Re: High-protein ^ cancer?

[Guest guest]

Two interesting topics posted today - the one below where Al points

out that a low-calorie, low-protein diet may help stave off cancer,

and where Tony said:

" High carbohydrate, low-fat diets increase cholesterol because

carbohydrates get metabolized to palmitate (C16:0) which is a

saturated fatty acid that can increase cholesterol. When the diet

does not have enough omega-6, i.e., linoleic acid (C18:2), your

cholesterol will be high. "

So the message here (besides eating fewer calories) is: low protein

and low carbohydrates...and high fat??

What percentages of protein/carbo/fat should I be striving for? I

know Jeff recommends keeping fat at <= 20%. But that would boost the

percentages of fat and carbos. I'm confused.

Diane

===============================================

>

> They could (may) be CRONers. The pdf of the paper is

> availed.

>

> Low-protein, low-calorie dieters show lower levels of

> hormone linked to cancer

> Last Updated: Wednesday, December 6, 2006 | 11:56 PM

> ET

> CBC News

>

>

> People who eat a low-protein, low-calorie diet have

> lower levels of a hormone linked to cancer compared to

> those who eat other diets, researchers have found.

>

> Overweight people are at higher risk of developing

> post-menopausal breast cancer, endometrial cancer,

> colon cancer, kidney cancer and a type of esophageal

> cancer.

>

> Now a study suggests eating less protein may help

> protect against cancers not directly linked to excess

> eight.

>

> Dr. Luigi Fontana, a medical professor at Washington

> University, and his team compared participants in

> three groups:

>

> a.. Lean men and women who ate a low-protein,

> low-calorie, raw food vegetarian diet.

> b.. Lean men and women who did regular endurance

> running of about 77 kilometres per week and ate a

> standard Western diet.

> c.. Sedentary people who consumed a standard Western

> diet high in sugars, processed refined grains and

> animal products.

>

> " People on a low-protein, low-calorie diet had

> considerably lower levels of a particular plasma

> growth factor called IGF-1 than equally lean endurance

> runners, " Fontana said.

>

> " That suggests to us that a diet lower in protein may

> have a greater protective effect against cancer than

> endurance exercise, independently of body fat mass. "

>

> Each group included 21 people, who were matched for

> age, sex and other demographic factors. None were

> smokers or had diabetes, heart disease or other

> chronic illnesses.

>

> Both the runners and the sedentary participants ate

> about 50 per cent more protein than recommended, the

> researchers report in the December issue of the

> American Journal of Clinical Nutrition.

>

> While consuming 50 per cent more calories than

> recommended will likely lead to obesity, no one knows

> whether chronic over-consumption of protein also has a

> harmful effect, Fontana said.

>

> The study is a " hypothesis-generating " paper pointing

> to a connection between dietary protein and population

> studies that suggest a link between blood levels of

> insulin-like growth factor and cancer risk, he added.

>

> The team is planning more research to clarify what

> happens to cancer risk from eating more protein than

> recommended in the long term.

>

>

> Dr. Fontana et al have been busy. The first of the

> two pdf-availed papers appear to be from his Italian

> earlier studies.

>

> Dennis T Villareal, Bernard V , III, n

> Banks, Luigi Fontana,

> R Sinacore, and Klein

> Effect of lifestyle intervention on metabolic coronary

> heart disease risk factors in obese older adults

> Am J Clin Nutr 2006 84: 1317-1323.

>

> Background: Coronary heart disease (CHD) risk factors

> increase with age and body mass index (BMI; in kg/m2).

> However, whether lifestyle intervention ameliorates

> metabolic CHD risk factors in obese older adults is

> unknown.

>

> Objective: The objective was to determine whether

> lifestyle intervention improves metabolic CHD risk

> factors in obese older adults.

>

> Design: A 6-mo outpatient randomized controlled trial

> was conducted in obese (=/>BMI 30) older (=/>65 y)

> adults randomly assigned to diet and exercise therapy

> (treatment group; n = 17) or no therapy (control

> group; n = 10). The main outcomes were CHD risk

> factors.

>

> Results: Body weight decreased by 8.4% (8.2 kg) in the

> treatment group; weight did not change significantly

> (0.7 kg) in the control group (P < 0.001 between

> groups). Changes between the control and treatment

> groups, respectively, in waist circumference (1 and

> -10 cm), plasma glucose (4 and -4 mg/dL), serum

> triacylglycerols (0 and -45 mg/dL), and systolic (-2

> and -10 mm Hg) and diastolic (0 and -8 mm Hg) blood

> pressure were different (P < 0.05 for all). The number

> of subjects with the metabolic syndrome decreased by

> 59% in the treatment group but did not change

> significantly in the control group (P < 0.05). Serum

> free fatty acids increased by 10 µmol/L in the control

> group and decreased by 99 µmol/L in the treatment

> group (P < 0.05). Changes between the control and

> treatment groups, respectively, in C-reactive protein

> (0.8 and -2.5 mg/L) and interleukin 6 (1.6 and -2.4

> pg/mL) were different (P < 0.05 for both).

>

> Conclusions: Lifestyle intervention decreases multiple

> metabolic CHD risk factors simultaneously in obese

> older adults.

>

> Luigi Fontana, Klein, and O Holloszy

> Long-term low-protein, low-calorie diet and endurance

> exercise modulate metabolic factors associated with

> cancer risk

> Am J Clin Nutr 2006 84: 1456-1462.

>

> Background: Western diets, obesity, and sedentary

> lifestyles are associated with increased cancer risk.

> The mechanisms responsible for this increased risk,

> however, are not clear.

>

> Objective: We hypothesized that long-term low protein,

> low calorie intake and endurance exercise are

> associated with low concentrations of plasma growth

> factors and hormones that are linked to an increased

> risk of cancer.

>

> Design: Plasma growth factors and hormones were

> evaluated in 21 sedentary subjects, who had been

> eating a low-protein, low-calorie diet for 4.4±2.8 y

> (±SD age: 53.0±11 y); 21 endurance runners matched by

> body mass index (BMI; in kg/m2); and 21 age- and

> sex-matched sedentary subjects eating Western diets.

>

> Results: BMI was lower in the low-protein, low-calorie

> diet (21.3±3.1) and runner (21.6±1.6) groups than in

> the Western diet (26.5±2.7; P < 0.005) group. Plasma

> concentrations of insulin, free sex hormones, leptin,

> and C-reactive protein were lower and sex

> hormone-binding globulin was higher in the

> low-protein, low-calorie diet and runner groups than

> in the sedentary Western diet group (all P < 0.05).

> Plasma insulin-like growth factor I (IGF-I) and the

> concentration ratio of IGF-I to IGF binding protein 3

> were lower in the low-protein, low-calorie diet group

> (139±37 ng/mL and 0.033±0.01, respectively) than in

> the runner (177±37 ng/mL and 0.044±0.01, respectively)

> and sedentary Western (201±42 ng/mL and 0.046±0.01,

> respectively) diet groups (P < 0.005).

>

> Conclusions: Exercise training, decreased adiposity,

> and long-term consumption of a low-protein,

> low-calorie diet are associated with low plasma growth

> factors and hormones that are linked to an increased

> risk of cancer. Low protein intake may have additional

> protective effects because it is associated with a

> decrease in circulating IGF-I independent of body fat mass.

>

> -- Al Pater, PhD; email: Alpater@...

>

>

>

>

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>

[Guest guest]

Even the highest protein group, the Western diet eaters,

only got 14-20% of their calories from that macronutrient.

Not exceedingly high. My take on this study is that the

findings of benefit for the low-protein group was more due

to their CR and lower saturated fat intake than their low

protein, 6(!)-12%.

-

>

> > Two interesting topics posted today - the one below

> > where Al points

> > out that a low-calorie, low-protein diet may help

> > stave off cancer,

> > and where Tony said:

> >

> > " High carbohydrate, low-fat diets increase

> > cholesterol because

> > carbohydrates get metabolized to palmitate (C16:0)

> > which is a

> > saturated fatty acid that can increase cholesterol.

> > When the diet

> > does not have enough omega-6, i.e., linoleic acid

> > (C18:2), your

> > cholesterol will be high. "

> >

> > So the message here (besides eating fewer calories)

> > is: low protein

> > and low carbohydrates...and high fat??

> >

> > What percentages of protein/carbo/fat should I be

> > striving for? I

> > know Jeff recommends keeping fat at <= 20%. But

> > that would boost the

> > percentages of fat and carbos. I'm confused.

>

> -- Al Pater, PhD; email: Alpater@...

>

>

>

>

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