Omega Three Fatty Acids Flashcards
What are fatty acids?
n−3 fatty acids (popularly referred to as ω−3 fatty acids or omega-‐3 fatty acids) are a family of unsaturated fatty acids that have in common a final carbon-carbon double bond in the n−3 position; that is, the third bond from the methyl end of the fatty acid.
How do chemists name fatty acids?
Counting carbons from the carbonyl carbon, ALA has a chain of 18 carbons with 3 double bonds, in positions 9, 12 and 15.
How do physiologists count carbons on omega-three fatty acids?
physiologists count from the n (ω) carbon (red numbering).
Note that from the ω end (diagram right), the first double bond appears as the third carbon-‐carbon bond (line segment), hence the name “ω−3”.
This is explained by the fact that the ω end is almost never changed during physiologic transformations in the human body, as it is more stable energetically, and other carbohydrates compounds can be synthesized from the other carbonyl end, for example in glycerides, or from double bonds in the middle of the chain.
What are the three main fatty acids?
The three main omega-3 fatty acids are alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA)
Give a bit of history for the halth of omega three fatty acids.
Late 1970s Danish scientists demonstrated that Greenland Inuits had significantly lower levels of coronary heart disease
Also noted in Japanese islanders with high fish diets (Kagawa et al 1982)
These initial studies led to thousands of studies into the effects of omega 3 fatty acids on health
What is Lorenzo’s oil?
Lorenzo’s Oil is a combination of a 4:1 mix of oleic acid and erucic acid, extracted from rapeseed oil and olive oil designed to normalize the accumulation of the very long chain fatty acids in the brain thereby slowing the progression of adrenoleukodystrophy (ALD). It is specific to ALD and is NOT designed to be used to treat other leukodystrophies nor multiple sclerosis.
How does lorenzos oil work?
How it Works
The oil, if started early in boys with adrenoleukodystrophy (ALD) showing no symptoms, is now known to have some benefit in preventing the childhood cerebral form of adrenoleukodystrophy. Researchers are still trying to understand the complex relationships among fats in the body, and how Lorenzo’s oil could be further modified to be more effective. The oil is designed to normalize the accumulation of the very long-chain fatty acids in the brain that thereby halting the progression of ALD.
Why does omega-three need to come from diet?
The polyunsaturated fatty acids alpha-‐linolenic acid (ALA) and linoleic acid (LA) must come from the diet because they cannot be made by the body.
ALA, an omega-‐3 fatty acid, is converted in the body to the fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).
LA, an omega-‐6 fatty acid, is converted to the omega-‐6 fatty acid arachidonic acid (AA)
Thus omega 6 cannot be converted to Omega 3 so the only way to get omega 3 is from the diet
Most diets provide more than 10 times as much omega-‐6 than omega-‐3 fatty acids. There is general agreement that individuals should consume more omega-‐3 and less omega-‐6 fatty acids to promote good health.
What are good sources of ALS,
Good sources of ALA are leafy green vegetables, nuts, and vegetable oils such as canola, soy, and especially flaxseed.
Good sources of EPA and DHA are fish
LA is found in many foods, including meat, vegetable oils (e.g., safflower, sunflower, corn, soy), and processed foods made with these oils. EPA and DHA are metabolized through the same biochemical pathways as AA.
What are EPA and AA precursors for?
EPA and AA are also precursors for hormone-‐ like agents known as eicosanoids
What are eicosanoids responsible for?
Eicosanoids are a group of hormone-like chemicals that regulate many physiological functions
For example inflammation
Redness
Swelling
Pain
Heat (fever)
Is there a desirable mix of omega 3 and 6?
It is not known whether a desirable ratio of omega-‐6 to omega-‐3 fatty acids exists or to what extent high intakes of omega-‐6 fatty acids interfere with any benefits of omega-‐3 fatty acid consumption.
What is the impact of omega 3 on cardiovascular disease?
Impact on cardiovascular disease (CVD):
According to both primary and secondary prevention studies, consumption of omega-‐3 fatty acids, fish, and fish oil reduces mortality and various CVD outcomes such as
sudden death,
cardiac death, and
myocardial infarction.
The evidence is strongest for fish and fish oil supplements.
What is the impact f omega 3 on heart function?
Impact on heart function:
Animal and isolated organ/cell culture studies demonstrate that omega-‐3 fatty acids affect cellular functions involved in ensuring a normal heart rate and coronary blood flow.
Fish oils can lower blood triglyceride levels in a dose-‐dependent manner.
Fish oils have a very small beneficial effect on blood pressure
Possible beneficial effects on exercise capacity in patients with coronary atherosclerosis.
What is the impact of omega 3 on cognitive function?
Impact on cognitive function:
The quantity and strength of evidence is inadequate to conclude that omega-‐3 fatty acids protect cognitive function with aging or the incidence or clinical progression of dementia (including Alzheimer’s disease), multiple sclerosis, and other neurological diseases.
Summary
Noticed in 1970s that omega 3 FA are beneficial to health
Fish and fish oil are main sources
Alternatives are needed due to rising demand
Marine microbes may provide such a source
Economic hurdles remain to be overcome
Fish consumption effects on heart health
study
Kris-Etherton et al (2002)- Fish consumption, Fish Oil, Omega-3 Fatty Acids, and Cardiovascular disease:
Coronary Heart Disease
- Fish consumption favourably affects CHD mortality, including sudden death from heart attacks.
Against
- In the Seven Countries Study, although an inverse association between fish consumption and 25-year mortality from CHD across several populations was observed, when the confounding effects of saturated fatty acids, flavonoids, and smoking were considered, the association was not significant.
- US Physicians’ Health Study = no association between omega 3 consumption and reductions in myocardial infarction, and sudden cardiac death.
- In contrast, however, fish consumption was related to a reduced risk of total mortality.
- definitions of sudden death
- reference groups that had a less healthy lifestyle
- variability in the end points studied
- experimental design
- how fish intake was estimated
For
- In the US Physicians’ Health Study, men who consumed fish at least once weekly had a relative risk of sudden death of 0.48 (P=0.04) versus men who consumed fish less than once per month.
- Lower mortality caused by CHD in people that consumed fatty fish but not lean fish.
- Lots of conflicting results as methylmercury, which bioaccumulates in larger fish, may diminish the health benefits of omega-3 fatty acids.
omega three - bipolar
study
Stoll et al (1999)- Omega 3 Fatty Acids in Bipolar Disorder- A Preliminary Double-blind, Placebo-Controlled Trial
- Omega 3 fatty acids can inhibit neuronal transmission in a manner similar to that of lithium carbonate and valproate, which are both effective treatments for bipolar. These drugs work by stabilizing the patients’ mood.
- Used olive oil as a placebo.
- Overactive cell-signalling pathways are involved in the mechanisms causing bipolar, so by inhibiting neuronal signal transduction, the symptoms of bipolar could be reduced.
- The omega 3 has an antidepressant effect on the cohort.
- There was a distinct fishy aftertaste, particularly in the group which consumed the omega 3, which could have led to a placebo effect.
microorganism engineering of omega-three study
Amiri-Jami (2014)- Engineering of EPA/DHA omega-3 fatty acid production by Lactococcus lactis supsp. cremoris MG1363
- Fish and fish oils are the main dietary sources of EPA and DHA.
- To generate a sustainable source of EPA and DHA the synthesis genes were extracted from the marine bacterium Shewanella baltica, all unnecessary genes were deleted. This was combined with some genes from Escherichia coli, and placed into a vector then expressed in Lactococcus lactis
- This then produced 1.35±0.5 mg g-1 cell dry weight of DHA and 0.12±0.04mg g-1 cell dry weight of EPA.
- Need an alternative source of EPA and DHA as people no longer want to consume fish as its seen as unsustainable, and as the demand increases and fish stocks decrease, the prices are going up.
- The gene was isolated and transformed to different strains of E. coli, which resulted in the production of EPA and DHA.
- However, E. coli is not recognized as a food-grade microorganism, so cannot be used in food products. Instead, lactic acid bacteria are used, and they have been used as a safe vehicle to deliver vaccines to mucosal tissues for nearly 40 years.
- Produced both EPA and DHA at 30C.
