Flaxseed

Sara HansonNUTR 547-Nutrition Update

Summer 2006

Learning Objectives

• Identify health claims for flaxseed• List the main substance in Flaxseed

which may decrease risks for CVD• Describe the main interactions

flaxseed may have with supplements• Name the upper tolerable limit for

flaxseed powder• Describe the conclusion from the

cardioprotective study

Flaxseed and Flaxseed Oil

• Health Claims– Laxative– Breast Cancer

Prevention– Diabetes– Heart Disease– High Blood

Pressure– High Cholesterol

and Triglycerides

Flaxseed History (Linum usitatissimum)

• First cultivated 6000 BC in Eastern Turkey – Plant fiber used to make linen cloth

• Throughout history – Primarily used as a laxative. – Linseed oil (flaxseed oil) used for drying agent

in paint and varnish – Ingredient in animal feed and fertilizer

• In 1999, sales for dietary use of flaxseed increased by 177% after reported health benefits

Linum usitatissimum

Composition• Golden yellow to reddish brown flat seeds• Whole seed, ground seed (powder or meal), or

flaxseed oil• Whole Flaxseed

– 41% FAT, 28% dietary fiber, 21% PRO, and 3% CHO– Good source of magnesium, potassium, zinc, and B

vitamins– Soluble (25%) and insoluble fiber (75%)

• Flaxseed Oil– 73% PUFA, 18% MUFA, 9% SFA– Richest Source of Omega 3 fatty acid, ALA

• 55% of total fatty acids• Richest source of phytoestrogen called lignans

– possible use in breast cancer prevention

Cardiovascular Disease (CVD)

• “Refers to the class of diseases that involve the heart and/or blood vessels (arteries and veins)”

• “Technically refers to any disease that affects the cardiovascular system usually related to atherosclerosis”– HTN, stroke, CHD, rheumatic heart

disease, congestive heart disease, etc

CVD Prevalence

• The Leading cause of mortality in the U.S

• 61 Million Americans have CVD • African American (~40% men & women)• Caucasian (30% men, 27% women)• Mexican American (29% men, 27%

women)

CVD and Flaxseed

• Incorporation of “functional foods” into the diet may reduce risk of CVD– Nuts, fish, soy, flaxseed

• Functional foods are foods that have health benefits beyond the nutrients they contain 

• Flaxseed is considered a “functional food”– Contains a-linolenic acid (ALA), soluble fiber,

and lignans

• A-linolenic acid is the biologic precursor to ω-3 fatty acids

A-linolenic acid (ALA)

• ALA (C18:3 ω-3)• ALA EPA (C20:5 ω-3) and DHA

(C22:6 ω-3)• EPA and DHA

– decrease platelet aggregation, vasoconstriction, and thrombosis

– Proven cardioprotective properties

ALA EPA and DHA

Food/Supplement Interactions

• Whole flaxseeds decrease absorption of vitamins and supplements by mouth– Take one hour before or two hours after flaxseed

• Caution with mood altering herbs– St Johns Wort, kava, valerian

• Caution with blood pressure lowering herbs or supplements– black cohosh, calendula, California poppy, coleus,

eucalyptus oil, ginger, tumeric• Caution with other laxatives

– Aloe, black root, butternut bark, psyllium, dandelion• Caution with other blood thinners

– Alfalfa, ginseng, black cohosh, ginger, green tea, licorice root, Vit E, Warfarin

Dosage Recommendations• Supplement available in liquid,

capsule, or powder form• 1 Tbsp oil daily = 7 grams ALA, 2

grams linoleic acid• ALA is generally regarded as safe

in doses up to 3 g/day• Don’t exceed 45g for Flaxseed

powder– laxative effect

• Oil and Powder unstable and will degrade – Add to hot foods after cooking– must be refrigerated (prevent O2

& light)

Flaxseed Oil Increases the Plasma Concentrations of Cardioprotective (n-3) FattyAcids in Humans The Journal of

Nutrition (2006) 83• Objective

– Study the effect of flaxseed oil in increasing n-3 fatty acids in minority group w/ chronic disease

• Study Design– Randomized, double-blind placebo trial

• Subjects– 56 patients (49 women, 7 men). – 80% African American, 87% w/ mean age of 51yo,

Mean BMI of 37.4– 55% Hypertension, 12% Type 2 DM – Excluded participants using MVI, antioxidants,

and fish oil or (n-3) fatty acid supplements.

Flaxseed Oil Increases the Plasma Concentrations of Cardioprotective (n-

3) FattyAcids in HumansThe Journal of Nutrition (2006) 83

• Methods– Intervention Group –

3.0g ALA/d (5.2g Flaxseed Oil) Capsules

– Control Group – 5.2 g/d olive oil/d as capsules

– Both instructed to follow AHA diet

• Outcomes Measured– Plasma Fatty Acid

Levels were measured at 12 and 26 weeks

– Pills counted to check compliance

Flaxseed Oil Increases the Plasma Concentrations of Cardioprotective (n-

3) FattyAcids in Humans The Journal of Nutrition (2006) 83

• Results • Intervention Group

• Plasma ALA conc. increased by 70% • Plasma EPA increased by 60%• Plasma DPA increased by 34%• (n-6):(n-3) ratio decreased significantly

– Control Group• ALA unaffected• EPA and DPA not significant• (n-6):(n-3) ratio not significant

Results From 0-26 Weeks Intervention (Flax) vs. Placebo (Olive)

0

5

10

15

20

25

30

35

40

45

Flax - 0 Olive - 0 Flax - 12 Olive -12 Flax - 26 Olive - 26

ALAEPADHA

Flaxseed Oil Increases the Plasma Concentrations of Cardioprotective (n-

3) FattyAcids in HumansThe Journal of Nutrition (2006) 83

• Discussion and Conclusion – Plasma EPA levels can be increased by

providing dietary sources of precursor, ALA at a reasonable dose of ALA (3g/d)

– Diets that are rich in nuts, cereals, oils, and fortified breads may achieve 2-3g of ALA without using dietary supplements

The effect of Flaxseed supplementation in processed foods on serum fatty acids

Euro. Journal of Clinical Nut. (2002) 56 • Objective

– Study the effects of flaxseed as part of daily diet on serum lipids and fatty acids

• Study Design– Randomized, double-blind, cross-over

study• Subjects

– 83 people (62 women w/ mean age of 42.6y, 18 men w/ mean age of 45.6 y)

– 22 smokers

The effect of Flaxseed supplementation in processed foods on serum fatty acids

Euro. Journal of Clinical Nut. (2002) 56• Methods

– Test food prepared by major Finnish Food Company, served to employees at lunch

– Intervention Group - Flaxseed supplemented meals (Diet A). Ground Flaxseed (1.3 g/100g) and flaxseed oil (5 g/100g).

– Control Group - No Flaxseed (Diet B)

The effect of Flaxseed supplementation in processed foods on serum fatty acids

Euro. Journal of Clinical Nut. (2002) 56• Results

– Intervention Group• ALA, EPA, DPA significantly increased in

serum lipids• Serum enterolactone significantly increased

– Control Group• Not significant

The effect of Flaxseed supplementation in processed foods on serum fatty acids

Euro. Journal of Clinical Nut. (2002) 56• Results and Discussion

– The flaxseed supplemented test food significantly increased ALA, EPA, and DPA in serum lipids

– The amount of ALA in flaxseed oil is greater than any other vegetable oil with processed foods generally low in PUFAs.

– Flaxseed oil helped increased ratio between n-3 and n-6 fatty acids. May reduce risk of Cancer and CHD

Summary

• It is unclear whether there is any benefit from flaxseed for CVD

• Studies have been small with flaws in their designs

• The use of plant based ω-3 fatty acid, ALA may be an important alternative for providing optimal EPA and DHA concentrations and as a alternative to fish