Nutritional benefits of soy and Japanese longevity

Japanese Nutrition

Japanese

WHY DO THE JAPANESE LIVE LONGER?

NUTRITIONAL BENEFITS OF SOY:

As an annual Asian legume (meaning that it grows in a pod), soy is one of the most amazing members of the bean family, due mostly to its significant health benefits. Many studies done by nutritionist worldwide have confirmed that a plant-based diet is the most healthful choice. Soybean and its extracts, such as soybean oil, provide high-quality protein that is equal to that found in poultry, milk and other animal-based foods. However, not all soyfoods are low in fat, but most of them are cholesterol-free. An added bonus is that soybean and its byproducts do not contain saturated fat unless it is added during the processing stage or is combined with other ingredients containing saturated fat.

Because many forms of soy are low or modest in total fat, a person's overall diet will be inclined toward leanness. According to Alan Davidson, "consuming at least 25 grams of soy protein a day may reduce blood cholesterol levels and reduce the risk of heart disease" (1989, 156). This fact has been determined by the Food and Drug Administration which in October of 1999 began to allow foodstuff containing at least 6.25 grams of soy protein per serving to be labeled on soy products which shows that soy should be a part of a diet low in saturated fat and cholesterol (Davidson, 1989, 157).

In addition, the American Heart Association officially recommended that anyone who wished to lower his/her overall saturated fat/cholesterol levels should consume 35 to 50 grams of soy protein daily (Davidson, 1989, 164). Also, soybean products were added to their list of foods that were found to help lower cholesterol levels and even reduce the risk of heart disease.

Japanese 2

One particular study conducted at the University of Illinois determined that even 20 grams of soy protein consumed on a daily basis was highly effective in lowering blood cholesterol (London, 1992, 67).

As a consequence of these studies and recommendations, it has been suggested that soybean products helps to reduce the risk of developing some forms of cancer; in Asia, epidemiological studies have shown that this may indeed be true. In Japan, where its citizens have consumed soybean for many centuries, women have the lowest rate of breast cancer in the world. Also, the low rate of active prostate cancer in Japan might also be linked to soyfood products. The reason for these findings may have something to do with the fact that soybeans contain phytochemicals which have been shown to reduce cancer activity in animals and human tissue studies (London, 1992, 69).

The health benefits of soy products are more clearly linked to helping prevent osteoporosis, for scientists and nutritionists have isolated isoflavones in soy protein as the active agent against this crippling disease. Isoflavones appear to help reduce the loss of calcium in the bones and eating isoflavone-rich soy has even been shown to enhance bone mineral density. In addition, consuming soybean products seems to have some effect on the symptoms of menopause, for research suggests that soyfoods with naturally-occurring isoflavones help in reducing the severity and number of menopausal symptoms. Although researchers are as yet uncertain as to exactly how much isoflavone is needed, it seems to be in the range of 40 to 60 milligrams daily.

Japanese 3

Thus, the health benefits associated with soybean and its byproducts is obvious, yet it is still not clear which components, combinations or at what levels the consumption of soybean will provide the desired health benefits. But with all of these known and possible benefits, it is quite clear that soybean products have assisted the Japanese very well, due to lowering blood cholesterol levels, reducing the risk of a heart attack, lowering the risks of developing cancer and helping to increase bone density linked to osteoporosis, all of which have enabled the Japanese to live more healthy and longer lives. As Hiroko Shimbo points out, "Japanese cuisine and the Japanese themselves could not survive without. . .soybeans (due to) their importance in Japanese culture" (2000, 96).

NUTRITIONAL BENEFITS OF RICE:

Generally, rice without the hulls contains about eighty percent of starch, eight percent of protein and twelve percent of water, and because it is such a predominant food in the diets of Oriental persons, especially the Japanese, its nutrient composition is relatively more important than the nutritional composition of wheat in the Western world. On average, rice-eating nations obtain from sixty to eighty percent of their calories from this staple food, and it is easy to see how the nutrient composition of rice determines the health of those that consume it on a daily basis.

In Japan, rice comes in three different forms -- first, genmai, unpolished brown rice; second, haigamai, or partially polished, and third, seihakumai, a polished white variety. Of these three, the latter is most popular despite the fact that the polishing process removes much

Japanese 4

of the nutrients. Haigamai includes the rice germ and therefore the nutrients that are found in the vital part of the grain (Shimbo 149).

In its natural state, rice has good nutritional values as compared to other cereals used as staple foods around the globe. Brown rice has about the same caloric content, vitamins and minerals as whole wheat, somewhat less but better proteins and more fats and carbohydrates. White rice, however, loses a portion of its best proteins, vitamins and minerals when it is cooked in too much water which is then discarded.

It should be mentioned that white rice has a downside, being that when it is cooked and washed it loses many important vitamins and minerals. Washing and cooking practices in many Asian nations are obvious contributors to this problem. The more water used in cooking and the more water that is thrown away, the more vitamins and minerals lost, whether from brown rice, parboiled, white or even enriched rice (a process in which selected vitamins and minerals are sprayed on rice grains).

However, somewhat more thiamin (a crystalline compound of the B. complex vitamin group essential for normal metabolism and cardiovascular health), riboflavin (B vitamin complex necessary for the oxidative processes of carbohydrates, fats and proteins), niacin (B vitamin complex effective in improving circulation and reducing high blood cholesterol levels) and iron (essential for the synthesis of hemoglobin) are retained in all improved forms of rice.

In addition, rice, whether brown or white, contains many essential amino acids. Of the whole rice forms, brown rice ranks highest in amino acids and non-enriched white rice the lowest. Some of the amino acids found in all types of rice include histidine (aids in decreasing

Japanese 5

blood pressure) and isoleucine (essential for proper growth in infants and for nitrogen balance in adults).

In a very important study conducted by Wen Hua Ling and his associates in 2001, the nutritional benefits of rice, i.e. when prepared and consumed properly, became quite clear. According to Ling, "the treatment of cardiovascular disease with rice diets was suggested several decades ago" and it was reported that the "consumption of white rice decreased blood pressure and lowered hypercholesterolemia (a condition in which greater than normal amounts of cholesterol are present in the blood which may lead to atherosclerosis) in humans." Also, an even earlier study demonstrated that rice consumption "increased the concentration of plasma HDL-C and activity of blood GSH-Px" which improved "the lipid profile (i.e. free fatty acid fractions in the blood) and protected against oxidative stress, thus retarding atherosclerotic formation and development" (2002, 1425).

Additionally, Ling and his associates point out that rice, whether white or brown, contains important anti-oxidant enzymes "such as superoxide dismutase (the main enzymatic mechanism for clearing superoxide radicals from the body), catalase (an enzyme found in almost all biological cells) and glutathione peroxidase (another enzyme commonly linked with hemolytic anemia)" which helps to protect humans "against the injuries due to oxidative stress" (2002, 1426).

Thus, much like the nutritional benefits obtained from soybean product, rice is also an excellent source for vitamins, minerals and proteins necessary for good health. With its prime ingredients of thiamin which helps the body to maintain proper metabolism (meaning that it helps

Japanese 6

to prevent being overweight) and cardiovascular health (associated with the arteries and the heart) and niacin which improves circulation and reduces high blood cholesterol levels, rice clearly helps the Japanese to live longer and better lives.

NUTRITIONAL BENEFITS OF FISH:

As a prime source of protein, fish and fishery products are among the most nutritious foods available. Among those foods that provide the best in nutrition, fish and seafood are at the top of the list along with meat, milk and eggs. Fish and seafood contain complete protein, meaning that the protein supplies essential amino acids, especially those that cannot be manufactured by the body. Most fish contains eighteen to twenty percent of protein which is highly digestible.

Generally, fish is divided into two classes, being fat and lean. Each three and a half ounce serving of lean fish, such as ocean perch, cod and halibut (all of which are plentiful in the Pacific Ocean basin near Japan) and other white-fleshed ocean fish contains less than 100 calories (Davidson, 1989, 231). The fat species, such as salmon, mackerel and whitefish, contain a fat content that is less than twenty percent less than most red meat from other animals. Shellfish, like clams, oysters and other mollusks (also a part of the Japanese diet), tend to be leaner than fish.

Fish and shellfish are also rich in vitamins. Fat fish are rich in vitamins A, D and K. And an average serving of these types of fish provides ten percent of the daily adult vitamin A requirement and fifty percent of the vitamin D requirement (Davidson, 1989, 235). Important B. complex vitamins are also present in fish and shellfish; a normal serving yields about ten percent

Japanese 7

of thiamin, fifteen percent of riboflavin and fifty percent of niacin which surprisingly is very close to what rice provides in regard to these three vitamins.

The most common minerals found in fish and seafood products are iodine, magnesium, calcium, phosphorus, iron, potassium, copper and fluoride. These minerals are highly important in human physiology and are essential to good health. For example, eighty percent of the iodine in the body is located in the thyroid gland which contributes to normal body growth and to the metabolic system (i.e. proper digestion and the burning away of calories and fats); calcium contributes to bone density, the transmission of nerve impulses, muscle contraction, blood coagulation and cardiac function, meaning that it helps the heart to operate efficiently, and iron is necessary for the formation of hemoglobin which provides oxygen to all the internal tissues. In addition, fish plays a major role in a low cholesterol diet because the fatty acids present are polyunsaturated.

According to David S. Siscovick, those that consume fish "were only half as likely to suffer from cardiac arrest (as compared to) those who do not eat fish." The reason for this finding is based on the fact that fish and seafood contain "the primary dietary source of the long-chain omega-3 fatty acids (eicosapentaenoic acid and docosahexaenoic acid, DHA)" which increases "the levels of these fatty acids in cell membranes and results in a reduction of platelet clumping," meaning that these two amino acids reduce the likelihood of coronary heart disease and what is generally known as "hardening of the arteries" which leads to heart failure (1995, 1365).

Japanese 9

The nutritional value of seaweed is very dependent of the species, the geographic area and the temperature of the water. However, seaweed is always a rich source of iodine, much like fish products. The iodine content can be as much as 20,000 times more than sea water which explains why dried kelp has been used "as a food since the beginning of Japanese civilization," due to providing "important minerals, vitamins, protein and dietary fiber" (Shimbo, 2000, 61).

Seaweed has also been promoted for its therapeutic properties in alleviating constipation, gastric catarrh (inflammation of the stomach and intestines), mucous colitis (irritable bowel syndrome) and other related disorders. Interestingly, scientist and researchers back in the 1950's became interested in the longevity of the Hizato people situated in the Nagano province of Japan. What they found was that there were more of a percentage of 70-year-old persons in this province than in any other Japanese village, and after an extensive study, the conclusion was reached that the diet of the people of Hizato was a contributing factor to their longevity, due to the foods consumed being all types of vegetables (soybean, rice, bamboo shoots, etc.) and, of course, dried seaweed. In addition, about twenty-five percent of all food consumed in Japan consists of one form or another of seaweed, prepared and served in many forms (Schneider, 1986, 178).

As Catherine Skibola relates, "brown kelp seaweed makes up more than ten percent of the Japanese diet" which has been found to lower the rate of endometriosis (an abnormal gynecologic condition linked to ectopic growth and the function of the tissue within the uterus),

Japanese 10

and menstrual irregularities." Also, brown kelp has been demonstrated to lower the rates of breast, endometrial (uterine) and ovarian cancers" (2005, 298). Skibola adds that kelp has one very important danger, due to its high levels of iodine which could poison the body and produce negative effects on those afflicted with hyperthyroid conditions (2005, 299).

CONCLUSION:

As we have seen, the Japanese are among the healthiest group of persons in the world as a direct result of their consumption of soybean products, rice, fish and many varieties of seaweed. Compared to the United States and other western nations, the Japanese are far ahead when it comes to the nutrition benefits obtained from their basic diets of naturally-occurring foods. According to Leonard S. Marks, diet "has long been thought to influence the development of (certain) cancers that are common in Western countries and rare in Asia. As much as a ten-fold greater occurrence of prostate cancer in the U.S., compared to Japan. . . has been observed" (2004, 769).

Marks also declares that the link between diet and cancer rates can best be explained internally, for the "oxidative damage from saturated fat (in the Western diet) and the protective effect from soy phytoestrogens (in the traditional Japanese diet) are possible mechanisms " for the low rates of cancer among the Japanese as compared to Americans and Europeans. This vital information therefore illustrates why the Japanese live longer and more healthier lives. However, although the Japanese consume the right foods for a longer life, it should be mentioned that their diet is deeply ingrained in their culture which has enabled the Japanese to live at times well into their late 90's and even become centenarians.

Japanese 11