How the Omega-3 Index Guides EPA and DHA Intake

Chris Williamson: Are low omega-3 levels worse than smoking cigarettes?

Dr. Rhonda Patrick: I do not know that they are worse. Omega-3 fatty acids are essential for many things. I think you are referring to one specific study from Dr. Bill Harris's group. He is the head of the Fatty Acid Research Institute and the pioneer of the Omega-3 Index test, which is how you should measure your omega-3 levels.

The Omega-3 Index measures EPA and DHA in red blood cells. Most omega-3 tests measure plasma levels. Red blood cells take about 120 days to turn over, so they provide a longer-term marker of omega-3 status. A plasma test is more like asking what you ate for dinner in the last week. You may have eaten a lot of salmon even if you do not usually eat it.

Dr. Harris and his colleagues studied omega-3 levels and all-cause mortality, which includes deaths from all non-accidental causes. Cardiovascular disease is at the top of the list because it is the leading cause of death in most developed countries. They correlated all-cause mortality with the Omega-3 Index.

People with a low Omega-3 Index, 4% or less, were compared with people with a high index, 8% or higher. People with the high Omega-3 Index had a five-year greater life expectancy than people with the low index. People in the United States average about a 4% to 5% Omega-3 Index. In Japan, where people eat much more seafood, the Omega-3 Index is about 10%, and life expectancy is about five years longer than in the United States.

The researchers also stratified the data by other factors, including physical activity, BMI, and smoking. The graph makes this easier to see. Nonsmokers with a high Omega-3 Index had the longest life expectancy. Smokers with a low Omega-3 Index had the shortest. Smokers with a high Omega-3 Index had the same life expectancy as nonsmokers with a low Omega-3 Index. In that analysis, having a low Omega-3 Index was like smoking with respect to all-cause mortality.

Some smokers hear that and think all they have to do is supplement with omega-3. No. That is the wrong way to think about it. Most people know that smoking is terrible for health. This goes back to the framework I use for nutrition: What do we need? If you only focus on what to avoid, you still may not get what you need to run metabolism, neurotransmitter synthesis, and other processes. Omega-3 fatty acids are important for many things. With respect to smoking, it is astounding to see the graph. Nonsmokers with low omega-3 status lived as long as smokers with high omega-3 status.

Chris Williamson: Do you think the omega-3s directly caused this, or is there healthy-user bias upstream from the kinds of people who have omega-3s in their diet?

Dr. Rhonda Patrick: Great question. This is observational data, so it is always a correlation. You can never definitively say that it is causal. There could be healthy-user bias, although the analysis accounted for other factors.

People think about smoking and lung cancer or cancer risk, but the biggest problem with smoking is heart disease. Smoking increases lung-cancer risk in a dose-dependent manner. The more cigarettes you smoke, the higher the cancer risk. The increase is not linear for cardiovascular disease and heart-attack risk. Even a small amount of smoking can sharply increase heart-disease risk.

One of the biggest things omega-3s protect against is heart disease. Doctors prescribe them. Randomized controlled trials have given people high-dose purified omega-3 in the form of EPA, or a combination of DHA and EPA. A variety of studies have found lower risks of heart attack and death from cardiovascular disease in people given omega-3s compared with placebo.

Low omega-3 status in nonsmokers is probably affecting cardiovascular health. Inflammation is also a major driver of cardiovascular disease, and omega-3s can lower inflammation in many ways. To give the long answer to your question, no, you cannot definitively say that healthy-user bias is not involved.

Chris Williamson: But there is a mechanism that could explain how it works.

Dr. Rhonda Patrick: There is. Again, the analysis adjusted for other health factors, so you would expect some of those factors to show up.

Chris Williamson: Suppose someone says, "I had not thought about omega-3s. I should probably optimize those." What is the 80/20 approach to getting good omega-3s in the diet? Someone might struggle with seafood because it is difficult or expensive to cook at home. Where would you direct them for food or supplements? What do they need to know?

Dr. Rhonda Patrick: I mentioned the Omega-3 Index. You want to get to 8% or higher, and it is always good to measure. Studies have taken people with a low Omega-3 Index, around the typical American level of 4%, and given them about 2 grams per day of omega-3. That can raise their Omega-3 Index from 4% to 8%.

To give you perspective, physicians prescribe Lovaza, a DHA and EPA ethyl ester formulation, and Vascepa, a highly purified EPA formulation. They prescribe these at 4 grams per day. That is twice as much as 2 grams per day. Two grams per day can raise people from 4% to 8%. I think that is a good starting point for the average person. I take experimentally higher doses, but generally speaking, 2 grams per day is fairly safe for most people and can produce a high Omega-3 Index around 8%.

Chris Williamson: Where should people go? How can they assess quality without finding a Norwegian farmer who squeezes fish into a barrel himself? I remember cod-liver-oil tablets from years ago. There was controversy before there was even a podcasting universe to scrutinize it. What do people need to know when choosing an omega-3 supplement?

Dr. Rhonda Patrick: We have a lot of data now, and it is easy to access because third-party testing sites buy fish-oil supplements from store shelves and measure important things. They measure the concentration of EPA and DHA to see whether it matches the label.

Fish oil comes from fat, and fish can contain contaminants, including PCBs and mercury. Fish oil is generally purified, but you want to make sure that process was done well, so testing measures those contaminants. Oxidation is also important. Omega-3s are polyunsaturated fatty acids and are prone to oxidation. You do not want a total oxidation value greater than 10 because that is like consuming rancid fat.

ConsumerLab is a third-party testing site. I have no affiliation with ConsumerLab, but I use it. It lets people find affordable, good-quality fish-oil supplements. If you are a data nerd like me, you can use the International Fish Oil Standards site. It provides a lot of data, although you have to know what to do with it. It measures all these things and identifies the formulation.

The two main formulations are ethyl ester and triglyceride. Generally, the triglyceride form is the most bioavailable. When you eat fish, its omega-3s are in triglyceride form. During purification, omega-3s are removed from the triglyceride form and converted into an ethyl ester. Some companies then re-esterify them back into triglycerides to improve bioavailability.

Chris Williamson: So they are both pure and bioavailable.

Dr. Rhonda Patrick: Exactly, but not every company does that. Many people who receive prescription omega-3 to help prevent cardiovascular disease take an ethyl ester formulation.

Chris Williamson: That is what I have.

Dr. Rhonda Patrick: The thing to know is that you have to take it with a meal, preferably one with more fat. You will absorb very little if you take it on an empty stomach.

I mentioned that 2 grams per day of omega-3 can raise the Omega-3 Index from low to high, from 4% to 8%. When you look at the formulation, people needed less of the triglyceride form than the ethyl ester form to get there. I average it out and say 2 grams. If you can get the triglyceride form, it is a good form to use.

Chris Williamson: How much salmon, cod, or halibut do I need to eat each week if I want to get this through my diet?

Dr. Rhonda Patrick: I do not have empirical data to answer that. Wild Alaskan salmon is one of the best omega-3 sources because it has low levels of contaminants such as mercury and PCBs per ounce of fish. Salmon is a good source, but the amount you need depends on the cooking method and how thoroughly it is cooked. Omega-3s are somewhat heat-sensitive, so cooking can degrade some of them.

You would need to test. You could say, "I typically eat salmon two or three nights a week," and then wait 120 days because that is how long red blood cells take to turn over.

Chris Williamson: I know. Here is the program. Rhonda, just tell me how much salmon I need to eat. Come on, please.

Dr. Rhonda Patrick: Twice, at least. I would say you probably have to supplement on top of that. I do not know whether twice a week will necessarily raise the index from 4% to 8%.

Chris Williamson: I imagine many people listening will think, "I am going to find a good-quality, low-oxidation triglyceride omega-3 that is responsibly sourced. I will take 2 grams per day and probably have some kind of fish meal twice a week." Does that seem realistic?

Dr. Rhonda Patrick: Absolutely. That is what I do. I raise the dose a little more, but I take it throughout the day.