Chapter 1 : Introduction to Nutrition
Topics covered in this snack-sized chapter:
Nutrition is the science that deals with food composition and nourishment.
Knowledge of what to eat and in what quantities is a prerequisite to a healthy and happy life.
Nutrition science is the area of knowledge regarding the role of food in the maintenance of good health.
Food is anything solid or liquid, that when swallowed, does one or more of the following:
- Provides the body with the material from which it can produce heat or any form of energy.
- Provides material to allow growth, maintenance, repair or reproduction to proceed.
- Supplies substances, which normally regulate the production of energy or the process of growth, repair or reproduction.
Good nutrition requires a satisfactory diet, which is capable of supporting the individual consuming it in a state of good health by providing the desired nutrients in required amounts.
Good nutrition is vital to:
- Healthy growth and development of children and adolescents
Nutrition refers to the nurturing of our body, in our ability to keep it healthy and functioning as it is supposed to do.
Proper nutrition is the provision of healthy foods that will help the nourishment, growth, repair and strengthening of cells.
Proper diet and nutrition sustains life and is the cornerstone of healthy and happy living.
Good nutrition means getting enough macronutrients and micronutrients.
Macronutrients contain calories (energy):
- They include proteins, carbohydrates, and fats.
- They help provide energy and strength to the body.
Micronutrients include vitamins and minerals.
- They keep our cells working properly, but will not prevent weight loss.
Nutrition is the study of nutrients in food, how the body uses nutrients, and the relationship between diet, health and disease.
The nutrients known to be essential for human beings are:
Proteins are made up of smaller building blocks called amino acids.
The different amino acids that make up proteins are important for growth, tissue repair and replacement.
Carbohydrates are the main source of energy.
The most common and abundant form of carbohydrates are sugars, fibers, and starches.
Fats are also the body’s source of stored energy. They protect inner organs and act as an insulator for the human body to keep warm.
Fats help the body use some vitamins and keep the skin healthy.
Minerals are inorganic substances that are essential for the proper functioning of the body.
Humans need small amounts of about 14 minerals to maintain normal body function and good health.
Vitamins are complex organic substances, with zero caloric value and no appreciable weight in the body.
Vitamins are organic molecules that often serve as co-enzymes or parts of co-enzymes and therefore have catalytic functions.
Approximately 60% of the adult human body is composed of water.
Water is essential for normal body function as a vehicle for carrying other nutrients.
| Function
| Nutrients
|
| Provide Energy
| Carbohydrates
Proteins
Lipids
|
| Promote Growth and Development
| Proteins
Lipids
Vitamins
Minerals
Water
|
| Regulate Body Functions
| Proteins
Lipids
Vitamins
Minerals
Water
|
Dietary Reference Intakes (DRIs) provide the foundation for building a healthy diet by detailing human nutritional requirements, serving as standards for nutrient intake for healthy persons.
The Dietary Reference Intakes (DRIs
) are a comprehensive set of nutrient reference values for healthy populations that can be used for assessing and planning diets.
Establishing nutrient recommendations include the following DRI values:
- Estimated Average Requirement (EAR)
- Recommended Dietary Allowance (RDA)
- Tolerable Upper Limits (Upper Levels or ULs)
Estimated Average Requirement (EAR)
The EAR is the average daily intake of a nutrient that will meet the nutritional needs of half the individuals in the group.
E.g., vitamin C (females, 19 to 30y) = 60mg/d
Recommended Dietary Allowance (RDA)
The average daily dietary nutrient intake level that is sufficient to meet the nutrient requirements of nearly all (97.5%) healthy individuals in a particular life stage and sex group.
E.g., vitamin C (females, 19 to 30y) = 75mg/d
AI reflects the average daily amount of nutrient without an established RDA that appears to be sufficient.
Tolerable Upper Limits (Upper Levels or ULs)
The highest average daily nutrient intake level that is likely to pose no risk of adverse health effects to almost all individuals in the general population.
E.g., vitamin C (females, 19 to 30y) = 2000mg/d
Establishing Energy Recommendations include following DRI values:
- Estimated Energy Requirement (EER)
- Acceptable Macronutrient Distribution Ranges (AMDRs)
- Estimated Energy Requirement (EER)
Average energy intake required to maintain energy balance in healthy individuals based on sex, age, physical activity level, weight, and height.
- Acceptable Macronutrient Distribution Ranges (AMDRs)
The range of intakes of an energy source (e.g., carbohydrates, protein and fat) that is associated with a reduced risk of chronic disease yet can provide adequate amounts of essential nutrients.