Dietary Reference Intakes

Jennifer Hillan, MSH, RD, LD/N

Family, Youth, and Community Sciences

University of Florida/IFAS

Dietary Reference Intakes (DRIs)

• Background

• Definitions

• Uses

• Timeline

Background

• Recommended Dietary Allowances (RDAs) 1st ed.: 1941 10th ed.: 1989

• Primary goal: prevent diseases caused by nutrient deficiencies

• Developed for healthy groups, not individuals

• DRIs replace periodic revisions of RDAs

Food Insight, Sept/Oct 1998

Background (cont.)

Food and Nutrition Board

Health Canada

Background (cont.)

• Features of DRIs– Deficiency disease reduction– Chronic disease reduction– Safe upper levels of intake– New age group: >70 years

Food and Nutrition Board, 2000

Alphabet Soup?

Background (cont.)

• Dietary Reference Intakes– Estimated Average Requirement (EAR)– Recommended Dietary Allowance (RDA)– Adequate Intake (AI)– Tolerable Upper Intake Level (UL)

Food and Nutrition Board, 2000

Definitions

• Estimated Average Requirement (EAR)– healthy individuals– value meets needs of 1/2 of population group

Food and Nutrition Board, 2000

EAR

Daily requirement for nutrient

EAR

Number

of people

Definitions (cont.)

• Recommended Dietary Allowance (RDA)– healthy individuals– meets needs of 97-98% of population group– based on EAR

Food and Nutrition Board, 2000

RDA

EAR RDA

Daily requirement for nutrient

Number

of people

Definitions (cont.)

• Adequate Intake (AI)– used when cannot determine EAR – estimates / approximations– should meet needs of most individuals in group– more research needed

Food and Nutrition Board, 2000

Definitions (cont.)

• Tolerable Upper Intake Level (UL)– maximum amount that poses no risk to

individuals– NOT a recommendation

Food and Nutrition Board, 2000

Uses of DRIs

• Diet Assessment– Individual

• true status difficult to determine• EAR to determine possibility of inadequacy• UL to determine risk of over-consumption

– Group• EAR to estimate prevalence of inadequacy• UL to estimate prevalence of over-consumption

Food and Nutrition Board, 2000

Uses of DRIs (cont.)

• Diet Planning– Individual

• aim for RDA & AI• use UL as guide to limit intake

– Group• use EAR to set goals for intake of group

Food and Nutrition Board, 2000

Timeline

1997: First report (calcium, phosphorus, magnesium, vitamin D, and fluoride)

1998: Second report (B vitamins and choline)

2000: Third report (vitamins C and E, selenium, and carotenoids)

2000-2003: Estimated release dates for remaining reports

Food Insight, Sept/Oct 1998

Antioxidants

Vitamin C, Vitamin E, Selenium, and Carotenoids

Functions of Antioxidants

• First must understand free radicals– Sources:

• cellular activities• environment

– Oxygen and Nitrogen molecules with unpaired electrons

• highly reactive, unstable

• attack and damage cells

– Linked to development of variety of diseases

Rock, 1998

Functions of Antioxidants (cont.)

Scavenge free radicals

Repair damage

Vitamin C

• Donates electrons to free radicals

• EAR– women: 60 mg/day– men: 75 mg/day

Food and Nutrition Board, 2000

Vitamin C (cont.)

• RDA– women: 75 mg/day– men: 90 mg/day– smokers: additional 35

mg/day

• UL: 2,000 mg/day• Sources: citrus fruits,

broccoli, peppers

Food and Nutrition Board, 2000

Vitamin E• Scavenger of free radicals• EAR: 12 mg/day or 18 IU• RDA: 15 mg/day or 22 IU• UL: 1,000 mg/day or 1,500 IU• Sources: Nuts, seeds, vegetable

oils

Food and Nutrition Board, 2000

Selenium

• Component of enzymes that destroy free radicals

• EAR: 45 mcg/day• RDA: 55 mcg/day• UL: 400 mcg/day• Sources: seafood,

liver, meat

Food and Nutrition Board, 2000

Carotenoids

• Conflicting evidence• No RDA or UL set• Carotenoid-rich fruits

& vegetables recommended, NOT supplements

Food and Nutrition Board, 2000

Summary

• Target intake levels: RDA, AI

• Avoid UL or higher– Avoid supplements

• exception is Vitamin E

• Increase intake of fruits and vegetables