Avocado Consumption Increases Neural Lutein Concentrations

which Improves Cognitive Function

Elizabeth J. Johnson, Ph.D.

Antioxidants Research Laboratory

Jean Mayer USDA Human Nutrition Research Center on Aging

Tufts University

Background

Rationale

• There is a need for novel, cost-effective public health strategies that

will delay, slow, or prevent cognitive decline associated with aging.

• Our preliminary studies suggest that lutein may also be important in

cognitive function in the elderly.

• Avocados are likely a highly bioavailable source of lutein.

Rationale

• There is a need for novel, cost-effective public health strategies that

will delay, slow, or prevent cognitive decline associated with aging.

• Our preliminary studies suggest that lutein may also be important in

cognitive function in the elderly.

• Avocados are likely a highly bioavailable source of lutein.

Rationale

• There is a need for novel, cost-effective public health strategies that

will delay, slow, or prevent cognitive decline associated with aging.

• Our preliminary studies suggest that lutein may also be important in

cognitive function in the elderly.

• Avocados are likely a highly bioavailable source of lutein.

Methods

Subjects

• Men and women aged >50 y (n=20, treatment group; n=20, control group)

who meet the following criteria:

lutein intake of <3 mg/d

macular pigment density <0.5 OD

MMSE score >24

BMI 19-29 kg/m2

• Exclusions:

carotenoid supplements for >2 mo prior to study start

>2 alcoholic beverages/day

fat absorption/metabolism

anemia, diabetes, bleeding disorders, hyperlipidemia

Subjects

• Men and women aged >50 y (n=22, treatment group; n=22, control group)

who meet the following criteria:

lutein intake of <3 mg/d

macular pigment density <0.5 OD

MMSE score >24

BMI 19-29 kg/m2

• Exclusions:

carotenoid supplements for >2 mo prior to study start

>2 alcoholic beverages/day

fat absorption/metabolism

anemia, diabetes, bleeding disorders, hyperlipidemia

Study Design

Month/Study Measures 0 1 2 3 4 5 6

Avocado or control meal pick-up/delivery x x x x x x

Height, weight, blood draw x x x

Macular pigment & cognitive measures x x x

Mood & fatigue, FFQ x x x

Telephone calls x x x x

Current medication review x x x

Dietician interview x x x

Compliance calendars x x x x x x

Test Assessment

Choice reaction time General alertness and motor speed

Delayed matching to sample Forced choice recognition memory for non-

verbalizable patterns, testing matching and short

term visual memory

Spatial span

Spatial span reverse

Working memory capacity, and is a visuospatial

analogue of the Digit Span test

Paired associates learning Episodic and new learning

Spatial working memory Retention and manipulation of visuospatial

information. This self-ordered test has notable

executive function demands, and measures

strategy use as well as errors.

Rapid visual information processing Sustained attention

Stockings of Cambridge Spatial planning test which gives a measure of

frontal lobe

Cognitive Measures

CANTAB, Cambridge Cognition Ltd

www.macularmetrics.com

Heterochromatic flicker photometer(for measure of macular pigment optical density, MPOD)

Section through fovea of rhesus monkey (Macaca mulatta). © Max Snodderly, 2002

Biomarker Measures in Plasma

Biomarker Method Reference or Source

Bioavailability: carotenoids Reverse-phase HPLC Johnson, et al., 2000

Oxidative capacity:LDL LDL resistance against

Cu2+-induced oxidation

Chen, et al., 2005

Inflammation: b-amyloid Direct solid-phase

enzyme immunoassay

Innugenetic, Inc.,

Belguim

Inflammation: CRP Chemiluminescent

assay

DPC, Los Angeles, CA

Results

No change in inflammation of

oxidative stress in either group.

No change in inflammation of

oxidative stress in either group.

Measures in normal range.

bc

a

Serum Lutein, nmol/L (mean + SD)

Month

Change from baseline, P value: a0.001, b0.05, c0.0005

Macular Pigment Density (mean + SD)

Month

ab c

Change from baseline, P value: a0.05, b0.005, c0.0005

Lutein supplement vs Avocado

Lutein Supplement* Avocado

subjects (n) 11 20

age, yrs 60-80 50-85

lutein, mg/d 12 0.5

study duration, days 120 180

total lutein dose, g/d x day 1.44 0.9

serum lutein (∆ from baseline), nmol/L 315 84

MP density (∆ from baseline), OD 0.041 0.101

*Johnson et al, AJCN 87:1521-9 (2008)

Lutein supplement vs Avocado

Lutein Supplement* Avocado

subjects (n) 11 20

age, yrs 60-80 50-85

lutein, mg/d 12 0.5

study duration, days 120 180

total lutein dose, g/d x day 1.44 0.9

serum lutein (∆ from baseline), nmol/L 315 84

MP density (∆ from baseline), OD 0.041 0.101

*Johnson et al, 2008

Lutein supplement vs Avocado

Lutein Supplement* Avocado

subjects (n) 11 20

age, yrs 60-80 50-85

lutein, mg/d 12 0.5

study duration, days 120 180

total lutein dose, g/d x day 1.44 0.9

serum lutein (∆ from baseline), nmol/L 315 84

MP density (∆ from baseline), OD 0.041 0.101

*Johnson et al, 2008

Lutein supplement vs Avocado

Serum Lutein

(∆ baseline), nmol/L/lutein total doseMacular Pigment Density

(∆ baseline), OD/ lutein total dose

Lutein supplement vs Avocado

Serum Lutein

(∆ baseline), nmol/L/lutein total doseMacular Pigment Density

(∆ baseline), OD/ lutein total dose

~2x ~4x

Why?

HDL

MUFA major transporter of lutein neural tissue

Control Group:

No relationships between lutein status and cognitive function

were observed.

Avocado Group:

The change in MP density (6-0 months) was related to the

change in spatial working memory (p<0.009)

• The change in MP density (6-0 months) was related to

improved efficiency of approaching a problem (p<0.036)

• No significant relationships between change in serum lutein

and cognitive function.

Relationship between Lutein Status and Cognitive Function

Control Group:

No relationships between lutein status and cognitive function

were observed.

Avocado Group:

The change in MP density (6-0 months) was related to the

change in spatial working memory (p<0.009)

The change in MP density (6-0 months) was related to

improved efficiency of approaching a problem (p<0.036)

No significant relationships between change in serum lutein

and cognitive function.

Relationship between Lutein Status and Cognitive Function

Spatial Span forwarda

Paired Associates Learningc

Spatial Working Memoryb

Control, n = 20

Avocado, n = 20

Significant time effect (p <): a0.05, b0.01, c0.001

No differences between groups

p <0.05

p <0.05

Significant time effect:

• Learning effect?

• Bioactives in potatoes/chickpeas?

Per 100 g Avocado Chickpea Potato

Lutein, mg 0.5 0.0 0.0

MUFA, g 9.8 0.4 0.0

Vitamin C, mg 8.8 0.1 13.0

Folate, mg 89 25 9

Conclusion

A dietary intervention with avocados to increase

neural lutein levels could be an effective dietary

strategy for cognitive health in older adults.

Acknowledgments

Antioxidants Research Laboratory:

Rohini Vishwanathan, Ph.D

Emily Mohn, M.S.

Oliver Chen, Ph.D.

Jordan Haddock, B.S.

Metabolic Research Unit

Helen M. Rasmussen, Ph.D, R.D.

Neuroscience and Aging Laboratory

Tammy M. Scott, Ph.D,

Supported by Hass Avocado Board and USDA 58-1950-0-014