PROBIOTICS: GOOD BACTERIA TO PREVENT DISEASE
Gabe Mirkin, M.D.
More than 100 years ago, Nobel Prize winner Ilya Metchnikoff proposed his autointoxication theory to explain why people age and die. Most food that you eat is absorbed in the upper intestinal tract. He said that food which is not absorbed there goes to the colon where bad bacteria ferment it to produce toxic chemicals that are absorbed into the bloodstream to cause disease and shorten life. Therefore you should eat foods containing good bacteria that displace the bad bacteria and prevent them from making these toxic products. Scientists laughed at Metchnikoff, but research in the last ten years may turn him from a quack into a prophet.
When you eat, enzymes from your intestines, stomach, liver and pancreas break down the carbohydrates into their building blocks called sugars; proteins into amino acids; and fats into glycerol, fatty acids and monoglycerides, that can be absorbed into your bloodstream. However, many plant foods contain undigestible starches that cannot be broken down, so they cannot be absorbed in the upper intestinal tract. Therefore they pass to your lower intestinal tract where bacteria ferment these undigestible starches to form other chemicals, including short chain fatty acids that protect your intestinal lining from irritation and cancer, and are absorbed into your bloodstream to lower cholesterol and prevent heart attacks.
Humans have used these good bacteria, such as lactobacillus, to ferment and preserve milk and plant products. Recent research shows that normal intestinal bacteria make up approximatly 95 percent of the total number of cells in the human body. The good bacteria help to prevent bad bacteria from infecting you, and may help to prevent intestinal diseases such as ulcerative colitis, Crohn's disease and cancer.
Researchers have shown that two nondigestible carbohydrates, fructooligosaccharides and inulin, can help heal intestines swollen and damaged by diarrhea-causing bacteria. Several recent studies show that normal intestinal bacteria prevent cancers that would have been caused by such chemicals as the rat colon carcinogen, 1,2-dimethylhydrazine.
Other studies show that these nondigestible carbohydrates increase absorption of the minerals, calcium, magnesium, zinc, and iron; and prevent and treat osteoporosis in animals. So even though Metchnikoff had the wrong explanation, he was right about good bacteria. Eat whole grains, beans, seeds, nuts, vegetables and fruits for their nonabsorbable carbohydrates, to establish a healthy colony of good bacteria in your intestines.
A diet high in whole grain foods is associated with a significantly lower risk of developing cardiovascular disease, including heart disease and stroke, according to an analysis conducted by researchers at Wake Forest University School of Medicine.
"Consuming an average of 2.5 servings of whole grains each day is associated with a 21 percent lower risk of cardiovascular disease compared to consuming only 0.2 servings," said Philip Mellen, M.D., lead author and an assistant professor of internal medicine. "These findings suggest that we should redouble our efforts to encourage patients to include more of these foods in their diets."
These results were published on line in Nutrition, Metabolism & Cardiovascular Diseases and will appear in a future print issue.
The findings are based on an analysis of seven studies involving more than 285,000 people. By combining the data from these seven studies, researchers were able to detect effects that may not have shown up in each individual study. The studies were conducted between 1966 and April 2006.
Mellen said the findings are consistent with earlier research, but that despite abundant evidence about the health benefits of whole grains, intake remains low. A nutrition survey conducted between 1999 and 2000 found that only 8 percent of U.S. adults consumed three or more servings of whole grain per day and that 42 percent of adults ate no whole grains on a given day.
"Many consumers and health professionals are unaware of the health benefits of whole grains," said Mellen.
A grain is "whole" when the entire grain seed is retained: the bran, germ and the endosperm. The bran and germ components are rich in fiber, vitamins, minerals, antioxidants, and healthy fats. These are the parts removed in the refining process, leaving behind the energy-dense but nutrient-poor endosperm portion of the grain. Examples of whole grain foods include wild rice, popcorn, oatmeal, brown rice, barley, wheat berries and flours such as whole wheat.
In addition to protecting against cardiovascular disease, which accounts for one-third of deaths worldwide, there is evidence that whole grains also project against diabetes and other chronic conditions.
"Years ago, scientists hypothesized that the higher rates of chronic diseases we have in the West, including heart disease, are due, in part, to a diet full of processed foods," Mellen said. "Subsequent studies have born that out - especially with whole grains. Greater whole grain intake is associated with less obesity, diabetes, high blood pressure, and high cholesterol - major factors that increase the risk for heart disease and stroke."
According to nutritionists, consumers should look for "100 percent whole grain" on food labels or look for specific types of whole-grain flour as the main ingredient, such as "whole wheat."