Influence of Lactation History on Breast Nipple Aspirate Fluid Yields and Fluid Composition

Abstract

Analysis of nipple aspirate fluid (NAF) can be useful for understanding the impact that various lifestyle factors have on the biology of the breast. In this study, breast NAF was obtained at baseline from premenopausal women who volunteered for a dietary intervention trial. The influence of lactation history on both fluid yields and fluid composition was explored. We examined the levels of fat-soluble micronutrients (tocopherols, carotenoids, retinol), one lipid oxidation product (8-isoprostane), cholesterol, and protein in NAF. Roughly half of the women in the trial had never lactated, but this did not affect fluid yields appreciably. Carotenoid and tocopherol levels were significantly higher in NAF from women who lactated 6 months or more versus women who had lactated for shorter periods of time or never, but 8-isoprostane, protein, and cholesterol levels were not affected appreciably by lifetime lactation history. Longer times after weaning were associated with higher cholesterol levels, and there also was a suggestion the fat-soluble micronutrients declined with time after weaning. This is of interest since high cholesterol levels in breast fluid have been associated with an increased breast cancer risk, while carotenoids and tocopherols are thought to be protective. The results of this study provide further evidence of the potential benefits of prolonged lactation via its influence on NAF composition.

Effects of High Fruit-Vegetable and/or Low-Fat Intervention on Breast Nipple Aspirate Fluid Micronutrient Levels

“…The basic approach has been described previously in more detail (40). The breast aspirator is similar to that used by Sartorius (41,42), and it was an inexpensive, easy-to-use method for subjects to express their own breast fluids.…”

A strong association between body fat mass and protein profiles in nipple aspirate fluid of healthy premenopausal non-lactating women

“…For example, the average level of proteins in NAF is 71-170 mg/ml, which is much higher than the 6-8 mg/ml reported for plasma [2,3]. Several NAF proteins, including hormone-regulated proteins and cancer markers such as prostate-specific antigen and carcinoembryonic antigen, have been identified using antibodies [4,5].…”

Nutrients and nipple aspirate fluid composition: the breast microenvironment regulates protein expression and cancer aetiology

“…It is well known that some micronutrients can protect lipids from oxidation, and carotenoids also exhibit anticarcinogenic effects through mechanisms such as regulation of gene expression [51]. Starting from the evidence that increased levels of both carotenoids and tocopherols in plasma/serum are associated with decreased BC risk, and that low intake of carotenoids may be associated with increased BC risk [53,59,61], a recent study indicated that retinol, total carotenoid and total tocopherol levels were higher in NAF from women who breast-fed a child for more than 6 months versus those who never lactated, evidencing also that in women who had lactated the fatsoluble micronutrient and protein levels declined with time after weaning, while cholesterol levels significantly increased [11]. This study strengthened the hypothesis that high cholesterol levels in breast NAF are associated with increased BC risk, while carotenoids and tocopherols may be protective.…”

“…Several prospective or cohort studies have reported an inverse Vitamins [11,25] provitamin A [9] vitamin E [9] retinol [10,11,25] association between breast cancer risk and serum/plasma carotenoids, including a-and b-carotenes and lutein [59,60]. Despite being a relatively minor component among total carotenoids, it is intriguing that lutein showed a significant inverse association [25].…”

“…In the Nutrition and Breast Health Study, it was also reported that plasma levels of c-tocopherol (but not b-tocopherol) decreased significantly in low-fat diet habit [25]. Based on the evidence that tocopherol and retinol levels found in NAF were not targeted by any intervention and did not show significant changes [10,11,25], it is possible that the breast tissue stores of tocopherols are less affected by diet than those of plasma. Previous studies indicate that a high fruit-vegetable diet can be useful to increase carotenoids in breast secretions (e.g., NAF and milk), which in turn may be useful for prevention of breast cancer, as increased plasma carotenoid levels have been associated with decreased BC risk [53,59].…”