Interaction of dietary sucrose and fiber on serum lipids in healthy young men fed high carbohydrate diets.

High sucrose diets may cause increased serum triglycerides and decreased high density lipoprotein concentration. To determine whether dietary fiber protects against these effects, four groups of six healthy young men were assigned to one of four very high carbohydrate diets providing 0, 18, 36, or 52% of calories as sucrose. Each diet was fed in both low (less than 14 g) and high (greater than 34 g) levels of dietary fiber for 10 days each. Triglycerides increased during the 36 and 52% sucrose diets compared to 0 and 18% sucrose diets, and fiber protected partially against this rise. Serum cholesterol and LDL cholesterol were lower during the 0 and 18% sucrose diets than the 36 or 52% sucrose diets but fiber had no effect. HDL cholesterol decreased during all low fat diets, with a trend toward a greater decrease during the high sucrose diets. The results suggest that fiber protects against carbohydrate-induced lipemia but has no effect on cholesterol during very high carbohydrate diets.

Lack of effect of dietary fiber on serum lipids, glucose, and insulin in healthy young men fed high starch diets.

Eight healthy young men were fed a 72% carbohydrate high starch diet either high or low in dietary fiber for 4 days in a double cross-over design. Both groups showed a slight transient increase in plasma triglyceride level and a decrease in total and high-density lipoprotein cholesterol. There were few differences in glucose and insulin levels after glucose and meal tolerance tests after each diet. Fasting triglycerides and high-density lipoprotein cholesterol were inversely related at base-line; insulin response to oral glucose was inversely related to high-density lipoprotein cholesterol levels at the end of the study. We conclude that a high carbohydrate high starch diet, whether high or low in fiber, caused little increase in triglycerides, with little difference between the high and low fiber diets. Dietary fiber did not influence the fall in plasma cholesterol or high-density lipoprotein cholesterol concentrations over and above that seen after the low fiber diet.

Alterations of fecal steroid composition induced by changes in dietary fiber consumption.

The short-term effects of high carbohydrate diets of normal foods either high or low in dietary fiber on fecal steroids and fiber was assessed in eight healthy young men. Each subject consumed in random order for 4 days a diet containing 59 g (high fiber) or 21 g (low fiber) neutral detergent fiber. After a 9-day rest period he consumed the other diet. Analysis of random fecal samples during their usual diet and after 4 days of each experimental diet showed an increased in primary bile acids from less than 4 to 32% of total bile acids, and a decreases of coprostanol from 76% (control diet) or 64% (low fiber diet) to 45% of total neutral sterol after the high fiber diet. Fecal fiber concentration doubled after the high fiber diet. We conclude that 4 days of high fiber diet is sufficient to cause a large increase in primary and decrease in secondary fecal steroids. Such changes have implications for prevention of arteriosclerosis and cancer of the colon.

Combined effects of aerobic exercise and omega-3 fatty acids in hyperlipidemic persons.

Because both aerobic exercise and fish oil ingestion have been shown to decrease plasma lipids, we examined the effects of combining these modalities in hyperlipidemic subjects. Thirty-four subjects were randomly assigned to one of four groups as follows: fish oil and exercise (FE), N = 7, 50 ml of oil daily and 3 d.wk-1 of aerobic exercise; fish oil (F), N = 7, 50 ml of oil daily; corn oil (CN), N = 10, 50 ml of oil daily; and control (C), N = 10. Blood samples were drawn at baseline and at the end of 4, 8, and 12 wk. The FE and F groups showed significantly lower triglycerides with respect to treatment as compared to the CN and C groups. The FE, F, and CN groups exhibited lower total cholesterol values than the control group but were not different from each other. HDL cholesterol was significantly increased after treatment in the FE and F groups as compared to the CN and C groups. Serum apo-B, LDL cholesterol, and LDL protein decreased significantly in the FE group but not the F group from baseline to 12 wk. VO2max increased and percent fat decreased only in the FE group. In conclusion, aerobic exercise improved the effects of fish oil on LDL cholesterol and apo-B and improved fitness and body composition in hyperlipidemic subjects.

The effect of dietary fiber and other factors on insulin response: role in obesity.

Epidemiologic evidence favors the hypothesis that obesity may result from the fiber-depleted diet of industrialized societies. Since hyperinsulinemia is a universal characteristic and perhaps causal of obesity, the possibility is considered that dietary factors causing excess insulin secretion might lead to obesity. Dietary glucose causes a slightly greater insulin rise than cooked starch containing an equal amount of carbohydrate, and high fiber starchy foods cause a much lesser insulin response than does glucose in solution. Doubling the dose of carbohydrate in a meal causes only a small increase in glucose response but a large increase in insulin response. Dietary fiber could act by displacing some of the carbohydrate that would normally be absorbable in the small intestine, or could translocate the carbohydrate to a point lower in the intestinal tract where less effect on insulin secretion would be observed. Evidence is presented that a higher fiber diet is associated with a higher concentration of fasting circulating free fatty acids, a lesser post-cibal decrease in circulating free fatty acids and triglycerides and less chronic increase in fasting triglycerides than a low fiber diet. These differences are associated with a lesser insulin response to high fiber meals. The extreme fluctuations between the fed and fasted states seen with low fiber diets are thus dampened by high fiber diets. The less complete inhibition of lipolysis during the fed state, and more intense lipolysis during fasting, suggested by the above data, might tend to prevent obesity. The mechanisms of the lesser insulin response to high rather than low fiber meals are not known, but the possibility that dietary fiber decreases the GIP response is considered.

Effect of lactate consumption on exercise performance.

BACKGROUND: Maintenance of plasma glucose is important in endurance performance. Gluconeogenesis or carbohydrate ingestion maintain glucose after hepatic glycogen depletion. Lactate may also serve as a gluconeogenic precursor as well as a blood buffer. METHODS: To determine if an 8% carbohydrate (CHO) sports drink with and without a 2% lactate (L) solution increased endurance performance, peak power, and delayed blood acidosis, seven trained cyclists participated in a double-blind randomized study (6 males and 1 female) performed a bicycle test to determine max VO2max HR and the HR associated with the first respiratory exchange ratio (RER) value greater than 1.0 (target HR). Four bicycle rides to exhaustion, separated by one week, were done at a constant workload at a HR 10 beats below each subject's target HR. After a 12-hour fast, subjects received 100 g CHO 2-3 hrs before each test. Mean exercise heart rate was 86-87% max HR. During the final 30 s of each ride the Wingate power test was performed. Subjects consumed either (placebo, 2% L, 8% CHO or 8% CHO plus 2% L) every 20 min. Blood samples were collected before, every 30 min during and immediately following the test. RESULTS: No significant differences were observed in total time (placebo: 95.3 +/- 25.8, 2% lactate: 95.7 +/- 30.0, 8% CHO: 105.2 +/- 37.2, 8% CHO + 2% lactate: 89.0 +/- 28.1 min) or peak power (placebo: 798.2 +/- 241.1, 2% L: 750.1 +/- 279.2, 8% CHO: 789.4 +/- 353.5, 8% CHO + 2% L: 716.3 +/- 331.3 Watts) among drinks. There were no differences in insulin, glucose, pH and HCO3- after the power tests among the drinks. CONCLUSION: Exercise performance is unaffected by oral supplementation with lactate.

Hypertension and exercise. Where do we stand?

Several risk factors have been identified in patients with essential hypertension. The question is whether regular exercise programs can either prevent or alleviate elevated blood pressure. Published studies generally indicate that aerobic exercise of large-muscle groups can be used as an interventional regimen for hypertension. For mild hypertension, moderate-intensity walking is recommended at least three times a week. Improvement may not be evident in less than 6 months. When exercise alone is not effective or when hypertension is more severe, exercise can still be used as an adjunct to pharmacologic therapy.

Understanding osteoporosis. Cornerstone of prevention and treatment.

Osteoporosis, especially in the elderly, may be preventable. Postmenopausal white women appear to be primarily at risk. Investigations into the etiology have concentrated on calcium metabolism. New noninvasive tests may supplant iliac biopsy, which is currently the definitive test for osteoporosis. The importance of adequate calcium intake and exercise should be stressed, even in childhood. Once the disease is established, estrogen and calcium therapy and exercise may be beneficial.

Medical grand rounds. West Virginia University Health Sciences Center. Bites and stings. Part 1. Spiders.

Most animals can bite or sting. In narrowing the kingdom down to those that harm humans, the field still is vast. It would be interesting to explore the rich variety of pathology produced in us by moray eels, lionfish, sea urchins, jellyfish, sting rays, fire ants, kissing bugs, flies, lice, mosquitoes, ticks, mites, fleas, puss caterpillars, centipedes, snakes, dogs and cats, camels, and myriad other creatures including homo sapiens (not a trivial biter)--but for this grand rounds, the topic will simply be spiders (Part 1), bees and vespid (Part 2). Vespids are the wasps, yellow jackets and hornets.

West Virginia physicians: cardiovascular risk factors, lifestyles and prescribing habits.

Physicians educate their patients by direct teaching and by serving as a role model. Through the use of questionnaires, we evaluated the degree to which physicians in West Virginia participate in these activities. Thirty-five percent of the 2,404 licensed physicians in the state returned completed questionnaires. Although 90% prescribed appropriate diets and recommended exercise for their patients, the physicians who responded were often less likely to follow their own advice. Twenty percent of the male physicians and 13% of the female doctors were obese; 30% had LDL cholesterol levels over 130 mg./dl.; 13% had HDL cholesterol values of less than 35 mg./dl.; and 8% had triglycerides over 250 mg./dl. Participation in regular exercise (30 minutes three times per week) was reported by 48% of the male physicians and 47% of the female physicians. Eight percent of the men were smokers, as were 1.9% of the females. These results suggest that the role model aspect of patient education may need to be improved among some West Virginia physicians. It is an inexpensive method of directing attention to lifestyle in order to decrease preventable disorders such as coronary artery disease, obesity, diabetes, and hypertension.

Heart disease in women.

Heart disease is a significant problem in women. Age, smoking, and hyperlipidemia are potent risk factors, as is the presence of diabetes. Hypertension is less of a risk factor in women than men. Diagnosis of coronary artery disease is most difficult in women, especially using non-invasive techniques, because of a lower prevalence of disease. Thrombolytic therapy may be associated with more bleeding in older, smaller women. Angioplasty and surgical bypass may be more difficult because of smaller coronary artery size in women. Exercise, aspirin, and estrogens appear to decrease the incidence and mortality of heart disease in women, but concern has been raised that the use of resources for the study, prevention and treatment of heart disease has a gender bias, with men receiving more than their fair share.

Coronary risk factors in type II diabetes: response to low-intensity aerobic exercise.

Patients with non-insulin-dependent diabetes are at greatly increased risk for coronary artery disease. Although exercise training has been shown to decrease risk factors, the presence of obesity, older age, and a sedentary lifestyle make a high-intensity exercise program an unrealistic choice of therapy. Therefore, we examined the effect of a low-to-moderate-intensity (mean 69 per cent of maximal heart rate) walking program on lipids, glucose, insulin, glycosylated hemoglobin and cardiovascular fitness. Nine women and seven men, mean age 56, were randomly assigned to a control or an exercise group which exercised three times per week for two months. Supervised exercise sessions consisted of 40-45 minutes of walking and/or slow jogging. Subjects continued on their usual diets. The trained group showed a significant improvement in VO2max from 1.65 to 1.95 L/min. Resting systolic blood pressure decreased from 141 to 130 mm Hg after training, and resting heart rate decreased from 88 to 81. Glycosylated hemoglobin decreased in the exercise group in seven or eight subjects and in only two of eight controls. Triglycerides decreased in the exercise group from 285 to 223 mg/dl. Body weight, total and HDL cholesterol, glucose, and insulin did not change in either group. These data indicate that a low-to-moderate level of aerobic training, independent of dietary changes, is an effective and feasible method of improving cardiovascular risk factors: physical fitness, systolic blood pressure, plasma triglycerides, and glycemic control in non-insulin-dependent diabetic subjects.