Does Vitamin B-12 Affect Estrogen Levels?

When we speak of estrogen, we are actually speaking of a group of female sex hormones rather than a single substance. Estrogens affect many body processes, including the more obvious and well-known, such as the development of female sexual characteristics and the reproductive cycle. Vitamin B12 is one of the water-soluble vitamins 24. There may be a connection between estrogen and vitamin B12.

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Estrone and estradiol are the most prevalent forms of estrogens. As hormones, estrogens travel through the blood stream and interact with cells in the breast, uterus, bone, liver, brain and heart. Estrogen levels normally fluctuate during the menstrual cycle and begin to decrease as a woman approaches menopause. Estrogens also have less well-known effects, such as their effect on cholesterol, which helps to prevent heart disease in premenopausal women.

  • Estrone and estradiol are the most prevalent forms of estrogens.

Vitamin B12

Vitamin C & Estrogen Level

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Vitamin B12 is naturally available in some foods; it may be added to some foods and is also available in the form of dietary supplements and as a prescription medication 4. Humans use vitamin B12 for the formation of red blood cells, for neurological functions and to manufacture DNA. Meat, fish, poultry, eggs, milk and milk products are good food sources of vitamin B12; most plants do not contain this vitamin, but it may be added to breakfast cereals and grain products.


A study reported in the January 2000 “Mayo Clinic Proceedings” found that postmenopausal women who were given estrogen therapy for six months showed no significant changes in vitamin B12 levels 23. Another study, reported in the January 2006 “International Journal of Vitamin Research,” found that obese postmenopausal women who took a vitamin supplement containing vitamin C, folate, vitamin B6 and vitamin B12 over an 8-week period had increased levels of estradiol, one of the primary estrogen hormones 2.

More Research

Why Do Women Need Estrogen?

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An article in the April 2005 “Maturitas” reported a study of postmenopausal women who had also undergone surgical removal of both the uterus and ovaries. Some of the women were given estradiol as a nasal spray and a control group was not given the medication. Among those women who received estradiol, vitamin B12 levels showed a tendency to increase, while vitamin B12 levels in the control group did not change.


At this time the exact connection between vitamin B12 and estrogens is unclear. Vitamin B12 deficiency in most women is unlikely 4. Most people who eat a balanced diet including meat and dairy products are unlikely to develop deficiencies of vitamin B12, but vegetarians need to take more pains to assure their intake is adequate. According to the Office of Dietary Supplements, the recommended intake for vitamin B12 varies, from 0.4 micrograms for infants from birth to six months of age, to 2.8 micrograms for a woman who is breastfeeding 4.