Food Science Human Nutrition Week 1

Influences on food choices:

• Hunger and satiety

• Habit

• Social interactions

• Emotions

• Personal preference

• Marketing

• Ethnic heritage or tradition

• Convenience and availability

• Food fads

• Positive and negative associations

• Health

Issues with the marketing tendencies of the food industry

They create highly processed foods that are cheap, tasty and desirable, and market them widely to increase their financial gains. However these products are often energy dense and low in nutrients, meaning they are not necessarily healthy. Marketing towards children can promote an unhealthy diet.

Nova classification

A classification system with categories for foods according to their level of processing. Includes:

• Unprocessed/minimally processed foods

• Processed culinary ingredients

• Processed foods

• Ultra - processed foods

Unprocessed/Minimally processed foods

Foods which haven’t undergone processing and are eaten in their natural form, or have undergone minimal processing such as peeling, milling, grinding and pasteurisation. eg: milk, vegetables, beans

Processed culinary ingredients

Ingredients sourced from minimally processed foods and used to season and cook culinary dishes. eg: salt, sugar, oil, butter

Processed foods

Food products created by combining minimally processed foods with processed culinary ingredients. eg: bread, cheese, canned foods, cured meat.

Relationship between level of food processing and chronic disease according to research

Diets high in highly processed foods increase risk of chronic disease while diets low in highly processed foods decrease risk of chronic disease.

Nutrient composition of the body

• 60% water

• Fat of around 13-30%

• Protein makes up around 20%

• Carbs, vitamins and minerals make up a very small proportion of body weight.

Macronutrients

Nutrients that contribute energy to the body and are needed in large quantities. They are organic molecules (contain carbon)

Types of macronutrients:

• Carbohydrates (17kJ/g)

• Protein (17kJ/g)

• Fat (37 kJ/g)

Micronutrients

Nutrients required by the body in small amounts.

Types of micronutrients:

• Vitamins (organic)

• Minerals (inorganic)

Types of nutrients

• Macronutrients

• Micronutrients

• Water

Is alcohol a nutrient and why?

No, it is not a nutrient, since it interferes with healthy functioning of organs and brain. However it contributes energy at 29kJ/g.

How the body uses energy

Energy from food is used to fuel all daily functions of the body. If the energy is not used straight away, it is stored for later use as fat. Energy consumption exceeding daily use will increase fat stores. Energy consumption insufficient for daily needs will decrease fat stores.

Water soluble vitamins

• B1 Thiamin

• B2 Riboflavin

• B3 Pantothenic acid

• B6 Pyridoxine

• B7 Biotin

• B9 Folate

• B12 Cobalamin

• C Ascorbic acid

• (Basically all B group vitamins and vitamin C)

Fat soluble vitamins

Vitamins A, D, E and K (think ants drink, eat and kill)

Minerals

Inorganic substances that do not provide energy.

• Essential minerals: cannot be produced by the body therefore must be sourced from food.

16 Essential Minerals

Macrominerals:

• calcium

• phosphorus

• potassium

• sodium

• chloride

• magnesium

• sulphate

Microminerals / trace minerals:

• iron

• iodine

• zinc

• chromium

• selenium

• fluoride

• molybdenum

• copper

• manganese

Why is water an essential nutrient

The amount needed exceeds the body’s ability to produce it, so it must be sourced externally. It provides the environment in which biochemical reactions can take place, as well as allows for transport of vital compounds around the body. It fills the spaces between cells and forms the structure of large molecules such as protein.

When is nutrition information deemed scientific and therefore worthy of trust?

When the information is backed by research gathered using the scientific method.

Epidemiological/Observational Studies

Research takes place through observation of a relationship between a factor and its outcome, with no active involvement or manipulation of variables conducted by the researcher.

Types of Epidemiological Studies:

• Cross Sectional

• Case Control

• Cohort / Longitudinal

Cross Sectional Study (Epidemiological)

Data collected from a group of people at a Single point in time

Case Control study (Epidemiological)

Data collected from a group of people with a certain condition or disease compared with a group of people who do not.

Cohort/Longitudinal study (Epidemiological)

Data collected from a group of people over a period of time.

Strengths of Epidemiological Research Design

• can conduct research where an experimental research design would be considered unethical (eg: if participants needed to see if a particular drug caused cancer and only participants who already took the drug for other reasons were observed)

• Can be used for large studies

• Determines associations, which can raise questions for further study

Weaknesses of Epidemiological Research designs

• Cannot establish cause - effect relationships

• Results may therefore be open to interpretation and dispute

• Variables can’t be controlled

Experimental Research Design

A researcher actively manipulates and controls variables to investigate whether there is a causal effect between variables.

In Vivo experiment

Experimental research where research is carried out inside living organisms.

In Vitro

Experimental research that is carried out outside a living organism (eg cells in a culture when chemicals are added)

Strengths of an Experimental Research Design

• Variables can be controlled and manipulated to establish a cause effect relationship

Weaknesses of experimental research designs

• Experimental designs may not be able to be performed for ethical reasons

• Results from animal trials cannot always be generalised to humans

Features of a good research design

• Control group to provide a standard to which experimental results can be compared. If the experimental group results differ from control group results, it can be assumed that the IV caused the change in DV.

• Double blind experiment: neither participants nor researchers know which participants are in the experimental or control group. This helps to prevent bias.

• Large sample size.

Information taken when conducting a nutrition assessment of an individual

• Historical information (health, medical history, family history, socioeconomic status etc)

• Anthropometric data (weight, height, skin fold measurements etc)

• Physical examination (hair, eyes, skin, nails etc)

• Lab tests (blood and urine tests)

Information taken when conducting a nutrition assessment of a population

• National and state surveys

Measures for dietary intake assessment

• food records

• food frequency

• 24 hour recalls (what they have consumed 24 hours before the interview)

These responses are compared to Nutrient Reference Values and the Australian Guide to Healthy Eating.

Nutrient Intake Values

• EAR (Estimated Average Requirement)

• RDI (Recommended Daily Intake)

• AI (Adequate Intake)

• UL (Upper Level of Intake)

• Suggested Dietary Targets (SDT)

EAR

Estimated daily nutrient level required to meet the requirements of half the healthy individuals in a particular life stage and gender group.

RDI

The average dietary daily intake level that meets the requirements of 97-98 percent of healthy individuals at a particular life stage and gender group. Intake at or above this level is unlikely to be inadequate.

AI (Adequate Intake)

An estimated adequate intake of the particular nutrient set based on population median intake and assuming that Australian populations were not deficient for that particular nutrient. An AI is set when there is not enough evidence to form an EAR and subsequently a RDI.

UL (Upper Level of intake)

The highest average daily intake that is unlikely to pose risk for health problems. The greater the daily intake goes above UL, the higher the risk for adverse health impacts.

Energy Recommendations

• Estimated Energy Requirement (EER): The average amount of dietary energy predicted to maintain energy balance in a healthy adult of defined age, gender, weight, height and level of physical activity, consistent with good health.

• Acceptable Macronutrient Distribution Range (AMDR): an estimated range of intake for each macronutrient (expressed as a percentage contribution to energy) for individuals, which would allow for an adequate intake of all the other nutrients whilst maximising general health.

Double burden of malnutrition

When both undernutrition and overnutrition coexist within the same individual or population.

• eg in an individual: overnutrition of macronutrients simultaneously with undernutrition of micronutrients.

Stages of Nutrient Deficiency

• Stage 1: Inadequate nutrient intake or absorption, which may be due to primary deficiency or secondary deficiency.

• Stage 2: Reduced stores of nutrient in body (covert and subclinical)

• Stage 3: Abnormal functioning in the body

• Stage 4: Physical signs and symptoms of nutrient deficiency that are overt and clinical.

Risk Factors for Overnutrition related chronic diseases

• Genetics

• Age

• Sex

• Tobacco

• Physical inactivity

• Socioeconomic status

• Ultra processed foods

• Processed meat

• soft drinks

Types of risk factors: non-modifiable and modifiable (we have control over)

Chronic diseases relating to overnutrition

• Heart disease

• Stroke

• Cancer

• Diabetes

Principles of Dietary Planning

• Adequate energy and nutrients for body’s needs

• Balanced quantities of foods from each of the food groups

• Nutrient density for the least energy

• Moderation - regular consumption of minimally processed foods and occasional consumption of ultra processed foods.

• Variety of foods from each food group

Number of KJ in a Calorie

1 Kcal = 4.2 KJ

Australian Dietary Guidelines

1. Achieve and maintain a healthy weight, be physically active and choose amounts of nutritious food and drinks to meet your energy needs.

2. Enjoy a wide variety of nutritious foods from the five food groups each day (vegetables, fruits, grains, protein, dairy)

3. Limit intake of foods containing saturated fat, added salt and added sugars

4. Encourage, support and promote breastfeeding

5. Care for your food; prepare and store it safely.

Equity and Social Determinants of health for Aboriginal and

Torres Strait islanders - Australian Dietary guidelines Appendix A

• Enjoy traditional foods whenever possible

• Find alternative calcium sources to dairy, as lactose intolerance is prevalent in Indigenous communities.

• Choose foods most like traditional bush foods when shopping.

Australian Guide to Healthy Eating

Visual guide that illustrates the proportion of the five food groups that should make up your diet each day. The five food groups are:

• Vegetables and legumes

• grains and cereals

• Meat and alternatives

• Milk, cheese, yoghurt and alternatives

• fruit

Lean Meat and Poultry, seeds, legumes, beans

• source of protein

• source of vitamins and minerals (niacin, thiamin, B6, B12, iron, magnesium, potassium and zinc)

• 1 serve =

  • 65g cooked meat

  • 80g cooked chicken

  • 2 large eggs

  • 1 cup cooked lentils

  • 30g nuts/seeds

• 2.5 serves a day recommended for women, 3 for men.

Dairy and Alternatives

• source of protein

• source of calcium, riboflavin, B12, magnesium, potassium, vitamin D

• 1 serve = 1 cup milk

• 200g yoghurt

• 2 slices cheese

• 2.5 serves per day recommended

Unsaturated Fats and Oils (not one of the 5 food groups)

• source of vitamin E

• Source of omega 3 and omega 6

• small amounts needed only

Discretionary foods and beverages

• contain saturated fats, added sugar and salt, alcohol

• Not necessary for good health

Labelling Requirements for packaged food according to Food Standards Code

• Name and description of food

• warning statements

• Ingredients list - in descending order of weight

• Date marking

• Directions for use and storage

• Nutrition information panel

• Nutrition, health and related claims

• Country of origin

Nutrient Claims on food packaging/advertisements

Voluntary statement relating to amount of nutrient in a product

Health claims

Must be backed by scientific evidence. Can only be made on food products that meet Nutrient Profiling Scoring Criterion (NPSC).

Two types of health claims:

• General health claim: claims about a nutrient and its effects on health, without mentioning a specific disease or symptom of a disease.

• High health claim: references a specific disease or biomarker in relation to the nutritional content.

Reasons a plant based diet may be chosen

• Health reasons

• Religeon

• Animal ethics

• Environmental concerns

Nutrients at risk of underconsumption with a plant based diet

• iron

• protein

• B12

• zinc

• calcium

• Omega 3 fatty acids

• vitamin D

Functional Foods

Foods that have health benefits beyond their nutrient contributions (i don’t fully know what this means)