Nutrients

• The foods we eat are made up of different components that we call nutrients.

• These nutrients are divided into two categories:

  • Macronutrients make up the largest part of the food we eat and supply us with the energy we need for daily life and physical exercise.

  • Micronutrients are found in small amounts in food.

    • They include vitamins and minerals, which help in energy transfer and tissue synthesis.

Carbohydrates, Proteins, and Fats

• Macronutrients are the human body’s direct sources of energy:

  • Carbohydrates → 4 Calories per gram (kilocalories)

  • Proteins → 4 Calories per gram (kilocalories)

  • Fats → 9 Calories per gram (kilocalories)

• Macronutrients supply us with the energy we need for daily life and physical exercise.

Vitamins and Minerals

• Micronutrients act as co-agents in the bioenergetic process.

  • They do not provide energy themselves but rather play an indispensable role in helping the body’s metabolic processes along.

• Vitamins help to regulate metabolic reactions in the body, in contrast to other dietary components which are utilized in the reactions.

  • Ex: Fats, Carbohydrates, and Proteins

• Minerals are inorganic substances needed by the body for good health.

  • Besides helping the body get energy from macronutrients, minerals help produce bones, proteins, and blood.

  • Ex: Iron

Classifying Carbohydrates (“Carbs”)

• Carbohydrates are divided into two main types:

  • Simple (Sugars) → Are digested and absorbed much more rapidly than complex carbohydrates and can cause large swings in our blood sugar levels.

    • Ex: Table Sugar, Soft Drinks, Fruit Juices, Honey, Processed Foods, and Junk Foods.

  • Complex (Starches) → Are digested and absorbed more slowly than simple carbohydrates.

    • As an added benefit, foods containing complex carbohydrates often contain many of the vitamins, minerals, proteins, and fibre that our bodies need.

The Glycemic Index

• The blood sugar (or blood glucose) level refers to the concentration of glucose (sugar) present in the blood.

  • The body tightly regulates blood glucose levels.

• The Glycemic Index is a measure that we can use to help us understand how foods will affect our blood sugar when we eat them.

  • This index indicates the rate of carbohydrate digestion and its effects on blood glucose levels.

“Empty Calories”

• Refined sugars provide calories, but lack vitamins, minerals, and fibre.

  • For this reason, they are often called “Empty Calories.”

    • The extra calories are converted to fat and stored in the body as fat tissue.

• Complex carbohydrates, such as fruits, grains, and vegetables, are considerably better for us.

Proteins: Essential “Building Blocks”

• Proteins are molecules that make up a large portion of our body and they are involved in virtually all of our body’s cellular functions.

  • They are essential nutrients and the building blocks of body tissue.

• The average adult body consists of 10 to 12 kg of proteins, which are mostly found in our muscles.

  • Proteins are directly involved in the fundamental chemical processes of life and they play important roles in how our bodies move and function.

  • Proteins can also serve as a fuel source (4 kilocalories per gram)

Amino Acids

• Proteins are species-specific and organ-specific

  • Within a single organism, muscle proteins differ from those of the brain or liver.

• When we eat foods that contain proteins, the body digests them and breaks them down into individual amino acids or small clusters of Amino Acids known as Peptides.

• Amino acids are the building blocks of proteins.

  • Twenty different amino acids are used to create the more than 50,000 proteins found in the body.

• Essential Amino Acids → 9 amino acids must be supplied by the foods we eat

• Non-Essential Amino Acids → Our bodies can produce the other 11 amino acids

Daily Protein Requirements

• Daily protein requirements differ from individual to individual, depending on the energy demands placed on each person’s body.

Dietary Fat: The Good and the Bad

• Dietary fat is important for our overall health, but some types of fat should be limited.

• There are four types of fat, in two broad groups:

  • Unsaturated Fats:

    • Mono-Unsaturated

    • Polyunsaturated Fats

      • “Good” Fats

  • Saturated Fats:

    • Saturated

    • Trans Fats

      • “Bad” Fats

The Unhealthiest Fat of All

• Nutritionists all agree that the worst type of dietary fat is the kind known as trans fat.

  • Trans fat results from a process called hydrogenation.

    • This process turns oils into solids.

    • It also makes healthy vegetable oils behave more like saturated fats.

• On food label ingredient lists, this manufactured substance is often listed, somewhat innocuously, as “partially hydrogenated oil.”

Staving off Heart Disease

• Diets high in saturated fats have been linked to heart disease and vascular disease, leading to an increased risk of heart attacks and strokes.

  • Diets rich in unsaturated fats are not believed to increase the risk of heart and vascular disease, as there appears to be less fat deposited in the coronary arteries.

    • Nutrition experts now recommend that we replace saturated fats (and trans fats) in our diet with mono- and polyunsaturated fats.