Flower Sprout Image
Download this image | Download other images

Nutrients Dictionary

This is a guide to some of the terms that you will find used in the nutrient pages.


Vitamins are a group of compounds, required in minute amounts but are essential for good health. There are about 20 vitamins, most of which cannot be made by the body, and must therefore be obtained from the diet. Each vitamin performs one or several essential functions within the body. Vitamins can be divided into two groups, fat soluble vitamins (A,D,E,K) and water soluble (B complex and C). Water soluble vitamins are easily destroyed during processing, storage and the preparation and cooking of food. The fat soluble vitamins are less vulnerable to losses during cooking and processing. The body is capable of storing some vitamins (A, D, E, K and B12), the rest need to be provided by the diet on a regular basis. A well balanced diet, containing a wide variety of different foods will be able to provide all the vitamins and minerals you need.


Minerals are inorganic substances that perform a wide range of vital functions throughout the body. They are vital for building strong bones and teeth, controlling body fluids inside and outside cells, and turning the food we eat into energy.


Phytochemicals or ‘phytonutrients’ as they are sometimes called are naturally occurring compounds that plants produce to protect themselves against bacteria, viruses and fungi. Although they are not nutrients in the true sense of the word because they're not essential in the diet, they are biologically active and there is a growing amount of evidence to suggest that they can help protect against various types of cancer, heart disease, and chronic degenerative diseases like cataracts and arthritis.

A compound which protect cells against the damaging effects of free radicals. Vitamins C, E, beta-carotene and selenium along with many of the phytochemicals found in fruit and vegetables acts as antioxidants.

Free Radicals
Highly reactive molecules that can cause damage to cell walls and DNA (the genetic material found within cells). They are believed to be involved in the development of heart disease, some cancers and premature ageing. Free radicals are produced naturally in the course of everyday life but certain factors such as smoking tobacco, pollution and exposure to sunlight can accelerate their production.

Biologically active compounds found in many plants. There are literally thousands of different phytochemicals which are believed to help protect our bodies against disease ¢ many are antioxidants, others act as anti cancer agents or help boost the immune system. Fruit, vegetables, beans and pulses are rich sources of phytochemicals. The main groups of phytochemicals are:

  • Flavonoids - A growing number of studies suggest that members of this group help to protect against heart disease. Many are believed to have an anticancer effect.
  • Phytoestrogens - Believed to help protect against hormone related cancers such as breast and prostate cancer and may help relieve symptoms associated with the menopause.
  • Phenolic compounds - Studies suggest members of this group may help to keep the blood vessels healthy protecting against heart disease, stroke and circulatory problems.
  • Carotenoids - Members of this group are powerful antioxidants and are believed to help protect against cancer, heart disease and the eye disease age related macular degeneration.
  • Sulphur compounds - Believed to help lower high blood cholesterol levels and stimulate the immune system.
  • Fructoligosaccarides - Promote the growth of friendly bacteria in the colon.
  • Monoterpenes - Believed to boost the production of enzymes that help to inactivate carcinogens.
  • Saponins - May help to reduce blood cholesterol levels and inactive carcinogens in the digestive tract.
  • Glucosinolates - Believed to help inactive carcinogens by interfering with cancer cell replication and mobilising cancer-fighting enzymes in the body.

Reference Nutrient Intake (RNI)
Refer to the amount of a particular nutrient, which is sufficient to meet the nutritional needs of almost all individuals within the population. The figures are published by the Department of Health and vary depending on age, sex, and specific nutritional needs such as pregnancy. They are equivalent to what used to be called Recommended Daily Amounts or Intakes (RDA/RDI). Vegetables described as an 'excellent' source will provide over 50% of the RNI for women aged between 19 and 50. If it is described as a 'good' source it will provide over 25% and a 'useful' source will provide more than 10%.