PSY351 Nutrition and Behavior
What is a nutrient?
• A chemical substance in food that helps maintain the body
• Some provide energy
• All help build cells and tissues, regulate bodily processes such as breathing
• No single food supplies all the nutrients the body needs to function
• Split between macro & micro-nutrients
Macro-nutrients
Protein
• 20 common amino acids make up proteins
• Amino acids connect to make small peptide chains
• Peptide chains combine to produce much longer strand -> protein, which has 3D structure,
forming receptor site for neurotransmitters.
• Essential amino acids – can't be synthesized by the organism & must be supplied by diet. There
are 8 of these: phenylalanine (converted to tyrosine), valine, threonine, tryptophan (converted
to serotonin), isoleucine, methionine, leucine and lysine. Unlike fat & starch, the body doesn’t
store excess amino acids for later use, so it must be in food every day.
• Non-essential amino acids - don’t have to be consumed as the body can convert some other
molecules to that structure. 12 of these: alanine, asparagine, aspartic acid (neurotransmitter),
cysteine, glutamic acid (neurotransmitter), glutamine, glycine, proline, serine, tyrosine
(converted to dopamine/noradrenaline/adrenaline), arginine and histidine.
• Two major functions – enzymes that catalyze biological reactions, and structural function
Carbohydrates
,• All carbs consist of monosaccharides, di-saccharides and poly-saccharides
• The brain is the most metabolically active organ in the body, and uses glucose as its fuel, needs a
continuous supply of glucose to function.
• If levels of glucose fall, you get hypoglycemia – problems with memory, mood, vision, speech
• Too much glucose can cause damage to the structure of molecules and may influence the aging
process.
, • Glucose forms starch, glycogen & cellulose:
• After eating a meal, you get a burst of glucose in bloodstream which is stored in liver in chains,
producing glycogen (storage molecule). After not eating for a while, this glycogen is broken
down and released as glucose.
• Starch is a long chain of glucose, storage form in plants.
• Cellulose, indigestible by humans, comes through the body as fiber.
Microbiome/microbiota
, • Microbiota – number of types of species of gut bacteria. 100 trillion of them.
• Microbiome – genetic material that these bacteria include
• Fast developing area of interest.
• Drugs act different if the population of microbiota are different.
• Digesting fiber encourages development of friendly bacteria, preventing weight gain, diabetes,
heart disease and cancer
• The gut microbiome controls the immune system
• Gut/brain interaction
Fats
• Fatty acids have 2 different structures: saturated (single carbon bond) and unsaturated (double
carbon bond)
• Saturated fats – bad, found mainly in animal products and coconut/palm kennel oils. Biggest
dietary cause of high LDL levels (bad cholesterol). Predisposes heart disease & dementia
• Unsaturated fats – good, found in rapeseed/sunflower/corn oil. It helps lower cholesterol if used
in place of saturated fats.
• Trans fats – formed when vegetable oil hardens (hydrogenation). Raises LDL cholesterol. Found
in fried foods, commercially baked foods, processed foods and margarine.
• 60% of dry weight of brain is fat, of which a quarter is cholesterol (essential part of sex
hormones, vitamin D & steroid hormones from the cortex of adrenal gland). If you do not eat
cholesterol, the body makes it.
• The fat of the brain is made up of two families of essential, poly-unsaturated fatty acids: omega-
3 and omega-6.
• 20% of the brain has DHA, an omega-3 fatty acid. Most of us don’t eat enough (found in oily,
fatty fish). Debate on whether lack of omega-3 in diet inhibits brain development, increases
depression and dementia.
Micronutrients
Vitamins
What is a nutrient?
• A chemical substance in food that helps maintain the body
• Some provide energy
• All help build cells and tissues, regulate bodily processes such as breathing
• No single food supplies all the nutrients the body needs to function
• Split between macro & micro-nutrients
Macro-nutrients
Protein
• 20 common amino acids make up proteins
• Amino acids connect to make small peptide chains
• Peptide chains combine to produce much longer strand -> protein, which has 3D structure,
forming receptor site for neurotransmitters.
• Essential amino acids – can't be synthesized by the organism & must be supplied by diet. There
are 8 of these: phenylalanine (converted to tyrosine), valine, threonine, tryptophan (converted
to serotonin), isoleucine, methionine, leucine and lysine. Unlike fat & starch, the body doesn’t
store excess amino acids for later use, so it must be in food every day.
• Non-essential amino acids - don’t have to be consumed as the body can convert some other
molecules to that structure. 12 of these: alanine, asparagine, aspartic acid (neurotransmitter),
cysteine, glutamic acid (neurotransmitter), glutamine, glycine, proline, serine, tyrosine
(converted to dopamine/noradrenaline/adrenaline), arginine and histidine.
• Two major functions – enzymes that catalyze biological reactions, and structural function
Carbohydrates
,• All carbs consist of monosaccharides, di-saccharides and poly-saccharides
• The brain is the most metabolically active organ in the body, and uses glucose as its fuel, needs a
continuous supply of glucose to function.
• If levels of glucose fall, you get hypoglycemia – problems with memory, mood, vision, speech
• Too much glucose can cause damage to the structure of molecules and may influence the aging
process.
, • Glucose forms starch, glycogen & cellulose:
• After eating a meal, you get a burst of glucose in bloodstream which is stored in liver in chains,
producing glycogen (storage molecule). After not eating for a while, this glycogen is broken
down and released as glucose.
• Starch is a long chain of glucose, storage form in plants.
• Cellulose, indigestible by humans, comes through the body as fiber.
Microbiome/microbiota
, • Microbiota – number of types of species of gut bacteria. 100 trillion of them.
• Microbiome – genetic material that these bacteria include
• Fast developing area of interest.
• Drugs act different if the population of microbiota are different.
• Digesting fiber encourages development of friendly bacteria, preventing weight gain, diabetes,
heart disease and cancer
• The gut microbiome controls the immune system
• Gut/brain interaction
Fats
• Fatty acids have 2 different structures: saturated (single carbon bond) and unsaturated (double
carbon bond)
• Saturated fats – bad, found mainly in animal products and coconut/palm kennel oils. Biggest
dietary cause of high LDL levels (bad cholesterol). Predisposes heart disease & dementia
• Unsaturated fats – good, found in rapeseed/sunflower/corn oil. It helps lower cholesterol if used
in place of saturated fats.
• Trans fats – formed when vegetable oil hardens (hydrogenation). Raises LDL cholesterol. Found
in fried foods, commercially baked foods, processed foods and margarine.
• 60% of dry weight of brain is fat, of which a quarter is cholesterol (essential part of sex
hormones, vitamin D & steroid hormones from the cortex of adrenal gland). If you do not eat
cholesterol, the body makes it.
• The fat of the brain is made up of two families of essential, poly-unsaturated fatty acids: omega-
3 and omega-6.
• 20% of the brain has DHA, an omega-3 fatty acid. Most of us don’t eat enough (found in oily,
fatty fish). Debate on whether lack of omega-3 in diet inhibits brain development, increases
depression and dementia.
Micronutrients
Vitamins
