Super Immunity (3 page)

Twenty-five years ago, we worshipped vitamins and minerals, and nutritional scientists hardly knew phytochemicals existed; now those compounds are considered the major micronutrient load in natural foods, and their effects are recognized as broad and profound. In other words, we now know that vitamins and minerals are not nearly enough. To have normal immune function we require hundreds of additional phytochemicals, found in natural plants. Supplements are appearing in the marketplace that contain these beneficial compounds and they show promise, but nothing can match the immunity-building power of a diet that contains an adequate amount and broad array of these health-enhancing substances from unrefined plant foods.

Today, the American diet takes over 60 percent of its calories from processed foods—a percentage that has increased gradually but inexorably over the last hundred years. This category encompasses most foods made with added sweeteners, with white flour, and with oils. Processed foods include the following: white bread, bagels, chips, pasta, donuts, cookies, breakfast bars, cold cereals, soft drinks, pretzels, condiments, and premade salad dressings. These processed foods are generally mixed with additives, coloring agents, and preservatives to extend shelf life, and they're placed in plastic bags and cardboard boxes.

USA FOOD CONSUMPTION DATA

USDA Economics Research Service, 2005; www.ers.usda.gov/Data/FoodConsumption/FoodGuideIndex.htm#calories.

Soft drinks, sugar, corn syrup, and other sweeteners now occupy a major share of the dietary pie. The amount of cheese and chicken has also increased significantly in the American diet over the last century, with the consumption of calories from animal products now at over 25 percent. With so many animal products and processed foods in the modern diet, there is little room for unrefined or unprocessed vegetation.

Americans consume less than 10 percent of their calories from unrefined plant foods such as fruits, beans, seeds, and vegetables. However, that 10 percent figure is misleading, because about half the vegetable consumption in America is white potato products, including fries and chips! If you remove the white potato from consideration (not a particularly nutritious food), the other produce would amount to less than 5 percent of the American diet.

The modern diet is not slightly deficient in just a handful of micronutrients; it is grossly deficient in hundreds of important plant-derived, immunity-building compounds. These are not optional; you can't have a lifetime of good health without them.

To identify these important antioxidants and phytochemicals deficient in the American diet, we must recognize a broad class of beneficial compounds, including the whole carotene family (including lycopene, beta-carotene, alpha-carotene, lutein, and zeaxanthin); and an assortment of other compounds that maximize cell function, thus enabling the healing properties of immune cells—compounds such as alpha-lipoic acid, flavonoids, bioflavonoids, polyphenols and phenolic acids, quercetin, rutin, anthocyanins and proanthocyanins, allium compounds, allyl sulfides, glucosinolates, isothiocyanates, lignans, and pectins. All these classes of compounds impact our health; and without them our health, and especially our immune system, dramatically suffers.

No matter how many different dietary theories there are out there, pretty much everyone agrees that vegetables are “good for you.” But just how good they truly are has been debated. Sadly, the data from observational studies is often flawed simply because most people don't eat enough vegetables to have a measurable impact on their health! However, some long-term observational studies do indeed demonstrate that vegetable consumption is the most important factor in preventing chronic disease and premature death.
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The Nature and Function of Antioxidants

Since neither processed foods nor animal products contain a significant load of antioxidant nutrients or any phytochemicals, the modern diet is dramatically disease-promoting. In other words, we are eating ourselves to sickness. Antioxidants are vitamins, minerals, and phytochemicals that aid the body in removing “free radicals” and controlling free-radical production.

Why is this so important? Free radicals are molecules that contain an unpaired electron, which causes them to be highly chemically reactive. This unstable molecule is destructive as it comes in contact with structures and other molecules within the cell. Without sufficient antioxidants—the natural enemy of free radicals—an excess of free radicals creates inflammation and leads to premature aging. Vitamin C, vitamin E, folate, selenium, and alpha-and beta-carotene, as well as various other phytochemicals, have antioxidant effects.

The vast majority of antioxidants are made available to the body through our consumption of fruit, vegetables, and other natural plants. They are not found in any significant quantity in animal products, nor are they in processed foods. (Phytochemicals have a broad array of beneficial effects outside of their antioxidant role, and these effects are still being studied and need to be further understood.)

Oxidative damage occurs when free-radical activity in cells increases and free radicals burst out of their cellular compartments to affect broader regions of the cell. Free radicals are not all bad; in fact, they have an important role: they chew up waste and can be used by immune cells as they attack and remove damaged cells that could be a danger to us if they continued to deteriorate and potentially developed into cancer. However, the problem with free radicals and other toxins in the cells is that without a relatively robust daily exposure to a broad array of antioxidants and phytochemicals, such as nature intended us to have, the free radicals increase in amount and leave their confined areas. They begin to destroy normal tissue, not just garbage and abnormal tissue. This damages the cells and increases the concentration of cellular toxins.

Because vegetables are so rich in these beneficial compounds, vegetable consumption, especially green vegetable consumption, is an easy way to measure the total antioxidant capacity of a diet. One way scientists can assess our vegetable consumption is with a blood test for alpha-carotene. Beta-carotene, high in carrots and other orange vegetables, is the most widely studied carotenoid, but alpha-carotene more accurately reflects vegetable intake—first because alpha-carotene is not present in most multivitamins and supplements, and second because it is an excellent marker of high-nutrient vegetable intake (given that dark green and orange-colored vegetables are the richest sources of alpha-carotene). Alpha-carotene is one of over forty carotenoids, a family of antioxidants with documented disease-protective and lifespan-promoting benefits.

A recent study measured alpha-carotene in all study participants and then tracked deaths over a fourteen-year follow-up period. The researchers found that increased alpha-carotene was associated with decreased risk of death from all causes. Those with the highest alpha-carotene had a 39 percent decrease in risk of death compared to those with the lowest alpha-carotene.
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Similar relationships were found between alpha-carotene and risk of death from specific causes—and not just cardiovascular disease and cancer, but other causes as well, notably infection.

Alpha-carotene itself does provide significant antioxidant benefit—but, more important, alpha-carotene is a marker of the thousands of additional compounds in green and orange vegetables, working synergistically to keep the body healthy. Green vegetables are the highest in overall nutrient density, meaning that they contain the most micronutrients per calorie, and of course they are the foods richest in alpha-carotene.

The large, long-term study cited above gives much support to my recommended high-nutrient diet-style, given that many foods high in alpha-carotene tend to be high in other micronutrients overall. When dietary intake of micronutrients (abundant in both diversity and amount) is optimized, a dramatic reduction in later life disease and enhancements in lifespan are possible. In other words, when we eat a significant and diverse amount of unprocessed vegetables, our chances of staying healthier and living longer increase.

Foods with a high ratio of alpha-carotene to calories include the following:

Bok choy

Cabbage

Red peppers

Carrots

Swiss chard

Green peppers

Asparagus

Collards

Broccoli

Peas

Winter squash

A phytochemically deficient diet is largely responsible for a weak immune system. Populations with a much higher intake of vegetables have much lower rates of cancer, and the longest-living populations throughout history have been those with the highest intake of vegetables in the diet.
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I would go so far as to say that phytochemicals are the most important discovery in human nutrition over the last fifty years. Several hundred phytochemical plant nutrients have been identified and about 150 have been studied in detail, though there may be more than a thousand plant-derived molecules that support human immune defenses. The concentration of phytochemicals is often highlighted by vibrant colors of black, blue, red, green, and orange. The classes of phytochemicals contain widely varied structures and unique health benefits, which is why a broad variety is most beneficial.

The variety of types include the following, some of which were introduced above: allium compounds, allyl sulfides, anthrocyanins, betalains, coumestans, flavonoids, flavonols glucosinolates, indoles, isoflavones, lignans, liminoids, organosulfides, pectins, phenolic compounds, phytoesterols, protein inhibitors, terpenes (isoprenoids), and tyrosol esters; and there are hundreds of compounds within each category.

Many phytochemicals in freshly harvested plant foods are lost or destroyed by modern processing techniques, including cooking (in some instances). Natural plant foods are highly complex, so their exact structure and the majority of beneficial compounds they contain are still not completely identified. It's clear, though, that the function and production of immune cells are supported by a wide exposure to an assortment of phytochemicals. The lack of a wide assortment of plant-derived phytochemicals in their native form is responsible for the development of most preventable diseases, including cancer.
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Just to make this clear, I am saying here that a piece of chicken is like a cookie: they are both foods without a significant antioxidant or phytochemical load. Both animal products and processed foods lack these immunity-supporting nutrients. The more phytochemically deficient foods we eat, the weaker our immunity and the higher our risk of getting sick and possibly developing cancer. The various low-fat diet trends of egg whites, white meats, and pasta are actually immune system–destructive and cancer-causing for various reasons, primarily because of the aforementioned lack of protective phytochemicals.

In various studies, phytochemicals have been found to play protective roles not covered by vitamins and minerals, including the following:

• Inducing detoxification enzymes

• Controlling the production of free radicals

• Deactivating and detoxifying cancer-causing agents

• Protecting cell structures from damage by toxins

• Fueling mechanisms to repair damaged DNA sequences

• Impeding the replication of cells with DNA damage

• Inducing beneficial antifungal, antibacterial, and antiviral effects

• Inhibiting the function of damaged or genetically altered DNA

• Improving immune cells' cytotoxic (destructive) power—that is, the power to kill microbes and cancer cells

This list could be condensed into one primary role: phytochemicals are the fuel that runs our body's anticancer defenses. A diet rich in phytochemicals is the best artillery we have to fight the war on cancer. This defense includes the cell-killing power of the immune system, which needs to be able to destroy invading microbes (viruses and bacteria) and to kill the body's own abnormal cells before they can become cancerous. As DNA “breakages” increase in number, and the cell becomes more and more bizarre, the immune system responds and attempts to remove it. The process of inducing one of the body's abnormal (that is, precancerous or cancerous) cells to die before it can cause damage is called “apoptosis.”

Nutrition's Scientific Credentials

Superior nutrition and its impact on human health continues to generate considerable debate and even skepticism, especially as individuals look to defend their prior opinions or dietary preferences. Nevertheless, the vast amount of scientific data demonstrating benefits to immune function—that is, to increasing one's defenses against both infection and cancer—has become overwhelming in recent years.