PREVIOUS YEAR QUESTIONS | FOOD SCIENCE & NUTRITION | L-32|

Dietary fiber, also known as roughage, is the indigestible part of plant foods.

Fiber is mostly in vegetables, fruits, whole grains, and legumes. There are two types of fiber — soluble and insoluble — and both play important roles in health:

Insoluble fiber does not dissolve in water and adds bulk to the stool, preventing constipation.

Soluble fiber absorbs water, forming a gel-like substance in the digestive system. Soluble fiber may help lower cholesterol levels and help regulate blood sugar levels.

This article looks at the different types of fiber, why they are important, and suggests some healthful fiber-rich foods.

Dietary fiber is an essential part of a healthful diet. It is crucial for keeping the gut healthy and reducing the risk of chronic health conditions.

Most people in the United States do not get enough fiber from their diets. According to some estimates, only 5% of the population meet the adequate intake recommendations. This means that most people in the U.S. could get health benefits from increasing their daily fiber intake.

Eating fiber has many health benefits:

Protection against heart disease

Several studies over the past several decades have examined dietary fiber’s effect on heart health, including preventing cardiovascular disease and reducing blood pressure.

Types of Proteins

There is a total of seven different protein types under which all proteins fall. These include antibodies, contractile proteins, enzymes, hormonal proteins, structural proteins, storage proteins, and transport proteins.

Antibodies: Antibodies are specialized proteins that defend the body against antigens or foreign invaders.

Contractile Proteins: Contractile proteins are responsible for muscle contraction and movement, see Molecular Motors).

The cytoplasm of cells is a colloidal network of contractile proteins. Actin filaments are the major components of this network. See Muscle Cells (Myocyte)

Enzyme activation energy

Enzymes: All enzymes identified thus far are proteins.

Enzymes, which are the catalysts of all metabolic reactions, enable an organism to build up the chemical substances necessary for life—proteins, nucleic acids, carbohydrates, and lipids—to convert them into other substances, and to degrade them.

Life without enzymes is not possible.

Hormonal Proteins: Hormonal proteins are messenger proteins that help coordinate certain bodily functions.eg:

Growth factors are highly specific proteins, a subdivision of cytokines. Growth factors stimulate the division and differentiation of a particular type of cell. In skeletal muscle hypertrophy, growth factors include insulin-like growth factor (IGF). IGF is secreted by skeletal muscle. It regulates insulin metabolism and stimulates protein synthesis..

Testosterone is an androgen, or a male sex hormone. The primary physiological role of androgens are to promote the growth and development of male organs and characteristics. Testosterone affects the nervous system, skeletal muscle, bone marrow, skin, hair and the sex organs.

Cortisol is a steroid hormone (hormones which have a steroid nucleus that can pass through a cell membrane without a receptor) which is produced in the adrenal cortex of the kidney. It is a stress hormone.

The most common example of a structural protein is collagen which is found in the bones, cells and skin.

Structural proteins are also found in cells. They are used to provide an internal structure to the cell (the cytoskeleton) and are sometimes involved in cell movement. Structural proteins are especially important in larger cells.

Storage Proteins: Storage proteins reserve amino acids for the body until ready for use. Examples of storage proteins include

Ferritin a storage protein that stores iron.

Membrane proteins

Transport Proteins: Transport proteins are carrier proteins that move molecules from one place to another in the body.

The respiratory protein hemoglobin acts as oxygen carrier in the blood, transporting oxygen from the lung to body organs and tissues.

Cytochromes, another type of transport protein, operate in the electron transport chain as electron carrier proteins.