Diet in Puberty Affects Hormone Levels: Could Low-Fat Eating by Teens Lower Breast Cancer Risk?

[Guest guest]

Original article:

webmd.com/content/Article/59/66683.htm

 

Diet in Puberty Affects Hormone Levels

Could Low-Fat Eating by Teens Lower Breast Cancer Risk?

 

By Sid Kirchheimer

WebMD Medical News

 

Reviewed By Brunilda Nazario, MD

on Tuesday, January 14, 2003

 

Jan. 14, 2003 -- Small changes in diet during puberty can have a big effect on

levels of estrogen and other hormones that have been implicated in boosting

breast cancer risk in women, raising hope that girls may be able to eat their

way to a lower risk decades later.

 

And it doesn't appear to take much. Years of consuming just slightly less

saturated and total fat calories than today's typical " heart-healthy "

recommendations helped slash some hormone levels in teenaged girls by as much as

50%, according to a new study. In adults, elevated levels of these hormones are

associated with an increased breast cancer risk.

 

" The real take-home message of this study is indeed, the quality of diet during

puberty seems to have some sort of influence on hormones, " says researcher and

study author Linda Van Horn, PhD, RD, professor of preventive medicine at

Northwestern University's Feinberg School of Medicine. " Whether that will

translate to breast cancer prevention down the road, we don't know. But it's

long been suspected that diet surrounding the time of puberty might influence

breast tissue development. "

 

Her study, reported in the Jan. 15 issue of the Journal of the National Cancer

Institute, is actually a secondary finding from the ongoing Dietary Intervention

Study in Children (DISC), a federally-funded trial that began in 1987 to test

the efficacy and safety of cholesterol-lowering diets in young children.

 

" When DISC began, the idea of putting growing children -- even those with high

cholesterol -- on a so-called 'low-fat' diet was quite controversial, " Van Horn

tells WebMD. " The popular notion was that it would hurt their growth. "

 

DISC monitored hundreds of boys and girls with high LDL " bad " cholesterol levels

from the time they were 8 to 10 to their late teens. All the kids were of normal

weight. The researchers placed the girls on an eating plan that limited total

fat intake to about 28% percent, with about 8% from saturated fat (the kind that

increases LDL " bad " cholesterol), and the rest from unsaturated fats.

Cholesterol was limited to 75 mg for every 1,000 calories consumed. Another

group of girls and their families were given written material on nutrition

recommended by the American Heart Association.

 

Today, most Americans are urged by the American Dietetic Association and the

American Heart Association to follow a diet similar the DISC plan -- with no

more than 30% of total calories coming from all fat sources and no more than 10%

from saturated fats.

 

" While we were studying all these boys and girls to see how diet affected their

cholesterol, we decided to take some extra blood for hormone assays to see if

diet might also influence hormonal changes, " says Victor Stevens, PhD, a

psychologist also involved in the DISC study. " Then we called the girls up to

get their menstrual cycle data. "

 

All the girls in the study had blood sex hormone levels measured before, during,

and after puberty. The two groups appeared to go through puberty at the same

time.

 

The researchers found that estrogen levels during the menstrual cycles were

significantly lower in the girls who had consumed a diet with a lower total fat

and saturated fat content. The average progesterone level during the later part

of the cycles were also significantly lower.

 

" This is a great finding because there have been some studies saying there is no

correlation between dietary fat intake and breast cancer risk. But the problem

is that all of those studies have been on adults -- we really don't know what

happens at the prepubescent stage, when breast tissue is developing, " says

Wahida Karmally, PhD, a Columbia University nutritionist and spokeswoman for the

American Dietetic Association. " Cancer doesn't happen overnight, it takes years

or decades to develop. The age when girls go into puberty might be a very

important time to watch fat and monitor diet in order to reduce this risk. "

 

So what can parents do for their young daughters?

 

" The keys to getting your kids to eat more healthfully is to control what food

is in the house and to show by example, " says psychologist Stevens. " Of course,

we started working with these kids when they were 8 to 10, and that age, parents

have a lot of control over what kids eat. But even with teenagers, controlling

the food that is in the house is the top strategy for getting kids to eat more

healthfully. If you have junk food in the house, they will eat it. If there is

fruit, they will eat that. But if you show them you are eating healthy, they

will most likely eat that way, too. "

----------------------------

SOURCES: Journal of the National Cancer Institute, January 15, 2003

<> Linda Van Horn, PhD, RD, professor of preventative medicine, The Feinberg

School of Medicine, Northwestern University, Chicago, Illinois

<> Victor Stevens, PhD, assistant director for epidemiology and disease

prevention, Kaiser Permanente Center, Portland, Oregon.

<> Wahida Karmally, PhD, director of nutrition, Irving Center for Clinical

Research; associate research scientist, Columbia University, New York; and

spokeswoman, American Dietetic Association.

 

© 2003 WebMD Inc. All rights reserved.