Find explanations for key health and nutrition terms.
Any substance foreign to the body that evokes an immune response.
Compounds in foods and beverages that can help protect healthy cells from the damaging effects of oxidative stress, a condition which has been implicated in a number of long-term health problems. Antioxidants neutralize free radicals by donating electrons, preventing them from stealing electrons from stable molecules. Vitamins C, E and A (as beta-carotene), and the mineral selenium, as well as certain phytonutrients (such as polyphenols) can act as antioxidants.
A state of relaxed and expanded arteries.
A slow, progressive condition in which the artery walls thicken and harden, and may eventually block passage from plaque collection. This accumulation occurs with elevated cholesterol, especially LDL cholesterol (or “bad” cholesterol), with subsequent chronic inflammation. Complications from a reduction in blood flow and decreased oxygen include coronary heart disease and stroke.
Also referred to as medical research, it involves any research activities conducted to aid and support the field of medicine.
Measurement based on a person’s weight and height (kg/m2) and considered a reliable indicator of body fatness. A BMI of 18.5-24.9 is considered within normal range. A person with a BMI less than 18.5 is considered underweight whereas a person with a BMI of 25.0-29.9 is considered overweight. A BMI of 30 or greater is considered obese.
Disease affecting the heart or blood vessels including coronary heart disease, stroke, congestive heart failure, hypertension, and coronary artery disease and other arterial disorders. Often, atherosclerosis is the underlying disease process.
An important structural component of cell membranes in the human body. Cholesterol is transported in blood plasma by lipoproteins (LDL, HDL) and is involved in making bile acids (for lipid absorption), steroid hormones, and fat-soluble vitamins (including vitamin D).
Any mental process that involves symbolic operations, such as perception, memory, creation of imagery, and thinking, as well as awareness and capacity for judgment.
Hearty American grape with a thick, dark purple skin and seeds that naturally contain phytonutrients called polyphenols. Seedless grapes, like red table grapes, do not appear to contain the same quantity of these polyphenols. Concord grapes are one variety of Vitis labrusca. Concords are different from European wine grapes, Vitis vinifera, such as Cabernet and Chardonnay.
A protein found in the blood, the levels of which rises in response to inflammation.
Used by the Food and Drug Administration in food labeling, the daily nutrient intake recommendations to meet the needs of most of the population, based on the Reference Daily Intakes and Daily Reference Values.
These are naturally occurring compounds that comprise the largest and most studied sub-group of polyphenols. This group also includes the majority of phytonutrients found in the skins and seeds of Concord and Niagara grapes. There are thousands of different flavonoids found in nature and fruits, vegetables, and plant-derived beverages (e.g., wine, grape juice, tea) contain many different types. Several of these biologically active compounds help to protect the plant from disease and damage and they are being actively studied to determine their potential role in human health. Sub-classes of flavonoids include flavonols, like quercetin, flavanols, like proanthocyanidins, and anthocyanins.
A non-invasive measure used to assess endothelial function (the function of cells lining blood vessels) by determining the ability of an artery (blood vessel carrying blood away from the heart) to relax and dilate in a situation of increased blood flow.
Atoms or groups of atoms that have one or more unpaired electrons. They are a normal part of everyday life, and are produced during activities like exercising or digestion (when our bodies convert food into energy). Free radicals are highly reactive, but our bodies have a natural defense system – so in small numbers, they are not a big problem. However, exposure to certain environmental factors like pollution and UV radiation can also result in the formation of free radicals. And, when there are too many free radicals for our bodies to protect against, they can set off a chain reaction, which in turn can result in oxidative stress.
A term used to describe the surprisingly low incidence of heart disease among the French despite their typically high saturated fat diets.
Often called the “silent killer” because there are few symptoms, high blood pressure is measured in millimeters of mercury (mmHg) and given as two numbers, systolic (pressure created from a beating heart) over diastolic pressures (pressure inside blood vessels when the heart is at rest). Hypertension is positively related to the risk for cardiovascular events and is clinically classified by stages (normal, prehypertension, Stage 1 and Stage 2 hypertension). Blood pressure at > 140/90 mmHg is classified as Stage 1 hypertension.
A system of layered biological processes, which assist in protecting against infection and disease by identifying foreign substances such as pathogens or tumor cells and destroying them.
Part of the complex biological response to injury resulting from pathogens, irritants, or trauma, inflammation can be classified as acute or chronic. Acute inflammation is a short-term response and is critical for protecting the human body and maintaining health. Chronic inflammation arises when this inflammatory response persists and it has been linked to certain chronic health problems (e.g., cardiovascular disease).
One of the five major groups of lipoproteins that enable lipids, like cholesterol to be transported in the bloodstream. LDL is often referred to as the “bad” cholesterol because elevated values (> 100 mg/dL) are associated with increased risk of cardiovascular disease.
Essential nutrients that the body needs in large quantities, like carbohydrates, fats, and proteins.
A group of metabolic factors that increase one’s risk for cardiovascular disease, stroke, and Type 2 diabetes. These include elevated waist circumference, triglycerides, blood pressure and fasting glucose as well as reduced high density lipoprotein (HDL) levels.
Generally refers to small molecules that are the intermediates and end products of metabolism.
Essential nutrients that the body needs in small quantities, like vitamins, minerals, and trace elements.
A white, seeded grape that, like its cousin the Concord, contains natural phytonutrients. Seedless grapes, like green table grapes, do not appear to contain the same quantity of phytonutrients. Niagara grapes are a variety of Vitis labrusca grapes, which is the same genus and species as Concords.
A molecule produced in many cells of the body and involved in many metabolic reactions. Important to cardiovascular health, when NO is released by the endothelial cells of the arteries, it helps them relax and wider arteries allow for greater blood flow.
A common test tube measure used to measure the antioxidant potential or power of certain foods and beverages. A higher ORAC score means more antioxidant power. ORAC measures antioxidant power in a laboratory and does not test antioxidant activity or health effects within the body.
A condition causing damage to healthy cells as a result of an abundance of free radicals (or reactive oxygen species). It has been identified as a possible factor in causing some chronic health problems.
Plant-based nutrients (phyto = plant) that appear to have health-promoting effects, but are not considered essential for human survival. Foods containing phytonutrients include fruits (like Concord and Niagara grapes), vegetables, legumes, whole grains, nuts and tea. Polyphenols, including flavonoids (e.g., flavonols, flavanols, flavanones, flavones, isoflavones, anthocyanins), phenolic acids, and stilbenes, comprise one group of phytonutrients.
The clumping together of platelets in the blood; part of the sequence of events leading to the formation of a thrombus (clot).
This sub-group of phytonutrients is found in a variety of foods, including grapes and grape juice, onions, tea, red wine, blueberries and certain nuts. They are often concentrated in the skins of fruits, and act as a protector from pathogens, parasites, and predators – in addition to contributing to the flavor and color of fruits and vegetables. Research is currently investigating whether these plant-based nutrients can also protect the health of humans.
Synonymous with free radicals, at low levels these chemically reactive molecules contribute positively to regulating cellular processes and gene expression. At higher levels they may cause oxidative damage to nucleic acids (such as RNA and DNA), proteins, and lipids and participate in apoptosis (programmed cell death).
This natural compound is a protector of plants that is sometimes found in the skins of deep-purple Concord grapes. This phytonutrient falls under the polyphenol sub-group of stilbenes. Optimal conditions for development of this phytonutrient include a cool and wet climate, without excessive sunshine; thus, the resveratrol content varies by grape cultivar, geographic location, and exposure to fungal infections. In early laboratory studies, this phytonutrient shows promise in supporting certain aspects of health, including cardioprotective effects and promoting immune health. Scientists became interested in studying resveratrol as part of the possible link to the French Paradox.
A measure that looks at the antioxidant function of certain elements found in the blood. This analysis is often done after the subject consumes a food or beverage with known antioxidant power.
Guide to Navigating Research Studies
The definition of scientific research is performing a methodical study in order to prove a theory or answer a question. The following is a brief overview of different types of research used in health and nutrition exploration 1:
1. Hulley SB, Cummings SR, Browner WS, Grady D, Hearst N, Newman TB. Designing Clinical Research: An Epidemiologic Approach. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2007.
An observational study, usually a retrospective study (a study that looks backward in time) that compares two groups of people: 1) those with the specific condition (e.g., disease) being studied (cases) and, 2) a similar group of people without that condition (controls). Researchers compare these two groups of people and important characteristics, such as certain lifestyle choices, to determine what factors may be associated with the condition under investigation.
A type of study that often includes patients with specific health conditions who could benefit from receiving a new treatment. These studies can also be performed in healthy subjects. The end goal of a clinical study (also called clinical research or clinical trial) is to determine effectiveness and safety of a health intervention in humans.
An observational study, usually prospective (looking forward), that follows a group of similar people over time. The goal is to determine which factors and exposures affect the development of a specific outcome or health condition (e.g., disease) during the study’s time period.
A type of observational study, often given as a survey, that examines a group of subjects during a single occasion, or over a very short period of time. This type of study aims to describe the relationship between health-related conditions (e.g., metabolic syndrome, hypertension) and other factors that exist in the general population (e.g., dietary intake, physical activity levels), during a particular time period.
A type of study in which researchers simply observe subjects and measure the associations between certain characteristics (e.g., fruit/vegetable intake) and specific outcomes (e.g., obesity). Examples of observational studies include case-control studies, cross-sectional studies, and cohort studies. While these studies gather important information, they cannot prove that a specific treatment or factor affects health.
A small scale, preliminary study that is conducted to determine the potential for a larger study.
A stage of research that often occurs prior to trials involving humans. This type of research can help determine mechanisms of action of a treatment, or how the treatment is causing the effect, as well as help ensure the safety of treatment in subsequent human trials.
Testing performed in a controlled environment, such as a test tube or a Petri dish, instead of living organisms. In vitro literally means "within the glass" in Latin.
These experiments are performed on tissue (e.g., animal or human cells) taking place outside of the organism, such as in a laboratory setting. In Latin, this means "out of the living."
These tests are done on whole, living organisms. Technically, animal and human testing are two forms of in vivo research, which means "within the living." These experiments may be performed outside of a laboratory setting.
A study designed to provide the most credible information about the cause and effects of treatment. These types of studies are recognized as unbiased because they involve the random assignment of treatments to subjects being studied.
The tendency throughout any stage of research to generate findings that may not reflect "true values." In clinical trials, researchers try to avoid many kinds of bias, including selection by randomizing subjects, measurement by creating placebos and performing blind trials, and confounding by carefully designing the study and analyzing the findings.
Study in which subjects do not know whether they receive the treatment or the placebo, which assists in prevention of bias. Double-blinded studies are a higher level of scientific rigor because neither the participants nor the investigators know who is receiving the treatment or the placebo. A double-blind crossover study means each participant undergoes both the treatment and control scenario, typically with a wash-out period in between.
Study that allows researchers to isolate the effect size of the treatment by comparing a group given a simulated treatment (e.g., grape flavored drink) to those with the real treatment (e.g., Concord grape juice), which reduces measurement bias. The placebo should match as closely as possible to the treatment without containing the active ingredients.
Study involving participants who are randomly assigned to either the treatment or the placebo group, reducing selection bias.