In nutrition, the process of moving nutrients (protein, carbohydrates, fats) and micronutrients (e.g., vitamins and carotenoids) from the digestive system into the bloodstream. Most (micro)nutrients are absorbed in the small intestine.

Defines a daily dietary intake level for a nutrient sufficient to meet the requirements. However, the amount established is somewhat less firmly believed to be adequate for everyone in the demographic group than the Recommended Daily Allowance (RDA). An AI is set when no RDA has been established.

A medical condition, usually of older adults, which results in a loss of vision in the center of the visual field (macula) because of damage to the light sensitive tissue lining the inner surface of the eye (retina).

The most common cause of dementia in older adults. Symptoms include memory loss and confusion, which worsen over time. Alzheimer’s disease is characterized by the formation of amyloid plaque in the brain and nerve cell degeneration. The brain is particularly vulnerable to oxidative stress, which is thought to play a role in the pathology of neurodegenerative diseases like Alzheimer's disease.

Organic compounds (e.g., NH₂CH₃) that are derivatives of ammonia (NH₃), wherein one or more hydrogen (H) atoms have been replaced by an atom (group) such as an alkyl group (CH₃).

The condition of having less than the normal number of red blood cells or hemoglobin in the blood, resulting in diminished oxygen transport. Anemia has many causes, such as iron, vitamin B12, or vitamin B9 deficiency.

Pain generally experienced in the chest, but sometimes radiating to the arms or jaw, due to a lack of oxygen supply to the heart muscle.

Antioxidant substances, such as vitamins and carotenoids, are thought to protect the body against the destructive effects of free radicals. Antioxidants neutralize free radicals by donating one of their own electrons, ending the electron-"stealing" reaction. They act as scavengers, helping to prevent cell and tissue damage that could lead to cardiovascular disease and cancer.

Oxidation of low-density lipoprotein (LDL) cholesterol is important in the development of fatty build-ups in the arteries (see Atherosclerosis). Antioxidant substances, such as vitamins and carotenoids, can potentially prevent LDL oxidation and its harmful effects.

A chronic inflammatory disease of the airways, characterized by recurrent episodes of reversible airflow obstruction.

Atherosclerosis is a condition in which the wall of arterial blood vessels thickens as the result of a build up of fatty materials ─ so-called plaques. If a plaque suddenly ruptures it can cause the formation of a clot (thrombus) that rapidly slows or stops blood flow, leading to death of the tissues fed by the artery. A thrombosis of a coronary artery can cause a myocardial infarction (heart attack) and a thrombosis of a brain artery can cause a stroke. Atherosclerosis of the blood vessels to the legs (peripheral artery disease) can lead to pain when walking.

The underlying cause of atherosclerosis is a chronic inflammatory response in the arteries leading to a hardening of the vessel walls. This process is promoted by the oxidation of low density lipoprotein (LDL) cholesterol through free radicals. Antioxidant nutrients can potentially protect the arterial wall against the damaging oxidative effects.

A nutritional balance study involves the measurement of the intake of a specific nutrient as well as the elimination of that nutrient in urine, feces, sweat, etc. If intake is greater than loss of a particular nutrient the individual is said to be in "positive balance." If intake is less than loss, an individual is said to be in "negative balance" for the nutrient of interest.

A balance study is useful for determining the amount of a nutrient that will prevent deficiency; however, it provides little information regarding the amount of a nutrient required for chronic disease prevention or optimum health.

The fraction of an administered compound that reaches the blood distribution network (heart, blood, and blood vessels) and is transported to site of action (target tissue).

The amount of mineral in a given area of bone. BMD is positively associated with bone strength and resistance to fracture. Measurements of BMD are used to diagnose osteoporosis.

Diseases affecting the heart and blood vessels, encompassing a number of conditions that result from atherosclerosis, including heart attack (myocardial infarction), congestive heart failure, and stroke.

The blood, heart, and blood vessels form the cardiovascular system.

A disorder that causes numbness, pain, and weakness of the hand and fingers due to compression of the median nerve at the wrist. It may result from repetitive stress injury of the wrist or from soft tissue swelling, which sometimes occurs with pregnancy or thyroid hormone deficiency (hypothyroidism).

(also known as anecdote, case history, or single case report)
Individual observations based on small numbers of subjects.

 
Case reports are considered to provide weak empirical evidence because the risk of bias is very high. Case reports may indicate areas for further research.

A study that compares retrospectively people with a specific disease or outcome of interest (cases) to people from the same population without that disease or outcome (controls), and which seeks to find associations between the outcome and prior exposure to a particular factor of interest (e.g., a micronutrient).

 
Due to the potential for many forms of bias (e.g., when selecting cases and controls or recalling nutrition behaviors) in this study type, case control studies provide relatively weak empirical evidence even when properly executed.

A process in which the rate (speed) of a chemical reaction is either increased (accelerated) or decreased (slowed down, inhibited) by a chemical substance known as catalyst. The catalyst, unlike other reagents that participate in the chemical reaction, is not consumed by the reaction itself and may participate in multiple chemical transformations.

A clouding of the lens of the eye, progressively impairing vision. Cataracts appear to be formed by protein oxidation in the lens of the eye; such oxidation may be prevented by antioxidants, such as vitamin A, vitamin C, vitamin E, and beta-carotene.