Vitamin E is a group of fat-soluble compounds known for their antioxidant properties, which protect body tissues from damage caused by free radicals. Prolactin is a hormone produced primarily by the pituitary gland, a small endocrine gland at the base of the brain. This article explores the relationship between vitamin E and prolactin levels, examining current scientific understanding of how vitamin E might influence this hormone.
Understanding Prolactin’s Functions
Prolactin, also known as lactotropin, is a polypeptide hormone produced and secreted by lactotroph cells in the anterior pituitary gland. While most recognized for its role in enabling milk production (lactation), prolactin has over 300 diverse functions in the human body. During pregnancy, elevated prolactin, alongside estrogen and progesterone, stimulates mammary gland development and prepares them for milk synthesis. After childbirth, suckling further stimulates prolactin release, promoting milk flow.
Beyond lactation, prolactin plays a role in reproductive health, influencing fertility and sexual function. It also contributes to the regulation of the immune system and is involved in metabolic processes, including those related to energy balance and pancreatic development. Prolactin secretion is tightly regulated, primarily by dopamine from the hypothalamus, which acts as an inhibitory factor. Elevated prolactin levels, called hyperprolactinemia, can lead to symptoms such as spontaneous milk production (galactorrhea), absence of menstrual periods (amenorrhea), and infertility in both men and women. Conversely, low levels of prolactin, or hypoprolactinemia, can affect lactation and reproductive health.
How Vitamin E May Influence Prolactin
Research into vitamin E’s influence on prolactin levels suggests a complex interplay, often linked to its antioxidant properties and its impact on the endocrine system. Some studies indicate that vitamin E may help lower prolactin levels, potentially by protecting pituitary cells and dopamine neurons from oxidative stress. This protective action can ensure the efficient production and release of dopamine, which is the primary inhibitor of prolactin secretion. By influencing the sensitivity of the pituitary gland to dopamine, vitamin E might enhance dopamine’s inhibitory effect on prolactin release.
One human study involving uremic patients on hemodialysis showed a significant decrease in serum prolactin levels after oral vitamin E supplementation (300 mg/day) for eight weeks, suggesting an inhibition of central prolactin secretion. Animal studies also suggest that lower vitamin E levels may lead to increased prolactin concentrations. Conversely, adequate vitamin E supplementation could be associated with a decrease in prolactin. This may relate to an increase in brain dopamine content, which inhibits prolactin synthesis and secretion.
Further proposed mechanisms involve vitamin E’s protective effects against polyunsaturated fats (PUFAs), which are thought to have estrogen-like effects that can influence hormonal balance, including prolactin. Vitamin E’s anti-estrogenic properties are considered similar to the beneficial effects of progesterone, potentially leading to anti-prolactin effects. However, the precise mechanisms by which vitamin E impacts prolactin are still being investigated, and more comprehensive human studies are needed to fully understand this relationship.
Sources and Safe Use of Vitamin E
Vitamin E is naturally present in various dietary sources.
Excellent sources include:
Plant oils such as sunflower, safflower, corn, and soybean oils.
Nuts like almonds, peanuts, and hazelnuts.
Seeds such as sunflower seeds.
Green leafy vegetables like spinach and broccoli.
Fortified breakfast cereals, fruit juices, and spreads.
The recommended daily allowance (RDA) for vitamin E for adults is 15 milligrams (mg) per day. While generally safe to consume vitamin E from food sources, high doses of vitamin E supplements can pose risks. The tolerable upper intake level for adults is generally considered to be 1,000 mg per day, though some studies have associated adverse effects with doses lower than this. Excessive vitamin E intake, particularly from supplements, can lead to blood thinning and may increase the risk of bleeding, including hemorrhagic stroke. It can also interfere with blood clotting and interact with anticoagulant medications. Therefore, consult a healthcare professional before taking vitamin E supplements, especially when attempting to manage hormone levels or if pregnant or breastfeeding.