Re: Atkins Research Results
- From: Susan <nevermind@xxxxxxxxxx>
- Date: Wed, 19 Apr 2006 11:07:28 -0400
x-no-archive: yes
In case you want a broader perspective... In fact, just do a Medline search for "hyperinsulinemia AND cancer" and get an eye opener.
Susan
High Dietary Glycemic Load May Increase Colorectal Cancer Risk in Women
Mindy Hung
Feb. 3, 2004 - A diet with a high dietary glycemic load may increase the
risk of colorectal cancer in women, according to results of a prospective
cohort study published in the Feb. 4 issue of the Journal of the National
Cancer Institute.
"The growing recognition that colorectal cancer may be promoted by
hyperinsulinemia and insulin resistance suggests that a diet inducing high
blood glucose levels and an elevated insulin response may contribute to a
metabolic environment conducive to tumor growth," write Susan Higginbotham
and colleagues from the University of California at Los Angeles.
Investigators followed a cohort of 38,451 subjects from the Women's Health
Study, aged 45 years or older at baseline, in April 1993 to January 1996.
Researchers administered a 131-item semiquantitative food-frequency
questionnaire at baseline to assess average dietary intake during the
previous year.
Women with more than 70 blanks in the questionnaire, or those with a total
daily energy intake of less than 2,514 kJ or more than 14,665 kJ were
excluded. Subjects also filled out a risk factor questionnaire at baseline
and annually thereafter.
Glycemic load was estimated for each woman by multiplying the glycemic load
for each food by the frequency of consumption and then summing over all
foods. They obtained the overall glycemic index (the average glycemic index
of carbohydrates in the diet) by dividing the participant's dietary glycemic
load by total carbohydrate intake. Glucose was the standard in calculating
glycemic index and glycemic load values.
The researchers identified 174 patients with incident colorectal cancer (148
with cancer of the colon and 26 with cancer of the rectum). The mean dietary
glycemic load for the cohort was 117, and the mean overall glycemic index
was 53.
Statistically significant positive associations of both dietary glycemic
load and overall glycemic index were seen with colorectal cancer in
age-adjusted models. In multivariable analyses that included total energy
intake and nutrient risk factors (fat, fiber, folate, calcium, and vitamin
D) in the models, colorectal cancer risk estimates for dietary glycemic load
increased (adjusted relative risk [RR], 2.85; 95% confidence interval [CI],
1.40 - 5.80, comparing extreme quintiles of dietary glycemic load; P =
..004). However, overall glycemic index risk estimates were essentially
unchanged (adjusted RR, 1.71; 95% CI, 0.98 - 2.98; P = .04, comparing
extreme quintiles of overall glycemic index).
Risk estimates for total carbohydrate (adjusted RR, 2.41; 95% CI, 1.10 -
5.27, comparing extreme quintiles of carbohydrate; P = .02), nonfiber
carbohydrate (corresponding RR, 2.60; 95% CI, 1.22 - 5.54; P = .02), sucrose
(corresponding RR, 1.51; 95% CI, 0.90 - 2.54; P = .06), and fructose
(corresponding RR, 2.09; 95% CI, 1.13 - 3.87; P = .08) were consistent with
but lower than the dietary glycemic load findings.
Higginbotham and colleagues acknowledge risk factors such as body mass
index, physical inactivity, smoking, alcohol use, and nutrient intake would
most likely bias risk estimates toward the null, implying that true risk may
be greater than their estimates.
They note that their research was also limited by the fact that when the
glycemic index value of a particular food was unavailable, they used the
reported value for a similar food.
"A diet with a high glycemic load may increase the risk of colorectal cancer
by affecting insulin and insulin-like growth factors or, as suggested by the
cross-sectional association between dietary glycemic load and C-reactive
protein, by exacerbating proinflammatory responses, either locally or
systemically," they write. "Further work is needed to elucidate these
mechanisms."
The study was supported by grants from the National Institutes of Health.
J Natl Cancer Inst. 2004;96:229-233
Reviewed by Gary D. Vogin, MD
Int J Obes Relat Metab Disord 1996 Dec;20(12):1067-72 Related Articles, Links
Weight-loss with low or high carbohydrate diet?
Golay A, Eigenheer C, Morel Y, Kujawski P, Lehmann T, de Tonnac N.
Department of Internal Medicine, University Hospital Geneva.
OBJECTIVE: With obesity being recognized as an important cardiovascular risk factor, it is important to determine the optimal hypocaloric diet for decreasing that risk. The goal of this study was to compare the effects of two hypocaloric diets of similar caloric value, but differing in carbohydrate content (25% and 45%). SUBJECTS: Sixty-eight out-patients were followed for 12 w. DESIGN: The patients were assigned to one of two groups that received either a low (25% CHO, n = 31) or a high (45% CHO, n = 37) carbohydrate hypocaloric diet (5.0 MJ/d, 1200 Kcal/d). RESULTS: After 12 w, the mean weight loss was similar and did not differ significantly between the two groups: 10.2 +/- 0.7 kg (25% CHO) and 8.6 +/- 0.8 kg (45% CHO). Furthermore, loss of adipose tissue was similar, 8.1 +/- 0.5 kg (25% CHO) and 7.1 +/- 0.7 kg (45% CHO). Despite a high protein intake (1.4 g/kg/ideal body weight) there was loss of lean body mass: 2.2 +/- 0.4 kg (25% CHO) and 1.4 +/- 0.3 kg (45% CHO). The waist/hip ratio diminished significantly (P < 0.001) and identically in both groups. The fasting blood glucose (even though normal, along with cholesterol and triglyceride concentrations, were significantly decreased after weight loss. The fasting blood insulin which was mildly elevated before weight loss decreased more markedly with the 25% CHO diet compared to the 45% CHO diet (P < 0.003). The glucose/insulin ratio improved significantly (P < 0.05) after weight loss with both diets (0.17 +/- 0.04 mmol/mU (25% CHO) vs 0.10 +/- 0.03 mmol/mU (45% CHO). CONCLUSIONS: Neither diet offered a significant advantage when comparing weight loss or other, metabolic parameters over a 12 w period. However, considering the greater improvement of fasting blood insulin, the glucose/insulin ratio and blood triglyceride, the low carbohydrate diet (25%) could be more favourable in the long-term. The improvement of fasting blood insulin could be explained by the differences in monounsaturated fat composition in the low carbohydrate diet.
PMID: 8968851 [PubMed - indexed for MEDLINE]
1: Diabetes Educ. 1997 Nov-Dec; 23(6): 643-6, 648, 650-1. Related Articles, Links
Protein: metabolism and effect on blood glucose levels.
Franz MJ.
International Diabetes Center, Minneapolis, Minnesota 55416, USA.
Insulin is required for carbohydrate, fat, and protein to be metabolized. With respect to carbohydrate from a clinical standpoint, the major determinate of the glycemic response is the total amount of carbohydrate ingested rather than the source of the carbohydrate. This fact is the basic principle of carbohydrate counting for meal planning. Fat has little, if any, effect on blood glucose levels, although a high fat intake does appear to contribute to insulin resistance. Protein has a minimal effect on blood glucose levels with adequate insulin. However, with insulin deficiency, gluconeogenesis proceeds rapidly and contributes to an elevated blood glucose level. With adequate insulin, the blood glucose response in persons with diabetes would be expected to be similar to the blood glucose response in persons without diabetes. The reason why protein does not increase blood glucose levels is unclear. Several possibilities might explain the response: a slow conversion of protein to glucose, less protein being converted to glucose and released than previously thought, glucose from protein being incorporated into hepatic glycogen stores but not increasing the rate of hepatic glucose release, or because the process of gluconeogenesis from protein occurs over a period of hours and glucose can be disposed of if presented for utilization slowly and evenly over a long time period.
Publication Types:
Review
Review, Tutorial
PMID: 9416027 [PubMed - indexed for MEDLINE]
1: J Clin Endocrinol Metab. 2001 Mar; 86(3): 1040-7. Related Articles, Links
Effect of protein ingestion on the glucose appearance rate in people with type 2 diabetes.
Gannon MC, Nuttall JA, Damberg G, Gupta V, Nuttall FQ.
Section of Endocrinology, Metabolism, and Nutrition, University of Minnesota, Minneapolis, Minnesota 55417, USA. ganno004@xxxxxxxxxx
Amino acids derived from ingested protein are potential substrates for gluconeogenesis. However, several laboratories have reported that protein ingestion does not result in an increase in the circulating glucose concentration in people with or without type 2 diabetes. The reason for this has remained unclear. In people without diabetes it seems to be due to less glucose being produced and entering the circulation than the calculated theoretical amount. Therefore, we were interested in determining whether this also was the case in people with type 2 diabetes. Ten male subjects with untreated type 2 diabetes were given, in random sequence, 50 g protein in the form of very lean beef or only water at 0800 h and studied over the subsequent 8 h. Protein ingestion resulted in an increase in circulating insulin, C-peptide, glucagon, alpha amino and urea nitrogen, and triglycerides; a decrease in nonesterified fatty acids; and a modest increase in respiratory quotient. The total amount of protein deaminated and the amino groups incorporated into urea was calculated to be approximately 20-23 g. The net amount of glucose estimated to be produced, based on the quantity of amino acids deaminated, was approximately 11-13 g. However, the amount of glucose appearing in the circulation was only approximately 2 g. The peripheral plasma glucose concentration decreased by approximately 1 mM after ingestion of either protein or water, confirming that ingested protein does not result in a net increase in glucose concentration, and results in only a modest increase in the rate of glucose disappearance.
Publication Types:
Clinical Trial
Randomized Controlled Trial
PMID: 11238483 [PubMed - indexed for MEDLINE]
1: J Am Coll Nutr. 1992 Dec; 11(6): 701-6. Related Articles, Links
Glucose appearance rate following protein ingestion in normal subjects.
Khan MA, Gannon MC, Nuttall FQ.
Section of Endocrinology, Metabolism and Nutrition, Minneapolis VA Medical Center, MN.
The fate of amino acids deaminated following protein ingestion is uncertain. Presumably, the majority of the carbon skeletons of the amino acids are converted into glucose in the liver. In the present study, tritiated glucose dilution tracer studies have been used to determine the effect of a protein meal on the glucose appearance rate in plasma. Five normal male subjects ingested 50 g of protein in the form of cottage cheese. The glucose appearance rate was determined using a constant infusion of 3H-glucose, and compared to the glucose appearance rate following the ingestion of just water in the same subjects over an 8-hour period. The total amount of protein deaminated and converted to urea also was quantitated. Urea production could account for the metabolism of 29.3 g of protein ingested, or 58.5%. Glucose appearing in the circulation as a result of amino acid metabolism determined by tracer methodology was 9.68 +/- 5.7 g. Based on the gluconeogenic potential of cottage cheese (42.3 g of glucose from 50 g of cottage cheese protein), this could only account for at most 43% of protein metabolized, or 23% of the total amount of protein ingested. The fate of the remaining amino acids metabolized remains to be determined.
PMID: 1460185 [PubMed - indexed for MEDLINE]
Title: Metformin and Carbohydrate-Modified Diet May Help Sustain Weight Loss
URL: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=R
Retrieve&db=PubMed&dopt=Abstract&list_uids=14633321
Heart Dis 2003 Nov-Dec;5:6:384-92. "Long-term (2-4 year) weight
reduction with metformin plus carbohydrate-modified diet in euglycemic,
hyperinsulinemic, midlife women (syndrome w)"
12/16/2003 01:49:00 PM
By Jill Taylor
The combined regimen of metformin and a carbohydrate-modified diet
promotes long-term weight stabilisation in obese, middle-aged, nondiabetic
women with documented insulin abnormalities, say American researchers. The
majority of patients who successfully lose weight in traditional dietary
programs regain the weight within 2 to 4 years, and few treatment strategies
for sustained weight reduction exist that are effective, safe, and
acceptable. In a previous study, women with Syndrome W, an early variant of
the Metabolic Syndrome, achieved significant weight loss with metformin and
a carbohydreate-modified, hypocaloric, low-glycaemic-index diet. To assess
the long-term efficacy this regimen, Harriette R Mogul, MD, MPH, and
colleagues of New York Medical College, Valhalla, United States, conducted a
retrospective analysis of 21 study participants who returned for medication
renewal and annual surveillance visits. All patients included in the
analysis had achieved a 1-year weight loss of more than 10% or body mass
index (BMI) normalisation. Baseline characteristics included an average age
of 55.2 years, BMI of 34.2 kg/m[2, and weight of 196.9 lbs. The researchers
observed weight maintenance at the final (2 to 4 years) follow-up visit in
90.5% of the women, with the mean weight at final follow-up highly
correlated with mean weight at 1-year protocol completion. Furthermore, a
significant and robust decline in fasting insulin (-27.5% -43.8%, P < .002)
was observed at all follow-up visits. Metformin was well tolerated, without
reported side effects or electrolyte imbalance. Although researchers
acknowledge clear methodologic limitation, they hope that the study findings
will encourage clinicians to contemplate the potential viability of defining
and treating insulin abnormalities in euglycemic women with midlife weight
gain who fail to respond to other obesity interventions. "We believe this
effective novel obesity treatment, which is easily implemented in a clinical
setting, could have important implications for women with Syndrome W, and
quite possibly for other subpopulations of obese nondiabetic Americans with
progressive weight gain and documented hyperinsulinemia," they conclude.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=R
Retrieve&db=PubMed&dopt=Abstract&list_uids=14633321
Am J Clin Nutr. 2003 Jul;78(1):31-9. Related Articles, Links
Effect of a high-protein, energy-restricted diet on body composition, glycemic control, and lipid concentrations in overweight and obese hyperinsulinemic men and women.
Farnsworth E, Luscombe ND, Noakes M, Wittert G, Argyiou E, Clifton PM.
Department of Physiology, University of Adelaide, SA, Australia.
BACKGROUND: It is not clear whether varying the protein-to-carbohydrate ratio of weight-loss diets benefits body composition or metabolism. OBJECTIVE: The objective was to compare the effects of 2 weight-loss diets differing in protein-to-carbohydrate ratio on body composition, glucose and lipid metabolism, and markers of bone turnover. DESIGN: A parallel design included either a high-protein diet of meat, poultry, and dairy foods (HP diet: 27% of energy as protein, 44% as carbohydrate, and 29% as fat) or a standard-protein diet low in those foods (SP diet: 16% of energy as protein, 57% as carbohydrate, and 27% as fat) during 12 wk of energy restriction (6-6.3 MJ/d) and 4 wk of energy balance ( approximately 8.2 MJ/d). Fifty-seven overweight volunteers with fasting insulin concentrations > 12 mU/L completed the study. RESULTS: Weight loss (7.9 +/- 0.5 kg) and total fat loss (6.9 +/- 0.4 kg) did not differ between diet groups. In women, total lean mass was significantly (P = 0.02) better preserved with the HP diet (-0.1 +/- 0.3 kg) than with the SP diet (-1.5 +/- 0.3 kg). Those fed the HP diet had significantly (P < 0.03) less glycemic response at weeks 0 and 16 than did those fed the SP diet. After weight loss, the glycemic response decreased significantly (P < 0.05) more in the HP diet group. The reduction in serum triacylglycerol concentrations was significantly (P < 0.05) greater in the HP diet group (23%) than in the SP diet group (10%). Markers of bone turnover, calcium excretion, and systolic blood pressure were unchanged. CONCLUSION: Replacing carbohydrate with protein from meat, poultry, and dairy foods has beneficial metabolic effects and no adverse effects on markers of bone turnover or calcium excretion.
PMID: 12816768 [PubMed - indexed for MEDLINE]
Cancer Causes Control 2002 Apr;13(3):255-61 Related Articles, Links
Nutrient intake and ovarian cancer: an Italian case-control study.
Bidoli E, La Vecchi C, Montella M, Maso LD, Conti E, Negri E, Scarabelli C, Carbone A, Decarli A, Franceschi S.
Epidemiology Unit, Centro di Riferimento Oncologico, Aviano, Italy. epidemiology@xxxxxx
OBJECTIVE: The role of selected macronutrients, cholesterol, and fatty acids in the etiology of epithelial ovarian cancer was analyzed using data from a case-control study carried out in five Italian areas between January 1992 and December 1999. METHODS: Cases comprised 1,031 women with incident, histologically confirmed epithelial ovarian cancer, admitted to the major teaching and general hospitals of the study areas. Controls comprised 2,411 women admitted for acute, non-neoplastic conditions to the same network of hospitals. Information on dietary habits was elicited using a validated food-frequency questionnaire including 78 food groups and recipes. Odds ratios (OR) and their corresponding 95% confidence intervals (CI) were computed by subsequent quintiles of nutrient intake. RESULTS: Direct associations with ovarian cancer emerged for starch intake (OR = 1.4 in the highest vs the lowest quintile of intake; 95% CI 1.1-1.8), while inverse associations emerged for monounsaturated (OR=0.7; 95% CI 0.5-0.9), and polyunsaturated (OR = 0.7; 95% CI 0.5-0.9) fatty acids. Among fatty acids, oleic (OR = 0.7; 95% CI 0.5-0.9), linoleic (OR = 0.7; 95% CI 0.5-0.9), and linolenic (OR = 0.8; 95% CI 0.6-1.0) acids were inversely related to ovarian cancer. When, however, six macronutrients were included in the same model, only the adverse effect of high starch intake remained significant. Results were consistent in separate strata of menopausal status, parity, and energy intake. CONCLUSIONS: Starch was directly associated, and unsaturated fatty acids were inversely associated, with ovarian cancer risk.
PMID: 12020107 [PubMed - indexed for MEDLINE]
.
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