Short Articles on Hormones and Nutrition


Grapefruit Juice and Hormone Levels
Grapefruit juice slows down the action of the P450 pathways in the liver, meaning that substances cleared from the body through those pathways are held in the body longer. This effect is used to advantage with organ transplant recipients who take their anti-rejection drugs with grapefruit juice in order to prolong the effects of the drugs.

Estrogen is cleared through the P450 pathways (and others), and researchers set out to find out whether drinking grapefruit juice with oral (by mouth) estrogen and progesterone would increase hormone levels. Eight healthy postmenopausal volunteers were given 2 mg of estradiol valerate and 100 mg of micronized progesterone. Blood samples were collected at 0, 2, 3, 5 and 24 hours after the hormones were taken. Serum levels of estradiol and progesterone were measured by radio immune assay (RIA). The same trial was repeated a week later but the hormone pills were swallowed with 200 ml of grapefruit juice. Grapefruit juice on average slightly increased serum levels of estradiol and progesterone; this increase reached statistical significance only for the estradiol level 24 hours after the hormones were taken. The variability of response to the progesterone was so great that the researchers were unable to draw a conclusion.

These researchers would have had a lot more information to work with if they had used saliva hormone levels, which measure bioavailable hormones. Oral progesterone is broken down into many metabolites as it moves through the digestive system, and this may account for the variability of results.

Fingerova H, Oborna I et al, Ceska Gynekol. 2003 Mar;68(2):117-21.

Dilantin Decreases Estrogen Levels
While grapefruit juice slows the metabolism of estrogen (see above), the seizure drug Dilantin (phenytoin) increases it, thus reducing estrogen levels. Women who take Dilantin are advised that birth control pills may not be effective because they may be excreted too quickly to maintain their effects. Dilantin can also cause birth defects, liver toxicity, serious skin rashes, overgrowth of the gums, increased facial hair, bone mineral loss, and folic acid deficiency (which may be what causes the birth defects). Dilantin has been used for many off-label health problems, but it’s clearly not a drug to take lightly.

Eating Meat and Eggs Does not Increase Breast Cancer Risk
During the 90s, much ado was made about a possible link between eating saturated fat and increased breast cancer risk. In most of the research, consumption of hydrogenated oils (trans fatty acids) was never accounted for or if it was, it was not published. As time passed, this link was discounted, primarily because of the weakness of the studies, so I was glad to see evidence showing that breast cancer is not associated with meat or egg consumption.

Eggs are one of the healthiest foods you can eat, and hormone-free meat supplies valuable high quality protein. The researchers are associated with the famous Nurse’s Health Study in Boston, and examined data on diet and breast cancer. The 88,647 women included in the data had been followed for 18 years, with 5 assessments of diet and nutrient intake. During the followup period, 4,107 women developed invasive breast cancer. Those who ate the most animal protein had a two percent higher risk of breast cancer, while those who ate the most red meat had a 7 percent lower risk of breast cancer, and those who ate the most meat of all kinds had an 11 percent lower risk of breast cancer.

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