PubMed Health⌕ Search

Biomedical subjects

P Crapo

Publications and source records attributed to P Crapo.

6 recordsLinked to original sources
PubMed1988

Glucose infusion rates from various complex carbohydrates estimated from two models.

Due to the importance of diet in the management of noninsulin dependent diabetes, we are interested in constructing a model to study the glycemic response to different foods in normal and diabetic subjects. In this study, serum glucose and insulin values from individual normal subjects (Diab. 26, 1178) following the ingestion of different foods (corn, rice, bread, potato) high in complex carbohydrate were analyzed to determine glucose infusion rates (J) into the blood from the gut as a function of time following the ingestion of the food item. A Modular Modeling Program was designed to allow selection of data, curve fit, model, and tuning of parameters. The two models used were from Ackerman et al (Phys. Med. Biol. 9, 203) and the minimal model (VI) from Bergman and Cobelli (Fed. Proc. 39,110). The models were modified so that glucose and insulin values were used as input and J was the output. There was a good correspondence between the shape of the J curves predicted by the two models. While the J curves resembled serum glucose curves, they generally reached a peak earlier and declined more rapidly. Two peaks occurred in the J curves for bread, corn and rice. The second peaks may correspond to a delay in the release of glucose during digestion. The resulting infusion rate characterization of these foodstuffs maybe useful for modeling responses in diabetic patients with normal gut function but with impaired peripheral glucose utilization and in detecting abnormal gut function.

Blood Glucose↗
PubMed1976

Postprandial plasma triglyceride and cholesterol responses to a low-fat meal.

Postprandial plasma cholesterol and triglyceride (TG) levels were measured after the consumption of a relatively low-fat (35% of calories) diet in 41 subjects. Plasma cholesterol levels did not change appreciably during the postprandial state. In 34 subjects a biphasic plasma TG response curve was noted, with an initial peak occurring 1 to 3 hr after feeding and a secondary TG peak 4 to 7 hr after the meal. The primary peak was greater than 90%, accounted for by chylomicrons, whereas the secondary peak represented very low-density lipoproteins (greater than 82%). Furthermore, the heights of the primary and secondary peaks were closely correlated to the fasting TG level (r = 0.61 and 0.72, respectively) indicating that the fasting TG concentration is an important determinant of the postprandial TG response. Because low-fat (high-carbohydrate) diets are known to raise fasting TG levels in patients who do not have fasting hyperchylomicronemia, and because relatively few patients have chylomicrons in the fasting state, these data suggest that such diets may lead to day long increases in plasma TG levels in the majority of subjects.

Adult↗
PubMed1976

Induction of hypertriglyceridemia by a low-fat diet.

We have studied the effects of moderate dietary fat restriction on plasma triglyceride, cholesterol, glucose, and insulin response in 27 subjects. Compared with a control diet (45% fat, 40% carbohydrate [CHO], 15% protein) the low fat (higher CHO) diet (30% fat, 55% CHO, 15% protein) produced a 41% increase in fasting triglyceride level (155 +/- 17 to 219 +/- 23 mg%) with no change in fasting plasma cholesterol level. Furthermore, this increase in triglyceride levels; induced by the higher CHO content of the low fat diet, was seen in 26 out of 27 subjects. Postprandial triglyceride, glucose, and insulin levels were also higher on the low fat (higher CHO) diet. Since hypertriglyceridemia is a significant risk factor for the development of coronary heart disease, and since our data indicate that the moderate increase in dietary CHO associated with a low fat diet will elevate plasma triglyceride levels, we believe that more caution is necessary before recommending the wide-spread use of low fat diets for heart disease prevention.

Adult↗
PubMedDate not supplied

Fructose, xylitol, and sorbitol.

In conclusion, fructose, sorbitol, and xylitol are calorie-containing non-glucose sugars that produce a lessened postprandial hyperglycemia in the absence of severe insulin insufficiency when given as pure substances. However, the day-long quantitative reduction of hyperglycemia that may result from substantial substitution of these sweeteners for glucose and sucrose in the diabetic diet, and the long-term effectiveness and safety when they are ingested in substantial quantities in mixed meals, has not been established. Certainly all overweight persons should look upon these substances as little or no help in their diet plan. It appears that use of these substances up to levels of 50--60 g/day in place of glucose or glucose-containing disaccharides has no known side effects; amounts above this level can cause diarrhea. Xylitol has been reported as possibly being tumorigenic. The use of limited amounts of fructose and sorbitol is acceptable, and may ultimately be found to provide some advantages in dietary management of persons at ideal body weight who count these calories. However, studies will be necessary before firm conclusions can be drawn regarding metabolic effects of these sweeteners and before significant use in diabetic diets can be recommended.

Diet, Diabetic↗