food groups still works for adults. But males and females benefit by having a different mix of macronutrients and micronutrients. Here are two examples:

• Females typically need more iron than males. That’s because females lose iron through blood loss during menstruation. Pregnancy and childbirth can cause iron-deficiency anemia.
• Males need a bit more vitamin B5 than females. Vitamin B5 supports muscle mass, among other things. Males typically have more muscle mass than females.

The nutrient picture changes as we age. Medication or medical conditions may affect your appetite. When you eat less, you miss out on essential nutrients. People age 65 and older may benefit by focusing on foods that boost vitamin D and calcium for strong bones.

Medical conditions that affect nutrition

There are medical conditions that affect nutrition regardless of your age. For example:

• Cancer cachexia happens when cancer speeds up your metabolism, so your body uses more energy than you get from food
• Depression can cause you to lose interest in planning and eating nutritious meals
• Dysphagia (difficulty swallowing) can make it hard for you to eat certain foods, which increases the chance you’ll miss out on getting certain nutrients
• Malabsorption syndrome refers to conditions that keep your body from absorbing nutrients

Conditions that affect nutrition can lead to macronutrient and micronutrient undernutrition. These are types of malnutrition. They can cause serious complications:

• Macronutrient undernutrition means you don’t get enough protein, carbohydrates or fats. Your body needs macronutrients for energy. When you don’t get enough macronutrients, your body starts conserving energy. It does that by breaking down tissue or slowing organ function.
• Micronutrient undernutrition is when you have a serious vitamin or mineral deficiency. For example, a lack of iron can lead to iron-deficiency anemia.

What’s the difference between calories and nutrients?

They’re both a way to keep track of what you eat. Calories are a unit of energy. They measure how much energy food provides your body. Nutrients are essential chemical substances your body needs to function and can have different calories (for example, lipids have more calories than carbohydrates).

Who can help me with nutrition questions?

A registered dietitian (RD) is probably your best source of information about nutrients. They’ll discuss your needs, explain how specific nutrients may be helpful and how to build nutrients into a meal plan.