WMST 245

SECTION 8

FOOD AND NUTRITION

HUMANS NEED NOURISHMENT. THEY GET IT FROM SIX KINDS OF NUTRIENTS – ALL ARE IMPORTANT, AND THE FIRST THREE GIVE US ENERGY

1. CARBOHYDRATES2. FAT3. PROTEIN4. VITAMINS5. MINERALS6. WATER

HOW MUCH FOOD DO HUMANS CONSUME EACH DAY?

WE CAN’T EXPRESS THIS AS OUNCES OF CEREAL OR LBS OF CHEESE, BECAUSE WE CAN’T COMPARE THESE. WE HAVE TO USE AN INDEX CALLED KILO-CALORIES

THE AVERAGE CONSUMPTION OF KCALS EACH DAY DEPENDS ON WHERE PEOPLE LIVE.

THE AVERAGE IN THE USA IS ABOUT 3,770 [as much as 40% may be wasted, making the net figure 2,262].

THE AVERAGE IN ETHIOPIA IS ABOUT 1,850

HOW MUCH ENERGY DO WE NEED TO LIVE?

IT DEPENDS:

• AGE• HEIGHT• WEIGHT• CLIMATE• MALE OR FEMALE• WORK/ACTIVITY• PREGNANT OR LACTATING?

HOW MUCH ENERGY DO WE NEED TO LIVE?BASAL METABOLIC RATE (BMR) IS THE

“MINIMAL EXPENDITURE OF ENERGY COMPATIBLEWITH LIFE”

Height (ins.) Weighta (lb) 18-30 years (kcal/day)

30-60 years (kcal/day)

>60 years (kcal/day)

Men 63 125 1540 1530 1250 67 140 1650 1620 1350 71 158 1770 1710 1450 75 175 1890 1800 1560 Women 59 104 1190 1240 1090 63 119 1290 1300 1160 67 134 1390 1360 1230 71 150 1500 1420 1310 a. Weight is a median acceptable weight for height; body mass index (Wt/ Ht2) = 22 for men, 21 for women

HOW MUCH ENERGY DO WE NEED TO LIVE?ADULT PHYSICAL ACTIVITY LEVEL (PAL)

MULTIPLY BMR BY THE PAL COEFFICIENT

Activity Level PAL coefficient Chair-bound 1.2 Seated work 1.4-1.7 Standing work 1.8-1.9 Strenuous physical work 2.0-2.4 Significant sports (30-60 minutes, 4-5X per week)

+0.3 (increment)

Women Work Crew Builds a Road in Lesotho, 1969

Women working with plow in the field: As women struggle to subsist with labor and capital scarcity, they often are forced to adjust cropping patterns that can decrease production or damage the

environment.

HOW MUCH ENERGY DO WE NEED TO LIVE?CHILDREN (KCals per Day)

Age (years) Weight (lbs) Light Activity Mod. Activity Heavy Activity Boys 1 23 854 942 5 41 1346 1486 10 69 1885 2126 2370 15 125 2659 2991 3406 Girls 1 22 783 865 5 39 1226 1352 10 72 1706 1933 2160 15 118 2048 2331 2613

HOW MUCH ENERGY DO WE NEED TO LIVE?COLD CLIMATES

We need more energy if we live in cold climates:  At 15 degrees C (59 degrees Fahrenheit) add 100

Kcal per dayAt 10 degrees C (50 degrees Fahrenheit) add 200

Kcal per dayAt 5 degrees C (41 degrees Fahrenheit) add 300

Kcal per day

Inuit women drying fox skins on a rack, at Bernard Harbour, Northwest Territories (Nunavut)

HOW MUCH ENERGY DO WE NEED TO LIVE?PREGNANCY & LACTATION

To support pregnancy needs additional Kcals of

energy, which may be obtained by reducing

activity or increasing food consumption. The

optimal amount of additional energy is about 96

Kcal per day in the first trimester, 265 Kcal per

day in the second trimester, and 430 Kcal per day

in the third trimester. A woman who is

breastfeeding needs an additional 500 Kcals per

day to support lactation.

HOW DO WE MEASURE WHETHER ANYONE IS GETTING ENOUGH TO EAT?

FOUR GROUPS OF MEASURES

•CLINICAL – bodily symptoms like hair pigment, edema (swelling), eyesight problems

•BIO-CHEMICAL – metabolic symptoms in blood or other fluids e.g. anemia

•DIETARY – food intake surveys

•ANTHROPOMETRIC – measurements of weight and height

MONITORING GROWTH IN CHILDREN

ASSESSING UNDER-NUTRITION WITH ANTHROPOMETRIC MEASURES

•Weight-for-Height•Height-for-Age•Weight-for-Age•Mid-Upper Arm Circumference (MUAC)•Skinfolds•Head Circumference

•Proxies for Length •Body Mass Index

BODY MASS INDEX

BMI (BODY MASS INDEX) = Weight/Height2

When weight is measured in kilograms (kg) and height in metres (m), the “acceptable” range of BMI is 18.5 to 25

e.g. someone five feet eight inches tall weighing 150 lbs has a BMI of 22.8e.g. someone five feet ten inches tall weighing 180 lbs has a BMI of 25.8[[to get in the “acceptable range” this person would need to weigh between 129

and 174 lbs]]e.g. someone five feet four inches tall weighing 135 lbs has a BMI of 23.2e.g. someone six feet tall weighing 200 lbs has a BMI of 27.1e.g. someone six foot four inches tall weighing 280 lbs has a BMI of 34.1e.g. someone six foot two inches tall weighing 240 lbs has a BMI of 30.8

Note: 1 kg = 2.2046 lbs; 1 metre = 3.280833 feet

The degree of athletic activity is important in assessing BMI

DIETARY DEFICIENCIES

THE BIG THREE:

IRON: DEFICIENCY CAUSES ANEMIA, TIREDNESS, REDUCED CAPACITY TO WORK, INCREASED SUSCEPTIBILITY TO INFECTION; SPECIAL PROBLEMS FOR PREGNANT WOMEN

IODINE: DEFICIENCY CAUSES GOITER, AND WHEN SEVERE, LOSS OF IQ, POOR BRAIN FUNCTION, AND CRETINISM; IT IS “THE LARGEST PREVENTABLE CAUSE OF MENTAL RETARDATION”

VITAMIN A: DEFICIENCY CAUSES NIGHT-BLINDNESS, AND WHEN SEVERE, BITOT’S SPOT AND TOTAL BLINDNESS; ALSO CAUSES PREMATURE DEATH FROM RESPIRATORY, & GASTRO-INTESTINAL DISEASE

OTHER DIETARY DEFICIENCIES

VITAMIN D: DEFICIENCY CAUSES RICKETS (SOFT & DEFORMED BONES, BOW-LEGGEDNESS)

VITAMIN C: DEFICIENCY CAUSES SCURVY (BLEEDING GUMS & GUM DISEASE, LOOSENING OF TEETH)

B-VITAMINS: BERI-BERI (THIAMINE: degeneration of the central nervous system and gastro-intestinal system); PELLAGRA (NIACIN: dermatitis, gastro-intestinal problems, central nervous system symptoms); “PERNICIOUS ANEMIA” (B12)

ZINC: DEFICIENCY RETARDS CHILD GROWTH, CAUSES DIARRHEA, DIFFICULTY ABSORBING OTHER MICRONUTRIENTS

SECONDARY MALNUTRITION

UNDERNUTRITION ATTRIBUTABLE NOT TO LACK OF FOOD AVAILABILITY BUT TO INABILITY TO ABSORB NUTRIENTS.

EXAMPLES ARE:

EATING DISORDERS

DIARRHEA FROM INTESTINAL PARASITES OR UNSAFE DRINKING WATER (only a part of the food eaten is available to the body – the rest is not digested properly or is shared with parasites)

INFECTIOUS DISEASES SUCH AS MEASLES (the body’s immune system uses a lot of energy to try to fight off the diseases; some of the food eaten is used to supply this energy to the immune system)

Young girl receives a measles vaccination at a health clinic in Demak, Indonesia

UNDERNUTRITION

UNDERCONSUMPTION OF PROTEIN AND CALORIES IS THE PROBLEM RELATED TO FOOD SHORTAGE

PROTEIN AND CALORIES ARE NUTRIENTSTHAT PEOPLE GET ALMOST EXCLUSIVELY FROM FOOD -- NOT FROM “SUPPLEMENTS” OR “FORTIFICATION”

UNDERNUTRITION

WHERE DO CALORIES AND PROTEIN COME FROM?

CALORIES: TRANSFORMING SOLARENERGY INTO HUMAN ENERGY BY“PHOTOSYNTHESIS”

PROTEIN: GETTING NITROGEN INTO THECHEMICAL EQUATION:

• LIGHTNING STORMS• NITROGEN FIXING BACTERIA• SEA ALGAE

NUTRITIONAL ROLE OF PROTEIN

1. BUILDING CELLS THAT MAKE UP MUSCLES, MEMBRANES, CARTILAGE, HAIR

2. CARRYING OXYGEN AROUND THE BODY

3. CARRYING NUTRIENTS INTO AND OUT OF CELLS AND HELPING TO ASSIMILATE FOOD

4. CONTRIBUTING TO DEVELOPMENT OF ANTIBODIES THAT FIGHT DISEASE

5. WORKING AS ENZYMES TO SPEED UPDIGESTIVE PROCESSES

QUALITY OF PROTEIN

PROTEIN IN THE BODY IS CONSTRUCTEDFROM 22 AMINO ACIDS – THE BODY MAKES 13

OF THEM, BUT:

9 “ESSENTIAL” AMINO ACIDSCANNOT BE MADE BY THE BODY

THEY MUST BE IN THE DIET.

A FOOD THAT CONTAINS ALL 9 ESSENTIALAMINO ACIDS IN SUFFICIENT CONCENTRATIONS

TO MEET HUMAN NEEDS IS CALLED

A “COMPLETE PROTEIN”

ANIMAL PRODUCTS (MEAT, MILK, EGGS)ARE “COMPLETE PROTEINS”

PLANT PRODUCTS (CEREALS, LEGUMES) AREMISSING ONE OR MORE OF THE ESSENTIAL AMINO ACIDS OR CONTAIN THE ACID IN TOO LOW A CONCENTRATION

THE NEED FOR BALANCE AMONG THE ESSENTIAL AMINO ACIDS: THE BODY MUST HAVE AMINO ACIDS IN CORRECT PROPORTIONS IN ORDER TO PRODUCE PROTEINS

VEGETABLE VS ANIMAL?

CALORIE DEFICIENCYAPPEARS TO BE BIGGER PROBLEM

THAN PROTEIN DEFICIENCY

NUTRITIONIST NEVIN SCRIMSHAW:

“ADULT PROTEIN NEEDS ARE MET BY MOSTTRADITIONAL DEVELOPING COUNTRY DIETS WHEN THEY ARE CONSUMED IN SUFFICIENT

QUANTITY TO MEET NORMAL ENERGY NEEDS.”

1995 FOOD AVAILABLE IN SUB-SAHARAN AFRICACALORIES: 2144 PROTEIN: 51.6 gms.

If you get enough calories, chances are you get enough protein.If you get enough protein, you may not get enough calories.

HOW MUCH OF A NUTRIENT IS ENOUGH”?(HOW DO WE SET STANDARDS?)

DIFFERENT PEOPLE HAVE DIFFERENT NEEDS A CHILD’S NEEDS ARE DIFFERENT FROM AN ADULT’S A WOMAN’S NEEDS ARE DIFFERENT FROM A MAN’S A WOMEN PREGNANT OR LACTATING NEEDS MORE AN ACTIVE PERSON HAS DIFFERENT NEEDS FROM A

SEDENTARY PERSON LIVING IN A COLD CLIMATE INCREASES NEEDS NEEDS DIFFER WITH HEALTH STATUS SOME PEOPLE HAVE DIFFERENT NEEDS FOR

UNEXPLAINED REASONS – THEY HAVE “DIFFERENT METABOLISM”

EVEN AFTER SPLITTINGTHE POPULATION INTO GROUPS

THERE ARE DIFFERENCES INNUTRIENT REQUIREMENTS AMONG

MEMBERS OF A SINGLE GROUP:

E.G. NOT ALL WOMEN BETWEEN AGES OF 25 & 35 HAVE THE SAME

NUTRIENT REQUIREMENTS

2.5% of thepopulation

2.5% of thepopulation

Bell-shaped curve showing the distribution of nutrient requirements in the population, and how the RDA is setat two standard deviations above the mean, greater than the needs for 97.5 % of the population:

some peopleneed a lot ofcalories orprotein

averageor meanlevel

some peopleneed fewer nutrients thanthe average person

RDA: recommendednutrient level

WHO SETS THE STANDARDS?

IN THE USA, STANDARDS ARE SET BY THE FOOD & NUTRITION BOARD OF THE NATIONAL ACADEMY OF SCIENCES INSTITUTE OF MEDICINE

IN THE LATE 1990S, THE BOARD REVIEWED STUDIES, AND ISSUED MORE COMPREHENSIVE GUIDELINES INCLUDING THE FOLLOWING ELEMENTS:

RDA (Recommended Dietary Allowance): average daily intake sufficient to meet needs of almost all (97-98%) healthy persons

AI (Adequate Intake): estimated only when RDA can’t be determined; based on observed intakes by health persons

UL (Upper Intake Level): the highest daily intake likely to pose no risks of toxicity for almost all persons

EAR (Estimated Average Requirement): intake meeting the need of half of all healthy individuals in the population

REFINING THE STANDARDS

EACH OF THE REFERENCE VALUES OF THE FOOD & NUTRITION BOARDS TAKES INTO ACCOUNT GENDER, DIFFERENT LIFE STAGES, BIOAVAILABILITY OF NUTRIENTS FROM DIFFERENT SOURCES, INTERACTIONS BETWEEN NUTRIENTS AND BETWEEN NUTRIENTS & DRUGS, AND INTAKE FROM FOOD FORTIFICATION AND SUPPLEMENTATION

IN JAN. 2001 THE BOARD RELEASED INTAKE RECOMMENDATIONS FOR VITAMINS A & K, AND 12 MINERALS: arsenic, boron, chromium, copper, iodine, iron, manganese, molybdenum, nickel, silicon, vanadium, and zinc. Recommendations for calcium, fluoride, magnesium, phosphorus and selenium were released previously

http://www.iom.edu

PROBLEMS WITH NUTRITIONALSTANDARDS

•DIFFERENT INDIVIDUALS HAVEDIFFERENT NUTRITIONAL NEEDS

• COMPARING DISTRIBUTIONS OFNEEDS AND INTAKE.

• THE NUTRITIONAL NEEDS OF ANINDIVIDUAL MAY CHANGE OVER TIME.

•IMPORTANCE OF QUALITY OF PROTEIN