POLYSACCHARIDES – WHOLE GRAINS ARE HEALTHIER PART 2
In addition to fibers and resistant starch, whole grains contain an appreciable amounts of oligosaccharides, ie carbohydrates with a low degree of polymerization. The oligosaccharides have an effect similar to that of soluble fibers. In addition, they increased the number of bifidus bacteria and decrease the potentially harmful E coli germs concentration, clostridium and bacteroides.
Secondly, non-digestible poliglucides increase the fecal volume and decrease the intestinal transit time. Each bran gram of wheat increases the fecal weight by 5.4 g. Studies on 20 populations of 12 countries have shown an inverse relationship between the weight of feces and the risk of colon cancer. The high fecal volume and the reduced intestinal transit time decrease the chances of mutagenic substances to act on the intestinal epithelium. In addition, secondary bile acids, which are believed to favors cell proliferation, are fixed and diluted by fibers. The fibers fermentation decreases the intestinal pH too, reducing the solubility of free bile acids, thereby reducing their action as cocarcinogens.
Thirdly, cereals contain numerous antioxidants, including phenolic acids, caffeic acids, ferulic acids and antinutrient phytic acid.
Ferulic, caffeic acids from bran are tumor inhibitors.
Phytic acid forms chelates with different metals, which suppresses the redox reactions (harmful) of iron catalyst. Also, intestinal bacteria produce considerable amounts of oxygen radicals, and the phytic acid in cereals may suppress intestinal epithelial lesions.
Vitamin E is another antioxidant that is removed during flour refining process. It is an intracellular antioxidant that protect polyunsaturated fatty acids in the cell membranes of oxidative damage. Also, vitamin E, keep the selenium in reduced state and inhibit the formation of nitrosamines.
Fourth, whole grains contain lignans. Lignans are phytoestrogens, ie estrogen compounds found in plants and that structurally are similar to endogenous estrogens. White flour does not contain lignans. Rich sources of lignans, besides whole grains, are the flaxseeds, pumpkin seeds, caraway seeds and sunflower seeds. The largest amounts of lignans are found in the flax seeds. Along with other phytoestrogens lignans changes the blood hormone levels, reducing the risk of cancer, particularly of the breast and bowel.
Some studies argue that there is a link between insulin and colon neoplasms. Insulin should be an important growth factor of the intestinal epithelium, stimulating the tumor cell growth.
Epidemiological studies have shown that the same factors that are accompanied by elevated insulin levels, like obesity and sedentary lifestyle, are associated with an increased risk of colon cancer. Also, in women, diabetes is supplied with an increased risk of intestinal cancer. In the western world, the breast cancer frequency is increased in the conditions that shows resistance syndrome components in insulin, ie: hyperinsulinemia, dyslipidemia, hypertension pressure and atherosclerosis. Whole grain consumption decreases the blood sugar levels in diabetics.
Unfortunately, the population is not aware of the benefits of whole cereals. In the US, for example, where cereals represent 23% of total energy consumption, whole grain products represent only 1%. There is a totally wrong tendency to use additionals with different substances instead whole grains, that can lead to unbalanced intake.
The number 27 September 2000 of the American Medical Association Journal (2000, vol. 284, p. 1534), researchers at Harvard University released a study carried out on 75.521 of US women, aged between 38 and 63 years, who were watched for 12 years. The research has shown that whole grains products have a protective effect against ischemic strokes accidents. Even a single portion of whole cereals per day had beneficial effects.