Tang nutrition vit a

Using Bio-fortified Crops for

Community Intervention Studies

Guangwen Tang, Ph.D.

Carotenoids and Health Laboratory

Jean Mayer USDA

Human Nutrition Research Center on Aging

Friedman School of Nutrition Science and Policy

Tufts University

To combat vitamin A deficiency:

• vitamin A capsule supplementation

• food fortification

• dietary approach (the best and major

long-term solution)

Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University

Food Sources of Vitamin A

animal products plant products

preformed

vitamin A

pro-vitamin A

carotenoids

CH2OH

+

ß-carotene

retinol

in SERUM

ß-carotene

Provitamin A Carotenoids Can

Convert to Vitamin A



Food matrix DoseConversion

Factor (by wt)Reference

carrot

n = 7

10 mg b-C

3 mg 2H8 vitamin A

15 : 1

(8 to 25 : 1)

Tang, et al.

AJCN 2005

spinach

n = 14

11 mg b-C

3 mg 2H8vitamin A

21 : 1

(11 to 47 : 1)Tang, et al.

AJCN 2005

Conversion Factors of Plant b-Carotene to Retinol

Using Isotope Reference Method in Adult Subjects

21 to 12,500 mg

b-carotene 100 mg50 g

50 g 85 mg retinol

50 g 3,000 mg

b-carotene 200 mg15 to 1

200 ml

90 mg retinol

15 g 130 mg retinol

300 mg retinol

305 mg retinolor

30 g

RDA: men 900 mg and women 700 mg retinol

Children 4 – 8y, 400 mg


Subjects DoseConversion

Factor (by wt)Reference

Golden Rice

5 Adults

1 – 1.5 mg b-C

0.5 – 1 mg 13C10

vitamin A

3.8 : 1

(2 to 6 : 1)

Tang, et al.

AJCN 2009

Golden Rice

24 Children

1 mg b-C

0.5 mg 13C10

vitamin A

2.0 : 1

Tang, et al.FASEB J. 2010

Yellow Maize

US Women

n = 5

0.6 mg maize b-C

250 g

porridge

6.5 : 1

( 3.9 to 13.3 : 1)

Li, et al.

AJCN 2010

Zimbabwean

Men, n = 8

1.2 mg maize b-C

300 g porridge

1 mg 13C8vitamin A

(reference dose)

3.2 : 1

(1.5 to 5.3 : 1)Muzhingi et al

FASEB J. 2010

Conversion Factors of an Acute Dose of

Golden Rice or Maize b-Carotene to Retinol


These results indicate that

Golden Rice and high b-

carotene yellow maize are

more bioavailable to provide

vitamin A nutrition.


Based on the Progress in Nutrition:

How do we maximize impact and

speed up delivery?

Win community support !!!

Conduct community studies to feed these

staples daily to needed children.

It will provide direct evidences on improving

vitamin A status with the biofortified staples.


Choose right locations

Inform and communicate with local

government agency

School and parent supports

Good intervention study practice

Large scale intervention trials

to evaluate the efficacy

Hengyang, South of Hunan Province

South-west Zhejiang Province


A Small Town of Xianju County


Recruitment meeting:

Local Office, Parent, Teacher, and Scientists


Meeting with Parents


Presenting the Protocol


Asking Questions

Sterilizer Cabinet for Utensils


Purchase Foods from Reliable Sources

Distributing Labeled VA Capsules

as a Reference Dose



Providing Healthy Meals

Get Ready for Blood Draw

Before the End of Study Meeting

Gifts for Participation

Putting Gifts Together

Sign to Receive Gifts for Participation


Large scale community

efficacy intervention trials

will bring the new crops

to their daily life, gain first-hand

health impact information,

and promote the acceptance.

Tang nutrition vit a

Education