As Professor Crawford has just pointed out, you have a very important mission here. It is nothing less than the health improvement of your nation. I am a biochemist, and I want to lead you through some ideas on how the molecules of the nutrients we eat have an impact upon our health and how they play a role in the diseases we suffer.
I believe that with careful planning you can give people proper food. It is through the food that we can have primary prevention of disease. Why wait for disease to develop and then spend billions to treat it? The Centres for Disease Control in the USA assert that CHD and CVD are preventable diseases. Well let’s get on with preventing them. That will be done by educating people to make better uses of the food that is available.
In the two families of fatty acids you have just been introduced to, the omega-3 and omega-6 families, the most abundant are the 18 carbon forms, the omega-6 linoleic acid and the omega-3 alpha-linolenic acid. We eat thousands of milligrams of these each day, but the vital hormones that regulate our physiology are made from the longer chain fatty acids. 6 double bonds.
These have 20 and 22 carbon chains and 3,4,5 and
The topic of our discussion is the impact of omega-3 and omega-6 fatty acids on our health. You can take a finger-tip blood sample and measure the relevant amounts of each that a person has. With such a sample you can make a simple analysis of a person’s status. That is the percentage of omega-3s in these highly unsaturated fatty acids (HUFAS). It is a simple diagnostic measure which has great utility. What begins as a vitamin-like story turns out to be a hormone story.
This graph illustrates heart attack rates among different populations.
They eat different things and if you measure their blood and look at the proportion of their HUFAs which is omega-6, you will see that in the U.S. this is very high, and we also have a very high incidence of coronary heart disease (CHD). People who have more omega-3 than omega-6 have a very low incidence. So the measure of a person’s deficit is their level of omega-3 compared with their omega-6. The issue and challenge is, are we eating foods that will give us more omega-3 than omega-6? If we are they will give us a much better status.
We know that people die from ischaemia and thrombosis and these are caused by a series of steps which results inthe formation of excessive omega-6 eicosanoids, the hormone-like products. We can measure these in the blood. Aspirin blocks these steps and reduces the risk. There is a pandemic of CHD all around the World. People are taking aspirin, but primary prevention could change this. It would change the proportion of omega-3s to omega-6s in the tissues, so this amplification of oxidative injury to the blood vessels would not occur.
All of these things are known in great detail. There are literally thousands of intermediary compounds involved. But what this shows is that food does have a direct connection to death. The imbalance in the fatty acids leads to these imbalances, which are very well documented. So I urge people to be more aware of what is in their tissues. If they have more than 50% omega-6, they are at much greater risk than if they had less than half as omega-6. A simple gas chromatogram analysis will show the peaks within 4 minutes. I believe this will allow people to know what their individual status is. As the cost falls, it will become an important health risk-assessment tool.
So we now know that if we have more than half as omega-6 we are at higher risk, and if you have less than half as omega-6 you are at low risk. This is a measure of our omega-3 deficit. It is quite severe in the U.S.A. We live with that, or I should say we die with that. We are used to it. It is the typical American lifestyle.
We can survey either individuals or populations and give advice on whether people should be eating either more omega-3 or less omega-6. I now use my more than 50 years’ experience to explain why some of the advice on lipids is so paradoxical. The maxims used in health care are based on an assumed association with some ‘marker’, such as cholesterol. But that doesn’t mean that the marker causes the disease. Putting it in simple language, I think you can recognise that seeing smoke predicts that there is a fire, but that does not mean that the smoke caused the fire. Treating symptoms does not always remove the cause, just as we know that waving away the smoke does not put out the fire. So we have to be careful in dealing with associations.
One of the pieces of ‘smoke’ the Shellfish Association has had to deal with over the years is the issue of cholesterol. There is a hypothesis that cholesterol causes death, but I lay before you some recent evidence from Japan. Some 170,000 individuals were studied, and when you look at their blood cholesterol values for both men and women, you see in particular for men, those with the highest blood cholesterol, over 240 (UK equivalent 6.0) actually have the lowest risk of death. Those that have less than 160 (4.0) have the greatest risk of death.
So there is something about this biomarker and its association with death that does not work very well around the World, even though our doctors in the U.S. swear by it. We need to think more carefully about this particular ‘smoke’.
Here are some data from the Seven Countries Study, in which they did a 25 year follow-up. It showed the absolute death rate from CHD, relative to cholesterol level.
You will see that cholesterol is a poor predictor of CHD risk. It is not a predictor at all among the Japanese, who have more omega-3 than omega-6 in their HUFAs. Among populations with more omega-6 than omega-3 there is an association, but this doesn’t mean it is the cholesterol that causes the deaths. The food energy that causes excess cholesterol may be fatal in those populations, only to the degree that there is omega-3 deficiency. For those people who do not have omega-3 deficit, cholesterol level is not a predictor of risk. A very important point.
So how can this be? Well, biochemists know all these things and can remind you that food energy imbalance itself is also associated with both elevated cholesterol and with risk of death. If we eat a lot of food, we can burn it off to CO2. If we do a lot of work or a lot of exercise, this is where the food goes.
However, if you have a big meal and all this energy is not fully used, your body produces triglycerides which are put into the blood stream by the liver. They are hydrolysed to free fatty acids and LDL-cholesterol. These free fatty acids cause insulin resistance, which elevates blood glucose. This can lead to Type 2 diabetes. The free fatty acids can go into the tissues and accumulate. This is associated with obesity. Free fatty acids create vascular injury. These are all well documented. The interesting thing is that LDL-cholesterol is produced simultaneously with free fatty acids, the release of which is an extreme irritant.
When we eat a big meal and this occurs, at the same time we make mevalonate and isoprenoids. These amplify the transient ‘insults’. We know that it is very common for people who eat big meals to also take statins. These work by slowing down this synthesis of mevalonate and they also do reduce cholesterol, though that is just ‘blowing away the smoke’. Suppressing the mevalonate is ‘putting out the fire’.
Many large scale clinical trials by drug companies are simply used as marketing tools. The year 2008 was a banner year of embarrassing results for some of these. With one, they delayed over a year while looking for a comfortable way to introduce the public to the fact that ever greater efforts to lower LDL-cholesterol were not reducing CHD death. It opened the way for the first time for the mass media to suggest that maybe LDL-cholesterol is not the cause and that indeed there may be some other cause. Three other trials looked at lowering blood glucose to reduce heart deaths, and these also failed. From the drugs companies’ point of view they were miserable results.
It’s not the cholesterol and glucose that cause death, rather the free fatty acids causing insulin resistance. So these trials, designed for marketing purposes, showed that cholesteroldid not cause the deaths. The Japanese data has been saying that all along.
A recent trial called the Jupiter Trial showed that another inflammatory marker could be reduced by statins. So it was put to the public along the lines that ‘we have yet another reason to sell more statins’, because statins lower inflammation and lower ‘the fire’. But in fact the primary imbalance that is causing the problem is excessive omega-6 (hormonal) signalling and a relative omega-3 deficit.
So you can see that over the past year, millions of dollars have been spent, bringing us this information that smoke is not fire and that we should deal with the causes of the fire. Now we have the tools for primary prevention and we know that we can do this by diet alone. We know what the relationship is between diet and these markers in our blood and tissues and there are data bases from which to choose food combinations.
Once you understand that excess food energy can cause insults and omega-6 can amplify these, then you can effectively diminish them. You can teach the public that this is what will help; eat more omega-3, less omega-6 and eat fewer calories per meal. The answer is in the numbers.
We have produced this software (KIM 2) which you can download from the internet ( It shows you how many milligrammes of short and long chain omega-3s and omega-6s there is in each portion of food. Sometimes it is quite shocking to see.
In fish and shellfish you have a certain amount of short chain 3s and 6s, but then you have these wonderful long chain omega-3s, a characteristic of seafood.If you compare them with turkey, chicken or pork raised on grains, you can see the problem people are up against. If they eat chicken, it will have 1,400 mg of omega-6, but only a very small amount of omega-3. Turkey is the same and pork is no more reassuring.
Vegetables are good, but plants don’t make the long chain fatty acids. Pulses, like chick peas, will add 900 mg of omega-6 to an otherwise healthy meal, but not many people know this.
Walnuts have been listed as healthy because they have some omega-3 in them, but they also have a great deal of omega-6. The marketers don’t have to tell you the whole truth; they tell you the part of the truth they wish to tell you. With seafood you can tell the whole truth. In the UK the balance is about 67% omega-6 to 33% omega-3. Eating another portion of shellfish a week may get rid of your omega-3 deficit.
You don’t need to worry about cholesterol. You have been diverted by this story about cholesterol for years. It was a hypothesis that is finally dead. Even the marketers of statins are starting to say ‘golly, it might not have been LDL-cholesterol after all!’ It is the fire of the omega-3 deficit causing all the problems.