phd program in space life science functions of nutrition in space scott m. smith, ph.d. nutritionist...

PhD Program in Space Life Science

Functions of Nutrition in Space

Scott M. Smith, Ph.D.Nutritionist Manager for Nutritional BiochemistryNASA Johnson Space Center


Nutritional Biochemistry Lab – NASA/JSC

Charge: determine the nutritional requirements for extended duration space flight Calorie requirements Vitamin A, E, and D,

Calcium, Iron, and Zinc

Courtesy of NASA


Functions of Nutrition in Space

Meet energy / nutrient requirements

Psychosocial aspects of the food system

Nutrition as a countermeasure Changes in the diet to

mitigate negative effects of space flight

Importance of defining the nutritional requirements for crews before departure


Concerns: Nutrition in Space Flight Nutrient Requirements

Energy CHO (fiber), Fat, Protein Fat-soluble vitamins Water-soluble vitamins Minerals, Fluid

Systems Bone, Muscle, Cardio

Fluid/Electrolyte Immunology Hematology, Neurology Endocrine, Behavioral

health & performance, Gastrointestinal

Countermeasures Energy, Amino acids,

Protein, Sodium Fatty acids Antioxidants, Vitamin D Bisphosphonates, K-Citrate Medications, Exercise Other

Vehicle/Mission Food System, Duration Radiation, extra vehicular

activity Schedule


Apollo Skylab Shuttle Mir E1-4 E5-130

102030405060708090

100110

% W

HO

pre

dic

ted

Food intake is one of the primary challenges in space

Dietary intake across the space programs

Percent of World Health Organization predicted energy requirement

Crew members can meet their nutritional requirements through food while in space

Energy

Adapted from Smith, SM, 2005, 2008

Energy intake across different space programs


Percent of body weight loss at the end of a mission

Effects of long duration flights: Excess loss of

10% body mass

Other effects: Fluid shift Salt loading Emesis

0 20 40 60 80 100 120 140 160 180 200 220-15

-10

-5

0

5

10

Mission Duration (days)

%

fro

m P

refl

igh

t

Energy

Each symbol is a difference crew member

Adapted from Kloeris, LH, 2007


Question From the Audience

Are these weights measured after attempts

are made to restore plasma volume

to normal levels?


Percent of body weight loss at the end of a mission

Effects of long duration flights: Excess loss of

10% body mass

Other effects: Fluid shift Salt loading Emesis

0 20 40 60 80 100 120 140 160 180 200 220-15

-10

-5

0

5

10

Mission Duration (days)

%

fro

m P

refl

igh

t

Energy

Each symbol is a difference crew member

Adapted from Kloeris, LH, 2007


Likely consequences of poor food intake Fair/poor function of

cardiovascular system Loss of muscle mass Loss of bone mass

NTX (urinary N-telopeptide)

PICP (serum type I procollagen carboxy-terminal propeptide)

OC (plasma osteocalcin)

Reproduced from J Bone Miner Res 2004;19:1231-1240 with permission of the American Society for Bone and Mineral Research

Energy


Dietary intake record using Food Frequency Questionnaire

0 50 100 150 2000

50

100

150

-10

-5

0

5

Body Mass

Energy intake

Day of Flight

En

erg

y In

take

(% W

HO

)

Bo

dy

Mas

s(%

f

rom

pre

flig

ht)

Courtesy of NASA

Food Frequency Questionnaire

Energy: Case Study

Adapted from Smith, SM, 2005


SN Control Pre Post0

102030405060708090

100110

25 (

OH

) V

itam

in D

(nm

ol/

L)

Consortium for Research in Elder Self-Neglect (SN) of Texas (CREST) Study

25 (OH) Vitamin D Elderly individuals Average age: 77 years Consequences of poor

Vitamin D intake below

25 nmol/L Rickets, Osteomalacia

U.S. Astronauts Pre and Post flight 4-6 months on board ISS Increased incidence of

disease between 25-80 nmol/L

Elderly Individuals

Astronauts



Parathyroid Hormone (PTH) is normalized when Vitamin D is above 80 nmol/L

The higher Vitamin D the lower the PTH levels

Bone and Beyond

Reproduced from New England Journal of Medicine. 338(12):777-783, 1998. Copyright © 1998. Massachusetts Medical Society. All rights reserved.


Bone and Beyond

Vitamin D status has been related to: Fracture risk and Bone Mineral Density Muscle strength/function, falls Cancer (prostate, breast, colon) Multiple sclerosis Blood pressure/heart disease Diabetes (type 1)


Recommendations Optimal Vitamin D status:

25D levels ≥ 80 nmol/L

Vitamin D sources: Foods

Fortified milk, orange juice Fish (e.g., salmon, tilapia,

tuna) Few other sources of Vitamin

D Sunlight

UV conversion of 7-dehydrocholesterol to previtamin D3 in the skin

Supplements


Antarctica

Courtesy of NASA

Polar Vitamin D Study in Antarctica

Blind supplementation study 4 groups in the study -

randomized: 400 IU Vit. D 1000 IU Vit. D 2000 IU Vit. D Individuals who

did not take the supplements but provided samples or

took their own Vit. D supplements


Courtesy of NASA

Credit:: NASA

Hyperresorptive bone loss Running on the treadmill does

nothing for bone health in space

Nutrition is a countermeasure against bone loss

Bone Loss in Space


Nutrition and Bone Dietary protein has a

significant impact on bone health

Higher ratio of animal protein to potassium in the diet provide more acid precursors

An increased ratio leads to more bone breakdown

NTX (N-telopeptide) APro/K (ratio of animal

protein intake to potassium intake)

0.50 0.55 0.60 0.65 0.70 0.75

0

250

500

750

1000

1250

1500

1750

r = 0.80*

APro/K (g/mEq)

NT

X (

nm

ol/

d)

Courtesy of NASA

Adapted from Zwart, SR, 2004


Nutrition and Bone Pilot Study: Antioxidant

countermeasure to mitigate oxidative damage Treatment: Grape juice, Vitamin

E & 0.5 mg NAC every day for 2 weeks

N-acetylcysteine (NAC) contains cysteine, a sulfur containing amino acid Metabolism increases acid load

which affects bone

N-telopeptide (NTX) - marker of bone resorption 50% increased excretion in bed

rest subjects, 100% increased excretion for astronauts

6 subjects – healthy astronauts 2 weeks placebo: no change in

N-telopeptide 2 weeks: Grape juice, Vitamin E

& 0.5 mg NAC/day Increased excretion of bone

markers identical to bed rest subjects


Nutrition and Bone

Courtesy of NASA

Space flight diet is high in sodium 5-8 grams Na/day

C-telopeptide (CTX) – marker of bone breakdown

Low Na+ diet before and during bed rest ~50% increase in CTX

High Na+ diet during bed rest

Na+ associated with pH High Na+ load leads to

acid that has negative effect on bone Unpublished data, graph not displayed


Nutrition and Bone

Vitamin K influence on bone

Related to synthesis of gamma-carboxyglutamic acid residues in proteins

Estimated by measuring Vit. K status - undercarboxylated osteocalcin (Uosteocalcin)

Vit. K = Uosteocalcin

0

5

10

15

20

25

Day

1-8

5

Day

131

-179

Day

86-

130

(Vit

amin

K)

Pre Mission PostU

Os

teo

ca

lcin

(%

)

Courtesy of NASA

Adapted from Vermeer, C, 2004


Nutrition and Bone European Data on MIR

1 astronaut before and after flight

After 85 days Uosteocalcin goes up without supplementation of Vit. K

With Vit. K supplementation Uosteocalcin goes down.

Omega-3 fatty acids Sources: spinach, salmon Relationship between omega-

3’s and bone Could mitigate cancer risk,

muscle loss and bone loss

0

5

10

15

20

25

Day

1-8

5

Day

131

-179

Day

86-

130

(Vit

amin

K)

Pre Mission PostU

Os

teo

ca

lcin

(%

)

Courtesy of NASA

Adapted from Vermeer, C, 2004


Mir ISS NEEMO0

50

100

150

8(O

H)d

G (

%

)

0 200 400 600 800 10000

5

10

15

20

25

Days of flight

Bo

dy

iro

n (

mg

/kg

)

Courtesy of NASA

Credit: NASA

Iron storage increases during flight

Urinary 8-hydroxy guanosine marker for oxidative damage

to DNA Increased after flight and

NEEMO Radiation/oxygen issues

have implications for cataracts and other health issues.

Iron and OxygenAdapted from Smith, SM, 2004



Unpublished data not displayed

Courtesy of NASA

The more total body iron the more oxidative damage

Iron and Oxidative Damage


Courtesy of NASA

Changes in iron metabolism during bed rest.

Transferrin receptors go down during bed rest suggesting excess iron

Total body iron vs. 8(OH)dG


Bed Rest


NEEMO – oxidative damage

Courtesy of NASA

NEEMO analogue Hyperbaric environment

Total body iron increases Malonaldehyde increases –

marker of oxidative damage Inverse relationship between

total body iron and SOD – seen with iron overload

Iron excess is related to oxidative damage.

Pre

MD6/

7

MD9/

11R+0 R+6

-20

0

20

40

60

80

To

tal

bo

dy

iro

n (

%

)Pre

MD6/

7

MD9/

11R+0 R+6-50

0

50

100

150

MD

A (

%

)

Adapted from Zwart, SR, 2008


Courtesy of NASA

Space Suit

Peggy Whitson - extra vehicular activity (EVA) suit

Provides thermal protection

Reduced pressure environment


Courtesy of NASA

First Blood & Urine Samples on ISS

Vitamin D levels before & after flight Flight day 15 to

flight day 80 – levels hold

800 IU/day of Vitamin D is recommended



Courtesy of NASA

Cape Canaveral – Kennedy Space Center

phd program in space life science functions of nutrition in space scott m. smith, ph.d. nutritionist...

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