Omega-3 and Omega-6 Fatty acids

Fatty acids are organic compounds composed of carbon chains of varying lengths, with an acid group on one end and hydrogen bound to all the carbons of the chain. Essential fatty acids (EFAs) are those that are necessary for health, but cannot be synthesized by the body.

Oral Health

Oral tissues, such as the gingiva (gums), teeth, and muscles of mastication (chewing muscles), are living tissues, and they have the same nutritional requirements as any other living tissue in the body. When adequate, nutritious food is not available, oral health may be compromised by nutrient-deficiency diseases, such as scurvy.

Oral Rehydration Therapy

Oral rehydration therapy (ORT) involves the replacement of fluids and electrolytes lost during an episode of diarrheal illness. Diarrheal illnesses are pervasive worldwide, and they have a particularly large impact in the developing world.

Organic Foods

In response to a need to standardize the use of such terms as organic and natural, the U.S. Congress passed the Organic Foods Production Act of 1990, which established the U.S.

Organisms, Food-Borne

Food-borne organisms are bacteria, viruses, and parasites that can cause illnesses which are either infectious or toxic in nature. They enter the body through the ingestion of contaminated food or water.


Osteomalacia is a disease in which insufficient mineralization leads to a softening of the bones. Usually, this is caused by a deficiency of vitamin D, which reduces bone formation by altering calcium and phosphorus metabolism.


Osteopenia is defined as the stage of low bone density that precedes osteoporosis. At this stage, bone density is below average but not as low as occurs with osteoporosis.


Osteoporosis, which is characterized by a decrease in the mass of otherwise normal bone is the most common metabolic bone disease. Normal bone is made of a hard outer shell (the cortex) and an inner network of spicules (fibers), called trabeculae, that give bone its characteristic strength.


The term overweight is used to describe an excess amount of total body weight including all tissues (fat, bone, muscle, etc.) and water. Obesity, in contrast, is an excess amount of body fat.

Pacific Islander Americans, Diet of

The Pacific Islands contain 789 habitable islands and are divided into the three geographic areas: Polynesia, Melanesia, and Micronesia. According to the 2000 U.S.

Pacific Islanders, Diet of

The Pacific Ocean—the world's largest ocean—extends about 20,000 kilometers from Singapore to Panama. There are 789 habitable islands within the "Pacific Islands," a geographic area in the western Pacific comprising Polynesia, Melanesia, and Micronesia.


Pasteurization, a process discovered by Louis Pasteur (while trying to inactivate spoilage organisms in beer and wine), occurs when a product is heated to a specific temperature for a specified length of time. This process is now applied to a wide array of food products, such as milk, fruit juice, cheese, and water.


Pellegra is a disease caused by a dietary deficiency of, or a failure to absorb, niacin (vitamin B3) or the amino acid tryptophan, a precursor of niacin. First reported in 1735 by Don Gasper Casal, a Spanish physician, pellagra means "rough skin." Primary symptoms include the "3 Ds": dementia (mental symptoms), dermatitis (scaly skin sores), and diarrhea.


Pesticide use is widespread in agriculture throughout the world, raising serious questions about the dangers theses substances pose to human health and the environment. Pesticides are substances intended to prevent, destroy, or repel injurious plants or animals.

Phenylketonuria (PKU)

Phenylketonuria (fee-nyl-key-ton-uria), or PKU, is an inherited metabolic disease that results in severe developmental delay and neurological problems when treatment is not started very early and maintained throughout life. The disease is caused by the absence of the enzyme phenylalanine hydroxylase, which normally converts the amino acid phenylalanine to another amino acid, tyrosine.


Phytochemicals are naturally occurring chemicals in plants that provide flavor, color, texture, and smell. Phytochemicals have potential health effects, as they may boost enzyme production or activity, which may, in turn, block carcinogens, suppress malignant cells, or interfere with processes that can cause heart disease and stroke.


Pica is defined as a compulsion to consume nonfood substances. Persons with pica crave items such as dirt, clay, paint chips, plaster, chalk, cornstarch, laundry starch, baking soda, coffee grounds, cigarette ashes, burnt match heads, cigarette butts, and rust.

Plant-Based Diets

Plant-based diets are comprised of meals made predominately from a variety of vegetables, fruits, grains, beans, and nuts, with minimal amounts of processed foods. Many professional organizations recommend a plant-based diet to help prevent chronic diseases such as cancer, heart disease, and obesity.

Popular Culture, Food and

Food is very much a part of popular culture, and the beliefs, practices, and trends in a culture affect its eating practices. Popular culture includes the ideas and objects generated by a society, including commercial, political, media, and other systems, as well as the impact of these ideas and objects on society.