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THE UNIQUE NUTRIENTS OF SEAFOOD

Dr. Weston Price, in his studies of native peoples, found that they consumed much seafood (both scalefish and shellfish) wherever available; indeed, fishing cultures were among the most physically well developed and disease resistant found. Let’s explore why this may have been so. This discussion includes the results of several studies that have been done to determine the benefits of seafood.

EFFECTS OF THE NUTRIENTS IN SEAFOOD

Much recent medical research has focused on the physiological effects of fish consumption and on the fatty acids in fish oils. Essential fatty acids have collectively been referred to as Vitamin F. Fatty acids consist of chains of carbon atoms bonded to hydrogen. “Unsaturated” means that some of the chemical bonds in the carbon chain are unstable; oxygen may form bonds with the carbon atoms adjacent to these unstable bonds and cause rancidity. A highly unsaturated oil can stay liquid at cold temperatures, while saturated fatty acids such as those found in butter or meat are solid at room temperature.

Eicosapentaenoic acid (EPA) is found in high concentrations in certain fish. As mentioned earlier in the book, EPA is a long-chain, highly unsaturated fatty acid that can be used in metabolism to make some important prostaglandins, as can several other fatty acids, including gamma-linolenic and arachidonic acids. Prostaglandins are hormonelike substances exerting control over events throughout the body, for example, the production and release of chemicals by blood platelets and cells lining the walls of blood vessels. These chemicals control the tendency of the platelets to form a clot. They thus influence the chances of a thrombus (clot) forming, lodging in the coronary arteries, and causing a coronary thrombosis (heart attack).

Linoleic and alpha-linolenic acids are essential fatty acids; the body cannot make them and they must be supplied in the diet. Though experimental animals freely convert alpha-linolenic acid to EPA, some researchers believe that EPA should also be considered essential for humans. This is due to the fact that we have, at most, a limited ability to make EPA, and it has unique and beneficial effects.

Many prostaglandins made from either EPA, dihomo-gamma linolenic acid (DGLA) (linoleic acid is a precursor of DGLA), or arachidonic acid affect the same bodily functions, though in different ways. For many functions, the body can utilize prostaglandins made from any of the three. All produce critical prostaglandins. What seems to be required for optimal function is properly balanced production of prostaglandins made in the body, on the one hand, from arachidonic acid, and on the other, from DGLA and EPA. Prostaglandins made from arachidonic acid are called the series 2 prostaglandins; those made from linoleic acid and DGLA are called the series 1 prostaglandins; and those made from EPA the series 3 prostaglandins. Figure 6.1 details the metabolic pathways of the fatty-acid precursors of these three series of prostaglandins. EPA is concentrated in the fat of marine (saltwater) fish and shellfish, especially the cold-water varieties. Concentrations of a closely related fatty acid, docosahexaenoic acid (DHA), occur in the same sources. DHA is also concentrated in the brain and in retinal cells of the eyes of mammals, including humans; the significance of this will be demonstrated in experiments discussed later.

Figure 6.1. Foods, Fatty Acids, and Prostaglandins

Chloroplasts—the green cells in plants—contain small amounts of alpha-linolenic acid, which mammals can convert to EPA. While grazing animals convert alpha-linolenic acid to EPA, the extent to which the human body can do so is not clear. One research team in the Clinical Chemistry Department of Aalborg Hospital in Denmark gave a volunteer one tablespoon of cod-liver oil three times a day for one week (far more than what should be consumed on a regular basis). Cod-liver oil is about 10 percent EPA. A tenfold increase in the EPA content of the blood fats occurred within the week. Linseed oil was given to the same person two months later, in the same dose; after one week the individual showed only insignificant increases in EPA.

The human body nevertheless may well make the conversion of alpha-linolenic acid to EPA under certain circumstances, the EPA then being utilized for synthesis of prostaglandins. All of the prostaglandin pathways are inhibited by many influences, including deficiencies of magnesium, zinc, iron, vitamin B₆, or other nutrients; excessive alcohol consumption; cortisone-like drugs; increased adrenaline associated with stress; aging; and especially the presence in the body of unnatural fatty acids such as those found in margarine and hydrogenated vegetable oils.

In converting alpha-linolenic acid to EPA, the proportion of different kinds of fatty acids in the diet has a major influence. Had the individual been on a diet very low in arachidonic and linoleic acids—unlikely, since they predominate in most modern foods—he may have formed measurably more EPA from the linseed oil.

Balance is critical. Sources of linoleic acid include most vegetable, nut, and seed oils. Sources of EPA, DHA, and alpha-linolenic acid include fish and shellfish and green vegetables, including lettuce and other salad greens. Arachidonic acid is richly supplied in meat and dairy foods.

A STUDY OF FISH CONSUMPTION AND HEART DISEASE

In an article entitled “The Inverse Relation Between Fish Consumption and Twenty-Year Mortality from Coronary Heart Disease,” which appeared in the New England Journal of Medicine in 1985, a team of Dutch researchers detailed the results of a twenty-year study of 852 middle-aged men in the town of Zutphen, the Netherlands.

Men free of known heart disease were selected in 1960. Dietary histories were obtained from the participants and their wives, with special attention being paid to fish consumption. Twenty percent of the men ate no fish in 1960. Among the rest, the intake varied from a fraction of an ounce to 11 ounces per day. The average for all the men was 0.75 of an ounce per day.

The research team followed these men for twenty years; 78 of them died of coronary heart disease. Statistical analysis was done on all data. The conclusion: an “inverse dose-response relation” existed between the amount of fish a man ate and his chances of dying of coronary heart disease. The more fish consumed, the less risk of heart attack; this relationship held true from trace amounts up to the maximal intake.

The results of the men who were eating an average of at least 1 ounce of fish per day were compared with those eating no fish; their death rate from coronaries was more than 50 percent lower. Statistical analysis proved these results independent of all other factors for coronary heart disease; fish consumption was a protective factor, independent of all variables. The influence of EPA on clotting tendencies is one possible reason for these results, but another that has emerged in recent years is the beneficial effects of the vitamin D that is richly supplied in fish.

The men were divided into groups by the amount of fish consumed. Those with the highest intake averaged 2.5 ounces of fish per day. Two-thirds of it was lean (cod and plaice) and one-third fatty (herring and mackerel), providing about 0.4 grams of EPA per day, mostly from the fatty fish. However, the consumption of lean fish also proved to protect against heart disease, and the more consumed, the greater the protection. Nutrients in addition to EPA seem to be involved.

While more fish gave greater protection, the men averaging only 1 ounce a day of any fish—one or two modest portions a week—had less than half the death rate from heart disease than those eating no fish. The conclusion is that regular inclusion of some seafood in the diet seems prudent. Traditional Greenland Eskimos, shown in several studies to have an extremely low incidence of coronary heart disease when living on their native diet, eat upward of 14 ounces of fatty fish per day.

A STUDY OF FISH OILS AND HIGH BLOOD FATS

An article by B. Phillipson et al., entitled “Reduction of Plasma Lipids, Lipoproteins, and Apoproteins by Dietary Fish Oils in Patients with Hypertriglyceridemia,” appeared in the same issue of the New England Journal of Medicine as the Dutch study on fish consumption. Hypertriglyceridemia refers to the presence of excessively high triglycerides in the blood. Triglycerides are normal fats found in the blood; they are a type of plasma lipid. Excessive amounts have been correlated with the overconsumption of carbohydrates, especially refined carbohydrates. Heart disease and circulatory disorders are related to high triglyceride levels.

In this study, twenty patients were placed on three successive controlled diets differing only in the kind of fat included. The first diet was low in fat and contained no fish oil. The second contained fish oil (in fish and in supplements) amounting to 20 to 30 percent of the daily calories. The third substituted an equal amount of polyunsaturated vegetable oils for the fish oil of the second diet.

In every patient, blood triglyceride levels fell while on the diet rich in fish oils. In four weeks triglycerides fell an average of 64 percent for the patients with moderate elevation of triglycerides, and they fell an average of 79 percent for the patients with severe elevation. The new levels were, on the average, less than one-third of the old. Cholesterol levels fell 27 percent for the moderate group and 45 percent for the severe group. It is important to note that while triglyceride levels are significant, cholesterol levels are a phony issue and in fact are not related to heart disease. Numerous studies have demonstrated that the incidence of coronary artery disease is not connected to blood cholesterol levels and that the use of cholesterol-lowering drugs does not result in increased survival. Also note that virtually all of the diets Weston Price studied were rich in cholesterol, and the people had no heart disease.

The reductions were from the levels measured while the patients were on the low-fat diet prior to the diet rich in fish oil. Many then still had milky looking blood plasma, a characteristic of fatty blood. Within days on the diet rich in fish oil, this disappeared.

When the patients were taken off the fish-rich diet and placed on the diet rich in polyunsaturated vegetable oils, they experienced alarming developments. Among those who had moderately elevated blood fats prior to being on the diet rich in fish oil, levels of triglycerides rose considerably, but remained below previous levels. Vegetable oils are known to reduce triglycerides; they proved less effective than fish oils.

The vegetable oils caused more striking effects in the patients who had severely elevated blood fats prior to being on the diet rich in fish oil. These people had experienced large reductions in triglycerides and cholesterol while on the diet rich in fish oil. Within three to four days on the diet rich in vegetable oils, all had increases in triglyceride levels. After ten to fourteen days, levels had on the average tripled. Because abdominal pain and liver tenderness was developing in many of these patients, and because of the severely elevated blood fats, the vegetable-oil-rich diet was discontinued at that point. The plan had been to continue it for four weeks, the same length of time the diet rich in fish oil was used.

A return to the diet rich in fish oil was followed by the disappearance of the abdominal pain and liver tenderness. The triglycerides dropped to the previous levels, and eventually became even lower as the diet was continued.

These dramatic results demonstrate the danger of believing advertisements implying alleged health benefits of polyunsaturated vegetable oils. Because early studies determined that in most individuals these oils caused reductions in some blood fats, the public was led to believe large quantities were beneficial. More recent studies have shown that these oils do not reduce the blood fats thought to do the most harm when elevated, that is, the very-low-density lipoproteins (VLDL) and associated triglycerides. These fractions of the blood fats are most affected by fish oils.

Polyunsaturated vegetable oils are suspected of being cancer-causing agents and of speeding up biochemical processes involved in aging. Some of the fatty acids that vegetable oils supply in large quantities are essential nutrients, but the diet rich in fish oil supplied adequate amounts without the inclusion of vegetable oils. Limiting dietary polyunsaturated vegetable oils aids the body’s ability to convert the alpha-linolenic acid in plant chloroplasts to EPA, and thus increases production of more favorable prostaglandins. Olive oil contains about one-tenth the polyunsaturated fatty-acids found in most vegetable oils; I recommend moderate use of 100 percent extra-virgin olive oil.

The diet rich in fish oil in the study just described supplied from 20 to 30 grams of EPA per day (nearly twice that of even Eskimo diets, and far too much for proper fatty-acid balance); 2 ounces of fatty fish such as mackerel or salmon supply about 1 gram of EPA. Both the twenty-year study and the fish-oil study point toward great benefits from seafood consumption. This is not to be taken as a recommendation to take fish-oil supplements. However, I do recommend a modest amount of cod-liver oil, up to one-half teaspoon a day, to supply vitamins A and D, along with small amounts of EPA and DHA. This should be consumed in the context of a diet rich in saturated fat. Take cod-liver oil in small quantities, for overdosing is possible.

A STUDY OF FISHERMEN AND FARMERS IN JAPAN

Further insight into the amount of seafood one might eat for optimal protection against coronary heart disease, as well as other disorders involving abnormal clotting of the blood, is provided in a study by a group of Japanese researchers (Aizan Hirai et al.) in the British medical journal Lancet in 1980. The main source of dietary protein in Japan is fish, and the Japanese have a low incidence of heart disease. (It is important to note, however, that many groups we have discussed ate little or no fish and had scant evidence of heart disease.) Believing EPA might be a major reason for the low incidence of heart disease, the researchers carried out platelet aggregation studies to look for differences between the people of a fishing village and those of a farming village.

In the fishing village, the average daily intake of fish among the people was 9 ounces per person, supplying 2.5 grams of EPA. In the farming village, the average was 3 ounces, supplying 0.9 grams of EPA. In the fishing village, the people had significantly higher blood levels of EPA.

In the platelet aggregation studies, the platelets of the people in the fishing village showed significantly less tendency to adhere and form a clot. Consistent with EPA’s role as a precursor of prostaglandins that cause decreased platelet aggregation, the tendency of platelets to clot is directly related to the level of EPA in the blood.

The difference in platelet aggregation between the fishermen and the farmers was apparently due to the greater fish consumption and subsequently higher blood levels of EPA of the fishermen. The farmers ate as much fish as the group of men who were the biggest fish eaters in the twenty-year Netherlands study—an average of 3 ounces a day. The fishermen ate three times as much, approaching the consumption of Greenland Eskimos.

While the Netherlands group (eating an average of 3 ounces of fish daily) had more than 50 percent less coronary heart disease than those eating no fish, they were not immune; some had heart attacks. Decreased platelet aggregation among fishermen eating 9 ounces of fish a day, compared with farmers eating 3 ounces a day, suggests that optimal levels of fish intake may be closer to 9 ounces per day than to 3.

A STUDY OF A MACKEREL DIET ON BLOOD PLATELETS

As described in an article in Lancet in 1980 (Siess et al.), mackerel nearly exclusively constituted the diet of seven volunteers studied by West German researchers; the daily intake was from 18 to 29 ounces. Blood studies were conducted, with particular attention being paid to platelets.

A platelet is formed when certain bone-marrow blood cells called megakaryocytes fragment. Each platelet has a membrane surrounding it, and this membrane is a storehouse for fats. The researchers found that the composition of these fats, while the subjects were on the mackerel diet, became similar to the composition of fats in mackerel; within a few days of beginning the diet, the volunteers’ membranes became rich in EPA.

The tendency of the blood to clot thus changes when eating large amounts of foods rich in EPA; changes occur in the structure of the cells responsible for clotting. Recall the old saying: “You are what you eat.”

Concern has been expressed that EPA-rich diets may cause problems related to an inability of the blood to clot, and Eskimos on their native diets in fact have longer bleeding times than most Americans. But their blood does clot well and their wounds heal well. An EPA-deficient diet may shorten bleeding time. Bear in mind, though, that EPA may be overdone.

THE ROLE OF FISH OILS IN VISION AND INTELLECTUAL FUNCTION

In a 1985 article in Transactions of the Association of American Physicians, researchers stated that sharpness of vision and brain development are related to blood levels of EPA and DHA. These fatty-acids are essential for good vision. DHA is a normal constituent of the cells of the retina, and the amount present is dependent upon the amount in the diet. Animal tests at Oregon Health Sciences University in Portland indicated that deficiencies reduced the ability of retinal cells to be stimulated, with consequent reduction in sharpness of vision.

In other studies at the Oregon Regional Primate Center, the development of vision during gestation and early life was impaired when female monkeys were fed a diet deficient in EPA, DHA, and linolenic acid for two months prior to and during their pregnancies. The infant monkeys were then fed the deficient diet; when twelve weeks old, their vision was only half the strength of monkeys fed a normal diet. The cells of the retina and brains of animals with deficient vision were analyzed; the fat content showed very low levels of EPA and DHA, explaining the loss of sharp vision.

The ability of Maori to see the moons of Jupiter with the naked eye was apparently related to the rich supply of EPA, DHA, alpha-linolenic acid, and other fatty acids supplied in their foods (they certainly did not take any fish-oil supplements!).

EPA and DHA, especially DHA, are also found in high concentrations in the cerebral cortex of the normal human brain. Deficiencies may impair the functioning of the brain—learning, reasoning, and overall intellectual powers. Rats fed a diet deficient in these fatty acids were unable to learn to run a maze as well as rats fed a control diet.

The wisdom of primitive diets is demonstrated by this research; every traditional culture Weston Price studied emphasized foods rich in vitamins A, D, and K₂. Seafood, organs, and in some cultures dairy products from pasture-fed animals were particularly emphasized for mothers to be (prior to and during pregnancy, and later during lactation) and young children. Recent research has indicated the human brain acquires about half its fat composition before birth, and most of the rest during the first year after. Native people did everything that research now indicates people should do to ensure the optimal development of the next generation.

THE RESEARCH OF DR. WESTON PRICE AS IT PERTAINS TO VITAMINS A, D, AND K₂

Dr. Price measured vitamins A and D in dairy products, as well as his unknown activator X. Dr. Price presented evidence in Nutrition and Physical Degeneration that this fat-soluble activator X played an essential role in immunity and the utilization of minerals. He measured the amount of it in dairy products, and found the substance in the milk fat of only those cows that ate rapidly growing green grass. X-Factor butter oil is extracted, without heat, from the dairy fat of cows that eat 100 percent rapidly growing pasture.

Price determined that the activator X (now known to be vitamin K₂) was critical for the normal growth and maintenance of bones and teeth. We now know also that it is responsible for calcium deposition throughout the body and is of critical importance in maintaining the integrity of the circulatory system and thus the health of the heart.

The wide facial structures and freedom from cavities seen in Price’s photographs of native people are examples of typical physical development in people consuming optimal amounts of natural vitamins A, D, and K₂ in the proper balance as proffered by the foods they typically ate. Modern diets are sadly lacking in these vitamins, which may be derived from the dairy products of grass-fed animals, especially butter and cream, as well as from seafood and grass-fed meats and organs.

Cod-liver oil is an excellent supplemental source of vitamins A, D, and K₂; it may be used to complement dietary sources. Natural, unadulterated cod-liver oil contains substantial amounts of vitamins A and D in their natural ration of ten to one. Cod-liver oil boosts immunity, enhances and maintains brain function, regulates blood pressure, eases pain and inflammation, and helps alleviate depression. It really is something of an elixir.

Bone broth made from the bones of grass-fed animals is a great way to include natural vitamins A, D, and K₂ in the diet. To learn more about the wonderful health benefits of broth, see Nourishing Broth by Sally Fallon Morell and Kaayla Daniel. The book includes a detailed account of how broth also supplies collagen, another nutrient missing in the modern diet and crucial in maintaining truly vibrant health and recovering from disease.