Omega-3 Fatty Acids - Online Tutor, Practice Problems & Exam Prep

Omega fatty acids are unsaturated fatty acids identified by the position of their first double bond from the omega carbon, the last carbon in the chain. Omega-3 fatty acids, such as alpha-linolenic acid, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), have a double bond three carbons from the omega carbon. These essential fatty acids cannot be synthesized by the body and are crucial for normal growth, linked to reduced cardiovascular disease risk. They are commonly found in vegetable oils, cold-water fish, and marine algae.

Omega-3 Fatty Acids

In this video, we're going to introduce and begin our lesson on omega fatty acids. Before we start, I want to point out this alternate version of our original lipid map, which is really only here to remind us that we're still talking about fatty acids in this lesson, and we have not yet moved on from talking about fatty acids. Also, just as a reminder, we're not going to talk about the isoprene lipids over here until after we finish talking about all of the fatty acids and the fatty acid-based lipids.

Omega fatty acids are just a type of fatty acid and omega is a Greek symbol that looks like this, and so omega fatty acids, all they really are, are just unsaturated fatty acids that are classified by the first double bond, but numbering from the omega carbon. Typically, with fatty acids, we number the fatty acid carbon atoms starting from the carboxylic acid carbon and we give this the lowest number and we number around this way. However, when it comes to omega fatty acids, we number the carbon atoms from the omega carbon, which is again the last carbon atom here and so, with omega carbon atoms, we number the carbon atoms in the opposite way.

This omega naming system and numbering system is really used to highlight biologically relevant features and differences, such as biologically relevant double bonds. Moving forward, we're going to talk about very specific omega fatty acids, specifically the omega 3 fatty acids, and so we'll talk about those in our next lesson video. So, I'll see you guys there.

Omega-3 Fatty Acids

In this video, we're going to talk specifically about omega-3 fatty acids. And so, omega-3 fatty acids, as the name implies, are just fatty acids with a double bond located exactly 3 carbon atoms away from the omega carbon. If we take a look at our example down below, we're showing you 3 classic examples of omega-3 fatty acids, and these are alpha-linolenate which is right over here, eicosapentaenoate or EPA right here in the middle, and docosahexaenoate or DHA over here on the far right. Notice that all 3 of these omega-3 fatty acids all have a double bond that is located exactly 3 carbons away from the omega carbon, which again is the last carbon, furthest from the carboxylic acid group.

What's important to note about these omega-3 fatty acids is that they are actually essential in the human diet for normal growth. The reason that they are essential is that these omega-3 fatty acids cannot be produced by human cells at a substantial rate. For that reason, they're actually essential in the human diet. Omega-3 fatty acids have been linked to decreased risk of cardiovascular disease as well as decreased risk of heart attacks and blood clots. So there's definitely good evidence that omega-3 fatty acids are again essential in the human diet.

Omega-3 fatty acids can be commonly obtained in the diet through multiple sources but are very common in vegetable oils such as corn oil, with alpha-linolenate being common in corn oil. They're also very common in cold water fish such as salmon, and eicosapentaenoate or EPA here is very common in cold water fish. Omega-3 fatty acids are also common in marine algae, which fish are going to live in and sometimes eat, and the omega-3 fatty acids in marine algae can be passed down the food chain. Ultimately what you'll notice is the docosahexaenoic acid over here, we've got this marine algae. Something interesting to note is that these omega fatty acids, when they're arranged like this, they actually kind of look like fish themselves. We've got these shapes here, that kind of resemble you can see this shape right here, it's kind of the same shape that you see right here. So they kind of do look like goldfish a little bit. Hopefully, the Goldfish can be a little reminder of these omega fatty acids for you guys.

The last thing I want to note here is that omega-6 fatty acids are just going to be fatty acids with a double bond located exactly 6 carbon atoms away from the omega carbon. Whenever you see omega and a number, that number is just telling you how many carbon atoms away that double bond is from the omega carbon. This concludes our introduction to omega-3 fatty acids, and we'll be able to get some practice applying the concepts that we've learned in our next couple of practice videos. So, I'll see you guys there.

Draw the structure of docosahexaenoic acid (22:6Δ^{4,7,10,13,16,19}) and indicate what type of omega fatty acid it is.

a) Omega-3 fatty acid. 

b) Omega-6 fatty acid. 

c) Omega-9 fatty acid.

d) Omega-4 fatty acid.

• A. Omega-3 fatty acid.
• B. Omega-6 fatty acid.
• C. Omega-9 fatty acid.
• D. Omega-4 fatty acid.

Assuming the standard shorthand naming system is used, which of the following is an omega-3 fatty acid?

a) 20:1Δ¹⁴

b) 18:3Δ^9,12,15

c) 20:1Δ^3,12

d) 18:2Δ^9,12

• A. 20:1Δ¹⁴
• B. 18:3Δ^9,12,15
• C. 20:1Δ^3,12
• D. 18:2Δ^9,12

Which of the structures below is an example of an omega-3 polyunsaturated fatty acid? 

a) A

b) B

c) C

d) D

• A.
• B.
• C.
• D.

Here’s what students ask on this topic:

What are omega-3 fatty acids and why are they important?

Omega-3 fatty acids are a type of unsaturated fatty acid characterized by a double bond located three carbon atoms away from the omega carbon, the last carbon in the chain. Examples include alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). These fatty acids are essential for human health because the body cannot synthesize them at a substantial rate. They play a crucial role in normal growth and development and have been linked to a reduced risk of cardiovascular diseases, heart attacks, and blood clots. Omega-3 fatty acids are commonly found in vegetable oils, cold-water fish like salmon, and marine algae.

What are the best dietary sources of omega-3 fatty acids?

Omega-3 fatty acids can be obtained from various dietary sources. Some of the best sources include cold-water fish such as salmon, mackerel, and sardines, which are rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Vegetable oils, particularly flaxseed oil, chia seeds, and walnuts, are excellent sources of alpha-linolenic acid (ALA). Marine algae also contain significant amounts of omega-3 fatty acids and are a primary source for fish. Including these foods in your diet can help ensure you get an adequate intake of essential omega-3 fatty acids.

How do omega-3 fatty acids benefit cardiovascular health?

Omega-3 fatty acids have been shown to offer several benefits for cardiovascular health. They help reduce triglyceride levels, lower blood pressure, and decrease the risk of heart attacks and strokes. Omega-3s also have anti-inflammatory properties, which can help prevent the development of atherosclerosis, a condition characterized by the buildup of fatty deposits in the arteries. Additionally, these fatty acids can improve endothelial function and reduce the risk of blood clots, further contributing to heart health. Regular consumption of omega-3-rich foods can thus play a significant role in maintaining cardiovascular health.

What is the difference between omega-3 and omega-6 fatty acids?

Omega-3 and omega-6 fatty acids are both types of polyunsaturated fatty acids, but they differ in the position of their first double bond from the omega carbon. Omega-3 fatty acids have their first double bond three carbon atoms away from the omega carbon, while omega-6 fatty acids have it six carbon atoms away. Both are essential fatty acids, meaning the body cannot produce them and they must be obtained through the diet. Omega-3s are known for their anti-inflammatory properties and cardiovascular benefits, whereas omega-6s are more involved in promoting inflammation and are found in higher amounts in the typical Western diet.

Can the body produce omega-3 fatty acids?

The human body cannot produce omega-3 fatty acids at a substantial rate, making them essential nutrients that must be obtained through the diet. While the body can convert a small amount of alpha-linolenic acid (ALA) into eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), this conversion is inefficient. Therefore, it is important to consume foods rich in omega-3 fatty acids, such as cold-water fish, vegetable oils, and marine algae, to meet the body's needs for these essential nutrients.