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BENEFICIAL EFFECTS OF HIGH DIETARY FIBER INTAKE IN PATIENTS WITH TYPE 2 DIABETES MELLITUS: A REVIEW

 

          According to The New England Journal of Medicine, taking high fiber diet, 50 grams of total fiber per day [see the table 1(soluble and insoluble fiber content provided 25 grams each)] lower fasting plasma total cholesterol concentration, decrease plasma VLDL:Cholesterol concentration, decrease fasting plasma LDL:Cholesterol concentration, decrease gastrointestinal absorption of cholesterol, increase fecal acidic sterol excretion but it did not affect the excretion of neutral sterols.

 

WHAT IS DIETARY FIBER and WHAT ARE THE BENEFITS OF TAKING FIBERS?

         

Fibers are an indigestible complex CHO found in plants. Fibers are not a single food / substances. Fiber in itself has no calories because the body cannot absorb it. Therefore, high fiber foods low in fat are low in calories such as fruits and vegetables. Fibers bulks up wastes and moves it through the colon more rapidly high-fiber foods expand the inside walls of the colon; preventing constipation, and make them absorb many times their weight in water, resulting in softer, bulkier stools and easier to be moved through thus less straining required to pass softer stool, so, the probability of developing hemorrhoids is usually reduced and preventing colon cancer. The faster the transit time the less contact time for toxins and reduced risk of colon problems. Dietary fiber may play several roles relative to diabetes, including potential effects on satiety, obesity, and the absorption of certain sugars. Fibers could play a role in preventing cardiovascular disease owing to its effect on blood cholesterol levels, especially where initial levels are high. Some studies have found an inverse relationship between fiber and myocardial infarction. Low fiber diets may be associated with the development of diverticular diseases of the colon.

 

WHAT ARE THE MODES OF ACTIONS OR EFFECTS OF THE DIFFERENT FIBERS, EITHER SOLUBLE OR INSOLUBLE, IN ATTAINING BALANCE OF OUR BODY?

         

Gums and Pectins may keep cholesterol level controlled by removing bile acids that digests fats. Psyllium, Guar gum, pectin, oat bran and glucomannan, improve glucose tolerance. Glucomannan from konjac root of Amorphophallus konjac stabilized blood sugar, prevents also hypoglycemia, reduce total blood cholesterol, LDL cholesterol, and triglyceride, and may help also in losing weights.  Ginseng may produce significant reduction in blood sugar. Soya beans’ protein contents contains large amount of glycine and arginine which will tend to reduce blood insulin levels therefore, low blood insulin levels decreases the hepatic synthesis of cholesterol. Soya beans are generally lower in fat and Soya proteins exert specific cholesterol-lowering effects which are highly desirable in the diabetic with a significant risk of atherosclerosis. Soya beans can also improve renal functions, and it is with antiangiogenic effect, antihypertensive effects.

 

WHAT ARE THE TYPES OF FIBERS?

 

Fibers come in two forms; soluble fiber dissolves in water forming gelatinous substance in bowel. Soluble fiber is found in oatmeal,  fruits, Psyllium ( Metamucil and Konsy), barley and legumes, peas, Brussels sprouts, lentils, carrots, cabbage, okra, apricots, prunes, dates, blackberries, cranberries, seeds, apples, bananas, citrus, seaweeds, to name a few. Soluble fibers, among its other benefits, seem to bind up cholesterol allowing it to be eliminated with the stool. If enough is removed it can lower the blood cholesterol 10-15%. The liver that makes the bile acids from cholesterol and if more bile is lost in the gut, the liver will use up cholesterol to replace the bile, again resulting in lower cholesterol levels. Soluble fiber delays stomach emptying. This in turn delays and spreads out the absorption of sugar, resulting in a more normal pattern of insulin secretion as well as better control of blood sugar.

          An insoluble fiber means it does not dissolve in water. It also cannot be used by intestinal-colon bacteria as food source, so these beneficial bacteria generally do not grow and produce intestinal gas.

Insoluble fibers may be found in bran (the outer covering of corns, oats, rice, and wheat), whole grains, cereals, edible skins of fruits and vegetables, celery, brown rice and some vegetables.

 

WHAT IS TYPE 2 DIABETES MELLITUS?

 

          Type 2 Diabetes Mellitus is a heterogeneous group of disorders usually characterized by variable degrees of insulin resistance, impaired glucose production. Distinct genetic and metabolic defects in insulin action and/or secretion give rise to the common phenotype of hyperglycemia in type 2 diabetes mellitus.  The usual patients of this type of Diabetes are the obese ones, with the age of 40 and above.

 

          After an overnight fasting, the patients with type 2 diabetes mellitus (the subjects of the study done by  NEW ENGLAND JOURNAL OF MEDICINE, Dr. Manisha Chandalia et al.), their plasma cholesterol and triglyceride concentrations ranged from 151-324 mg per deciliter and 67 to 390 mg per deciliter respectively. And their fasting plasma glucose concentrations were less than 200 mg per deciliter. Their glycosylated hemoglobin values ranged from 6.0 to 9.8 percent on these gathered test results will strongly give us a diagnosis that all the subjects are positive to diabetes mellitus, type 2 because their mean age was 61±9 years (range, 45 to 90), their mean body weight was 93.5±12.7 kg, and their body-mass index was 32.3±3.9.

          In the study conducted by Dr. Manisha Chandalia,M.D. et al., they ask six patients to receive the high fiber diet first, and the other seven received the American Diabetes Association diet first [12 men and 1 woman (9 non-Hispanic whites and 4 blacks)] (see the table 2 for sample menus of the study diets). In addition, on weekdays, all the patients ate at least one meal at the clinical research center. Other meals were supplied in packages so that they could be consumed at home. Their compliance to the designed diet is monitored and was asked to bring back all the left over or unconsumed food and to maintain a constant level of physical activity throughout the study. Several examinations are done like LIPID ANALYSES, PLASMA GLUCOSE AND INSULIN LEVEL, GLYCOSYLATED HEMOGLOBIN, 24-HOUR URINE SPECIMENS FOR QUANTITATIVE DETERMINATION OF GLUCOSE, FECAL STEROL BALANCE, PERCENTAGE OF CHOLESTEROL ABSORPTION.

         

          The study results was outstanding and made a conclusion that intaking of rich in soluble fibers(the subjects was asked to take unfortified foods, those rich in soluble fibers, like cantaloupe, grapefruit, orange, papaya, raisins, lima beans, okra, sweet potato, winter squash, zucchini, granola, oat bran, and oat meal)will definitely lowers all the results of the said examinations done. As compared to ADA diet, the high fiber diet resulted in lowering fasting plasma total cholesterol concentration by 6.7 percent, a lower plasma triglyceride concentration by 10.2 percent and a lower plasma VLDL cholesterol concentration by 12.5 percent. The fasting plasma LDL cholesterol concentration was lower by 6.3 percent. Although the fasting plasma HDL cholesterol concentration is also lower, there was no significant difference between the two diets. In addition, there is a marked decreased gastrointestinal absorption of cholesterol by 10 percent, increased fecal acidic sterol excretion by 41 percent but it did not significantly affect the excretion of neutral sterols.

 

          Therefore, increase intake of total dietary fiber, which consisted of predominantly of soluble fiber, significantly improved glycemic control and decreased the degree of hyperinsulinemia in patients with Type 2 diabetes and lowered plasma lipid concentrations. In conclusion, the study showed a very impressing effect and therefore is good to follow the diet used by the patients in their study.

 

 

 

 

 

 

 

Table 1: Composition of the Study Diet

 

 

COMPOSITION OF THE STUDY DIETS   CONSTITUENT                              ADA DIET      HIGH-FIBER DIET   Carbohydrate (% total energy)             55                      55 Protein (% total energy)                       15                      15 Fat (% total energy)                              30                      30       Saturated                                       7                        7       Cis monounsaturated                     17                      17       Polysaturated                                6                         6 Cholesterol (mg/day)                          300                    297 Fiber (g/day)                    Total                                        24                       50            Soluble                                     8                       25           Insoluble                                  16                       25

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 2: Sample Menus of the Study Diet

 

 

SAMPLE MENU OF THE STUDY DIETS   FOOD                                                                      WEIGHT IN GRAMS   BREAKFAST Orange sections                                                               300 Oatmeal                                                                              50 Scrambled egg                                                                  37 Olive oil                                                                              10 Decaffeinated coffee                                                          2 LUNCH Ham (5% fat)                                                                      52 Mayonnaise                                                                        12 Iceberg lettuce                                                                   10 Fresh tomato                                                                      15 Whole-wheat bread                                                            60 Corn (canned)                                                                     40 Green peas (canned)                                                        110 Dehydrated onion                                                                  2 Olive oil                                                                                10 Fresh green pepper                                                            10 Fresh celery                                                                         15 Fresh papaya                                                                     250 Instant tea                                                                              2      DINNER Chicken breast (skinned)                                                        90 Bran flakes                                                                             10 Oat bran                                                                                   5 Parmesan cheese                                                                    1 Egg substitute                                                                         10 Tomato (canned)                                                                    105 Low fat cheese                                                                        19 Spaghetti                                                                                19 Zucchini                                                                                195 Olive oil                                                                                  19 Whole-wheat bread                                                                 30 Fresh peaches                                                                       300 Instant tea                                                                                2   BEDTIME SNACK Fruit cocktail (canned)                                                            200 Cherries (canned)                                                                  100 Granola                                                                                   15