HUNT141

Nutrition definition

specifically = the sum of the processes of which a plant or animal takes in and utilizes food substances that are necessary for human nutrition

WHO definition of nutrtition

Nutrition is the intake of food, considered in relation to the body's dietary needs. Good nutrition - an adequate, well balanced diet combined with regular physical activity- is a cornerstone of good health

What can poor nutrition lead to?

Reduced immunity
Increased susceptibility to disease
Impaired physical and mental development
Reduced productivity

Nutrients

Nutrients are molecules found in food and beverages needed by the body for energy, growth, development and reproduction.

Types of nutrients

Water
Carbohydrates
Lipids
Proteins
Vitamins
Minerals

Double burden of malnutrtition

over and under nutrition

impacts more than 1/3 low and middle income countries (not all of them!)

Global burden of disease

"The Global Burden of Disease (GBD) provides a tool to quantify health loss from hundreds of diseases, injuries, and risk factors, so that health systems can be improved and disparities can be eliminated.' - https://www.healthdata.org/gbd/about

Food and nutrition guidelines

provide advice on foods, food groups and dietary patterns to provide the required nutrients to the general public to promote overall health and prevent chronic diseases.

Visual guides

provide a visual overview of what a standard diet should look like!

United states guidelines

The united states guidelines
Follow a healthy dietary pattern at every stage of life
Customize and enjoy nutrient dense food and beverage choices to reflect personal preferences, cultural traditions and budgetary considerations
Focus on meeting food group needs with nutrient - dense foods and beverages, and stay within calorie (energy) limits
Limit foods and beverages higher in added sugars, saturated fats and sodium AS WELL AS limit alcohol intake

US visual guide

My plate

Australia guidelines

To achieve and maintain a healthy weight, be physically active and choose amounts of nutritious food and drinks that meet your energy needs
Enjoy a wide variety of nutritious foods from the 5 major food groups each day (fruit, veg, grain, lean meats and dairy/alternatives)
Limit intake of foods containing saturated fats, added salt, added sugars, and alcohol.
Encourage, support and promote breastfeeding
Care for your food - prepare and store it safely

The Australian Visual guide

outdated - still provides important information on what the diet should look like

New Zealand visual guide

heart foundation NZ

NZ guidelines

Enjoy a variety of nutritious foods everyday including - plenty of fruit and vegetables, grain foods (mostly whole grains and those naturally high in fibre), some milk and milk products, some legumes, nuts seeds fish, poultry and/or red meat (note that meat is not the beginning source of protein, there is evidence to support this)

Chose and prepare drinks with unsaturated fats, little/no added sugar, low in salt, mostly whole and less processed (note there is no negative language that goes with these statements! Gives substitutions as well)

Make water your first choice over other drinks
Buy or gather prepare, cook and store foods in ways that keep it safe to eat

EAT lancet goals

human health
planetary health

EAT lancet targets

healthy diets
sustainable food production

EAT lancet strategies

1. seek international and national commitment to shift towards healthy diets
2. reorient agricultural priorities from producing high quantities of food, to producing healthy foods
3 . Sustainably intensify food production to increase high - quality output
4 . Strong and coordinated governance of land and oceans
5 . At least half food losses and waste, in line with the UN SDGs

What does good nutrition look like?

Plant based
Less animal products
Less processed foods
Less packaging
Implicating social factors - religion, culture, family etc
Cost efficient and inclusive

Macro nutrients

required in the diet in large quantities.

provides energy

macronutrient examples

=> carbohydrates,
=> fats
=> protein
=> alcohol - not considered a nutrient but does provide energy

Micronutrients

required in small amounts (vitamins and minerals)

Micronutrient examples

Vitamins - A,B,C,D,E,K
Minerals - inorganic elements - sodium, potassium, sulfur, iron, phosphorus, magnesium, zinc, iodine, selenium, fluorine

ATwater factors

calculates the metabolizable energy

Carbohydrates = 17kj per gram
Protein = 17 kj per gram
Fat = 37kj per gram
Alcohol = 29kj per gram

NRVs

Set of recommendations for the nutritional intake based on currently available scientific knowledge
They apply to almost all (97-98%) healthy people
Achieved by eating a variety of foods
Applies to average daily intakes
Includes the following - EARs, RDI, AI, AMDR, UL

EAR

Estimated Average Requirement

A daily nutrient level estimated to meet the requirements of half of the (50%) healthy individuals in a particular life stage and gender group
How much you need of that nutrients given your age, sex, gender, physical activity etc

RDI

recommended daily intake (individuals)

The average daily dietary intake level that is sufficient to meet the nutrient requirements of nearly all (97-98%) of healthy individuals in a particular life stage and gender group.
RDI = EAR + 2stdDev

AI

Adequate Intake
The average daily nutrient intake level based on observed or experimentally determined approximations or estimates of nutrient intake by a group of apparently healthy individuals that are assumed to be adequate.
Used when the RDI can't be determined

EER

Estimated energy requirements

The average dietary intake that is predicted to maintain energy balance in a healthy adult of defined age, gender, weight, height and physical activity level, consistent with health.
In children and lactating women, the EER is taken to include the needs associated with the deposition of tissues or the secretion of milk at rates consistent with good health.
EERs = EAR

UL

Upper limit of intake
The highest average daily nutrient intake level likely to pose no adverse health effects to almost all individuals in the general population.
As intake increases above the upper limit, the potential risk of adverse effects increases

AMDR

Acceptable Macronutrient Distribution Range

Determined using the atwater factors
Protein = 15-25%
Carbohydrates (CHO) = 45-65%
Fat = 20-35%

Digestion

Breakdown of food substances into simpler forms that can be absorbed and used

4 components of the digestive system

Gastrointestinal tract
Pancreas, gallbladder, liver
Hormones, enzymes nerves and blood
Mesentery

choking

Food gets trapped in the larynx, preventing airflow

Heartburn

Sphincter muscles release chyme to the wrong point of the digestive system - acid reflux up the oesophagus
Digestive acids and juices cause a burning sensation - heartburn!

coeliac disease

Permanent intestinal reaction to gluten
Villi (break down and absorb food by increasing surface area) are flattened, decreasing the bowel SA.
This interferes with the absorption of nutrients from food, causing vitamin deficiencies

Bariatric surgery

causing a gastric bypass which reduces the size of the stomach -> no need to eat as much to feel full, weight loss

absorption of nutrients

Nutrients are absorbed by the epithelial cell and travel via the hepatic portal vein
Liver is the body's major metabolic organ
Large fats and fat-soluble vitamins enter the lymphatic system through the blood (bypassing the liver)

GI tract health

Dietary patterns
Disease
Gut bacteria - human microbiome

probiotics

Bacteria found in bacteria containing foods such as yoghurt, miso and fermented foods. Are good for the gut microbiome

prebiotics

Food that is ingested by probiotics and good health bacteria that is used to increase their growth!

monosaccharides

Single sugars
Glucose -> essential energy source (sugar)
Fructose -> the sweetest! Found in fruit
Galactose -> rarely occurs naturally as a single sugar. Found in dairy

Disaccharide

Pairs of monosaccharides, one of which is always glucose.
Maltose -> glucose and glucose -> produced during the germination of seeds and fermentation
Sucrose -> glucose and fructose -> refined from sugar can and sugar beets
Lactose-> glucose and galactose -> milk and milk products
Starch -> storage form of glucose in plants-> found in grains, tubers and legumes

glycogen

Multi-branched polysaccharide of glucose
Main storage form of glucose in the body
Provides glucose during the fasted state to the body and central nervous system (60% to the brain)

dietary fibre

Dietary fibre is the fraction of the edible part of a plant or their extracts or synthetic analogues that are:
Resistant to the digestion and absorption in the small intestine, usually with the complete or partial fermentation in the large intestine
Promotes one or more of the following beneficial physiological effects -> laxation, reduction in blood cholesterol, modulation of blood glucose

resistant starch

Non starch polysaccharides -> resistant starch
Resistant to the enzymes in the small intestine that breaks down starch
Continues into the large intestine
Results in the release of short chain fatty acids

free sugars

all monosaccharides and disaccharides added to food by the manufacturer, cook, or consumer, plus sugars naturally present in honey, syrups, and fruit juices

Intrinsic sugars

Naturally occurring sugars found in whole, unprocessed foods such as fruits, vegetables, dairy, honey and some grains.

added sugars

typically extracted, concentrated and refined from sources such as sugar cane, fruit, coconut, sugar beet or corn.

what does the WHO recommend our free and added sugar intake to be

less than 10% of total energy

reducing sugar intake

Sugar tax -> not implicated in New Zealand
Labelling -> labels in the US have the added sugar quantities on the back of food packages
Non-nutritive sweeteners -> sugar substitutes that contain little to no calories

Amylase

is an enzyme made by the pancreas and by glands in the mouth. It breaks down starch and carbohydrates into sugars (i.e polysaccharides and starches into monosaccharides and disaccharides)

Carbohydrate metabolism

Glucose, galactose and fructose travel via the hepatic portal vein to the liver
Liver converts galactose and fructose into glucose

Glucose uses

Used for energy (brain)
Stored as glycogen (liver/muscle)
If energy requirements are met, glucose is converted into fat

Lactase

enzyme that converts lactose into glucose and galactose (in the gut)

if lactase persists...

If lactase persists -> lactase is being produced and is working, therefore no lactose intolerance.

is lactase doesn't persist..

lactose cannot be broken down and moves into the large intestine

What causes gas, bloating and overall digestive discomfort in those who are lactose intolerant?

Fermentation of lactic acid in the large intestine, producing methane.

What causes diarrhea in those with lactose intolerance?

Osmotic shock - water retention in the large intestine

glycemic index

a method of classifying foods according to their potential for raising blood glucose

Glycemic load

GI x carbohydrates / 100

High GI

(70-100) -> carbohydrates which break down quickly during digestion, releasing blood sugar rapidly into the blood stream

medium GI

(56-69) -> carbohydrates which break down moderately during digestion releasing blood sugar moderately into the bloodstream

Low GI

Low GI (0-55) -> carbohydrates which break down slowly during digestion, releasing blood sugar gradually into the blood stream

Dietary fibre NRVS

Adequate intake for New Zealander's = 25g per day (f) 30g per day (m)
Suggested dietary target (SDT) = 28g (f) 38g (m)

Gluten

Gluten - a viscoelastic mass that has the ability to form thin gas-retaining films that trap gases, allowing dough to expand, become softer, lighter and more palatable after baking

Colon cancer facts and information

Second highest cause of cancer death in New Zealand
Over 3000 New Zealanders are diagnosed each year
More than 1200 die from it
Over 350 <50 are diagnosed
1/18 new Zealanders will develop it in their lifetime
Men are at a more increased risk than women

Colon cancer risk factors

Age
Smoking tobacco
Obesity
Drinking alcohol
Lack of exercise
Chrohn's disease/ ulcerative colitis for more than 10 years
History in the family
Rare genetic conditions - HNPCC and FAP

Findings on colorectal cancer

Physically active = decreased risk
Consuming wholegrains = decreased risk
Consuming dietary fibre foods = decreased risk
Consuming dairy products = decreased risk
Red meat consumption = increased risk
Processed meat consumption = increased risk
Alcohol intake = increased risk
Being tall = increased risk

proteins

Any class of amino nitrogenous organic compound that have large molecules composed of one or more long chains of amino acids and are an essential part of all living organisms
Composed of amino acids
Any various of naturally occurring extremely complex substances that consist of amino acid residues joined by peptide bonds, contain the elements carbon, hydrogen, nitrogen, oxygen, sulfur and other elements

Protein functions

Contractile proteins, eg actin and myosin in muscle
Regulate gene expression - eg histones
Facilitate biochemical reactions - enzymes
Immune response - antibodies
Transport molecules - haemoglobin
Endocrine system - hormones such as insulin
Structural proteins - collagen

Indispensable amino acids

n=9 (must be obtained through the diet, cannot be made by the body)

dispensable amino acids

n=5 (able to be produced by the body)

Conditionally indispensable amino acids

normally synthesized but some health conditions may require dietary intake

Protein's NRVS

AMDR = 15-25%
EAR = 52g (male) 37g (female)
RDI = 64g (male) 46g (female)

What determines protein quality?

The essential amino acid factor
The ability to be digested

protein digestibility

Mg of limiting amino acids/mg of amino acid in reference protein x true fecal digestibility

protein efficiency ratio

Weight gain of test subject

DIAAs

Digestible Indispensable Amino Acid Score

Mg of limiting amino acid/mg of amino acid in reference protein / ileal digestibility

Limiting amino acid

the essential amino acid in lowest concentration in a food or diet relative to body needs - will limit protein synthesis

Amino acid pool

used to make more dispensable amino acids

oxidation for energy use

used in the formation of new proteins

used to make other compounds

if energy intake is exceeded, proteins will be stored in excess fat.

food sensitivity

the term used to describe the 3 unusual responses to food

Food eversion

Psychologically based food avoidance

Usually a conditioned response
No reaction to it - if food is disguised!
i.e avoiding a food because it gave you food poisoning, force fed food in past etc

Food intolerance

Any reproducible, abnormal, non - psychologically mediated reaction to food

Affects 10-15% of the population across a range of intolerances
Examples include:
-> lactose intolerance
-> tyramines in cheese and wine
-> salicylates
-> food additives

food allergy

A group of disorders characterised by abnormal or exaggerated reproducible responses to specific food proteins

IGE mediated response

IGE mediated reaction -> involves IgE antibodies
-> rapid onset -> seconds, minutes, hours
-> involves the skin, GI tract and respiratory tract

Non IGE mediated reactions

Non IgE mediated reactions
-> does not involve antibodies, but other unknown mechanisms instead
-> symptoms results in hours to days
-> difficult to assess in clinical settings (particularly due to the symptoms not being rapid)

Lipids

Any class of organic compounds that are fatty acids, or their derivatives. They are insoluble in water, but soluble in organic solvents

functions of lipids

Source of energy!
The structural components of cell membranes
Provides insulation -> maintain body temperature
Cushions and protect internal organs
Basis of many hormones

types of lipids

Triglycerides (triglycerol)
Fatty acids
Phospholipids
Sterols
Others, including fat soluble vitamins

triglycerides

>90% of dietary lipids
Provides energy storage and fatty acid storage
The structural component of lipoproteins

fatty acids

Chains of carbon molecules with a methyl group at one end of the chain and a carboxyl group at the other end of the chain



Length of the chain -> change the way the body utilizes fatty acids
Most fatty acids are between c10-c22
SCA, MCA, LCA and VLC

Double bonds - affects melting point
Saturated (carbon chain, hydrogens, no bonds)
Monounsaturated (1 double bond)
Polyunsaturated (more than 1 double bond)
Cis bonds vs trans bonds -> orientation of the bond

Position of the first double bond from the methyl end
N-3 or omega 3
N-6 or omega 6

SFA

saturated with hydrogen
no double bonds
high melting points

MUSA

double bond at 9 carbons from methyl end

PUFA

low melting points due to their double bonds
double bonds separated by methylene group
must get from diet - fish, nuts, canola, seeds

Essential fatty acids

Humans are not able to make a double bond with the first 6 carbons from the methyl (omega) end
Should make up 1-3% of energy

fatty acid deficiency symptoms

Growth retardation
Reproductive failure
Skin lesions, kidney and liver disorder
Neurological and visual problems

phospholipids

Chemical structures that allows them to have unique roles in the body
-> glycerol backbone + fatty acids + phosphate group
-> phosphate part is hydrophyllic
-> Fatty acid part is hydrophobic

Have many roles in the diet
-> cell membranes
-> plasma lipoproteins

5-10% of dietary lipid
Can be made into prostaglandins -> signaling, vasodilation, platelet aggregation, uterine contraction, bronchoconstriction

sterols

Sterols -> multiple ring structure
Found in plant and animal foods
Starting material for bile acids, sex hormones, adrenal hormones and vitamin D
Cholesterol is found only in animal foods, plant sterols lower cholesterol!

SCFA

c2-c6 carbons