Omega-3 and Coronary Heart Disease Biomarkers and Interventions

William S. Harris, PhD

President OmegaQuant Analytics

Sioux Falls, SD

Research Professor of Medicine Sanford School of Medicine University of South Dakota

Senior Scientist Health Diagnostic Lab, Inc.

Richmond, VA

Summary

Achieving optimal RBC levels of omega-3 fatty acids can help reduce

risk for cardiovascular disease

Objectives

1. Define 5 fatty acid classes in RBC’s

2. Describe how fatty acid status is assessed

3. Explain how RBC fatty acids relate to cardiovascular risk

4. Discuss mechanisms of action

5. Review recommended fatty acid intakes

Take Home Messages 1. The RBC membrane contains >20 individual fatty acids of 5

different classes

2. The RBC EPA+DHA content (the Omega-3 Index) is a valid and stable biomarker of omega-3 fatty acid status

3. For cardiovascular health, an Omega-3 Index >8% is optimal and an Index < 4% is deficient. Target trans fat levels are <1%.

4. Dietary doses of EPA+DHA reduce risk for CHD via non-traditional pathways by changing membrane physiochemical properties and improving the eicosanoid profile. Pharmacologic doses lower triglycerides.

5. Omega-3 EPA+DHA intakes should be 400-500 mg/day for most adults and twice that for CHD patients.

Objectives

1. Define 5 fatty acid classes in RBC’s

2. Describe how fatty acid status is assessed

3. Explain how RBC fatty acids relate to cardiovascular risk

4. Discuss mechanisms of action

5. Review recommended fatty acid intakes

Omega-6

Polyunsaturated Fatty Acids Non-Essential Fatty Acids

Omega-3

Polyunsaturated Fatty Acids

COOH Elaidic acid (EA)

C18:1n-9 trans; Trans Fatty Acid

Eicosapentaenoic acid, EPA C20:5n-3

COOH

-Linolenic acid (ALA) C18:3n-3

COOH COOH

Palmitic acid (PA) C16:0 Saturated Fatty Acid

COOH

Oleic acid (OA) C18:1n-9 Monounsaturated Fatty Acid

COOH

Arachidonic acid (AA) C20:4n-6

COOH -Linolenic acid (GLA) C18:3n-6

COOH

Linoleic acid (LA) C18:2n-6

Docosahexaenoic acid, DHA C22:6n-3

COOH

Types of Fatty Acids

α ω

A fatty acid is a chain of carbon atoms with an acid group on one end • Saturated • Monounsaturated • Polyunsaturated – Omega-6 and Omega-3 (n-6 or n-3) • Trans

• PUFA have >1 double bond; n-6 and n-3 families.

• Major n-6 PUFAs: linoleic acid (LA, C18:2n-6) and arachidonic acid (AA, C20:4n-6).

•All n-6 PUFAs can be synthesized from LA, but LA cannot be made de novo (i.e., essential).

• Linoleic - vegetable oils (corn, safflower, soybean, etc.) with small amounts in canola, olive and flaxseed oils. Arachidonic - only in animal products like meat and eggs (but not in dairy products).

Types of Fatty Acids N-6 Polyunsaturates (PUFAs)

• Major n-3 PUFAs are alpha-linolenic acid (ALA, C18:3n-3), eicosapentaenoic acid (EPA; C20:5n-3), docosapentaenoic acid (DPA; C22:5n-3) and docosahexaenoic acid (DHA; C22:6n-3)

• All n-3 PUFAs can be synthesized from ALA, but ALA cannot be made de novo (i.e., essential).

• ALA is in certain plant oils (canola, olive and flaxseed), whereas EPA and DHA come from seafoods.

Types of Fatty Acids N-3 Polyunsaturates

Take Home Message

The RBC membrane contains >20 individual fatty acids of 5

different classes

Objectives

1. Define 5 fatty acid classes in RBC’s

2. Describe how fatty acid status is assessed

3. Explain how RBC fatty acids relate to cardiovascular risk

4. Discuss mechanisms of action

5. Review recommended fatty acid intakes

Assessing Fatty Acid Status

RBC fatty acids are hydrolyzed from membranes, derivatized and analyzed by gas chromatography

Assessing Fatty Acid Status The Omega-3 Index

A measure of the amount of EPA+DHA in red blood cell membranes expressed as the percent of total fatty acids

Harris WS and von Schacky C. Prev Med 2004;39:212-220.

There are 64 fatty acids in this model membrane, 3 of which are EPA or DHA

3/64 = 4.6%

Omega-3 Index = 4.6%

Assessing Fatty Acid Status Low Biological Variability & Long-Term Marker

Plasma EPA+DHA

Harris and Thomas. Clin Biochem 2010;43:338–340

20 healthy volunteers tested weekly for 6 weeks Total Coefficients of Variability (CVs)

EPA+DHA in… • RBC = 4.1% • Whole Blood = 6.7% • Plasma = 16% • Plasma PL = 15%

0%

1%

2%

3%

4%

5%

6%

7%

8%

9%

10%

Pe

rce

nt

of

tota

l FA

s

0%

2%

4%

6%

8%

10%

12%

Week 0 Week 1 Week 2 Week 3 Week 4 Week 5 Week 6

Pe

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s

Pla

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RB

C

RBC EPA+DHA

Take Home Message

The RBC EPA+DHA content (the Omega-3 Index) is a valid and stable

biomarker of omega-3 fatty acid status

Objectives

1. Define 5 fatty acid classes in RBC’s

2. Describe how fatty acid status is assessed

3. Explain how RBC fatty acids relate to cardiovascular risk

4. Discuss mechanisms of action

5. Review recommended fatty acid intakes

RBC Fatty Acids and CVD Risk

Strong evidence • Omega-3 Index: Low levels = High risk Intermediate evidence • Trans fats: High levels = High risk • Linoleic acid (n-6): Low levels = High risk Little evidence • Saturated • Monounsaturated • Plant n-3 (α-linolenic acid)

Selecting Omega-3 Index Targets

GISSI-P:~9–10%

Greatest Protection

Least Protection

10%

8%

6%

4%

2%

DART:~8–9%

CHS: 8.8%

SCIMO: 8.3%

5 epi studies:~8%

PHS: 7.3%

Seattle: 6.5%

PHS: 3.9%

SCIMO: 3.4%

Seattle: 3.3%

8.1%

Harris WS and von Schacky. Prev Med 2004;39:212-220.

RBC Fatty Acids and CVD Risk

Omega-3 Index Risk Zones

Harris WS and von Schacky. Prev Med 2004;39:212-220.

8% 4%

Percent of EPA+DHA in RBC

Undesirable Desirable Intermediate Undesirable

Itomura, in vivo 2008;22:131-136.

Japan USA/EU

Risk for cardiac death in the US is 45x higher than in Japan

Iso et al. Circ 2006;113:195-202

He et al. Circ 2004;109:2705-2711

RBC Fatty Acids and CVD Risk

Marchioli and Harris, unpublished

Norway Spain

Germany

Japan

Korea

Alaska

0%

2%

4%

6%

8%

10%

12%

14%

0 5 10 15 20 25

EPA+DHA

Healthy subjects Ill subjects

USA

Germany

Norway

Spain

Japan

Alaska

Korea

The Omega-3 Index Worldwide

Omega-3 Index and Acute Coronary Syndromes (768 case-control pairs)

Multivariable logistic regression model including: age; race; gender; history of diabetes mellitus, hypertension, hyperlipidemia and/or myocardial infarction; a family history of coronary artery disease; and LDL-C, HDL-C, and triglycerides.

Block RC, et al. Atherosclerosis 2008;197 :821-828.

p=0.03

p=0.017

p<0.001

p for trend < 0.0001

RBC Fatty Acids and CVD Risk

The Omega-3 Index and Cellular Aging

RBC Fatty Acids and CVD Risk

Adapted from Farzanah-Far, et al. JAMA 2010;303:250-257

Blood Omega-3 is Inversely Associated with the Rate of Telomere Attrition

P<0.001 for trend

RBC Fatty Acids and CVD Risk

Omega-3 Index and Time to Death in 982 CHD Patients

Pottala et al. Circ CV Outcomes & Qual 2010;3 406-412

< 4.6% ≥4.6%

< 4.6% ≥4.6%

1.2 yrs

It took 1.2 years longer for 20% of the population to die in the higher vs. the lower omega-3 group

RBC Fatty Acids and CVD Risk

Why is the Omega-3 Index Target 8%?

• The average Omega-3 Index estimated from 11 studies was 8.1%

• An Omega-3 Index of >8% was associated with reduced probability for acute coronary syndrome compared to an Index of <4%

• The Omega-3 Index associated with the slowest rate of cellular aging was 8.7%

• The average Index in Japan (where CHD is rare) is 9-10%

RBC Fatty Acids and CVD Risk

Adapted from Siscovick DS et al. JAMA 1995;274:1363-1367.

Odds R

atio

3.3%

Midrange RBC EPA+DHA by Quartile

4.3% 5.0% 6.5%

90% reduction in risk

*p<0.05

vs Q1

Clinical Evidence – Cross Sectional Primary Cardiac Arrest and the Omega-3 Index Seattle PCA Study

3.6% 4.8% 5.6% 6.9%

Mean Blood Omega-3 FA (%) by Quartile

Clinical Evidence – Prospective Sudden Cardiac Death and the Omega-3 Index Physicians' Health Study

Albert CM et al. N Engl J Med 2002:346:1113-1118.

Rela

tive R

isk

90% reduction in risk

p for trend = 0.001

The Omega-3 Index, Brain Volume and Cognitive Function in Framingham

Quartile 1 vs 2-4 (<4.4% vs above)

n=1575; age=67

Model Covariates Total Cerebral Brain Volume (%)

Visual Memory Executive

Function

Abstract Thinking

Lower Index = Smaller Volume Lower Index = Poorer Function

A Age, sex, education, time interval

p=0.005 p=0.026 p=0.025 p=0.001

B A with apoE4 and homocysteine

p=0.005 p=0.026 p=0.038 p=0.002

C B with physical activity and BMI

p=0.008 p=0.024 p=0.046 p=0.002

D

B with diabetes, sBP, smoking, A-fib,

prevalent CVD and total cholesterol

p=0.011 p=0.079 p=0.108 p=0.001

Tan Z, et al. Neurology 2012

“The MRI finding of lower brain volume [in those with an Omega-3 Index <4.4%] represents a change

equivalent to approximately 2 years of structural brain aging.”

Johnston et al. Nutr Neurosci 2012 (in press)

Executive Functioning and Cognitive Flexibility by Quartile of the HS-Omega-3 Index in Army Members

Deployed in Iraq

P<0.01 for trend

0

20

40

60

80

100

120

1 2 3 4

Executive Function Score

Cognitive Flexibility Score

Sta

nd

ard

ized

Test

Sco

res

Omega-3 Quartile

N=78, mean age 31 yrs

Take Home Message

For cardiovascular (and possibly neurocognitive) health, an Omega-3 Index >8% is optimal and an Index <

4% is deficient.

Objectives

1. Define 5 fatty acid classes in RBC’s

2. Describe how fatty acid status is assessed

3. Explain how RBC fatty acids relate to cardiovascular risk

4. Discuss mechanisms of action

5. Review recommended fatty acid intakes

Effects of Omega-3*… • Reduced heart rate • Reduced inflammation • Improved vascular function • Reduced susceptibility to cardiac arrhythmias

Mediated by…. • Altered cell membrane physiochemical properties • Shifts in eicosanoid production • Altered gene expression

Mozaffarian and Wu. JACC 2011; 58:2047–67 * Primarily from nutritionally-achievable intakes: 500-1,000 mg/d

Take Home Message

Dietary doses of EPA+DHA reduce risk for CHD via non-traditional

pathways by changing membrane physiochemical properties and

improving the eicosanoid profile. Pharmacologic doses lower

triglycerides.

Objectives

1. Define 5 fatty acid classes in RBC’s

2. Describe how fatty acid status is assessed

3. Explain how RBC fatty acids relate to cardiovascular risk

4. Discuss mechanisms of action

5. Review recommended fatty acid intakes

AHA Scientific Statement on Omega-3s

Population Recommendation

Patients without documented CHD

Eat a variety of fish (preferably oily) at least twice a week*, include oils and foods rich in ALA

Patients with documented CHD

Consume ~1 gm of EPA+DHA per day, preferably from fish, supplements could be used in consultation with a physician

Patients needing TG lowering

2 – 4 gm of EPA+DHA per day provided as capsule under a physician’s care

Kris-Etherton, Harris, & Appel. Circulation, 2002;106:2747-57.

*Equal to about 400-500 mg EPA+DHA/day

AHA Recommendations for Women

Population Recommendation

Women with high blood cholesterol or triglycerides; for primary or secondary prevention

Consumption of omega-3 fatty acids in the form of fish or capsules (e.g., EPA 1800 mg/d)

Mosca et al. Circulation 2011;123:1243-6.

Our tests of 16 leading pill brands found that all contained roughly as much omega-3s as their labels claimed, and none were contaminated or spoiled. So choose them based mainly on price

Take Home Messages 1. The RBC membrane contains >20 individual fatty acids of 5

different classes

2. The RBC EPA+DHA content (the Omega-3 Index) is a valid and stable biomarker of omega-3 fatty acid status

3. For cardiovascular health, an Omega-3 Index >8% is optimal and an Index < 4% is deficient. Target trans fat levels are <1%.

4. Dietary doses of EPA+DHA reduce risk for CHD via non-traditional pathways by changing membrane physiochemical properties and improving the eicosanoid profile. Pharmacologic doses lower triglycerides.

5. Omega-3 EPA+DHA intakes should be 400-500 mg/day for most adults and twice that for CHD patients.