Janine Kruit, as the coordinator of the RuG Metabolism & Nutrition course, delivered the introductory lecture today, a day late, because she was too sick to teach yesterday. The altered course schedule is now available on the course’s Nestor environment [Blackboard].

The gist of the course is how nutrition, by affecting metabolism, can contribute to or substract from our health, i.e. nutrition → metabolism → health. The subject matter is broken down into the following topics/lectures:

  • energy metabolism [Lecture 2];
  • fat/carbohydrate/protein metabolism [Lecture 3/4/6]; and
  • metabolic regulation [Lecture 5].
  • Lecture 7 integrates the topics of the previous lectures.

After the lectures are finished on Thursday, the following tutorials are planned for group C (my group), with those that are obligatory for me in bold:

Tutorial schedule for Group C.

Date Time Room Subject Lecturer
Tutorial 1 Fri, March 20 13:00–15:00 3211.0125 Caloric restriction Kathrin Thedieck
Tutorial 2 Mon, March 23 10:00–12:00 3211.0125 Cardiovascular disease Uwe Tietge
Tutorial 3 Tue, March 24 10:00–12:00 3211.0125 Nutrition & epigenetics Torsten Plosch
Tutorial 4 Wed, March 25 09:00–11:00 3211.0125 Nutrition & microbiota Hermie Harmsen
Tutorial 5 Thu, March 26 11:00–13:00 3211.0125 Diet Maaike Oosterveer
Tutorial 6 Fri, March 27 11:00–13:00 3111.0017A Metabolic regulation Hans Jonkers
Tutorial 7 Tue, March 31 09:00–11:00 3111.0217 Eatmeter

Nutrients and nutrition

Besides some housekeeping details and a general overview of the course, in this introductory lecture, Janine also ran through some of the basics of nutrition and nutrient breakdown.

Nutrients are divided in

  • macronutrients, which include fats, proteins, and carbohydrates (incl. fibers); and
  • micronutrients: vitamins, minerals, dietary elements (sporenelementen), and bioactives (phytochemicals).

Nutrients are necessary to support energy metabolism, cell synthesis, optimalisation and cellulair repair.
Macronutrients can be classified based on whether they are essential as fuel and/or as substrate for cell synthesis.

Essential and non-essential macronutrients.

Nutrient Essential Not essential
Fats W3/w6 PUFA Energy source
Proteins Amino acids Amino acids
Energy source
Carbohydrates * Energy source

* [Janine leaves this empty, but, of course, carbohydrates are required as a glucose source, at least for the brain and red blood cells.]


Most nutrient absorption takes place in the small intestine. Proteins, lipids, carbohydrates, vitamins and minerals can be absorbed with or without prior digestion by the enzymes and salts present in bile acid. Undigested food stuffs get passed to the large intestine, where fermentation take makes available even more nutrients.

Digestion enzymes

  • Carbohydrates are split into monosaccharides by amylase, maltase, sucrase, and lactase. [More in a later lecture on carbohydrate metabolism.]
  • Proteins are split into peptides and amino acids by endopeptidases and exopeptidases. [More in the protein metabolism lecture.]
  • Fats are split into free fatty acids and monoglycerides by lipases.

Bile salts

Digestion of fats in the small intestine is aided by bile acid, which contains bile salts (Dutch: galzouten). Bile salts are amphiphilic, meaning that they are simultaneously lipophilic and hydrophilic.