Myths & Legends

NUTRITION BASICS

Dr Niikee Schoendorfer – n.schoendorfer@uq.edu.au

OBJECTIVES

Appreciate the finer aspects of macronutrients and their physiological functions

Recognise the determinants of nutrient needs

Calculate water requirements and factors necessitating increased requirements

Differentiate between the good, the bad and the ugly fats

Understand glycaemic index versus glycaemic load

Appreciate the roles of dietary fibre in both gastrointestinal and systemic health

Understand issues related to micronutrition

WHAT IS NUTRITION?

Nutrition is –

All the processes involved in taking in and utilization of food substances by which growth, repair and maintenance of activities in the body as a whole or in any of its parts, are accomplished.

This includes ingestion, digestion, absorption and metabolism (utilisation).

Some nutrients are capable of being stored in various forms and can be drawn upon when the food intake is not sufficient.

Thomas, C.L. (ed) 1993. Taber’s Cyclopedic Medical Dictionary, 17th ed, Davis,

Philadelphia p1337

CONTRIBUTION OF NUTRIENT

IMBALANCES TO DEVELOPMENT OF

CHRONIC DISEASES

Environmental Pollutants

UV Exposure Smoking

Inactivity

Stress Poor HygieneDamaged Cell

NourishmentGenetics

Habitual Nutrient Intakes

FunctionalCell

Absorption Efficiency

Metabolic Demand

Excretion Levels

DETERMINANTS OF NUTRIENT

NEEDS

Provide sufficient amounts to satisfy daily demands

Adequacy of intake

Balance and variety in food choices

Maintain adequate reserves

Habitual diet and dietary patterns

Defensive approach

OPTIMIZE CELLULAR

ACTIVITY AND

TISSUE/ORGAN FUNCTION

FUNCTIONS OF WATER

Recommended Daily Intake

2-3L/day (NHMRC 2009)

Water (L) = body weight x 0.03

• Role of water in body:

Participates in chemical and metabolic reactions

Thermoregulation

Maintain blood and cell volume

(Pinna, Rolfes & Whitney 2009, p. 399)

Detailed information available –‘Nutrition at a Glance’ ME Barasi,Blackwell Publishing 2007

PROTEIN

PROTEIN

• Greek word ‘protos’ meaning prime importance

• Second only to water in plant and animal tissues

• Constantly broken down and reassembled according to

body requirement

• Daily diet must be sufficient to replace what has been used

• Excess is either burned for energy or stored as fat

PROTEIN FUNCTIONS

• Growth and repair – DNA bases

• Structural constituent of most of the body

– Contractile muscles

– Fibrous other tissues

• Carry and store materials (transport proteins)

– Albumin – calcium, zinc and hormones

– Retinol binding protein (RBP) – vitamin A

– Hemoglobin – oxygen

– Transferrin – iron

– Ceruloplasmin - copper

PROTEIN FUNCTIONS

• Enzymes – digestive, catalytic

• Fibrinogen – blood clotting

• Blood group proteins – blood types

• Immune system proteins –

immunoglobulins and antibodies

• Proteoglycans – everything in

between tissues

PROTEIN FUNCTIONS

• Hormones – insulin, leptin, thyroxine

• Neurotransmitters production

• Cell membrane channels and pumps

• Transport proteins – albumin and globulin

maintain fluid volume in the capillaries

• Acid-Alkaline balance

DIETARY SOURCES

Protein quality

Digestibility

Amino acid composition

• Complete

Contain all essential amino acids

Animal sources only

• Incomplete

Lacking one or more essential amino acids

Plant sources

DIETARY SOURCES

• Complementary Proteins

Combining a variety plant foods that together contain all the essential amino acids

Not necessary per meal as body maintains an amino acid pool (Marsh 2012)

Rolfes, Pinna & Whitney 2009

EXCESSIVE PROTEIN INTAKE

• Caution with pre-existing or high risk of kidney disorders

Ingestion of a high protein diet, kidney blood flow increases

20-30% in 1-2 hours.

Need to monitor

• Mineral losses

May increase calcium excretion, esp. purified powders

• Obesity and heart disease

Animal proteins also high in saturated fat

• Cancer

High animal protein intake linked to colon cancer

(Insel 2011)

PROTEIN SUPPLEMENTS

• Protein powders –

Commonly used to increase skeletal muscle synthesis

May only occur in response to exercise

If excess is being consumed without exercise, may be burned for energy or stored as fat.

If used for energy, increased nitrogen excretion can increase the burden on the kidneys and increases fluid intake requirements

Purified protein powders lack other nutrient components found in foods which are needed to build muscle tissue

(Whitney 2011)

PROTEIN SUPPLEMENTS

• Amino Acid supplements –

Single amino acids do not occur naturally in nature

High concentrations and unusual combinations may be harmful

Excess single amino acids increase demand for a carrier at the

expense of another amino acid possibility of deficiency

High dose branch chain amino acids (popular with body builders)

can raise plasma ammonia levels which is toxic to the brain.

(Whitney 2011)

CARBOHYDRATES

DIETARY SOURCES

• Grains – breads and cereals, including corn

• Legumes – lentils, beans, peas

• Fruit and root vegetables

• Dairy foods – mainly milk and yoghurt

• Processed foods – sweets and hidden

TYPES AND FUNCTIONS

Based on number of sugar molecules

Simple sugars and starches

Used to provide energy

Unused → triglycerides → stored in fat cells

Fibre

Indigestible portion of plant foods

Move foods through digestive system

Absorb water, toxins and other substances

Adds bulk to stools

Increases beneficial microbiota in the intestines

WHOLE GRAINS

• Bran

“Outer shell”

Fibre, B vitamins, trace minerals

• Endosperm

Provides energy

Carbohydrate, protein

• Germ

Nourishment for the seed

Antioxidants, vitamin E, B vitaminswww.wheatfoods.org

REFINING GRAINS

(Slavin et al, 1999)

GLYCAEMIC INDEX (GI)

• Lower GI foods = difficult to digest slower release of sugars

• High GI foods = easy to digest release sugars more rapidly high insulin levels

• Processing of some grains can alter resistance to digestion

• Higher fiber and higher fat foods are also more resistant due to their complexity

EFFECTS ON BLOOD SUGAR

LEVELS

(Jenkins et al, 2002)

GLYCAEMIC INDEX (GI)

(Rolfes, Pinna & Whitney 2009)

GLYCAEMIC LOAD (GL)

What information does the glycaemic load provide us with?

How does it differ from the GI of a food?

http://www.mendosa.com/gilists.htm

GLYCAEMIC LOAD (GL)

Calculating the GL

Carbohydrate (g) x GI /100 = GL

eg.

½ cup of watermelon = 6g x 0.72 = GL of 4.3

½ cup of cornflakes = 47g x 0.71 = GL of 33

½ cup of white rice = 36g x 0.72 = GL of 26

LOW GLYCAEMIC/LOAD

FOODS AID TO:

Reduce post prandial blood glucose levels.

Increase satiety

Increase the variety of foods that are suitable for someone with diabetes.

Reduce the frequency of overnight hypoglycaemic episodes.

Reduce fasting blood glucose levels.

Reduce the dose of oral hypoglycaemic medication.

Reduce insulin requirements.

WESTERN DIETS AND

CARBOHYDRATES

Of major concern is the 40-50% of the Western Diet is carbohydrates, mainly from refined and processed nutrient poor sources.

(Australian Bureau of Statistics)

WESTERN DIETS AND

CARBOHYDRATES

Consequences

Depletion of nutrients required for

carbohydrate metabolism

Insufficient fibre consumption

Most of carbohydrates in the Western diet

are also of a high GL

Associated with

Stroke (Oh K et al, 2005)

High cholesterol (Fried,2003)

Inflammation (Nakanishi, 2005)

Diabetes mellitus (Liu, 2002)

PCOS (Marsh and Brand-Miller, 2005)

Gall bladder disease (Tsai et al, 2005)

EXCESSIVE REFINED

CARBOHYDRATES

DIETARY FIBRE

Fruits, vegetables, wholegrains and legumes are a good source

Adds bulk to foods, so the stomach turns off ghrelin (hunger hormone) sooner

Delays gastric emptying and release of sugars from GIT which benefits satiety and blood sugar regulation (Brown et al 1999)

Binds to bile acids, reducing both toxin and cholesterol resorption from the gut, the latter improving lipid profiles

(Brownlee et al. 2005)

SOLUBLE FIBRE

Found in fruits and vegetables

Digested by intestinal bacteria producing anti-inflammatory SCFA’s

Soluble fibers form gels

Water holding capacity depends on pH of GI tract, size of fibre particles or degree of processing

Coarsely ground bran with large particles increases hydration capacity than finely ground.

(Ink and Hurt 1987)

SOLUBLE FIBRE

Psyllium, pectin, guar and oat gum (mainly soluble fibre) significantly reduced serum cholesterol levels

Oatbran and soy bean fibre (soluble and insoluble fibre) had intermediate effects

Corn, wheat and rice bran were found ineffective mainly being due to higher levels of insoluble fibre.

Soluble rich fibres also decrease HMG CoA reductase activity which causes a decrease in cholesterol synthesis in rats

(Anderson et al 1994)

INSOLUBLE FIBRE

Non-fermentable fibres

Often referred to as roughage

Increase growth of beneficial bacteria in colon which is important for detoxification and increasing stool bulk

Increased scavenging of toxins and other metabolic byproducts

Provides substrates for endogenous synthesis of vitamins such as vitamin K, B12, SCFA’s

Decrease conversion of cancer causing substances into carcinogens (Garrow et al, 1998)

STARCHES

• Raw and unprocessed starches

Not well digested

Heating in the presence of moisture disrupts the structure

This is a reversible process

• Resistant starches

Release their sugars over

several hours after a meal

Legumes, beans and peas, whole and intact grains

(Kohlmeier, 2003)

FIBRE RECOMMENDATIONS

The World Health Organization recommends 12-24g of fibre per day for healthy people

25-30g/day of fibre is recommended to reduce the risk of diverticular disease, colorectal cancer, and breast cancer

Australian recommendations 25g/day for women and 30g/day for men

FIBRE FOOD VALUES

Food Serving Fibre (g)

Navy beans, ckd 1 cup 19.1

100% Bran cereal 1 cup 17.6

Kidney beans, ckd 1 cup 16.4

Lentils, ckd 1 cup 15.6

Prunes 1 cup, pitted 12.1

Quinoa, ckd 1 cup 9.3

Artichoke hearts 1 cup 9.1

Raspberries 1 cup 8.0

Spinach, frozen, ckd 1 cup 7.0

Oat bran ckd 1 cup 5.7

Instant oatmeal, ckd 1 cup 3.7

Rice, long-grained brown, ckd 1 cup 3.5

Mushrooms 1 cup 3.4

(Adapted from Higdon, 2005)

FIBRE FOOD VALUES

Generally speaking

Fruit and vegetables contain 1.5g / serve

Refined carbohydrates 1g / serve

Whole grains 2.5g /serve

Beans and legumes 8g/serve

FIBRE RESEARCH

Anderson JW, Allgood LD, Lawrence A, et al. 2000, “Cholesterol-lowering effects of psyllium intake adjunctive to diet therapy in men and women with hypercholesterolemia: meta-analysis of 8 controlled trials.” Am J Clin Nutr. Vol 71 Iss 2 pp 472-479.

“Psyllium supplementation significantly lowered serum total and LDL-cholesterol concentrationsin subjects consuming a low-fat diet. Psyllium is well tolerated and safe when used adjunctive to a low-fat diet in individuals with mild-to-moderate hypercholesterolemia.”

FIBRE RESEARCH

AbuMweis, S Jew, S Ames, N 2010, “β-glucan from barley and its lipid-lowering capacity: a meta-analysis of randomized, controlled trials” European Journal of Clinical Nutrition Vol 64, Dec pp1472-1480

“Increased consumption of barely products should be considered as a dietary approach to reduce LDL cholesterol concentrations.”

FIBRE RESEARCH

Bliss DZ et al. 2001. Supplementation with dietary fiber improves fecal incontinence, Nurs Res . Volume 50, Issue 4. pp. 203-13

“Supplementation with dietary fiber from psyllium or gum arabic was associated with a decrease in the percentage of incontinent stools and an improvement of stool consistency.”

FIBRE RESEARCH

Sherry, C Kim, S Dilger, R Bauer, L Moon, M Tapping, R Fahey, G Tappenden, K Freund, G 2010 “Sickness behavior induced by endotoxin can be mitigated by the dietary soluble fiber, pectin, through up-regulation of IL-4 and Th2 polarization.” Brain Behavior and Immunity, Volume 24, Issue 4, May 2010, Pages 631–640

“A diet rich in soluble fiber protects mice from endotoxin-induced sickness behavior by polarizing mice Th2 when compared to a diet containing only insoluble fiber. Mice fed soluble fiber became less sick and recovered faster from endotoxin-induced sickness behaviors than mice fed insoluble fiber.”

FIBRE RESEARCH

Deficiency has been associated with:

Constipation - Most patients with chronic constipation respond to fibre supplementation (Wald, 2000)

Diverticulitis coli - Low fibre diets prolong colonic transit time and result in increased intraluminal pressure due to low-volume stools (Ye, Losada and West, 2005)

Colorectal cancer - The association with colon cancer and dietary fiber is still inconclusive (Martinez 2005)

Coronary heart disease - Among other dietary changes, wholegrain cereals and an abundance of fruit and vegetables offers protection from many cardiovascular conditions (Hu and Willet, 2002)

Diabetes mellitus - Lowering of the glycaemic load by consuming high fibre foods can reduce the risk of diabetes mellitus (Gray, 1995)

FATS

FATS

Functions –

Energy reserve and insulation

Hormone and vitamin D synthesis

Important in transporting fat soluble vitamins such as A, D, E, and K

Essential part of the cell membranes

A source of eicosanoid producing essential fatty acids

TYPES OF FATS

Triglycerides

Saturated Fats

Trans Fats

Monounsaturated Fats

Polyunsaturated Fats

Omega 6

Omega 3

FAT IS GOOD!!

Depending on what kind….

Omega 3 fatty acids (fish oils-EPA, DHA; plant sources -ALA)

Mono-unsaturated fats (macadamia and olive oils)

SCFA’s

Decreased fat consumption since the 1960’s

not associated with obesity epidemic

CHO intake has increased dramatically

Glycemic index/glycemic load

SATURATED FATS

• Saturation affects the physical characteristics of the fat and its storage properties.

Stable structure

• Types:

Butyric acid: Butter and milk fat (SCFA)

Palmitic acid: Palm oil

Lauric acid: Coconut oil

Arachidic acid: Peanuts

Stearic acid: Beef, mutton, pork, cocoa butter

• WHO recommends maximum of 10% total energy intake.

FUNCTIONS

• Total cholesterol: HDL cholesterol ratio

• Lauric acid (coconut) – greatly decreased ratio

• Palmitic acid (palm) – no effect

• Steric acid (animals) - slightly increased ratio

Replacing saturated fats with

Unsaturated fats – decreased ratio

Carbohydrates – no effect on ratio but increased fasting triglycerides

Replacing trans fats with carbohydrates and unsaturated fats - decreased ratio (Mensink 2003)

HOW INTAKE OF OMEGA-3 FATTY

ACIDS IS HELPFUL

Stabilization of atherosclerotic plaques

Reduction of inflammation by moderating prostaglandin synthesis pathways

Improved ratio of omega-3 to omega 6 FA reduces arachidonic acid and pro-inflammatory, pro-platelet aggregatory cytokines

Enhances PGE1 and PGE 3 and less inflammatory leukotrienes

Thies F, et al. Association of n-3 polyunsaturated fatty acids with stability of atherosclerotic plaque: RCT, Lancet, 2003;361:477-85

Harper, Beyond the Mediterranean Diet: the Role of Omega-3 Fatty Acids in the Prevention of CVD, Prev Cardiol, 2003;6(3):134-46

POLYUNSATURATED

ESSENTIAL FATTY ACIDS

Omega 3 Omega 6

Chia seeds Corn oil

Flaxseeds / linseeds Safflower oil

Sardines Sunflower oil

Herring Soy bean oil

Mackerel Turkey

Salmon Salad dressing

Green lipped mussels Canola oil

Sydney rock oysters Vegetable oil

Walnuts Seeds

Seaweeds Nuts

TRANS FATS SATURATED FATS

Trans-fatty acids- the hydrogen atoms are on opposite sides of the double bond and the carbon chains are also on opposite sides; the effect of this is that the molecules can pack into straight line shapes just as saturated fatty acids do.

TRANS FATTY ACIDS

• Increase the risk of heart disease

• Increased risk of coronary artery disease

• Increased risk of thrombosis

• There have been no safe limits of trans fat consumption shown

Maximum intake of 1% of daily kJ recommended by the World Health Organization (WHO)

SOURCES

Cookies, crackers, cakes, muffins, pie crusts, pizza dough, and breads such as hamburger buns

Some stick margarine and vegetable shortening

Pre-mixed cake mixes, pancake mixes, and chocolate drink mixes

Fried foods, including donuts, French fries, chicken nuggets, and hard taco shells

Snack foods, including chips, candy, and packaged or microwave popcorn

Frozen dinners

(McCarthy et al 2008)

SHORT CHAIN FATTY ACIDS

SCFA’s support health by:

Providing energy for the distal intestinal epithelia

Assisting the regulation of electrolyte absorption

Anti-inflammatory properties

Enhances production of macrophages, t-helper cells, neutrophilsand antibodies, assisting immunity

Have other possible affects on the liver and other tissues

Decreases interluminal pH decreased secondary bile acid synthesis which has been shown to promote tumour generation

(Gropper and Groff 2009)

SHORT CHAIN FATTY ACIDS

Bacterial hydrolytic enzymes depolymerise the large undigested molecules, allowing microbiotica to ferment the component sugars and utilise the subsequent energy produced

Mainly acetate, propionate and butyrate.

Propionate carried by portal vein to liver for metabolism

decrease in cholesterol synthesis

converted to succinyl-CoA for glucose or energy production

Acetate travels to peripheral tissues and is metabolised by skeletal and cardiac muscles, kidneys and brain

Butyrate provides energy for colonic an epithelial cells Also been shown to decrease proliferation and differentiation of colon cancer cells in vitro.

(Tedelind et al 2007)

(Simopoulos 2008)

Detailed information available –‘Nutrition at a Glance’ ME Barasi,Blackwell Publishing 2007

FACTORS CONTRIBUTING TO

MICRONUTRIENT DEFICIENCIES

Chronic diseases

Chronic inflammation

Elderly

Malabsorption

Malnutrition

Substance abuse

Medications

STAGES OF MICRONUTRIENT

DEFICIENCY

1. Inadequate nutrient delivery

2. Depletion of nutrient stores

3. Biochemical changes

4. Physical manifestations of deficiency

5. Morbidity and mortality

VITAMINS AND

MINERALS

VITAMINS AND MINERALS

Macronutrients provide structure , function and produce energy

Micronutrients are essential as cofactors for all of these processes to occur

All essential nutrients are similar in that they are vital to life and available from foods.

Both deficiencies and excesses of supplemental vitamins and minerals can affect health!

VITAMINS

Water Soluble

Vitamin C

B group

Fat Soluble

A, E, D, K

WATER SOLUBLE VITAMINS

(Adapted from Groff and Gropper, 2000)

WATER SOLUBLE VITAMINS

• Absorbed directly into blood

• Not stored long in body except vitamin B12

• Excreted in urine

• Easily destroyed during

food storage or preparation

WATER SOLUBLE VITAMINS

• The organic nature of vitamins means they can be destroyed by exposure to light, air, cooking and storage.

• Preventative measures should be taken

Refrigeration

Cut fruits and vegetables should be stored in closed containers

Avoid high temperatures and long cooking times

Steam as opposed to boil

FAT SOLUBLE VITAMINS

• Differ from water-soluble vitamins in several significant ways:

(Whitney & Rolfes, 2008)

FAT SOLUBLE VITAMINS

• Participate in numerous activities throughout the body:

Vitamin A – Primarily involved in eye function, skin health, nervous system, bone tissue and immune function

Vitamin D – Regulates bone metabolism and cell renewal

Vitamin E – Antioxidant

Vitamin K – Involved in blood

clotting and bone mineralisation

MINERALS

Macrominerals

Calcium

Magnesium

Microminerals

Iron

Zinc

HIGH CALCIUM FOODS

• Seaweed

• Almonds, sesame seeds

• Green leafy vegetables

• Dairy products

• Tofu

• Salmon bones

• Sweet potato

CALCIUM FUNCTIONS

• Skeletal structure

• Cell to cell communication

• Muscle contraction with magnesium

• Nerve transmission

• Blood clotting with vitamin K

• Growth and repair of tissues

FACTORS INCREASING

DEMAND

• Menopause

Low oestrogen increases urinary excretion and bone loss

• Elderly

Low stomach acid reduces absorption

• Vitamin D deficiency

Decreases absorption and increases urine losses

Coffee and black tea

Decreases absorption

(Zimmerman, 2001)

FACTORS INCREASING

DEMAND

• Gallbladder disease

Reduced fat absorption allows fats to bind to calcium

Medication

Antacids, laxatives, steroids

• High sodium intakes

Increase urinary excretion

• Alcohol

(Zimmerman, 2001)

HIGH MAGNESIUM FOODS

• Wholegrains

• Nuts and seeds

• Dark green vegetables

• Legumes

• Seafood

• Potatoes

• Cocoa

FUNCTIONS

• Bone structure

Supports bone mineralization with calcium

• Enzyme cofactor

Over 300 enzyme processes

Energy metabolism

Balancing Calcium

Competing with magnesium may be functionally important in preventing muscle cramps, increased blood pressure, and coronary vasospasms.

(Kohlmeier, 2003)

FACTORS INCREASING DEMAND

Digestive problems

Prolonged vomit and diarrhea

• Rapid growth

Pregnancy

Childhood and adolescence

• Medications

Diuretics, laxatives

Chemotherapy, cortisone

• Diabetes mellitus(Saris et al, 2000)

FACTORS INCREASING DEMAND

• Stress

• Athletes

• Alcohol consumption

• Protein deficiency

• Kidney disorders

(Zimmerman, 2001)

HIGH ZINC FOODS

• Highest in protein rich foods

• Oysters

• Beef, turkey, crab

• Nuts and seeds

• cashews

• Legumes

• Ginger

FUNCTIONS

Manufactures heme for hemoglobin

Fatty acid, protein, carbohydrate,

vitamin A and alcohol metabolism

Antioxidant

Digestion

Growth and repair

Immune function

(Prasad 2013)

FACTORS INCREASING DEMAND

• High dose calcium, folate and iron

supplementation

• Vegetarian diets

• Digestive disorders

• Alcohol consumption

Reduced absorption and decreased excretion

• Diabetes mellitus

Increased urinary losses

(Gropper 2005)

IRON

• Heme iron

Found in foods that are from the flesh of animals (meat, poultry, and fish)

Has an absorption rate of 25%

• Nonheme iron

Found in plant-derived and animal-derived foods

Has an absorption rate of 17%

• Heme iron is better absorbed but nonheme iron absorption can

be enhanced with vitamin C

FUNCTIONS

• Oxygen transport and storage

• Energy production

• Free radical metabolism

DNA synthesis

Thyroid hormone synthesis

Vitamin A metabolism

Converts beta carotene to vitamin A

Amino acid metabolism

FACTORS INCREASING DEMAND

• Growth periods

• Vegetarians

• Coffee and tea consumption

• Low stomach acid

• Heavy/chronic bleeding

• Athletes

• Chronic inflammation or illness

• Nutrient deficiencies – Vitamin A, B6, Copper

(Zimmerman, 2001)

TAKE HOME MESSAGES AND

RECOMMENDATIONS

Stay up to date with scientific literature to provide educated opinions to your patients on the various ‘health fads’

Be aware of factors increasing the need for various nutrients and ensure your patients are consuming adequate levels

Recognise the need for discernment when investigating benefits of any commercial product

There are no miracle cures

You can always rely on your background understanding of physiological mechanisms and underlying biochemistry to get more of a clear picture of the facts