Progesterone cows milk/study on mens levels

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DGDispatch

Progesterone in Dairy Products Poses Risks: Presented at SABCS

By Gever

SAN ANTONIO, TX -- December 14, 2007 -- Physicians may want to advise patients

who

are at high risk for breast cancer and other progesterone-sensitive conditions

to avoid ice

cream, butter, and other fatty dairy products, based on a study presented here

at the 30th

Annual San Breast Cancer Symposium (SABCS).

People absorb significant amounts of bovine progesterone (identical to human

progesterone) from dairy products, thanks to the practice among dairy farmers of

keeping

dairy cattle pregnant most of the time, according to research led by H.

Goodson III,

MD, Senior Clinical Research Scientist, California Pacific Medical Research

Institute, San

Francisco, California.

" Given the magnitude of milk use, we must consider the possibility that a single

change in

food production technology might have a major influence on the health of young

persons

who, with the best of intentions, are encouraged to drink milk, " the report

said.

Dr. Goodson presented the findings in a poster session on December 14. His group

measured salivary progesterone levels in 17 male volunteers at baseline and 24

hours later

after consuming three servings of high-fat dairy foods (2 tablespoons butter, 2

ounces

cheese, and a quart of premium ice cream) between morning and afternoon. The

procedure was repeated a week later.

Salivary progesterone levels were seen to spike by 30% to 100% in nearly all

subjects after

both sets of feedings.

Dr. Goodson said males were chosen because their normal concentrations of

progesterone

are lower and less cyclic than in females and hence an effect would be easier to

measure.

" I'm more concerned about what happens in very young people, early in life when

differences between males and females are less [significant], " Dr. Goodson said.

Dr. Goodson said most dairy cows began to be maintained in nearly constant

pregnancy in

the mid-20th century to maximize calf production. This results in increased

progesterone

levels in milk.

Unnoticed dietary progesterone might explain several medical trends identified

in the

latter half of the 20th century, including rising incidence of breast cancer and

progressively earlier menarche in girls, Dr. Goodson's group suggested.

Because progesterone dissolves readily in fat, it should be absorbed more

efficiently in

high-fat products. Dr. Goodson said that plain milk, either skim or whole, is

probably a

less important source of dietary progesterone due to low concentration of fat

(4% for

whole milk). " It's the high-fat things that really get to you, " he said.

The group measured progesterone levels in high-fat dairy products. Foods that

were 70%

to 80% dairy fat contained 175 to 300 ng/mL of progesterone, they found.

" The amount of progesterone in 200 mL of ice cream would be approximately

one-one-

hundredth of a pharmacological adult dose of 2 mg, " according to the report.

Several previous studies have concluded that dairy consumption is unrelated to

breast

cancer incidence, according to Dr. Goodson and colleagues. But they also pointed

to a

more detailed study that examined particular dairy products, which did find

associations

between breast cancer incidence and high-fat cheeses as well as milk consumed in

adolescence.

Another study found that women who ate ice cream -- but not low-fat frozen

yogurt --

were significantly more likely to become pregnant. Dr. Goodson said dietary

progesterone

in ice cream could have been responsible by serving as progesterone replacement

in

women who may have luteal insufficiency, a form of infertility marked by low

progesterone availability.

The implications of this hidden source of dietary progesterone are largely

unexplored, Dr.

Goodson said. " You could speculate a lot. It's an interesting place to begin

speculating, " he

said.

[Presentation title: Milk Products Are a Source of Dietary Progesterone.

Abstract 2028]