Food. What’s in it?


Pear Ingredients (1-5). Photo by Leonie Elizabeth. January 2018


Food is comprised of many distinct chemical substances which can broadly be divided into nutritional and non-nutritional components.(6-8)

Nutritional components

Nutrients are chemical substances in the food we eat that interact within the body and are needed throughout the whole of life. There are six main types of nutrients in foods, divided into 2 main groups.

The macronutrients of protein, carbohydrate and fat are nutrients we require in relatively large amounts.

The micronutrients of vitamins, minerals, and trace elements are nutrients we need in relatively small quantities.

The nutritional components of food provide us with all the nourishment necessary for energy, growth and regulation of body functions. Food also contains water. (9)

Non-nutritional Components

Non-nutritional chemical components of food include colour, flavour, preservatives, food additives, condiments and pharmacological (drug-like) substances such as caffeine. Foods may also contain toxicants and unintentional contaminants.

All food components, even nutrients, are chemicals. Every nutrient is comprised of a single or combination of the various elements such as carbon, hydrogen, oxygen and a variety of other elements in an array of different combinations and structures. However, we do not generally think in terms of the water we drink, and the food we need for growth or regulation in terms of chemicals.

While food additives are sometimes depicted as being unnatural chemicals added to food, food naturally contains a vast array of chemical substances that impart flavour, colour, or have a preservative action. (10)

For simplicity, throughout this blog and website, I will refer to the nutritional components of food simply as nutrients, to distinguish from the non-nutritional components of food, which I shall refer to as food chemicals.

Food chemical groups

While much publicity has been given to food additives, foods naturally contain a vast array of chemical substances that impart flavour, colour or have a preservative action. There are many such chemicals in food. For example the substances that have been isolated in strawberries to give it flavour total more than 200 different chemicals. (10)

Many of these chemicals in foods are related in structure and for convenience can be grouped together.

One chemical group that imparts flavour to foods is salicylates. These related food components may be present in many different foods. For example orange, apple and tomato all contain salicylates. (11)

Benzoates have a similar structure to saliyclates. The benzoate preservatives in foods have a similar chemical structure to natural salicylates or natural benzoates.

Amines and glutamates are two other chemical groups that contribute to the flavour in some foods.

Biogenic Amines result from the breakdown of protein or from fermentation. Higher levels are found in aged foods such as cheese; fermented foods such as beer and wine; and also in some fruits and vegetables such as tomatoes, bananas and avocados. (11)

Glutamates are naturally present in foods such as tomatoes and mushrooms. Concentrated forms are added as food additives such as mono-sodium-glutamate. (11)

Food Processing effects

Today we are eating and drinking a wide array of different foods. Some are eaten as core foods in their natural state. Others are extracted, juiced, condensed or refined forms of the original. Some of these are not consumed on their own, but rather as ingredients such as butter, oil, or sugar. Other foods are combination of core foods or refined foods and ingredients;which are moderately processed foods; or ultra-processed with the addition of natural or artificial flavours and other food additives.

Food processing techniques such as dehydration or crushing can increase the energy density of the food by removing the water content. These techniques also concentrate the food chemical component. The addition of condiments such as herbs and spices, which are high in salicylates; natural additives such as acids, vinegar or yeast extracts; or food additives such as preservatives or colours; can add to the total chemical load of the non-nutritional part of the food.

Whether components in a food are nutritional or non-nutritional becomes important when we begin to look at restricted diets.


Disclaimer: Nothing in this article or on this website should be taken as medical or dietary advice. Anyone reading any information provided within should seek advice from their own medical practitioner for any issue, disease, illness or health-related problem they may have. Always seek your own advice from a medical practitioner or dietitian before changing your own diet.

References and Notes:

(1) D H Heinz, W G Jennings. Volatile Components of Bartlett Pears. Journal of Food Science. January 1966.

(2) Pears, raw

(3) The Food Processor, v 10.12.0. ESHA Research, Salem, Oregan USA

(4) A J Taylor, S T Linsforth. Natural Sources of Flavours: Pears in Food Flavour Technology. Wiley. 2009

(5) A Suwanagul. Ripening Pear Flavour Volatiles: identification, biosynthesis and sensory perception. PhD abstract. Oregon State University.

(6) Definition of Food: a nourishing substance that is eaten or otherwise taken into the body to sustain life, provide energy, or promote growth.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health. Seventh Edition 2003, by Saunders, an imprint of Elsevier Inc.

(7) Definition of nutrient: constituents of food necessary for normal physiological function. Farlex Partner Medical Dictionary. Farlex 2012.

(8) Definition of Physiology: the study of the processes and functions of the human body
Mosby’s Medical Dictionary, 9th edition 2009, Elsevier.

(9) E Whitney, S R Rolfes, T Crowe, D Cameron-Smith, A Walsh. Understanding Nutrition. Australia and New Zealand Edition. 2nd Edition. Cengate Learning. 2014.

(10) D Briggs, M Wahlqvist. Eating Matters. Methuen Hayes. 1985

(11) D H Allen, S Van Nunen, R Loblay, L Clarke, A Swain. Adverse Reactions To Foods. Medical Journal of Australia. September 1 1984. Special Supplement.

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