Doctoral Dissertation - Nutritional Assessment

In order to survive, the human organism needs to take oxygen, water and food. In this video I am talking about nutrition and its vital consequences for our health, as well as the importance of assessing nutrition in children and adolescents, in connection to my PhD research.

Video formats: MP4 | Ogg | WebM | It is also on YouTube


What is Nutritional Assessment?

Nutritional Assessment is the information obtained from dietary, biochemical, anthropometric and clinical studies [Lennernas, 1998].


Proteins, Fats and Carbohydrates

In 1827, a British physician, named William Prout, was the first to formally recognise the three macronutrients (proteins, fats and carbohydrates) which we need in our diet [Olson, 1998].

PROTEINS - the main building blocks of body tissue. Proteins function as [Tortora, 1990]:

  • Enzymes (catalyse chemical reactions)
  • Antibodies
  • Hormones
  • Contractile elements in muscle fibres cells

Proteins are broken down into AMINO ACIDS (20 different L-α-Amino Acids, 9 of which are essential which means that our body cannot produce them and we are relying on getting these from our food. )

  • Essential (L-Histidine*, L-Isoleucine, L-Leucine, L-Lysine, L-Methionine, L-Phenylalanine, L-Threonine, L-Tryptophan, L-Valine)
  • Nonessential

Proteins - 20 Amino Acids

* The Amino Acid L-Histidine was initially thought to be essential only for infants, however, longer-term studies have shown it is essential for adults as well [Kopple, 1975].

In young children, the amino acid Arginine, can be essential as well [Atanasov, 2006].


CARBOHYDRATES - consist of carbon (C), hydrogen (H) and oxygen (O) and come as combinations of sugar units which are normally grouped as Simple or Complex carbohydrates.



FATS - play an important role in our bodies. Although the energy which comes from fats is more than twice that of carbohydrates, fats are the body’s second favourite source of energy because they are more difficult to catabolise [Tortora, 1990].



A well-balanced diet plays an essential role for improving health and well-being. It also has an impact on the quality of our lives, as well as our life expectancy [Davidov, 2011]. Children and adolescents need adequate energy intake to ensure proper growth, development, and maturation. Nutrient needs are higher during adolescence than at any other time in the life cycle. While proper nutrition is important for everyone, it is of particular concern for children and adolescents who compete in sports [Nisevich, 2008]. Diet affects performance, and the foods that children consume before training and competition will affect how well they train and compete [International Olympic Committee, 2012].


Food Frequency Questionnaires (FFQ)

Food frequency questionnaires provide information on food consumption patterns and they are applied for measuring the average consumption of foods and estimation of nutrient intakes.

For school-age children and adolescents, there is no consensus as to which dietary assessment method is most accurate. The choice of which instrument to use may depend on the objectives and design of the study [Thompson, 2013].

Food Frequency Questionnaire for Young Athletes

For our studies, we have been applying a food frequency questionnaire, which was created at the National Sports Academy in Sofia, and used for adult athletes [Zaikova, 2010; Zaekov, 2012; Zaikova, 2012], but, was then adapted for our purposes in order to assess the nutrient intake of children.


Tell me what you eat and I will tell you what you are.

Tell me what you eat and I will tell you what you are

Be Active, Do Sports, Feel Great, Repeat!




Atanasov, P. (2006) Molecular basis of human nutrition, SNC, Sofia

Davidov, D. (2011) Physical fitness - health and well-being, NSA Press, Sofia

Gachev, E., Djarova, T. (2003) Biochemistry, New Knowledge, Sofia

International Olympic Committee. (2012) Nutrition for athletes. A practical guide to eating for health and performance

Kolimechkov, S., Petrov, L., Ilinova, B., Alexandrova, A., Andreeva, L., and Atanasov, P. (2013) Assessment of the physical development of pre-school and primary school children practising artistic gymnastics. Journal of Sport Science 4, 106-115

Kopple, J D; Swendseid, M E (1975). "Evidence that histidine is an essential amino acid in normal and chronically uremic man". Journal of Clinical Investigation 55 (5): 881–91.

Lennernas, M. (1998) Dietary assessment and validity: To measure what is meant to measure. Scandinavian Journal of Nutrition 42, 63-65

Nisevich, P. (2008) Sports Nutrition for Young Athletes. IDEA Fitness Journal, 65-67

Olson, R. E. (1998) Evolution of ideas about the nutritional value of dietary fat: introduction. The Journal of nutrition 128, 421S-422S

Protein (2016) Wikipedia. 3D structure of the protein, Retrieved from Wikipedia on 13 April 2016,

STK Sport (2016) Gymnastics Coaching Photogallery, Retrieved from STK SPORT on 13 April 2016,

Thompson, F., and Subar, A. (2013) Nutrition in the Prevention and Treatment of Disease, Chapter 1 - Dietary assesment methodology

Tortora, G., and Anagnostakos, N. (1990) Principles of Anatomy and Physiology, Sixth Edition ed., Harper & Row, Publishers, New York

Zaekov, N., Zaikova, D., Petrov, L., Andreeva, L., Atanasov, P. (2012) Web-based distance method of assessing nutrition in athletes, Science and Dietetics, 4, 4-7

Zaikova, D., Zaekov, N., Petrov, L. , Ilinova, B., Groshev, O., Jordanov, P., Atanasov, P. (2012) Control of nutrition and evaluation of the effect of dietary supplements for nonprofessional bodybuilders. IXth National Nutrition Conference, Sofia 2012, 201-204

Zaikova, D., Ilinova, B., Petrov, L., Groshev, O., Jordanov, P., Atanasov, P. (2010) Standard methodology for determining the biochemical and anthropometric indicators in anaerobic sports. Sport & Science, 3, (7)

STK SPORT PhD Research