文章基本信息

标题：Battling your … inner-space invaders: FOS and probiotics to the rescue
作者：Liz Brown
期刊名称：Better Nutrition
出版年度：2001
卷号：Nov 2001
出版社：Active Interest Media

Battling your �� inner-space invaders: FOS and probiotics to the rescue

Liz Brown

Anyone who has spent a buck or two in a video arcade understands the challenge of warding off enemies and protecting your defenses, whether the offending "bad guys" are cosmic creepy-crawlies, flying saucers, or googly-eyed ghosts. While the damage of such attacks onscreen is short-lived and even fun, the consequences of harmful bacteria overtaking your body's own defenses in real life can be serious -- and the resulting health problems last longer than a pocketful of quarters at the arcade.

YOUR BODY, YOUR WORLD

Your body is your mothership, or your world -- a self-contained biosystem that needs the right fuel (nutrients), training (physical activity), defenses (antioxidants and good bacteria) and all systems working within normal range--a balanced state of health, what is also called "homeostasis."

PLAYING BY THE RULES

To devise a strategy to protect your personal ecosystem, it's important to understand the rules of the game. Normally, a variety of beneficial bacteria in your intestines and urogenital tract protect you against harmful organisms, like yeast and viruses, that sneak in via the diet or other means. Here's how it works: friendly bacteria ward off "inner space invaders" by attaching to the gut and vaginal walls, and lowering the pH of this environment to levels where invading bacteria (disease-causing, "pathogenic" bacteria) can't live. But when the delicate balance of good bacteria is thrown out of whack by antibiotics, steroids, poor diet and stress, you're prone to enemy attack. Instead of merely losing a few points in a game, you might end up with diarrhea, a yeast infection, food poisoning or some other malady. Consuming live, beneficial bacteria (called probiotics) helps restore the balance of intestinal microflora, or good bacteria.

You're probably familiar with one of the most common strains of probiotics, Lactobacillus acidophitus. It is commonly added to dairy products (such as yogurt) and is available in supplement form. Its availability in the United States since the mid-1970s is due to a large body of research showing numerous health benefits and the fact that it combines well in foods. Other popular probiotic defenders that offer health benefits include Bifidus strains, L. bulgaricus and Streptococcus thermophilus; some supplements. combine various strains of these for optimal benefits. What are these benefits, you ask? Let's take a look.

ZAPPING CHOLESTEROL

Several studies have uncovered the potential benefits of probiotic strains on lowering cholesterol, thereby lowering the risk of heart disease.

In one recent study, low-fat milk containing L. acidophilus was fed to 27 people with varying cholesterol levels at a level of 200 ml (a little less than a cup) per day for 20 days. The average LDL ("bad") cholesterol level among participants decreased significanfiy in most groups (categorized by initial cholesterol levels), as did the ratio of LDL and total cholesterol to HDL cholesterol, or "good" cholesterol. People with borderline cholesterol levels experienced the most benefit.

In an eight-week, double-blind, placebo-controlled study, 70 healthy men and women of various weights consumed 450 ml (about two cups) of yogurt daily.

Overweight subjects who ate yogurt fermented with two strains of S. thermophilus experienced a reduction in LDL-cholesterol and increased fibrinogen, a protein in blood essential for coagulation (another marker of heart disease risk.)

SHIELDING AGAINST DIARRHEA

Numerous studies have shown that probiotics can be effective treatment for gastrointestinal disturbances. For example, Saccharomyces boulardii and Enterococcus faecium are used to prevent or shorten the duration of diarrhea associated with antibiotic use. S. boulardii is also used to prevent recurrence of diarrhea associated with Clostridium difficile, and fermented milks with L. rhamnosus can shorten diarrhea duration in infants with rotavirus enteritis.

TARGETING LACTOSE INTOLERANCE

People who lack the enzyme lactase have gastrointestinal trouble when trying to digest dairy products because of the lactose (milk sugar) content of these foods and because of the milk protein, casein. Probiotic bacteria in fermented and unfermented dairy products can improve lactose digestion and squelch symptoms of intolerance. L. acidophilus bacteria produce lactase in the gut, aiding in the digestion of dairy products.

FENDING OFF INFECTION

Infections in the urogenital tracts of women are common, with over 300 million cases of urinary tract infections, bacterial vaginosis and yeast infections worldwide each year. Infections happen when complex good bacteria in the bladder and vagina are dominated by infecting micro-organisms. Probiotic therapy aimed at restoring the balance of healthy bacteria in the bladder and vagina has yielded varying results in studies. But specifically chosen strains may prove to be an effective alternative treatment and prevention regimen to antibiotics.

While broad-spectrum antibiotics are commonly used to treat infections, they wipe out the good bacteria with the bad, leaving your body unprotected against future attacks. This drawback helps explain why these infections have an extremely high recurrence rate. Dr. William Crook, an expert on candida (yeast) overgrowth, recommends the narrow-spectrum antibiotic, Nystatin, in conjunction with dramatic reductions in sugar intake.

In one recent study, 60 strains of lactobacilli were investigated for their potential to regenerate the vaginal bacteria, or flora, of women with recurrent bacterial vaginosis (BV). This is a condition marked by lowered naturally present vaginal lactobacilli and an overgrowth of pathogenic bacteria. Four lactobacilli strains were powerful against BV-associated bacterial species, with all four producing a highly acidic (and, therefore, desirable) environment. The researchers determined that two of these strains could be candidates for restoring a healthy balance of bacteria to the vaginal tract in women with BV. Some practitioners recommend using a probiotic supplement added to lukewarm water as a douche for yeast infections.

POWERING UP IMMUNITY

Probiotics also enhance immunity, though the mechanisms by which they do so aren't entirely clear. Probiotics help by stabilizing the gut's bacterial balance and help its local immune defenses by controlling the balance of pro-inflammatory and anti-inflammatory compounds (like cytokines). This leads researchers to suggest that probiotics can be used to alleviate inflammation, restore the mucosal lining of the gut and make it less sensitive to attack. While probiotics may be a simple complement to conventional therapy for inflammatory bowel disease and Crohn's disease due to its effects on immune response, some researchers are waiting for more definitive study results.

THE CARE AND FEEDING OF BACTERIA

One area of research that has attracted attention in the beneficial bacteria realm is that of prebiotics, which selectively nourish good bacteria, helping them to protect us. Fructooligosaccharides, called FOS or neosugar, are prebiotics that some practitioners recommend to their patients in supplement form. These plant-derived, non-digestible sugars pass through the stomach and small intestines to the colon, where the good bacteria ferment them for fuel. FOS appears to preferentially feed good bacteria, leading to a drop-off in the bad bugs.

Although FOS is widely distributed in nature -- bananas, onions, garlic, tomatoes, barley and Jerusalem artichoke -- you would have to eat 13 bananas, 16 tomatoes and 429 cloves of garlic to get the amount of FOS that you would find in one teaspoon of a purified FOS powder.

Consulting a knowledgeable practitioner is the best way to find out which prebiotics and probiotics are most effective for specific conditions. Some experts recommend taking a basic acidophilus supplement when traveling, in times of stress or during and after a bout of antibiotics to keep your system in check. After all, in real life, the battle against inner space invaders is never-ending.