Read Eat to Live: The Amazing Nutrient-Rich Program for Fast and Sustained Weight Loss Online
Authors: Joel Fuhrman
Eat to Live: The Amazing Nutrient-Rich Program for Fast and Sustained Weight Loss (19 page)
When we have insufficient omega-3 fat, we do not produce enough DHA, a long-chain omega-3 fat with anti-inflammatory effects. High levels of arachidonic acid and low levels of omega-3 fat can be a contributory cause of heart disease, stroke, autoimmune diseases, skin diseases, depression, and possibly increased cancer incidence.
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Most Americans would improve their health if they consumed more omega-3 fat and less omega-6 fat. I recommend that both vegetarians and nonvegetarians make an effort to consume 1 to 2 grams of omega-3 fat daily.
ADD A FEW GRAMS OF OMEGA-3 FAT TO YOUR DIET
| Flaxseeds | 1 tablespoon | 1.7 g |
| Walnuts, English (12 walnut halves) | 4 tablespoons | 2 g |
| Soybeans (green, frozen, or raw) | 1½ cups | 2 g |
| Tofu | 1½ cups | 2 g |
A diet very high in omega-6 fat makes matters worse; your body makes even less DHA fat. We need enough DHA fat to ensure optimum health. The high level of omega-6 fat competes for the enzymes involved in fatty acid desaturation (conversion to longer-chain fats) and interferes with the conversion of alpha-linolenic
acid (omega-3) to EPA and DHA. Therefore, our high fat intake contributes to our DHA fat deficiency.
Our modern diet, full of vegetable oils and animal products, is very high in omega-6 fat and very low in omega-3 fat; the higher the omega-6 to omega-3 ratio, the higher the risk of heart disease, diabetes, and inflammatory illnesses.
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Diabetes is only one of many diseases linked to excessive omega-6 fats.
Source: Simopoulos, A. P. 1999. Essential fatty acids in health and chronic disease.
American Journal of Clinical Nutrition
. 70(3): 560–69.
Saturated fat, cholesterol, and trans fat also interfere with conversion to DHA. Among the most beneficial effects of a diet rich in plant foods are the low level of saturated fat and trans fat (harmful fats) and the relatively high level of essential fatty acids (beneficial fats). Both meat-based diets and vegetarian diets can be deficient in these healthy fats if they do not contain sufficient green leaves, beans, nuts, seeds, or fish. So, eat less of the fatty foods you usually consume and eat more walnuts, flaxseeds, soybeans, and leafy green vegetables.
The Fat DictionaryAll fats are equally fattening—containing nine calories per gram, compared with four calories per gram for carbohydrates and protein.
ARACHIDONIC ACID is a long-chain omega-6 fat produced by the body, but it is also found in meat, fowl, dairy, and eggs. Products made with excessive amounts of this fatty acid have the potential to increase inflammation and are disease-causing. They may increase high blood pressure, thrombosis, vasospasm, and allergic reaction. They are linked to arthritis, depression, and other common illnesses.
CHOLESTEROL is a waxy fat produced by the body and found in animal foods such as meat, fowl, dairy, and eggs. Eating cholesterol raises blood cholesterol, but not as much as eating saturated fats and trans fats. The amount of cholesterol in plants is so negligible that you should consider them cholesterol-free.
DHA FAT is a long-chain omega-3 fat that is made by the body, but it can also be found in fish such as salmon and sardines. DHA is used in the production of anti-inflammatory mediators that inhibit abnormal immune function and prevent excessive blood clotting. DHA is not considered an essential fat because the body can manufacture sufficient amounts if adequate short-chain omega-3 fats (flaxseeds, walnuts, soybeans, leafy green vegetables) are consumed. However, because of genetic differences in the enzyme activity and because of excess
omega-6 fats, many people who do not consume fatty fish regularly are deficient in this important fat.HYDROGENATED FAT Hydrogenation is a process of adding hydrogen molecules to unsaturated fats, thereby turning these oils, which are liquid at room temperature, into harder, more saturated fats such as margarine. Hardening the fat extends its shelf life so the oil can be used over and over again to fry potatoes in a fast-food restaurant or be added to processed foods such as crackers and cookies. While hydrogenation does not make the fat completely saturated, it creates trans fatty acids, which act like saturated fats. Evidence is accumulating to implicate the harmful nature of these man-made fats in both cancer and heart disease. Avoid all foods whose ingredients contain partially hydrogenated or hydrogenated oils.
MONOUNSATURATED FAT These fats have only one double bond in their carbon chain. They are liquid at room temperature and thought to have health benefits. The supposed health benefits of these fats appear when they are used in place of dangerous saturated fats. But even polyunsaturated oils will lower cholesterol if used in place of saturated fat. Monounsaturated fat is found in avocados, almonds, peanuts, and most other nuts and seeds. Keep in mind that no isolated or refined fat, even these monounsaturated fats, should be considered health food. Oils with the highest percentage of monounsaturated fat include olive, canola, and peanut oils.
POLYUNSATURATED FAT These fatty acids have more than one double bond in their chain. These fats include corn oil, soybean oil, safflower oil, and sunflower oil. They are soft at room temperature. These fats promote the growth of cancer in lab animals more than olive oil (a monounsaturated fat) does.
SATURATED FAT Some naturally occurring fats are called saturated because all of the bonds in their carbon chain are single bonds. These fats are solid at room temperture and are generally recognized as a significant cause of both heart disease and cancer. Saturated fats are found mainly in meat, fowl, eggs, and dairy. Coconut and palm oil are
largely saturated and are not desirable. The foods with the most saturated fat are butter, cream, and cheese.UNSATURATED FAT These fats are a mix of monounsaturated and polyunsaturated fats. Eating unsaturated fats lowers cholesterol when substituted for saturated fats, but excessive amounts may promote cancer.
There’s Something Fishy about Fish Oils
Most of the publicity about the beneficial effects of essential fats has focused on fish oils, which are rich in EPA, an omega-3 fat. One problem with fish oils is that much of the fat has already turned rancid. If you cut open a capsule of fish oil and taste it, you will find it tastes like gasoline. Not only are many people intolerant of the burping, indigestion, and smelling like a fish, but it is also possible that the rancidity of the fat places a stress on the liver. I have noted abnormal liver function in the blood tests of a few patients who were taking fish oil capsules. These few patients had their liver function return to normal when they stopped taking the fish oil.
Recently a lawsuit brought by environmentalists in California against eight supplement manufacturers or distributors claimed that popular brands of fish oil supplements contain unsafe and illegal levels of polychlorinated biphenyls, or PCBs, which are carcinogenic chemicals.
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Testing found that levels of PCBs in popular fish oil supplements varied wildly, from about 12 nanograms per recommended dose to more than 850 nanograms in the most contaminated product. The suit claimed that the manufacturers were in violation of California law for not disclosing any nonzero PCB levels in their products.
Large amounts of fish oils inhibit immune function.
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Lowering the function of natural killer cells is not a good thing, as our defenses against infection and cancer diminish. Because of this immune suppression, as well as the toxicity issues, I do not
routinely recommend that my patients take fish oil capsules—though there are a few exceptions.
This ability of fish oils to decrease the activity of the immune system makes them useful for some patients with autoimmune illnesses, such as rheumatoid arthritis or inflammatory bowel disease.
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Some rheumatoid arthritis patients are “fish oil responsive,” and many others are not. I often perform a three-month trial of fish oil supplementation to determine a patient’s responsiveness. With such patients, the risks of the added oil are minimal compared with the potential benefits, especially if they can avoid toxic drugs. Of course, when using fish oil supplements, consider only the highly purified types, free of PCBs and mercury.
Another case in which fish oils may be useful is the individual who does not convert omega-3 fats into DHA sufficiently. These people may be more prone to depression, allergies, and inflammatory skin disease such as eczema. There are blood tests available for a physician to analyze the fatty acid balance on red blood cell membranes and thereby determine a deficiency of DHA or omega-3 fat. These people often benefit from the addition of fish oils or plant-derived DHA. Laboratory-cultivated DHA made from microalgae is a pure form of DHA without mercury or other toxins. It is well tolerated and does not have a rancid taste or odor.
Does Fish Prevent Heart Disease?
There are two components to a heart attack or stroke. First, you must develop atherosclerotic plaque. This plaque builds up over many years from eating a diet deficient in unrefined plant foods. Almost all Americans have such plaque. Autopsy studies demonstrate atherosclerosis even in the vast majority of American children.
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Once this fatty plaque accumulates and partially blocks a coronary artery, a clot can develop in a defect or crack in the surface
of the plaque. This clot is called a thrombus, which can enlarge and completely block the vessel, causing a heart attack, or break off and travel upstream, obstructing a more distal coronary site. A traveling thrombus is called an embolus. Emboli and thrombi are the causes of almost all heart attacks and strokes.
Fish contains omega-3 fatty acids (EPA and DHA) that interfere with blood clotting much the same way aspirin does. Once you have significant atherosclerosis, it is helpful to take such anti-clotting agents, especially if you continue a dangerous diet. These fish-derived fats also have some effect on protecting the arterial walls from damage from other fats. For people eating saturated-fat-containing animal products, it is advisable to consume one or two weekly portions of fatty fish, such as sardines, salmon, trout, halibut, or mackerel, and reduce the consumption of other animal products accordingly. Increasing fish intake beyond one or two servings per week has not been shown to offer additional protection.
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However, the best way to prevent a heart attack or stroke is to follow a high-nutrient diet with little or no animal products, thereby ensuring that such blockages don’t develop in the first place. Then eating fish won’t matter. It is true that increasing blood levels of these important fish-derived fats reduces the incidence of heart attacks significantly.
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However, contrary to popular belief, not only vegetarians but also most others eating diets with adequate plant material get most of their long-chain omega-3 fatty acids from non-fish sources.
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In fact, the reason the fish-derived fats EPA and DHA are not considered essential fats is that almost all people have enzymes to convert the plant-derived omega-3 fat rapidly into EPA and DHA.
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Fish is a double-edged sword, especially because fish has been shown to increase heart attack risk if it is polluted with mercury.
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Keep in mind that even though men in Finland consume lots of fish, their mortality from coronary heart disease is one of the highest in the world.
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It seems that the cardioprotective effects of eating a little fish is lost when you eat lots of fish, most likely because lots of fish exposes you to high mercury levels,
which can promote lipid peroxidation.
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Lipid peroxidation occurs when body lipids react with oxygen to cause a compound that plays a major role in the development of diseases such as heart disease, diabetes, and arthritis.
In addition, those who consume fish in the hope of reducing their cardiac risk may be getting more than they bargained for—namely, toxic contaminants, including some that carry a cancer risk.
Fish is one of the most polluted foods we eat, and it may place consumers at high risk for various cancers. Scientists have linked tumors in fish directly to the pollutants ingested along the aquatic food chain, a finding confirmed by the National Marine Fisheries Service Laboratory. In some instances, such as with the PCBs in Great Lakes trout and salmon, it can be shown that a person would have to drink the lake water for one hundred years to accumulate the same quantity of PCBs present in a single half-pound portion of these fish, reported John J. Black, Ph.D., senior cancer research scientist for the Roswell Park Memorial Institute, to the American Cancer Society.
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From the flounder in Boston Harbor to English sole in Puget Sound, scientists report that hydrocarbon pollution from habitat concentrate in fish. There are high cancer rates around New Orleans, where fresh fish and shellfish are a staple of the local cuisine.
