High-protein ^ cancer?

[Guest guest]

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@...

________________________________________________________________________________\

____

Any questions? Get answers on any topic at www.Answers.. Try it now.