Glossary of Terms & Definitions
Listed Alphabetically - "O"

Obesity: Body weight more than 20% above a desirable standard do to excessive accumulation of fat.

Oblique: A plane that passes through the body or an organ at an angle between the transverse plane an either the midsagittal, parasagittal, or frontal plane.

Observational study: A study in which no experimental intervention or treatment is applied. Participants are simply observed over time.

One-carbon unit: A biochemical term for functional groups containing only one carbon in addition to other atoms. One-carbon units transferred by folate coenzymes include methyl (-CH3), methylene (-CH2-), fomyl (-CH=O), formimino (-CH=NH), and methenyl (-CH=).  Many biosynthetic reactions involve the addition of a one-carbon unit to a precursor molecule.

Optimum health: In addition to freedom from disease, the ability of an individual to function physically and mentally at his or her best.

Organic: Refers to carbon-containing compounds, generally synthesized by living organisms.

Osteoarthritis: A degenerative joint condition that is characterized by the breakdown of articular cartilage (cartilage within the joint). Symptoms of osteoarthritis include pain and stiffness in the affected joint(s), particularly after activity.

Osteoblasts: Cells associated with bone that are responsible for the new formation of bone in the bone remodeling process.

Osteoclasts: Cells associated with bone that are responsible for the breakdown or resorption of bone.  Bone remodeling is a continuous process of resorption and  formation.

Osteomalacia: A disease of adults that is characterized by softening of the bones due to loss of bone mineral. Osteomalacia is characteristic of vitamin D deficiency in adults, while children with vitamin D deficiency suffer from rickets.

Osteoporosis: A condition of increased bone fragility and susceptibility to bone fracture due to a loss of bone mineral density (BMD)

Oxidation: A chemical reaction that removes electrons from an atom or molecule.

Oxidative stress: An organism is said to experience oxidative stress when the effects of prooxidants (e.g. free radicals, reactive oxygen and reactive nitrogen species) exceed the ability of antioxidant systems to neutralize them.