An observational study is a study in which a researcher observes behaviour in a structured manner, without actually being able to influence or interfere with the behaviour. Like with experiments, observational studies attempt to find the cause and effect relationship. Cohort studies and case-control studies are two main types of observational studies that help to evaluate associations.
The oesophagus is the passage in the body where food passes from the pharynx to the stomach, aided by peristalsis - muscle contractions through the digestive tract.
Omega-3 is a type of polyunsaturated essential fatty acid which cannot be made by the body therefore we rely on dietary sources for our required intake. Omega-3s are needed for many of the body’s processes, and are important for brain and heart health. They are made up of 3 types of fat known as EPA (Eicosapentaenoic acid), DHA (Docosahexaenoic acid) and ALA (Alpha Linolenic acid). EPA and DHA can be found in fish and some plants oils, and ALA is found only in plant oils.
Oxidative stress is the imbalance between the speed of production of free radicals (an oxygen-containing molecule that is very reactive with other molecules), and the body’s ability to counteract the harmful effects of these by producing protective antioxidants.