Life Extension Magazine

Life Extension Magazine May 2005

Abstracts

Fiber

Dietary intake and coronary heart disease: a variety of nutrients and phytochemicals are important.

Until quite recently, the dietary focus on prevention of coronary heart disease (CHD) has been almost exclusively centered on reducing intake of cholesterol, total fat, and saturated fat. The food industry responded vigorously with low-fat products, some of which are helpful, particularly low-fat dairy products, but others that are less so, due to increases in refined carbohydrate content. Recent research shows that a variety of foods contribute to protection against CHD, including certain types of fatty acids, and a variety of components in fruit and vegetables, whole grains, and nuts. In particular, there is now an emphasis on reducing not only saturated fat, but also trans fat, whereas mono and omega-3 fatty acids have been shown to be protective. Many new studies have shown a link between intake of fruit and vegetables and whole grains and protection against CHD. This has been ascribed to their fiber, vitamin, mineral, and phytochemical content. In particular, there is accumulating evidence of protective effects for folate, vitamin B(6), vitamin B(12), vitamin E, vitamin C, flavonoids, and phytoestrogens. New recommendations to prevent heart disease require a greater focus on total dietary pattern with a return to the use of a variety of minimally processed foods.

Curr Treat Options Cardiovasc Med. 2004 Aug;6(4):291-302

Dietary fiber and risk of coronary heart disease: a pooled analysis of cohort studies.

BACKGROUND: Few epidemiologic studies of dietary fiber intake and risk of coronary heart disease have compared fiber types (cereal, fruit, and vegetable) or included sex-specific results. The purpose of this study was to conduct a pooled analysis of dietary fiber and its subtypes and risk of coronary heart disease. METHODS: We analyzed the original data from 10 prospective cohort studies from the United States and Europe to estimate the association between dietary fiber intake and the risk of coronary heart disease. RESULTS: Over 6 to 10 years of follow-up, 5249 incident total coronary cases and 2011 coronary deaths occurred among 91058 men and 245186 women. After adjustment for demographics, body mass index, and lifestyle factors, each 10-g/d increment of energy-adjusted and measurement error-corrected total dietary fiber was associated with a 14% (relative risk [RR], 0.86; 95% confidence interval [CI], 0.78-0.96) decrease in risk of all coronary events and a 27% (RR, 0.73; 95% CI, 0.61-0.87) decrease in risk of coronary death. For cereal, fruit, and vegetable fiber intake (not error corrected), RRs corresponding to 10-g/d increments were 0.90 (95% CI, 0.77-1.07), 0.84 (95% CI, 0.70-0.99), and 1.00 (95% CI, 0.88-1.13), respectively, for all coronary events and 0.75 (95% CI, 0.63-0.91), 0.70 (95% CI, 0.55-0.89), and 1.00 (95% CI, 0.82-1.23), respectively, for deaths. Results were similar for men and women. CONCLUSION: Consumption of dietary fiber from cereals and fruits is inversely associated with risk of coronary heart disease.

Arch Intern Med. 2004 Feb 23;164(4):370-6

Dietary fiber stabilizes blood glucose and insulin levels and reduces physical activity in sows (Sus scrofa).

The aim of this study was to test whether a diet with a high level of fermentable dietary fiber can stabilize interprandial blood glucose and insulin levels, prevent declines below basal levels, and reduce physical activity in limited-fed breeding sows. Stable levels of glucose and insulin may prevent interprandial feelings of hunger and, consequently, increased activity. Catheterized sows (n = 10) were fed twice daily (0700 and 1900 h) 900 g of a diet with either a low (L-sows) or a high level of fermentable dietary fiber (H-sows; sugarbeet pulp). Blood samples, taken between feeding times, were analyzed for glucose and insulin levels (basal and area under the curve) and stability of levels (variance and sum of absolute differences between levels in consecutive samples). The main focus was on samples taken after the postprandial peak. Behavior was videotaped for analysis of postures and posture changes. Basal glucose and insulin levels did not differ between treatments. H-sows had more stable levels than L-sows. Interprandial levels of H-sows were higher than or equal to basal levels. L-sows showed a decline in glucose below basal levels at 1400 h (P < 0.05). Before 1400 h, no difference in the frequency of posture changes was observed between treatments. After 1400 h, the frequency of posture changes increased more in L-sows than in H-sows. We concluded that sugarbeet pulp as a source of fermentable dietary fiber stabilizes glucose and insulin levels and reduces physical activity in limited-fed sows several hours after feeding. This may indicate a prolonged feeling of satiety.

J Nutr. 2004 Jun;134(6):1481-6

Experiences with three different fiber supplements in weight reduction.

BACKGROUND: Fiber supplements added to a caloric diet have additional effects on weight reduction in overweight subjects. The aim of this study was to compare the effect of various commercial fiber supplements (glucomannan, guar gum and alginate) on weight reduction in healthy overweight subjects. Material/Methods: One hundred and seventy six men and women were included to receive either active fiber substance or placebo in randomized placebo-controlled studies. The fiber supplements consisted of the viscous fibers glucomannan (Chrombalance®), glucomannan and guar gum (Appe-Trim®) and glucomannan, guar gum and alginat (Glucosahl). Results: All fiber supplements plus a balanced 1200 kcal diet induced significantly weight reduction more than placebo and diet alone, during a five week observation period. However, there were no significant differences between the different fibers in their ability to induce weight reduction, which was approximately 0.8 kg/week (3.8+/-0.9, 4.4+/-2.0, 4.1+/-0.6 in the Chrombalance, Appe-Trim(R) and Glucosahl group, respectively). Conclusions: Glucomannan induced body weight reduction in healthy overweight subjects, whereas the addition of guar gum and alginate did not seem to cause additional loss of weight.

Med Sci Monit. 2004 Dec 22;11(1):PI5-8

High intake of saturated fat and early occurrence of specific biomarkers may explain the prevalence of chronic disease in northern Mexico.

To investigate whether the high prevalence of coronary heart disease (CHD) and type II diabetes prevalent in Northern Mexico could be related to the presence at a young age of biomarkers for chronic disease, 25 boys and 29 girls (8-12 y old) from a low socioeconomic group were recruited. Plasma lipids, LDL phenotype, apolipoproteins (apos), glucose, and insulin were evaluated. Analysis of 3-d dietary records indicated the typical intake of this region to be high in total fat (37-43% energy) and saturated fat (11-13% energy). Boys and girls had an average of 6623 +/- 2892 and 6112 +/- 2793 steps/d, respectively, as measured by a pedometer, suggesting a low level of activity. Plasma total and LDL cholesterol (LDL-C) were within the 50th percentile. In contrast, the study population was characterized by having high triglycerides (TG) (95th percentile, 1.25 +/- 0.37 mmol/L in boys and 1.19 +/- 0.38 mmol/L in girls). HDL cholesterol (HDL-C) concentrations were low (25th percentile), 1.22 +/- 0.20 mmol/L in girls and 1.29 +/- 0.20 mmol/L in boys. There was also a high prevalence of the small dense LDL phenotype B (69%), which is associated with increased risk for CHD. These results suggest that the population of children studied may have 2 different components of risk, one being the high-fat diet, which could be associated with the elevated levels of plasma LDL-C present in the adult population. A second component, related to the insulin resistance syndrome, may be principally genetic and associated with the high TG, low HDL, and LDL phenotype B observed in these Mexican children.

J Nutr. 2005 Jan;135(1):70-3

Plant foods, fiber, and rectal cancer.

BACKGROUND: Associations between colon and rectal cancer and intakes of vegetables, other plant foods, and fiber have stimulated much debate. OBJECTIVE: We examined the association between rectal cancer and plant food and fiber intakes. DESIGN: Data from 952 incident cases of rectal cancer were compared with data from 1205 population-based controls living in Utah or enrolled in the Kaiser Permanente Medical Care Program in northern California RESULTS: Rectal cancer was inversely associated with intakes of vegetables (odds ratio: 0.72; 95% CI: 0.54, 0.98), fruit (0.73; 0.53, 0.99), and whole-grain products (0.69; 0.51, 0.94), whereas a high intake of refined-grain products was directly associated with an increased risk of rectal cancer (1.42; 1.04, 1.92). Similarly, relative to low fiber intakes, high intakes of dietary fiber reduced the risk of rectal cancer (0.54; 0.37, 0.78). The reduced risk of rectal cancer associated with vegetable (0.48; 0.29, 0.80), fruit (0.63; 0.38, 1.06), and fiber (0.40; 0.22, 0.71) intakes was strongest for persons who received the diagnosis after age 65 y. A threshold effect at approximately 5 servings of vegetables/d was needed to see a reduced risk of rectal cancer. CONCLUSIONS: The results suggest that plant foods may be important in the etiology of rectal cancer in both men and women. Age at diagnosis appears to play an important role in the association.

Am J Clin Nutr. 2004 Feb;79(2):274-81

Dietary fibre: more than a matter of dietetics. II. Preventative and therapeutic uses.

A nutrition rich in fibre has a preventive effect against constipation, colon diverticulosis, carcinoma of the large bowel and stomach, type 2-diabetes, metabolic syndrome and cardiovascular disease. In case of constipation, diverticulosis and diabetes this effect solely depends on dietary fibre. Regarding carcinomas and cardiovascular diseases, so far unknown factors integrated in or associated with fibre-rich food may also contribute to the preventive effect. Therapy with dietary fibre is indicated for constipation, colon diverticulosis, diarrhea, diabetes, and hypercholesterinemia. The individual dietary fibres differ substance-specifically. Food-integrated dietary fibre such as whole-grain bread, vegetables and fruit have their place in prevention. Dietary fibre preparations such as wheat bran, flax seed or sugar-beet fibre are useful in the treatment of constipation, colon diverticulosis and adiposity. Oat bran is preferentially used in hypercholesterinemia. Purified dietary fibres such as cellulose, guar, psyllium, and beta-glucan have an anti-diabetic, all viscous fibres an anti-lipaemic effect. The therapeutic dosages of dietary fibre preparations are 20-40 g/day and of purified fibres substances 10-20 g/day respectively.

Wien Klin Wochenschr. 2004 Aug 31;116(15-16):511-22