QUICKLINKS AND VIEW OPITONS
The Importance of Omega-3 Fatty Acids
Friday, November 14, 2003 5:33 pm Email this article
An interview with Artemis Simopoulos, M.D., author of The Omega Diet.
Artemis P. Simopoulos, MD was a Senior Editor of author of the book OBESITY: New Directions in Assessment and Management and contributed a marvelous chapter titled EVOLUTIONARY ASPECTS OF DIET: Fatty Acids, Insulin Resistance and Obesity. She has been researching evolutionary aspects of diet since 1984. She is one of the world's leading experts on the effects of essential fatty acids on health and disease. Her list of accomplishments are as impressive as I have ever seen.
Here is just a sampling of what she has done. She has written over 200 published papers, has edited six books and several journal supplements, and coauthored a wonderful book written for the lay population titled THE HEALING DIET. She is President of The Center for Genetics, Nutrition and Health, a member of the Board of Directors of the American Association for World Health, and for 9 years chaired the Nutrition Coordinating Committee at the National Institutes of Health (NIH). She was also a member of several White House delegations to the World Health Organization (WHO) and the Food and Agriculture Organization. Since 1989 has been the editor of the Karger series titled World Review of Nutrition and Dietetics. And in 1993 Dr. Simopoulos was awarded the first Presidential Award for Studies in the Field of Obesity and Weight Control from Columbia-Presbyterian Medical Center. Dr. Simopoulos can be reached as follows:
Artemis P. Simopoulos, MD
The Center for Genetics, Nutrition and Health
2001 S Street NW Suite 530
Washington, DC 20009
Hobbs: Dr Simopoulos, tell me a little about your background and how you became interested in diet and obesity.
Simopoulos: My training originally was in pediatrics. Then I went into endocrinology and metabolism, not limited to pediatrics. The first dietary guidelines that came out in 1980 used the body weight table that we developed based on the 1959 Metropolitan Body Weight Tables. In 1981 while at the NIH our office developed the definition of nutrition research and held a workshop on nutrition policy. Our office developed the first program announcement for research on obesity. It emphasized the need for research in the prevention, management and maintenance of weight loss in obese patients. We also had a workshop on body weight, health and longevity which was later published in a classic paper titled “Body Weight and Longevity” [Annals of Internal Medicine, 1984 Feb, 100(2):285-95]. For the first time we were able to show that obesity is an independent risk factor for cardiovascular disease. Until then it was believed that the increased risk was only due to obesity’s association with hypertension and diabetes. We were also able to define what is considered the desirable body mass index, above or below which there is an increase in mortality. All of the conclusions in that paper have since been confirmed by other researchers.
Hobbs: Your chapter EVOLUTIONARY ASPECTS OF DIET was very enlightening for me. Have you found anything new since it came out?
Simopoulos: Yes. I’ve written two papers since that book came out on fatty acids and insulin resistance as well as the effects of trans fatty acids on insulin resistance and body weight. Also there is new information regarding the intake ratio of omega-6-to-omega-3 fatty acids and their relationship to insulin resistance. The papers are in print and are coming out in the New York Academy of Sciences.
Hobbs: What is the new finding about the ratio?
Simopoulos: As the ratio of omega-6-to-omega-3 increases above 4-to-1 insulin resistance increases and the prevalence of diabetes increases.
Hobbs: What is the ratio in the typical American diet?
Hobbs: Is this maybe why insulin resistance is a problem in America?
Simopoulos: Yes. Approximately 25% of the known obese population is insulin resistant.
Hobbs: What do you think about low fat, high carbohydrate diets?
Simopoulos: I don’t think that it helps since 25% of the population is insulin resistance. It increases triglycerides and lowers HDL.
Hobbs: How does today’s diet differ from our hunter-gatherer ancestors during paleolithic times?
Simopoulos: Their diet was much higher in protein, lower in grains, but higher in fruits and vegetables and much lower in saturated fat than today’s diet. They also consumed a fair amount of eggs.
Hobbs: How much protein?
Simopoulos: About 34% vs approximately 12% in the American diet.
Hobbs: How were the vegetables different?
Simopoulos: They ate high amounts of green, leafy vegetables, rather than roots, and wild plants. Wild plants are characterized by higher levels of the omega-3 fatty acid alpha-linolenic acid (LNA), higher amounts of vitamin E, vitamin C, and glutathione - which is an important antioxidant - and modest amounts of beta carotene.
Hobbs: Are today’s eggs different?
Simopoulos: Yes. Free-ranging chickens eat a lot of grass, insects and worms. Their eggs have a balanced ratio of omega-6-to-omega-3 fatty acids of about 1-to-1. Today’s standard USDA egg, because of the way chickens are fed, has a ratio of 20-to-1.
Hobbs: What effect do the vegetables and eggs have on health?
Simopoulos: We consume much less omega-3 fatty acids - the essential omega-3 alpha-linolenic acid and the longer chain omega-3 fatty acid derivatives eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) found in fish oil - than we used to. We used to get omega-3 alpha-linolenic acid from wild plants, from eggs and from meat. Meat used to contain more omega-3 fatty acids also because the animals grazed on grass and wild plants rather than being grain fed. If you look at noodles that are made with omega-3-rich milk and omega-3-rich eggs obtained from free-ranging animals you will find that the noodles also contain omega-3 fatty acids. So, until recently omega-3 fatty acids were pervasive throughout the food supply.
Hobbs: What happened to the omega-3’s in our diet?
Simopoulos: Omega-3’s were taken out of much of the western diet. Much of the omega-3’s were taken out of soybean oil to make it more stable and give it a longer shelf life. So instead of the omega-3’s being 20% of soybean oil, they’re now less than 7%. This also reduces the omega-3 content of margarine. People also eat a lot of corn oil, which contains a lot of omega-6 linoleic acid, but no omega-3 alpha-linolenic acids. We also eat very little cold-water fish which contains high amounts of the omega-3 fatty acids EPA and DHA.
Hobbs: Does that include McDonald’s fish sandwiches?
Simopoulos: That’s interesting. We studied the McDonald’s fish sandwich and found that it’s full of omega-6 corn oil, but it does not contain any omega-3’s.
Hobbs: Is it possible to buy omega-3-rich eggs?
Simopoulos: Yes. There is a company called The Country Hen outside of Boston [phone number 508-928-5333] that has been producing omega-3-rich eggs for the past 8 years by feeding the chickens fish meal. A large egg company called Pilgrim Pride is also about to release and omega-3-rich egg.
Hobbs: What is the effect of these eggs on cholesterol?
Simopoulos: Interestingly enough, they lower cholesterol and prevent platelet aggregation.
Hobbs: What do you think about the recommendation a decade or so ago recommending to replace saturated fat with polyunsaturated fats like corn oil?
Simopoulos: This indiscriminate replacement of saturated fats with corn oil led to huge amounts of omega-6 linoleic acid into the food supply and threw the ratio of omega-6-to-omega-3 further out of balance. Corn oil contains omega-6 fatty acids, but no omega-3 fatty acids. For the first time in history of man humans are being exposed to pharmacological doses of omega-6 linoleic acid.
Hobbs: What are the effects of high-fructose corn syrup found in so many sweetened drinks and processed foods?
Simopoulos: It’s also a totally new phenomenon to have such high levels of fructose in the diet without being accompanied by the fiber, vitamins and minerals found in fruit. High fructose corn syrup was introduced in 1967 and now fructose accounts for about 8% of our total calorie intake. It increases triglycerides and under some circumstances cholesterol, and is much more lipogenic. In other words, large amounts of high-fructose corn syrup as well as corn oil are not good for health.
Hobbs: Do you think that the drastic increase in the intake of high-fructose corn syrup is part of the problem with Americans gaining weight?
Simopoulos: Yes, because fructose is lipogenic, in other words it is more easily converted to fat.
Hobbs: Tell me about the changes in fatty acid intake and the effects on health.
Simopoulos: Our metabolism is such that it requires a balance of omega-6 linoleic and omega-3 alpha-linolenic acids. Omega-6 and omega-3 fatty acids are the parent compounds for eicosanoids which includes prostaglandins, thromboxanes and leukotrienes. The eicosanoids generated from omega-6 linoleic acid - the fatty acid found in corn oil - are pro-thrombotic, pro-inflammatory, and pro-constrictive. The eicosanoids generated from omega-3 fatty acids - the alpha linolenic acid found in green leafy vegetables, linseed or flax seed oil, walnut oil and canola oil - are less inflammatory, less thrombogenic, and they dilate blood vessels. The consumption of the non-essential omega-3 fatty acids EPA and DHA from fish oil tends to decrease platelet aggregation, decrease inflammation, and increase vasodilation.
Hobbs: Is this omega-3 fatty acid deficiency or ratio imbalance implicated in diseases?
Simopoulos: Yes. Many of the chronic diseases - like coronary heart disease, hypertension, aging, obesity, and diabetes - are characterized by the omega-6-rich, omega-3-poor type of physiology. That is, pro-inflammatory, pro-thrombotic, and pro-constrictive. So if you have a genetic disposition for one of these diseases, the typical American diet increases the chances of getting the disease.
Hobbs: How much of a role does genetics play?
Simopoulos: Research is being performed on how fatty acids influence gene expression. For example genes that deal with fatty acid metabolism like fatty acid synthase, which is involved in lipogenesis - the conversion of carbohydrates to fat - are suppressed by both omega-6 and omega-3 fatty acids. But DHA, the omega-3 fatty acid found in fish oil and made from alpha-linolenic acid, suppresses it more powerfully than all others.
Hobbs: How important is DHA?
Simopoulos: Very important. It’s important for brain function and visual function.
Hobbs: How do the fatty acids affect cancer and tumors?
Simopoulos: Omega-6 linoleic acid found in corn oil increases tumor growth, whereas the omega-3 fatty acid suppress them.
Hobbs: Although the omega-3 alpha-linolenic acid can be converted to EPA and DHA, are there people who need to take EPA and DHA-containing fish oil supplements?
Simopoulos: Yes. Hypertensives, some diabetics and premature babies are limited in the ability to convert omega-3 alpha-linolenic acid to EPA and DHA. They need to supplement with fish oils as well as eating alpha-linolenic acid. This means either eating cold water fish, like salmon, mackerel or sardines [packed in sardine oil or olive oil, but not soybean oil], or taking a fish oil supplement.
Hobbs: What is the right dose?
Simopoulos: About 1 gram per day for health or 3 grams per day for people with diseases.
Hobbs: A combined total of EPA and DHA being 3 grams?
Hobbs: Do obese people suffer from deficiencies of EPA and DHA?
Simopoulos: Maybe. Low levels of DHA are associated with increases in body weight. A study in Pima Indians found that the lower the DHA content of muscle cell membrane phospholipids the higher the body weight. They also found that the lower the DHA the higher the insulin resistance.
Hobbs: Is that due to a dietary deficiency?
Simopoulos: We don’t know yet. It’s being studied right now. It may be dietary or it may be metabolic.
Hobbs: What are the adverse effects of consuming hydrogenated and partially hydrogenated oils and trans fatty acids found in so many processed foods?
Simopoulos: There are a lot of adverse effect. In fact, there are no beneficial effects. Margarine is worse than butter because margarine is made from hydrogenated oils and it contains trans fatty acids. Trans fatty acids found in hydrogenated oils raise triglycerides, raise LDL and lower HDL. At least butter doesn’t lower HDL. Partially hydrogenated oils inhibit the metabolism of omega-6 and omega-3 fatty acids at many steps and induce partial deficiencies of these essential fatty acids.
Hobbs: Do trans fatty acids affect body weight?
Simopoulos: Maybe. Animals fed trans fatty acids have larger fat cells although overall body weight is the same. In one clinical trial it was found that women who ate margarine at least four times per week had gained 5 lbs in six weeks compared to those who consumed it less frequently even though both groups consumed and expended the same number of calories.
Simopoulos: Yes. And trans fatty acids found in hydrogenated oils have also been shown to increase the risk of heart disease. Trans fats now make up 5 to 7% of our diet, so it seems likely that the combination of a high intake of trans fats as well as a high intake of omega-6-rich, omega-3-deficient corn oil may be part of the reason Americans are gaining weight. It’s also likely that this is contributing to chronic diseases like hypertension and diabetes.
Hobbs: Are you saying omega-3’s may be useful in preventing weight gain?
Simopoulos: Yes. Omega-3 fatty acids protect against weight gain in animals, although this has not been studied in humans yet. The American diet has an absolute and a relative deficiency of omega-3 fatty acids. That is, we don’t consume enough omega-3’s to start with and our over-consumption of omega-6’s from corn oil puts the ratio out of balance and also causes a relative deficiency.
Hobbs: What should we use instead of corn oil?
Simopoulos: Oils that are high in monounsaturates, like olive oil or canola oil or a combination of the two. Canola oil also contains omega-3 alpha-linolenic acid. The ratio of omega-6-to-omega-3 is 2-to-1. This compares to soybean oil which has a ratio of 7-to-1, and you don’t want that. And corn oil doesn’t contain any omega-3’s.
Hobbs: Do you prefer canola oil to olive oil?
Simopoulos: I like a combination of the two.
Hobbs: Do you think that our omega-3 deficiency has anything to do with decreasing fertility?
Simopoulos: I’m not sure. In animal studies they have found malformation of sperm, but no change in the amount.
Hobbs: What is the connection between insulin resistance and obesity?
Simopoulos: All obese individuals are insulin resistant. And all diabetics are insulin resistant. But a certain portion of the population, about 25%, are insulin resistant before they become diabetic or obese.
Hobbs: Are you saying that insulin resistance may contribute to obesity rather than being caused by obesity?
Simopoulos: Yes. It was recently found that insulin resistance precedes obesity, diabetes and hypertension in some individuals.
Hobbs: What causes insulin resistance?
Simopoulos: About 25% of the known obese population has a genetic predisposition to insulin resistance. A sedentary life-style also increases insulin resistance. And the ratio of omega-6-to-omega-3 fatty acids correlates with insulin resistance. Saturated fat may also increase it by reducing the number of insulin receptors and the action of insulin. However in rats, omega-3 fatty acids, and especially DHA from fish oil, prevents the saturated fat-induced increase in insulin resistance. Omega-6 linoleic acid found in corn oil correlates with hyperinsulinemia.
Hobbs: What is the best way to improve insulin sensitivity?
Simopoulos: Exercise, weight loss and omega-3 fatty acids.
Hobbs: Do you think that a deficiency of omega-3 fatty acids, especially DHA, is related to depression?
Simopoulos: There are a half a dozen studies showing that people with depression, schizophrenia and attention deficit disorder have lower levels of omega-3 fatty acids in blood and red cell membranes. Researchers are investigating whether this is caused by a lack of omega-3’s in the diet or whether these people have metabolic defects causing lower levels.
Hobbs: Do you think that flax oil is as beneficial as fish oil? [Flax oil is rich in the omega-3 alpha-linolenic acid which can normally be converted to EPA and DHA. Where as fish oil is rich in EPA and DHA.]
Simopoulos: Not as beneficial for everybody, but certainly beneficial for most people provided that they not consuming too much omega-6-rich corn oil. If you consume too much corn oil you prevent the conversion of omega-3 alpha-linolenic acid to EPA and DHA. You have the keep the ratio of omega-6-to-omega-3 less than 4-to-1.
Hobbs: Do you think there is a connection between omega-3 deficiencies and diabetes? If so, do you think that omega-3 supplementation would be useful in diabetics?
Simopoulos: Some diabetics and hypertensives have a problem converting omega-3 alpha-linolenic acid to EPA and DHA may need to supplement there diet with EPA and DHA by eating cold-water fish or taking a fish oil supplement. They need it for two reasons. First, to prevent the complications of hypertension and diabetes. And second, to improve insulin resistance.
Hobbs: Again, the appropriate dose would be 3 grams per day?
Simopoulos: Yes. Up to 3 grams per day has been shown to improve insulin resistance, lower triglycerides and raise HDL.
Hobbs: Why do you think Americans are getting fatter?
Simopoulos: We eat more, exercise less and don’t have the proper amounts of omega-6 and omega-3 fatty acids in our diets. We get too much omega-6 from corn oil and too little omega-3’s.
Hobbs: How much protein, fat and carbohydrate should we consume?
Simopoulos: 20% protein, 35% fat, and 45% carbohydrate.
Hobbs: Why only 20% protein? I read in your chapter that in Paleolithic times we ate 34% protein.
Simopoulos: I think that 20% is just more reasonable.
Hobbs: What is the best way to increase protein intake while also decreasing saturated fat intake?
Simopoulos: By eating lean meat, fish, legumes, skim milk, low fat cheese, and eggs that are balanced in omega-6 and omega-3.
Hobbs: You’ve written about purslane. What is it and how do you eat it?
Simopoulos: Purslane is a wild vegetable that is the eighth most common plant in the world. It has a number of nutritional and medicinal properties. It is the highest source of omega-3 alpha-linolenic acid containing 400 mg per 100 gram serving [3.5 ounces]. It also contains approximately 12 mg of vitamin E, 27 mg of vitamin C, 15 mg of glutathione and 2 mg of beta carotene. It’s the best example of a green leafy vegetable to eat. You can eat it in a salad or cook it like spinach.
Hobbs: What dietary changes do you recommend?
1. Increase protein intake.
2. Decrease saturated fat intake and replace with monounsaturated fat.
3. Eliminate hydrogenated and partially hydrogenated oils in order to reduce the intake of trans fats.
4. Decrease omega-6 intake and increase omega-3 intake to get a balance of the two.
5. Increase the intake of fruits and vegetables.
6. Reduce the intake of carbohydrates from cereal and grains and especially high-fructose corn syrup.
Thirty minutes of moderate exercise each day is also important for good health. Hippocrates was concerned about obesity and said that:
* “sudden death is more common in those who are natural fat than in the lean.”
He also noted:
* “But eating alone is not enough for health. There must also be exercise…”
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