W.M.I.S.B.PanampitiyaDepartment of Food Science and Technology

Faculty of AgricultureUniversity of Peradeniya

Omega-3- Fatty acid

• Omega-3 FA’s are polyunsaturated, meaning they contain more than one double bond

• They are called omega-3, because the first double bond counting from the methyl end of the fatty acid is located at the third carbon atom

Structure of omega 3 fatty acid :

Types of Omega-3-fatty acids

Alpha-linolenic acid (ALA)

Eicosapentaenoic acid (EPA)

Docosahexaenoic acid (DHA)

Alpha-linolenic acid (ALA)

The first part (18:3) suggests that ALA is an 18-carbon fatty acid with 3 double bonds

The second part (n-3) tells you that ALA is an omega-3 fatty acid

It is required for health, but cannot be synthesized in humans

ALA is considered a plant-derived omega-3 fatty acid

Humans can synthesize other omega-3 fatty acids from ALA:Eicosapentaenoic acid (EPA): 20:5n-3Docosahexaenoic acid (DHA): 22:6n-3

Docosahexaenoic acid (DHA)

• Found in very high concentrations in the cell membranes of the retina

• This consider as a marine- derived omega-3 fatty acid

Sources of Omega 3 fatty acids•Canola oil•Fish liver oils, Fish eggs•Human Milk•Organ meats

•Fish :salmon, tuna, halibut, shrimp, cod, sardines,

halibut•Other seafood :

algae and krill•Plants :

soybeans, tofu, kale, collard greens, winter squash•Nut oils :

flax seeds and walnuts

Pre-clinical evidence for benefit of omega-3 fatty acids during cancer therapy

May suppress the growth of existing cancers and may prevent or slow metastasis

May increase the efficacy of chemo- or radiation therapy

Hormone responsive tumors such as:

breast, prostate and colon cancers

seem especially sensitive to omega 3 fatty acids.

Marine-derived fatty acids have been found to inhibit proliferation and promote apoptosis in breast, prostate, and colon cancer cell lines cultured outside the body

Studies in animal models of cancer also indicate that increased intake of EPA and DHA decreases the occurrence and progression of mammary, prostate, lung cancer and intestinal tumors

Mean growth rate of tumour in nude mice

N-3 fatty acids affect to growth of metastatic or residual cancer cells

• Slowing cancer cell mitosis

• Increasing cancer cell death

• Altering estrogen metabolism

• Inducing differentiation

• Suppressing angiogenesis

EPA and DHA decreased mitosis and inhibited growth of breast and colon cancer cells

Slowing cancer cell mitosis

Increasing cancer cell death

• Apoptosis is programmed cell death. • When apoptotic pathways are functional, cells with unreparable genetic damage should die. • However, apoptotic pathways are frequently disrupted in cancers.

Inducing differentiationTerminally differentiated cells do not multiply. n-3 fatty

acids have been shown to induce differentiation of breast cancer cells

Altering estrogen metabolism

• Shift in estrogen metabolism towards 16a-hydroxylation increases the formation of proliferation in breast cells. Omega-3 supplements decreased 16a-hydroxylation

Suppressing angiogenesis

The growth of new blood vessels, must occur for cancers to grow

The n-3 products of cyclooxygenase do not stimulate angiogenesis

Breast cancerconsumption of an n-3 supplement for 3 months

significantly changed composition of breast adipose tissue

Colon cancer • Eating foods rich in omega-3 fatty acids seems to reduce the risk of colorectal cancer. n–3 fatty acids accumulate in biological membranes and may initiate signal-transduction processes or modify membrane structure.

Prostate cancerThere is some epidemiological support for a

protective effect of n−3 fatty acids on prostate cancer.

Lung cancer

• Fish or fish oil consumption will reduced risk of lung cancer

The possible problems or complications

The source of some omega-3 fatty acids may be a health concern.

People who are allergic to fish may have serious reactions to fish oil.

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