Dietary fiber may affect the development of cancers of the gastroin testinal tract and the breast... more Dietary fiber may affect the development of cancers of the gastroin testinal tract and the breast. The biological intermediates studied most have been fecal bile acids; both human and animal studies suggest a tumor-promoting role of bile acids in the development of colon tumors, although there are conflicting data from human studies. Short-chain fatty acids are major fermentation products of bacterial degradation of dietary fiber. If short-chain fatty acids explained the tumor-inhibiting properties of dietary fiber, the readily fermentable fibers such as guar and pectin would be more protective than cellulose and wheat bran, which has not been observed. Because these two hypotheses do not adequately explain modulation of tumor growth by dietary fiber, investigation of other intermediates is indicated. These include physical characteristics of the feces, such as abrasiveness; intestinal microflora; aqueous-phase bile acids, which may represent the bioavailable pool; alterations in mucins; mutagenicity of intestinal contents; alterations in mucosa! cytokinetics; activities of enzymes, such as ornithine decarboxylase or aryl hydrocar bon hydroxylase; neurogenic effects caused by changes in intestinal bulk or short-chain fatty acids; gut hormones or other peptide growth factors (local or systemic); enterohepatic circulation of hormones; transit time; pH; or decreased availability of total dietary energy.
Humans evolved as omnivores and it has been proposed that cooking meat allowed for evolution of l... more Humans evolved as omnivores and it has been proposed that cooking meat allowed for evolution of larger brains that has led to our success as a species. Meat is one of the most nutrient dense foods, providing high-quality protein, heme iron, zinc, and vitamins B6 and B12. Despite these advantages, epidemiologic studies have linked consumption of red or processed meat with obesity, type 2 diabetes, cardiovascular diseases, and cancers of multiple organs. Most observational studies report small, increased relative risks. However, there are many limitations of such studies including inability to accurately estimate intake, lack of prespecified hypotheses, multiple comparisons, and confounding from many factors - including body weight, fruit/vegetable intake, physical activity, smoking, and alcohol - that correlate significantly either positively or negatively with meat intake and limit the reliability of conclusions from these studies. The observational studies are heterogeneous and do not fulfill many of the points proposed by AB Hill in 1965 for inferring causality; his most important factor was strength of the association which in dietary studies is usually <1.5 but is not considered adequate in virtually all other areas of epidemiology outside nutrition. Accepting small, statistically significant risks as "real" from observational associations, the field of nutrition has a long list of failures including beta-carotene and lung cancer, low-fat diets and breast cancer or heart disease that have not been confirmed in randomized trials. Moderate intake of a variety of foods that are enjoyed by people remains the best dietary advice.
Journal of the American College of Nutrition, 2001
Although medical therapies are widely accepted by health practitioners, sometimes without adequat... more Although medical therapies are widely accepted by health practitioners, sometimes without adequate testing, nutritional therapy is frequently looked upon uniformly as without merit. There are many reasons for this attitude. However, a substantial body of literature has accumulated that objectively demonstrates the value of adding nutritional therapy to the prevention or treatment of some diseases or specific risk factors for diseases. Examples of successful nutrition therapy that can be combined with medical management include treatment of hypertension, hyperlipidemia, intermittent claudication, osteoporosis, respiratory distress syndrome, and arthritis.
Journal of the American College of Nutrition, Sep 1, 2004
Post dinner snacking may constitute a significant proportion of total daily energy intake and con... more Post dinner snacking may constitute a significant proportion of total daily energy intake and contribute to overweight and obesity in some individuals (night snackers). This study tested the hypothesis that providing a structured snack in the form of a "ready-to-eat" breakfast cereal would help regulate excess energy intake and contribute to weight loss in night snackers. Adults (18 to 65 years of age, BMI kg/m2 > or = 25), with self-reported night snacking behaviors, were randomized into a cereal group (CR) and a no-cereal group (NC). During a period of 4 weeks, the cereal group was instructed to consume a serving of ready-to-eat cereal with low-fat milk 90 minutes after their evening meal. Concurrently, the non-cereal group continued their regular diet ad libitum. At baseline, there were no significant differences between groups for age, body weight, body mass index, daily caloric intake, or evening caloric intake. There was a correlation between number of days of compliance with post-dinner cereal consumption and weight loss (r = -0.36, p = 0.057). After 4 weeks, the compliant subjects (cereal intake > or = 20 d) lost -1.85 +/- 3.56 lbs vs. -0.39 +/- 3.1 lb for the NC group (p = 0.06). Compared to baseline, the compliant CR group reduced their total daily caloric intake by -396.50 +/- 641.6 kcal (p < 0.02), whereas, the NC group experienced a reduction of -23.22 +/- 889.60 kcal/day during the same period (p = ns). Reduction in post-dinner calorie intake for the compliant CR group was significantly greater compared to the NC group (-141.74 +/- 385.58 kcal vs. 85.82 +/- 374.70 kcal; p = 0.042). Eating ready-to-eat cereal after the evening meal may attenuate caloric intake in night snackers and promote weight loss in compliant individuals.
Http Dx Doi Org 10 1080 01635588909514025, Aug 4, 2009
Rats treated with 7,12-dimethylbenz[a]anthracene were subjected to 25% caloric restriction for va... more Rats treated with 7,12-dimethylbenz[a]anthracene were subjected to 25% caloric restriction for varying times during the promotion/progression phase of mammary tumorigenesis. Caloric restriction was inhibitory to a statistically significant extent when it was maintained for the entire four-month study or only during the first or last two months. Restriction for the first month with subsequent ad libitum feeding led to rapid weight gain with concomitant appearance of tumors. These data indicate that caloric restriction can be instituted late in the tumorigenic process with an acute response of tumor growth to caloric intake or body weight.
Caloric restriction (CR) inhibits many neoplastic diseases in rodents, yet the biochemical mechan... more Caloric restriction (CR) inhibits many neoplastic diseases in rodents, yet the biochemical mechanism(s) for these effects are poorly understood. We have examined the effects oÃ-ad libitum (AL) feeding with 25 or 40% CR on the promotion of 7,12-dimethylbenz(a)anthracene-induced mam mary tumorigenesis in virgin female Sprague-Dawley rats. Further, we have also studied the influence of chronic CR on temporal alterations in circulating insulin, insulin-like growth factor I/somatomedin C, insulinlike growth factor H/multiplication-stimulating activity, and epidermal growth factor levels at 0, 1, 3, 5, 11, and 20 weeks in carcinogen-and vehicle-treated animals. Tumor incidence and multiplicity were markedly inhibited (/' < 0.05) with increasing CR. Fasting serum insulin-like growth factor I/somatomedin C levels exhibited a significant acute decline with CR at 1 and 3 weeks, but were comparable to AL-fed controls throughout the remainder of the 5-month study, despite continued differ ences in weight gain between AL and CR rats. Levels of insulin-like growth factor H/multiplication-stimulating activity exhibited no discern ible pattern in relation to CR. Serum insulin levels showed age-dependent increases, but were affected by increasing CR at all time points. Insulin levels were significantly ( /' < 0.05) reduced in 40% CR rats from 3 weeks onward compared to controls, while 25% CR resulted in nonsignificant (/' < 0.07) reductions throughout the study. No significant differences in growth factor levels were observed between 7,12-dimethylbenz(<z)anthracene-and vehicle-treated rats. Circulating epidermal growth factor was not detectable in any treatment group regardless of the nature or duration of the dietary regimen, time of blood collection, or subsequent tumor-bearing status. These data suggest that decreased serum insulin-like growth factor I/ somatomedin C and insulin levels with CR and their complex interactions in vivo may play a role in the inhibition of mammary tumor promotion byCR.
Pharmacological Research Communications, Nov 30, 1986
Fatty acid esters (at the 7 position) of chenodeoxycholic (CDCA) and ursodeoxycholic (UDCA) acids... more Fatty acid esters (at the 7 position) of chenodeoxycholic (CDCA) and ursodeoxycholic (UDCA) acids have been tested for their effects on formation and dissolution of gallstones in hamsters. The free bile acids were fed at a level of 0.2% of the diet and esters were fed at equimolar levels. The earlier finding that CDCA does not affect gallstone formation in hamsters fed the Dam and Christensen diet were confirmed. The acetic, butyric and lauric acid esters of CDCA had a very slight inhibitory effect on lithogenesis but CDCA 7 & oleate and linoleate completely inhibited gallstone formation. UDCA and its 7,joleate inhibited both formation and progression of gallstones. The observed effects are probably a function of the form of the bile acid and not of the esterifying acid. The observation that ethyl oleate has a slight litholytic effect suggests that the acid moiety of the ester may exert a slight influence.
Caloric restriction (CR) inhibits tumorigenesis in rodents. To under stand the basis for this eff... more Caloric restriction (CR) inhibits tumorigenesis in rodents. To under stand the basis for this effect the binding of insulin, insulin-like growth factor I/somatomedin C (IGF-I/Sm-C), insulin-like growth factor II/ multiplication stimulating activity (IGF-II/MSA), and epidermal growth factor were examined to membrane preparations of 7,12-dimethylbenz(a)anthraccne-induced mammary adenocarcinomas and several nor mal tissues from female Sprague-Dawley rats. Animals were fed ad libitum (AL) or 25% and 40% caloric-allyrestricted diets. Large, palpable (LP) and small, < 100 mg, nonpalpable (SNP) tumors were evaluated. Growth factor binding to tumors was differentially affected by CR. IGF-I/Sm-C binding was comparable for AL-LP, AL-SNP, and 25% CR-LP tumors, but elevated in 25% CR-SNP tumors. Scatchard analysis re vealed high and low affinity IGF-I/Sm-C binding sites, with AL-SNP and 25% CR-SNP tumors exhibiting similar levels of high affinity sites and at a greater concentration than AL-LP and 25% CR-LP tumors. Insulin binding to mammary tumors was low, i.e., 8-to 13-fold lower than IGF-I/Sm-C binding. The 25% CR-LP and SNP tumors bound 2to 5-fold more insulin than corresponding AL-LP and SNP tumors. Binding of IGF-II/MSA to these tumor preparations was high, approxi mately 11-to 25-fold greater than insulin binding, and was unaffected by CR or tumor size. The binding of epidermal growth factor was not detected in any tumor preparations. Receptor binding studies were confirmed with covalent cross-linking and sodium dodecyl sulfate-polyacrylamide gel electrophoresis analyses. Normal tissues exhibited tissue-and growth factor-specific alterations in binding with host CR. Thus, alterations in growth factor binding were not tumor specific, but were less pronounced than in mammary tumors. These findings suggest alterations in IGF-I/ Sm-C and insulin binding properties to rumors in relation to CR and tumor size may contribute, in part, to the inhibitory effects of CR on tumorigenesis.
International Journal of Food Sciences and Nutrition, 2006
The objectives of this study were to examine whether providing a structured post-dinner snack wou... more The objectives of this study were to examine whether providing a structured post-dinner snack would enhance weight loss among obese night snackers participating in a novel partial meal replacement (PMR) program and to examine the efficacy of that program. Sixty adults (age 18-65 years; body mass index &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;or=30 kg/m2), 29 randomized to the &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;post-dinner snack&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; and 32 to the &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;no snack&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; groups, completed the 8-week program. Both groups showed improvements in weight (-4.23 kg, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001), body mass index (-1.48 kg/m2, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001), body fat (-1.36%, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 00.0001), waist circumference (-6.40 cm, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001), and high-density lipoprotein-cholesterol (-2.72 mmol/l, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01), and on a night snacking question (-1.31, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001). The &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;post-dinner snack&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; group did not show significantly greater weight loss outcomes than the &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;no snack&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; group either before or after taking compliance into consideration. Providing a structured post-dinner snack along with a PMR program did not enhance weight loss treatment outcomes; however, the PMR program produced beneficial weight loss changes for obese night snackers.
This study was designed to determine the degree of energy restriction necessary to achieve signif... more This study was designed to determine the degree of energy restriction necessary to achieve significant inhibition of mammary tumor promotion in rats treated with 7,12-dimethylbenz[a]anthracene (DMBA). A control group of rats was fed a diet containing 5% corn oil ad libitum. Four other groups were pair-fed to the controls; these rats were subjected to energy restriction of 10, 20, 30, or 40%. Weight gains among the groups were proportional to energy intake. The differences in weight were due primarily to reductions in body fat stores. Tumor incidence was reduced slightly by 20% calorie restriction and significantly by 30 and 40% restriction. There were also reductions in number of tumors per tumor-bearing rat and in mean tumor weight. The groups subjected to 30 and 40% energy restriction had significantly reduced serum levels of insulin in the fasting state. These data suggest that body weight, body fat, and fasting serum insulin correlate with susceptibility to mammary tumor promotion and that insulin may be a growth factor for DMBA-induced tumors.
Dietary fiber may affect the development of cancers of the gastroin testinal tract and the breast... more Dietary fiber may affect the development of cancers of the gastroin testinal tract and the breast. The biological intermediates studied most have been fecal bile acids; both human and animal studies suggest a tumor-promoting role of bile acids in the development of colon tumors, although there are conflicting data from human studies. Short-chain fatty acids are major fermentation products of bacterial degradation of dietary fiber. If short-chain fatty acids explained the tumor-inhibiting properties of dietary fiber, the readily fermentable fibers such as guar and pectin would be more protective than cellulose and wheat bran, which has not been observed. Because these two hypotheses do not adequately explain modulation of tumor growth by dietary fiber, investigation of other intermediates is indicated. These include physical characteristics of the feces, such as abrasiveness; intestinal microflora; aqueous-phase bile acids, which may represent the bioavailable pool; alterations in mucins; mutagenicity of intestinal contents; alterations in mucosa! cytokinetics; activities of enzymes, such as ornithine decarboxylase or aryl hydrocar bon hydroxylase; neurogenic effects caused by changes in intestinal bulk or short-chain fatty acids; gut hormones or other peptide growth factors (local or systemic); enterohepatic circulation of hormones; transit time; pH; or decreased availability of total dietary energy.
Humans evolved as omnivores and it has been proposed that cooking meat allowed for evolution of l... more Humans evolved as omnivores and it has been proposed that cooking meat allowed for evolution of larger brains that has led to our success as a species. Meat is one of the most nutrient dense foods, providing high-quality protein, heme iron, zinc, and vitamins B6 and B12. Despite these advantages, epidemiologic studies have linked consumption of red or processed meat with obesity, type 2 diabetes, cardiovascular diseases, and cancers of multiple organs. Most observational studies report small, increased relative risks. However, there are many limitations of such studies including inability to accurately estimate intake, lack of prespecified hypotheses, multiple comparisons, and confounding from many factors - including body weight, fruit/vegetable intake, physical activity, smoking, and alcohol - that correlate significantly either positively or negatively with meat intake and limit the reliability of conclusions from these studies. The observational studies are heterogeneous and do not fulfill many of the points proposed by AB Hill in 1965 for inferring causality; his most important factor was strength of the association which in dietary studies is usually &amp;amp;amp;amp;amp;amp;lt;1.5 but is not considered adequate in virtually all other areas of epidemiology outside nutrition. Accepting small, statistically significant risks as &amp;amp;amp;amp;amp;amp;quot;real&amp;amp;amp;amp;amp;amp;quot; from observational associations, the field of nutrition has a long list of failures including beta-carotene and lung cancer, low-fat diets and breast cancer or heart disease that have not been confirmed in randomized trials. Moderate intake of a variety of foods that are enjoyed by people remains the best dietary advice.
Journal of the American College of Nutrition, 2001
Although medical therapies are widely accepted by health practitioners, sometimes without adequat... more Although medical therapies are widely accepted by health practitioners, sometimes without adequate testing, nutritional therapy is frequently looked upon uniformly as without merit. There are many reasons for this attitude. However, a substantial body of literature has accumulated that objectively demonstrates the value of adding nutritional therapy to the prevention or treatment of some diseases or specific risk factors for diseases. Examples of successful nutrition therapy that can be combined with medical management include treatment of hypertension, hyperlipidemia, intermittent claudication, osteoporosis, respiratory distress syndrome, and arthritis.
Journal of the American College of Nutrition, Sep 1, 2004
Post dinner snacking may constitute a significant proportion of total daily energy intake and con... more Post dinner snacking may constitute a significant proportion of total daily energy intake and contribute to overweight and obesity in some individuals (night snackers). This study tested the hypothesis that providing a structured snack in the form of a &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;ready-to-eat&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; breakfast cereal would help regulate excess energy intake and contribute to weight loss in night snackers. Adults (18 to 65 years of age, BMI kg/m2 &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; or = 25), with self-reported night snacking behaviors, were randomized into a cereal group (CR) and a no-cereal group (NC). During a period of 4 weeks, the cereal group was instructed to consume a serving of ready-to-eat cereal with low-fat milk 90 minutes after their evening meal. Concurrently, the non-cereal group continued their regular diet ad libitum. At baseline, there were no significant differences between groups for age, body weight, body mass index, daily caloric intake, or evening caloric intake. There was a correlation between number of days of compliance with post-dinner cereal consumption and weight loss (r = -0.36, p = 0.057). After 4 weeks, the compliant subjects (cereal intake &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; or = 20 d) lost -1.85 +/- 3.56 lbs vs. -0.39 +/- 3.1 lb for the NC group (p = 0.06). Compared to baseline, the compliant CR group reduced their total daily caloric intake by -396.50 +/- 641.6 kcal (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.02), whereas, the NC group experienced a reduction of -23.22 +/- 889.60 kcal/day during the same period (p = ns). Reduction in post-dinner calorie intake for the compliant CR group was significantly greater compared to the NC group (-141.74 +/- 385.58 kcal vs. 85.82 +/- 374.70 kcal; p = 0.042). Eating ready-to-eat cereal after the evening meal may attenuate caloric intake in night snackers and promote weight loss in compliant individuals.
Http Dx Doi Org 10 1080 01635588909514025, Aug 4, 2009
Rats treated with 7,12-dimethylbenz[a]anthracene were subjected to 25% caloric restriction for va... more Rats treated with 7,12-dimethylbenz[a]anthracene were subjected to 25% caloric restriction for varying times during the promotion/progression phase of mammary tumorigenesis. Caloric restriction was inhibitory to a statistically significant extent when it was maintained for the entire four-month study or only during the first or last two months. Restriction for the first month with subsequent ad libitum feeding led to rapid weight gain with concomitant appearance of tumors. These data indicate that caloric restriction can be instituted late in the tumorigenic process with an acute response of tumor growth to caloric intake or body weight.
Caloric restriction (CR) inhibits many neoplastic diseases in rodents, yet the biochemical mechan... more Caloric restriction (CR) inhibits many neoplastic diseases in rodents, yet the biochemical mechanism(s) for these effects are poorly understood. We have examined the effects oÃ-ad libitum (AL) feeding with 25 or 40% CR on the promotion of 7,12-dimethylbenz(a)anthracene-induced mam mary tumorigenesis in virgin female Sprague-Dawley rats. Further, we have also studied the influence of chronic CR on temporal alterations in circulating insulin, insulin-like growth factor I/somatomedin C, insulinlike growth factor H/multiplication-stimulating activity, and epidermal growth factor levels at 0, 1, 3, 5, 11, and 20 weeks in carcinogen-and vehicle-treated animals. Tumor incidence and multiplicity were markedly inhibited (/' < 0.05) with increasing CR. Fasting serum insulin-like growth factor I/somatomedin C levels exhibited a significant acute decline with CR at 1 and 3 weeks, but were comparable to AL-fed controls throughout the remainder of the 5-month study, despite continued differ ences in weight gain between AL and CR rats. Levels of insulin-like growth factor H/multiplication-stimulating activity exhibited no discern ible pattern in relation to CR. Serum insulin levels showed age-dependent increases, but were affected by increasing CR at all time points. Insulin levels were significantly ( /' < 0.05) reduced in 40% CR rats from 3 weeks onward compared to controls, while 25% CR resulted in nonsignificant (/' < 0.07) reductions throughout the study. No significant differences in growth factor levels were observed between 7,12-dimethylbenz(<z)anthracene-and vehicle-treated rats. Circulating epidermal growth factor was not detectable in any treatment group regardless of the nature or duration of the dietary regimen, time of blood collection, or subsequent tumor-bearing status. These data suggest that decreased serum insulin-like growth factor I/ somatomedin C and insulin levels with CR and their complex interactions in vivo may play a role in the inhibition of mammary tumor promotion byCR.
Pharmacological Research Communications, Nov 30, 1986
Fatty acid esters (at the 7 position) of chenodeoxycholic (CDCA) and ursodeoxycholic (UDCA) acids... more Fatty acid esters (at the 7 position) of chenodeoxycholic (CDCA) and ursodeoxycholic (UDCA) acids have been tested for their effects on formation and dissolution of gallstones in hamsters. The free bile acids were fed at a level of 0.2% of the diet and esters were fed at equimolar levels. The earlier finding that CDCA does not affect gallstone formation in hamsters fed the Dam and Christensen diet were confirmed. The acetic, butyric and lauric acid esters of CDCA had a very slight inhibitory effect on lithogenesis but CDCA 7 & oleate and linoleate completely inhibited gallstone formation. UDCA and its 7,joleate inhibited both formation and progression of gallstones. The observed effects are probably a function of the form of the bile acid and not of the esterifying acid. The observation that ethyl oleate has a slight litholytic effect suggests that the acid moiety of the ester may exert a slight influence.
Caloric restriction (CR) inhibits tumorigenesis in rodents. To under stand the basis for this eff... more Caloric restriction (CR) inhibits tumorigenesis in rodents. To under stand the basis for this effect the binding of insulin, insulin-like growth factor I/somatomedin C (IGF-I/Sm-C), insulin-like growth factor II/ multiplication stimulating activity (IGF-II/MSA), and epidermal growth factor were examined to membrane preparations of 7,12-dimethylbenz(a)anthraccne-induced mammary adenocarcinomas and several nor mal tissues from female Sprague-Dawley rats. Animals were fed ad libitum (AL) or 25% and 40% caloric-allyrestricted diets. Large, palpable (LP) and small, < 100 mg, nonpalpable (SNP) tumors were evaluated. Growth factor binding to tumors was differentially affected by CR. IGF-I/Sm-C binding was comparable for AL-LP, AL-SNP, and 25% CR-LP tumors, but elevated in 25% CR-SNP tumors. Scatchard analysis re vealed high and low affinity IGF-I/Sm-C binding sites, with AL-SNP and 25% CR-SNP tumors exhibiting similar levels of high affinity sites and at a greater concentration than AL-LP and 25% CR-LP tumors. Insulin binding to mammary tumors was low, i.e., 8-to 13-fold lower than IGF-I/Sm-C binding. The 25% CR-LP and SNP tumors bound 2to 5-fold more insulin than corresponding AL-LP and SNP tumors. Binding of IGF-II/MSA to these tumor preparations was high, approxi mately 11-to 25-fold greater than insulin binding, and was unaffected by CR or tumor size. The binding of epidermal growth factor was not detected in any tumor preparations. Receptor binding studies were confirmed with covalent cross-linking and sodium dodecyl sulfate-polyacrylamide gel electrophoresis analyses. Normal tissues exhibited tissue-and growth factor-specific alterations in binding with host CR. Thus, alterations in growth factor binding were not tumor specific, but were less pronounced than in mammary tumors. These findings suggest alterations in IGF-I/ Sm-C and insulin binding properties to rumors in relation to CR and tumor size may contribute, in part, to the inhibitory effects of CR on tumorigenesis.
International Journal of Food Sciences and Nutrition, 2006
The objectives of this study were to examine whether providing a structured post-dinner snack wou... more The objectives of this study were to examine whether providing a structured post-dinner snack would enhance weight loss among obese night snackers participating in a novel partial meal replacement (PMR) program and to examine the efficacy of that program. Sixty adults (age 18-65 years; body mass index &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;or=30 kg/m2), 29 randomized to the &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;post-dinner snack&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; and 32 to the &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;no snack&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; groups, completed the 8-week program. Both groups showed improvements in weight (-4.23 kg, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001), body mass index (-1.48 kg/m2, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001), body fat (-1.36%, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 00.0001), waist circumference (-6.40 cm, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001), and high-density lipoprotein-cholesterol (-2.72 mmol/l, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01), and on a night snacking question (-1.31, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001). The &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;post-dinner snack&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; group did not show significantly greater weight loss outcomes than the &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;no snack&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; group either before or after taking compliance into consideration. Providing a structured post-dinner snack along with a PMR program did not enhance weight loss treatment outcomes; however, the PMR program produced beneficial weight loss changes for obese night snackers.
This study was designed to determine the degree of energy restriction necessary to achieve signif... more This study was designed to determine the degree of energy restriction necessary to achieve significant inhibition of mammary tumor promotion in rats treated with 7,12-dimethylbenz[a]anthracene (DMBA). A control group of rats was fed a diet containing 5% corn oil ad libitum. Four other groups were pair-fed to the controls; these rats were subjected to energy restriction of 10, 20, 30, or 40%. Weight gains among the groups were proportional to energy intake. The differences in weight were due primarily to reductions in body fat stores. Tumor incidence was reduced slightly by 20% calorie restriction and significantly by 30 and 40% restriction. There were also reductions in number of tumors per tumor-bearing rat and in mean tumor weight. The groups subjected to 30 and 40% energy restriction had significantly reduced serum levels of insulin in the fasting state. These data suggest that body weight, body fat, and fasting serum insulin correlate with susceptibility to mammary tumor promotion and that insulin may be a growth factor for DMBA-induced tumors.
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