The Immune System: Part I
Your immune system is your personal defense system against attack of all kindsfrom viruses, bacteria, toxins and other enemies. Like all armed forces, the immune system is complex, with an array of weaponry at its disposal. It includes the lymph system (thymus, spleen, tonsils and lymph nodes), and specialized white blood cells called T-cells, whichin addition to many other activitiesproduce interferon, a substance particularly helpful in fighting viruses. Other white blood cellsB-cellsproduce antibodies in response to invading bacteria, fungi and parasites. If any of these invaders begin a new assault, the antibodies "recognize" them before they have time to spread. Quickly attaching themselves to the invader, they thus "tag" the enemy for attack by phagocytes, another type of white blood cell. Other members of the white blood cell battalion are natural killer cells (known as NK), which destroy cancer cells, virus-infected cells, free radicals and other harmful substances. In addition, the immune system arsenal contains many other specialized cells and operations.
The immune system is very sensitive to subtle changes in the balance of nutrients in the body. Deficiencies of nutrients are reflected quickly as a weakening of our immune defenses. Although we rarely see severe malnutritionwith its resulting poor immune systemin the West, we nonetheless know that a large number of people are not consuming the right kinds and amounts of nutrients. The result is less than optimal immunity.
FOODS THAT LOWER IMMUNITY
- Fats- particularly polyunsaturated oils such as corn and safflower oils- weaken our immune system in many ways. Diets high in any kind of fat are associated with a reduction in immune functioning. One study conducted at the University of Massachusetts showed that reducing fat from 32 to 23% of the diet boosted natural killer cell activity by 48%!
- Alcohol ingestion has been shown to severely depress neutrophils, cells that "eat" and destroy bacteria and tumor cells.
- Sugar and other sweets have been shown to reduce the ability of certain white blood cells to destroy bacteria. When 100 grams are eatenAmericans typically consume more than 150 grams a dayneutrophil activity can be reduced by 50%. In one experiment, this effect lasted as long as five hours after the sweets were consumed. Fruit sugar and honey, unfortunately, had just as negative effects as white sugar, while starchy foods had no effect at all.
FOODS THAT BOOST IMMUNITY
- Vegetarian diet. A German study, reported in Nutrition and Cancer, found that the white blood cells of vegetarians were twice as effective against tumor cells as those of meat eaters. The precise reason is unknown, but may have something to do with higher levels of phytochemical-rich vegetables and fruits as well as lower levels of fats in the diet.
- Vitamin C-rich foods. While this vitamin's reputation as an immune-enhancer has fluctuated over time, we do know that vitamin C boosts antibodies as well as white blood cell activity. Stress of any kindpsychological or physicalincreases our need for this vitamin. When you think vitamin C, think more than orange juice. You may be surprised to learn that broccoli contains three times as much vitamin C as does citrus. And even potatoes are packed with this helpful nutrient.
Part II
More immune boosting dietary practices
- Zinc. This mineral positively affects many immune mechanismsfrom the thymus to antibodies to T-cells. An Italian study found that small amounts of zinc quickly raised blood levels of T-cells in elderly people to those usually seen in much younger people. Since borderline zinc deficiencies are quite common, it's important to eat plenty of legumes such as black-eyed peas and pinto beans, and adequate amounts of whole grain breadsthe yeast helps make the zinc available. Pumpkin and squash seeds are particularly rich in zinc, and make a delicious snack.
- Carotenoids. Although beta carotene is best known in the huge carotenoid family, there is evidence that many members of this antioxidant group are helpful to our immune systems. Studies indicate that a high intake of carotenoid-rich foods (orange-colored vegetables and fruits, in particular) increase T-cells, natural killer cells, and antibody response. Pumpkins and winter squashes, as well as carrots, peaches, and cantaloupe, are especially good sources, though many green vegetables are also rich in carotenoids.
- Garlic. Several studies indicate that the "fragrant bulb" does as much for our immune systems as it does for our taste buds. It appears to increase not only the numbers of natural killer cells but also their potency. T-cells, as well, are stimulated by garlic intake.
- Chinese mushrooms. Shiitake mushrooms appear to be powerful immune stimulants. They contain an antiviral substance that boosts T-cells and macrophages, large cells that engulf and destroy foreign particles. This beefy mushroom is becoming more readily available in many supermarkets as demand for it increases.
HERBS AND IMMUNITY
There are times when we're battling a sore throat or other infectionwhen our immune systems can use an extra boost. Several herbs have extensive folk histories that indicate they can help us fight a variety of diseases. And, in the last few decades, laboratory studies have shown that indeed many of these herbs contain substances that do work specifically to boost the immune system in various ways.
- Echinacea (purple coneflower) is perhaps the best known of the Western immune-stimulating herbs. This attractive perennial grows in many cultivated gardens, but was originally a wildflower commonly found in the Midwest. Native Americans used echinacea for anything from blood purification to snake bite. Laboratory studies show echinacea to enhance the immune system through several mechanisms, most notably through activating T-cells and increasing virus-fighting interferon. It's particularly helpful with yeast and ear infections, and the common cold.
- Ginger. This pungent root stimulates the production of interferon, besides aiding with nausea and being just plain delicious. Grate some into vegetables, or treat yourself to small pieces of the candied root.
- Licorice has been used for thousands of yearsboth in Eastern and Western culturesfor its medicinal properties. It's particularly helpful in fighting viruses such as influenza and herpes. If you like your licorice sweet, read labels when buying licorice candy. Many of those tasty black twists are flavored with anise rather than the real thing. And a word of warning: take licorice in moderation: too much can cause the body to retain sodium and thus cause bloating.
ALLERGY AND THE TRIGGER-HAPPY IMMUNE SYSTEM
Approximately 50 million people in the U.S. alone sneeze in the fall, itch when they eat peanuts, wheeze when they pet cats or exhibit one of the many other symptoms of allergy. And some of these are at risk from dying from severe allergic reactions to various substances that are benign or only slightly irritating to most people. Even when allergy symptomshives, sneezing, migraineare not life-threatening, as they usually are not, they can certainly effect our ability to enjoy our lives. Of the 15% of North Americans that suffer from sneezing and itchy eyes, nearly one half claim they would rather have heartburn, while almost one third would prefer the flu to their allergies!
WHAT IS AN ALLERGY?
Health professionals often disagree about the precise definition of what constitutes an allergy. Some call any sensitivity reaction an allergy, while others claim that only reactions involving a specific antibody called IgE are true allergies. And there are many opinions in between these definitions.
In general, it is agreed that an allergic reaction is one that involves the immune system in varying ways. The immune system is designed to attack threats to the body such as bacteria and viruses. In the case of allergy, the immune system reacts to a harmless substance as though it were a threat. It mobilizes antibodies which attach themselves to the allergen as well as to basophils and mast cells, defensive cells packed with histamine. The combination is explosive: the cells break open, spewing histamine into the tissues where it attracts scavenger cells that cause swelling, itching and other familiar symptoms of allergy. Symptoms can appear virtually anywhere in the body: a skin rash may be the result of poison ivy or of something you ate.
Common Allergy Symptoms
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AVOIDING ALLERGIES
The tendency to have allergies is probably genetically determined. If both parents suffer from allergies, a person has a greater than 65% chance of also developing allergic symptoms. If only one parent has allergies, then the risk drops to around 30%. Whether or not the genetic
tendency lives itself out or not is dependent on many factors that are little understood at this time.
But even if we are allergy-prone, there are certain things we can do to help lessen the symptoms.
- To help reduce the sneezes and itchy eyes of hay fever at night, keep bedroom windows closed if possible. Units that filter the air are readily available; look for one containing a HEPA filter, excellent for removing allergens of all types from the air.
- Quercetin, a natural phytochemical in many foods, appears to dampen allergic responses by inhibiting the release of histamine. Red grapes, yellow squash, shallots and broccoli are good sources.
- Onions contain diphenyl-thiosulfinate, a natural chemical that has a very high anti-inflammatory activity. And onions also contain large amounts of quercetin. One study reduced asthma attacks by 50% in subjects who drank onion juice before inhaling a known asthma-inducing chemical. While we're unlikely to want to drink onion juice, a few raw slices of pungent onion on our salads may be a good idea.
- Vitamin C also works to tamp down inflammatory responses in the body. The American Journal of Epidemiology reports that adults eating the most vitamin C-rich foods had far fewer asthmatic attacks than those eating little of these foods. Drink a glass of orange juice for breakfast, and eat several slices of red peppers with your lunch and a cup of broccoli with dinner to provide a vitamin C boost to your body.
- A new British study found that children eating an all-Asian diet had far fewer allergic symptoms than their schoolmates eating a typical Western diet.
FOOD ALLERGIES
Many people suffer from food allergies or sensitivities, commonly to milk, wheat, peanuts and soy, although almost any food can trigger symptoms in certain people.
Food allergies (like all allergies) involve an over-reactivity of the immune system. Antibodies that are designed to protect us from disease for various reasons can react against proteins in foods, causing injury to our tissues and symptoms of food allergy such as bloating, headaches, hives and diarrhea.
Of course, unlike inhaled allergens such as ragweed or tree pollen, food allergens enter the body through the intestinal tract. The gut is ordinarily lined with an antibody called IgA, which helps attack food allergens that inappropriately "leak" across the mucosal surfaces of the intestine and cause trouble. Trans-fatty acids, found in all hydrogenated oilsappear to encourage this destructive permeability of the intestine.
People with food sensitivities have unusually low levels of IgA in their blood. And stress, besides its many effects on the immune system, can decrease the amount of IgA. This may help explain why allergies are often worse during high-stress periods.
There are many other immune system reactionsinvolving the four other major types of antibodies as well as T-cellsthat can come into play in food allergies of various types.
In addition, there are food "sensitivities" that, although they are not technically allergies, cause similar symptoms. Some foods contain substances such as histamine or other amino acids that can cause reactions in the blood vessels, leading to allergy-like symptoms.
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Foods commonly causing allergy-like symptoms
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THE ROTATION DIET FOR ALLERGIES
Whether our unpleasant symptoms are caused by true food allergy or by food sensitivities of various kinds, a dietary scheme known as the "rotation diet" can be helpful. This diet does not prescribe or forbid any particular food; rather, it suggests that we avoid eating the same foodsor food groupsevery day. The idea behind this is that the body can become over-sensitized to certain food components if it has to deal with them constantly, whereas if it has to metabolize them only infrequentlynot more often than every four daysit is less likely to develop a sensitivity or allergy to them. Theoretically, the body completely clears any food substance within 3 days.
How does the diet work? Try to vary your foods from day to day, particularly foods that are common allergens: soy, wheat, citrus, potatoes. For example, if you tend to have food allergies, it's probably wise to rotate your morning orange juice with apple
and other juices and fruits. And try substituting corn bread or rice crackers for wheat toast.
The diet is certainly helpful in avoiding the development of new food sensitivities. With already existing sensitivities, if they are not severe, you could try eating a small portion of the offending food not more frequently than every four or five days. Some people can avoid triggering reactions this way, while others will have to completely remove allergy-provoking foods from their diets. Experiment cautiously!
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Family Connections Botanically speaking, foods belong to families. If you are sensitive to one member of a family, it is best to avoid other members as well during the 4-day break from your allergen. For example, people sensitive to potatoes should avoid too frequent consumption of eggplant, tomatoes and peppersall members of the same family. And if cashews cause symptoms, be careful with their botanical cousins, mango and pistachio. Lists of plant families are available in many nutrition books. |
Longevity: Part I
Living Long and living well
The search for the fountain of youth or at least for a longer life has occupied mankind since antiquity. And indeed, the dream to live a longer life, with health and vigor intact, is becoming more and more of a reality. With advances in the study of how our bodies age, we now know that much of the degeneration of age once thought to be unavoidable need not accompany us as we move into our older years.
These days, we already live far longer than our ancestors, due in part to less childhood mortality. In Roman times, the average lifespan was a mere 22 years. Even as recently as the turn of this century people lived an average of only 47 years. Today, life expectancy in the U.S. is 75.5 years. And, according to Danish researchers, a child born this decade can expect to live 100 years.
For longevity enthusiasts, 8 or even 10 decades are not enough. Some scientists believe that the human body is designed to live 115 to 120 yearsif the slings and arrows of life, and bad habits, don't get to it first. Although there is not much we can do about many of the causes of accidental death, the bad habits are certainly within our control. Avoiding tobacco and alcohol, exercising adequately, and eating a diet that supports lifesuch as that suggested in our pagescan bring us not only a longer life, but also the health and vitality we need in order to enjoy our extended years.
Already, changes in diet, awareness of the benefits of exercise, and medical advances have had positive effects on aging persons. A federal survey of seniors over 64 showed a significant decrease in all types of chronic disabilities over the last decade. Astonishingly, the age group showing the most benefit were these over 84. A third of them report that their lives are not in any way compromised by ill health.
Living longer, healthier lives can be a great gift, if we have purpose, joy and love in our days. And it now appears that having these things lead, in turn, to a longer lifespan. A study of ex-Harvard men shows that those who had a loving childhood were far healthier in their 60s than those who did not. Astonishingly, this factor was more predictive of future health than was smoking or exercising. And being lonely in old age according to a study by immunologist Ronald Glaser of Ohio State reduces the activity of natural killer cells, part of the immune system that fights tumors and infections.
You do not need a "significant other" in order to reap the benefits of a relationship: studies show that any form of social contact (friends, church, or support group) boosts the immune system. On the other side of the equation, Daniel Goleman, science writer for the New York Times, reports that a meta-analysis performed at the University of California found that people who are chronically depressed, anxious or irritated have double the risk of getting a major disease. The bottom line: joining a class or an exercise or support group not only keeps the mind happy, it can keep the body happy as well.
The good news about aging
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Longevity: Part II
Improving Your Chances of healthy aging
The common problems of aging listed below were once thought to be inevitable. Today we know that by adjusting our lifestyles we can minimize many of these potential difficulties.
- Free radical or oxidant damage. These harmful compounds are by-products of both the unavoidable processes of life (such as breathing) and the avoidable metabolism of certain foods, particularly fats. Eating a low-fat diet reduces the free radical load on our bodies substantially. In addition, a diet high in antioxidantsthat is, primarily fruits and vegetableshelps counteract the action of free radicals. An antioxidant-rich diet has been associated with lower rates of cancer, heart disease, and other illnesses; it does this partially through delaying the "aging" of our cells.
- Weakening of the immune system. The strength of our immune system begins to decline at age 30. By 50, the thymus glandmaster gland of the immune systemhas shrunk radically. Although many aspects of immunity weaken as we age, there is still quite a lot we can do to boost our immune systems.
- Osteoporosis Weakening bones, with their resultant fractures and pain, are not the inevitable accompaniment of old age. We have been told that the answer is increasing calcium intake, particularly in the form of milk. But countries that have far lower rates of dairy intake than we do in the West turn out to have far fewer cases of osteoporosis. The reason? Scientists now know that eating too much proteinespecially from animal sourcesleaches calcium out of our bones, weakening them. And we in the West eat on average far more protein than we need. Whereas the calcium in milk may be a good idea, the fact that milk is also high in protein works against our retaining the helpful mineral. A better choice is to get our calcium from green vegetables. A cup of cooked kale contains over 100 mg of this bone-preserving mineral. Exercise, too (especially weight training) helps bone retain its calcium.
- Unsteady gait and weakness. The good news is that we're never too old to increase muscle strength and flexibility, both of which help us keep vigorous and active as we age. Studies have found that an older person who exercises can have greater aerobic capacity than his or her couch potato grandchild. And aging muscles respond well to weight training. Although they may not have the bulk they did when we were younger, with work they can retain most of their strength. Even low-intensity physical activities such as the popular Chinese exercise Tai Chi have been demonstrated to substantially improve stability in walking. Many health clubs offer Tai Chi classes and instruction in a safe program of exercise.
- Decreasing vision due to macular degeneration. This aging of the center of the retina is responsible for a large percentage of blurring, distortion and loss of vision in the elderly. It turns out, however, that Popeye's favoritespinachcontains a carotenoid, lutein, that helps protect the mac-ula from the damaging rays that cause its breakdown. If you hate spinach, try collards or kale; these greens are rich in lutein as well.
- Decrease in sexual function. The sex hormones that regulate our sex life are dependent on a good supply of specific vitamin and minerals from our food. To keep our sex lives going well into later years, we need to eat enough vitamin A-producing foodsthe orange and deep green fruits and vegetables. Vitamin Efound also in fresh greens as well as whole grains and nutsimproves circulation; good circulation enhances sexual performance. One often overlooked mineral is zinc, which is needed by the body to produce testosterone, a hormone that increases sexual desire in both men and women. Beans, both fresh and dried, are a good source.
LIFE SPAN
It's surprising, but true, that citizens of the United States, with one of the most expensive health care systems in the world, cannot expect to live as long as the inhabitants of many other countries. Even among developed nations, America falls somewhere in the middle, beaten in the longevity ratings by many of its European allies as well as by its neighbor to the north, Canada. But the country with the longest expected life span for its inhabitants is none of these; it's Japan. Although researchers do not know all the factors that result in longer life spans for the Japanese, they speculate that Japan has the advantage of developed countries (fewer deaths from infectious disease) combined with the healthier diet of simpler times. Although the McDonald's lifestyle is taking hold in the East, many Japanese still eat the low-fat, low-meat diet of their ancestors.
Yet, if we look at cultures rather than countries, even Japan is eclipsed in the longevity ratings by several pockets of long-lived people scattered in various regions of the world. The best-known of these groups are the Hunzas in the Himalayas, the Vilcabambas of the Ecuadorian Andes, the Bilcabambas of Peru, and the Abkhasians from the Black Sea region of the Caucasus mountains.
What, if anything, do these long-lived peoples have in common? For one, many of them are perched in dry, mountainous country at an elevation of about 4000 feet. Their hilly location makes for a lifestyle with significant levels of built-in daily aerobic activity. A low-meat diet is another aspect of daily life in these mountain valleys, although some of these cultures, notably the Abkhasians, eat a fair amount of fermented milk products.
The peoples with the shortest average life spans are the Greenlanders and the Inuit Eskimos. They can expect to live a shockingly brief 30 years. Their diet is both high in fat and low in vegetables, a combination only exacerbated by a far less vigorous lifestyle than their ancestors had, due of course to the snowmobile.
An interesting note: Although Americans as a whole live shorter lives than the Japanese, if they survive until their eighties their life expectancy is longer than that of their Japanese counterparts. According to the New England Journal of Medicine, an 80-year-old white American woman can expect to live an additional 9.1 years, while her male companion of the same age can expect 7 more years. Another thing to take into account when looking at life expectancy rates, is that high infant mortality skews the total life expectancy downward
| Average Life Expectancy Around the World | |
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Japan 79.4 Switzerland 77.7 Sweden 77.3 France 77.1 Netherlands 77.1 Canada 76.8 Greece 76.8 Iceland 76.7 Spain 76.6 Italy 76.5 Australia 76.5 Norway 76.4 Germany 75.9 United States 75.5 United Kingdom 75.4 Portugal 75.4 |
Denmark 75.0 Israel 74.3 Ireland 74.3 Soviet Union 69.0 Nepal 55.0 Cambodia 53.0 Laos 52.0 Chad 49.0 Angola 48.0 Rwanda 47.0 Guinea 45.0 Greenland 30.0 Inuit Eskimo 30.0 Based on the 1990 Harvard Survey and the World Health Report, Fighting Disease, Fostering Development, Geneva 1996. |
aging and mind
Keeping a Nimble Mind as we Age
Not so long ago, the stereotype of the forgetful, confused old person was deeply entrenched in the national psyche: many of us believed that memory loss and disorientation were unavoidable accompaniments of aging. Today, however, scientists know that degeneration of the mental faculties is not inevitable and that, like the body, the mind can stay fit with exercise and good nutrition.
Exercise, both physical and mental, turns out to be a key to vigorous mental health in our later years. Researchers at Harvard, Yale and other universities examined 1,192 senior citizens in 1988 and again three years later. They found two physical factors that related to mental fitness: lung function and levels of physical activity. The first of these, of course, improves as the amount of the second increases. Exercise improves mental agility through a variety of mechanisms. One of the researchers, Dr. Marilyn Albert of Harvard, suggests that exercise stimulates the flow of blood to the brain as well as nerve growth, resulting in more densely branched neurons in the brain. This, in turn, may result in a more efficient, sharper mind.
Animal studies back up this hypothesis. Rodents put through an exercise regime develop more capillaries in their brains than do their more slothful cousins. The more neurons and the more capillaries we can build, the more will be left after the inevitable loss of some of them to disease and a variety of other causes.
Physical exercise, it appears, is not the only way to shore up the structure of our brains. Keeping mentally challenged by new interests also causes our brains to develop more connections between neurons. "If you have a lot of neurons and keep them busy, you may be able to tolerate more damage to your brain," suggests Dr. Peter Davies of the Albert Einstein College of Medicine. It's never too late to take courses or learn a new language or a new skill. The payoff? A less dull life and a less dull mind.
quick tips for a quick mind
- The gingko tree is one of the most long-lived trees, with individual trees surviving for more than a thousand years. And while consuming gingko leaves won't give you that kind of lifespan, it may help you keep alert well into your later years. Many studies show that gingko improves brain function and memory. Part of its magic occurs through its power to increase circulation, throughout the body and particularly to the brain. Gingko is now widely available in health food stores and many supermarkets.
- Researchers suspect that diets high in antioxidants may help protect the brain from oxidant damage. The easiest way to make sure you consume enough of these helpful phytochem-icals is to eat a variety of fresh fruits, vegetables and grains.
- A fascinating study of centenarians who maintained their mental sharpness found that, compared to younger groups, they ate breakfast more regularly, ate slightly more vegetables, dieted less often, and had fewer major changes in body weight.
- Lower levels of stress have been correlated with a sharper mind in later years. High levels of stress hormones, it appears, damage brain cells. And although we cannot always avoid stress, there are things we can do to help manage the tensions that inevitably arise. Several studies have found that regular meditation decreases stress and increases beneficial, calming and anti-aging hormones. And laughter releases a cascade of helpful stress-busting and immune-boosting biochemicals in our bodies.
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