HUMAN NUTRITION
Chapter 1: Introduction to human nutrition and a global perspective
1. Nutrition – Integrated approach
• What is nutrition?
o Human nutrition is a complex multifaced scientific domain indicating how substances in foods
provide essential nourishment for the maintenance of life
• Integrated Approach
o Human nutrition:
▪ Process whereby cellular organelles, cells, tissues, organs, systems, and the body as a whole
obtain and use necessary substances obtained from foods (nutrients) to maintain structural
and functional integrity.
▪ Includes the spectrum of molecular to societal level (vb crocodile as diner uncommon in
Belgium but common in Africa, parties)
▪ Spectrum of molecular biology, genetics, biochemistry, chemistry, physics, food science,
microbiology, physiology, phtology, immunology, psychology, sociology, political science,
anthropology, agriculture, pharmacology, communications, and economics.
▪ Melting pot of different sciences
2. Nutrition – Conceptual Framework
• Conceptual Framework
o vb circulation role: vitB12 important in forming RBC, need lipids to protect CNS, social and
economical circumstances play a role on amount and type of food available
3. Relationship nutrition and health
• Nutritional situation => health consequences, outcomes
o Optimum nutrition: food-secure individuals with adequate, balanced & prudent diets
▪ => health, well being, normal development, high quality of life
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, o Undernutrition: hunger: food-insecure individuals living in poverty, ignorance, politically unstable
environments, disrupted societies, war
▪ = te weinig eten: te weinig energie (te weinig kcal) of te weinig micronutrienten (genoeg kcal)
▪ => decreased physical & mental development, compromised immune system, increased
infectious diseases, vicious circle of undernutrition, underdevelopment, poverty
o Overnutrition: overconsumption of food, especially macronutrients, plus: low physical activity,
smoking, stress, alcohol abuse
▪ = te veel eten: te veel energetisch (te veel kcal)
▪ => obesitas, metabolic syndrome, cardiovasculaire aandoeningen, type 2 diabetes etc.
o Malnutrition : nutrition transition : individuals and communities previously food insecure ->
confronted with abundance of palatable foods -> some undernourished, others too many
macronutrients and too few micronutrients
▪ => double burden of of infectious diseases plus NCDs
▪ => double burden of malnutrition
▪ => often characterized by this overnutrition of macronutrients and undernutrition of
micronutrients (obese + lack of micronutrients)
• Epidemiological point of view
o at young age high mortality: because of nutritional deficiencies and maternal disorders related to
nutrition our age
o what causes the most deaths: arrythmic heart disease, Alzheimer, lung cancer
o what causes the most premature deaths (vb die at 75 yrs): ischemic heart disease,…
o what risk factors drive the most death and disability combined: tobacco, high BP, dietary risks (Low
fruit, low whole grains, low vegetables) (= top 3 in Belgium), high BMI, high fasting plasma glucose
• Link between diet and health outcomes
o in research, often arrow 4 and arrow 3 (but wrong)
▪ Example: grow milk (low in proteins, rich in vitD and Fe) → company says that childs who
drink this will have a higher Fe & vitD status → thus will perform cognitively better at school
▪ Example: if you eat this food, you don’t develop osteoporosis; link chocolate and CVD → but
results take 40yrs?
▪ → thus clinical outcomes are difficult and sometimes not possible to study
o solution: (Valid) Surrogate Outcomes (SO) & (Non-validated) Intermediate Outcomes (IO)
▪ SO = predictors of clinical outcomes: vb bone mineral density for osteoporose
▪ IO = possible predictors of clinical outcomes: vb for CVD, use HDL, LDL and cholesterol
• Diet → plays in at Intermediairy Biological Mechanisms → risk of Coronary Heart Disease
o vb: homocysteine converted to methionine due to vitB12 (which is influenced by riboflavin and folic
acid from diet)
• Example: Mediterranean diet (fruit, vegetables, meat, fish, PA) gives a lower risk on all-cause mortality
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, • Example: Vitamin A deficiency
• Food and risk on chronic disease
o on young age, healthy balanced diet → timely intervention produces substantial risk reduction
(stippel)
o on later age, healthy balanced diet → impact of adult intervention is small → higher risk on chronic
disease
o conclusion: development is most important time to intervene to prevent disease
• The underlying drivers of improved nutrition status
• What can you do with food
o 1) Level 1: Nutrition-responsive disease you can directly tackle with nutrition
o 2) Level 2: Nutrition has only secondary preventive role (vb help prevent CVD when having diabetes)
o 3) Level 3: Nutrition cannot cure the disease, but has a supportive role (vb consume vitD and Ca
when having osteoporosis, vb undernutrition makes chemotherapy in cancer less effective)
o 4) Level 4: Nutrition-unresponsive (genetic) diseases you cannot tackle with nutrition
• Relationship Nutrition & Health
o Many other lifestyle and environmental factors influence health and well-being
o BUT nutrition is a major modifiable and powerful factor in promoting health, preventing and treating
disease and improving quality of life.
4. Nutrients: the basics
• Nutrients: the basics
o People eat food NOT nutrients
o It is the combination and amount of nutrients that determine health.
• Nutrition Defined
o Actions in the body include: Ingestion – Digestion – Absorption – Transport – Metabolism – Excretion
• What’s considered food?
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, o Foods contain nutrients and are derived from plant or animal sources
o Nutrients are used by the body to provide energy and to support growth, maintenance and repair of
body tissues
▪ ~ 50 nutrients identified at this time
• Classifying nutrients: 6 classes of nutrients
o Carbohydrates, lipids (fats), proteins, vitamins, minerals, water
o = all essential except for carboydrates (can survive without through ketose metabolism)
o flavonoids, polyphenols not essential considered
• A little more on energy
o Measure energy in kilocalories.
▪ What most think of as a “calorie” is really a kilocalorie
▪ Kcal = amount of energy needed to raise the temperature of 1 kg of water by 10C
o Measure energy in kilojoules (kJ) in some other countries
• Energy-Yielding Nutrients
o Kcal values of Energy nutrients
▪ Carbohydrate: 4 kcal/g
▪ Fat: 9 kcal/g
▪ Protein: 4 kcal/g
o Note: alcohol contributes 7 kcal/g that can be used for EN, but is not considered a nutrient
• Energy density
o Measure of the kcal per gram of food
o Foods with a high energy density provide more kcal per gram than low density foods.
• Nutrients
o NOT in isolation
o Interact with each other
o Nutrients should be studied in the context of the total body function
o Knowledge about the nutrients and their functions allow us to draw recommendations and
determine nutrient requirements
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