Hormones

Importance of Vitamin D for Female Hormones

Jasveer Matharu, Dr. Natalie Brown

Dec 8, 2023 • 15 min read

If you live in a country that doesn't get much sunlight at certain times of the year, you will have heard health professionals say that it's always recommended to take a Vitamin D supplement. With winter on its way and days feeling shorter and darker every day, we believed it was important to explore the role of Vitamin D in female hormonal balance and overall health. Thankfully, and for a change, there is abundant research on this topic!

The article is quite long, so if you don’t have the time to dive into each section -here are the top 3 points I’d like you to take away:

Vitamin D significantly impacts female hormonal health: Vitamin D may impact female hormonal health, influencing estrogen and progesterone levels, and playing a crucial role in menstrual regularity, fertility, pregnancy, and managing symptoms of conditions like PCOS and menopause.
Vitamin D deficiency can lead to hormonal imbalances: A deficiency in Vitamin D can lead to hormonal imbalances, contributing to menstrual irregularities and exacerbating hormone-related symptoms.
Practical Advice - Consume foods high in Vitamin D: Ensure adequate Vitamin D intake through diet and, consider supplements during the winter months, especially if you live in countries with less sunlight exposure, such as the UK. Foods rich in Vitamin D include fatty fish, fortified foods, and UV-exposed mushrooms.

What is Vitamin D?

Vitamin D, often referred to as the "sunshine vitamin," is both a nutrient we can eat and a hormone our bodies make. It is unique among vitamins because it can be synthesized by the human body when the skin is exposed to sunlight.

This section of the article will explore the basics of Vitamin D, including its forms, sources, biosynthesis, metabolism, and functions in the body.

What Are the Different Forms of Vitamin D?

Vitamin D2 (Ergocalciferol): This form is found in some foods such as mushrooms and is produced by plants in response to UV radiation.
Vitamin D3 (Cholecalciferol): More potent than D2, D3 is synthesized in the skin of humans and animals when exposed to sunlight and is also found in animal-based foods.

What Are the Sources of Vitamin D?

Sunlight Exposure: Ultraviolet B (UVB) rays from the sun are the primary natural source of Vitamin D.
Dietary Sources: Animal-based sources include fatty fish (like salmon and mackerel), liver, cheese, and egg yolks. Plant-based sources like mushrooms are exposed to UV light.
Supplements: Used to ensure adequate intake, especially in regions with limited sunlight.

What is better, Vitamin D2 or Vitamin D3?

The distinction between Vitamin D2 and D3 primarily lies in their sources and potency, rather than their functions in the body. Once converted to their active forms in the body, both Vitamin D2 and D3 essentially perform the same biological functions. However, there are some important differences to consider:

Source and Potency of Vitamin D2 vs Vitamin D3:

Vitamin D2 is derived from plant sources and certain fungi. It is less potent and has a shorter duration of action compared to D3.
Vitamin D3 is synthesized in the skin through sunlight exposure and is found in animal-based foods. Vitamin D3 is more potent and has a longer duration of action in the body.

Conversion and Activation:

Both Vitamin D2 and D3 are initially inactive and require two steps of conversion - first in the liver to form 25-hydroxyvitamin D (25(OH)D), and then in the kidneys to the physiologically active form, 1,25-dihydroxyvitamin D (1,25(OH)2D). The efficiency of these conversion processes can vary between D2 and D3, with D3 generally being converted more effectively.

Functions of Vitamin D in the Body

Bone Health: Both forms are important for maintaining bone health by promoting calcium absorption in the gut, maintaining adequate serum calcium and phosphate levels, and enabling normal mineralization of bone.
Immune System: They both play a role in modulating the immune system, although D3 may be more effective in this regard due to its higher potency and longer duration.
Cellular Functions: Vitamin D regulates genes involved in cell growth, differentiation, and apoptosis, which has implications for cancer research. Both Vitamin D2 and D3 are involved.

Is Vitamin D2 or D3 more effective?

Studies have shown that Vitamin D3 is more effective in raising and maintaining overall vitamin D levels in the blood compared to D2. This is particularly relevant when considering supplementation strategies.

For general health and particularly for bone health, Vitamin D3 is often the preferred choice due to its greater potency and efficacy. However, Vitamin D2 remains an important option, especially for those who prefer plant-based sources.

What is the recommended daily intake of Vitamin D?

The recommended daily intake of Vitamin D varies based on age, sex, life stage, and individual health conditions. Here are the general guidelines provided by the Institute of Medicine (IOM) and other health authorities:

Infants (0-12 months): 400 International Units (IU) per day.
Children (1-18 years): 600 IU per day.
Adults (19-70 years): 600 IU per day.
Adults (71 years and older): 800 IU per day.
Pregnant and Breastfeeding Women: 600 IU per day.

The maximum daily intake that is unlikely to cause harmful effects on health. The UL for vitamin D for adults and children ages 9+ is 4,000 IU (100 mcg).

It's important to note that these are general recommendations and individual needs may vary. Some health conditions, geographic locations with limited sunlight, and other factors may necessitate higher doses. It is always advisable to get a blood test and consult with your health care professional so you can take the right dose for you.

Female Hormones: An Overview

Types of Female Hormones

Estrogen: A key hormone in female reproductive health, involved in the regulation of the menstrual cycle. This peaks during the follicular phase, promoting the thickening of the uterine lining.
Progesterone: Essential for regulating the menstrual cycle and maintaining the early stages of pregnancy. This rises during the luteal phase, stabilizing the uterine lining for implantation.

Other:

Follicle-Stimulating Hormone (FSH): stimulates the growth of ovarian follicles in the ovary before the release of an egg.
Luteinizing Hormone (LH): triggers ovulation and the development of the corpus luteum.
Androgens: such as testosterone, play a role in follicle development and sexual desire.

Hormonal Regulation and Menstrual Cycle

Early Follicular (aka Menstruation): If fertilization does not occur, estrogen and progesterone levels fall, leading to the shedding of the uterine lining.
Late Follicular Phase: FSH promotes the growth of follicles in the ovaries. Estrogen levels rise ready for ovulation.
Ovulation: Triggered by a peak in LH, releasing the mature egg from the follicle.
Luteal Phase: After ovulation, the corpus luteum produces progesterone, preparing the uterus for potential pregnancy.

Learn more about the menstrual cycle phases in an in-depth article: Menstrual Cycle - Phases, Hormones and Their Functions

Interaction Between Vitamin D and Female Hormones

Understanding the interaction between Vitamin D and female hormones is crucial, as it has significant implications for women's health.

What is the Impact of Vitamin D and Hormonal Balance?

Vitamin D and Estrogen

Regulation of Enzymes Involved in Estrogen Synthesis: Vitamin D regulates the activity of enzymes involved in estrogen synthesis and metabolism. These enzymes, such as aromatase, play a key role in converting androgens (like testosterone) into estrogens. By modulating these enzyme activities, Vitamin D indirectly influences estrogen levels in the body.
Gene Expression Related to Estrogen Production: Vitamin D can affect the expression of genes that are involved in estrogen production. This is because Vitamin D receptors are present in various tissues, including those of the reproductive system. These receptors, when activated by Vitamin D, can influence the transcription of genes that regulate hormone production, including estrogen.

Why is regulating estrogen Important?

Menstrual Cycle Regulation: Estrogen plays a vital role in regulating the menstrual cycle, influencing the growth of the uterine lining and its preparation for potential pregnancy.
Reproductive Health: Estrogen levels are crucial for various aspects of reproductive health, including ovulation and the health of reproductive tissues.
Bone Health: Estrogen is essential for maintaining bone density. Especially in women up to age 25 where bone density is formed and postmenopausal women, who have lower estrogen levels, which increases the risk for osteoporosis. Vitamin D, in conjunction with estrogen, helps maintain bone health.
Cardiovascular Health: Estrogen has protective effects on the heart and blood vessels. Imbalances in estrogen levels can impact cardiovascular health.

Vitamin D and Progesterone

Progesterone, another key hormone, works in parallel with estrogen. Vitamin D's role in balancing estrogen indirectly affects progesterone levels as well, since these two hormones are often synchronized in their functions, particularly in the menstrual cycle and pregnancy.

There is evidence linking higher levels of Vitamin D with more balanced levels of estrogen and progesterone, which are key to maintaining regular menstrual cycles and overall reproductive health.

Vitamin D in Reproductive Health

Fertility: Studies indicate that Vitamin D may affect fertility by influencing the ovarian follicle reserve and improving the uterine environment, potentially enhancing the chances of conception. Vitamin D receptors are present in the ovaries and uterus, suggesting a direct role in reproductive processes.
Pregnancy: Studies indicate that women with higher Vitamin D levels in the third trimester of pregnancy showed a decreased risk of developing preeclampsia, a pregnancy complication characterized by high blood pressure and signs of damage to another organ system.

Vitamin D and Menstrual Health

As mentioned above, Vitamin D may influence menstrual cycle regularity through its effects on the hormones that regulate the menstrual cycle, with a deficiency in Vitamin D being associated with a higher prevalence of irregular menstrual cycles.

Vitamin D can also affect menstrual symptoms, increasing the number and severity of the symptoms especially in women deficient in Vitamin D. For example, a study by Bertone-Johnson et al. found that higher intakes of Vitamin D and calcium were associated with a lower risk of developing PMS. They suggested that these nutrients might play a role in reducing the severity of PMS symptoms. Another study by Thys-Jacobs et al. indicated that Vitamin D could be beneficial in managing PMS symptoms, particularly the physical and emotional symptoms.

Vitamin D and PMS Symptoms

Alleviation of Mood Swings and Depression:

Neurotransmitter Regulation: Vitamin D plays a role in synthesizing neurotransmitters like serotonin, which can influence mood. Serotonin levels are often fluctuating in women with PMS, leading to mood swings.
Vitamin D Receptors in the Brain: These receptors are found in areas of the brain associated with mood regulation. Adequate levels of Vitamin D might aid in maintaining a more stable mood, potentially reducing the severity of mood swings associated with PMS.

Physical Discomfort and Pain Relief:

Anti-inflammatory Effects: Vitamin D has anti-inflammatory properties. Since inflammation can exacerbate PMS symptoms, including pain and discomfort, Vitamin D might help in reducing these symptoms.
Muscle Function: Vitamin D is essential for muscle function and might help in alleviating cramps and aches that are common in PMS.

Vitamin D Deficiency and Hormonal Imbalances

Causes of Vitamin D Deficiency

Limited Sun Exposure: Geographic location, lifestyle choices, and use of sunscreen can limit UVB exposure.
Dietary Insufficiency: Inadequate intake of Vitamin D-rich foods.
Malabsorption Issues: Conditions like celiac disease and Crohn's disease can affect Vitamin D absorption.
Aging: The skin's ability to synthesize Vitamin D decreases with age.
Skin Pigmentation: Higher melanin levels in darker skin reduce the skin's ability to produce Vitamin D from sunlight.

Symptoms of Vitamin D Deficiency

Bone Pain and Muscle Weakness: Often the first signs of deficiency.
Fatigue and General Malaise: Common but non-specific symptoms.
Mood Changes: Including depression, which might be linked to low Vitamin D levels.

Effects of Vitamin D Deficiency on Female Hormones

Dysmenorrhea (menstrual cramps): Vitamin D has anti-inflammatory affects, it can reduce the production of prostaglandins which can play a major role in the pathophysiology of PMS and dysmenorrhea. Further research suggests vitamin D may influence several different mechanisms related to dysmenorrhea and PMS
Menstrual Irregularities: Vitamin D plays a role in the functioning of the ovaries and the regulation of menstrual cycles. Deficiency might contribute to irregular periods. Studies have shown a correlation between Vitamin D deficiency and conditions like amenorrhea (absence of menstruation).
Polycystic Ovary Syndrome (PCOS): Women with PCOS often have lower levels of Vitamin D. While the causal relationship is not fully established, Vitamin D supplementation is sometimes used as part of PCOS management. Moreover, Vitamin D's role in insulin regulation and inflammation may be particularly relevant for PCOS, which is often characterized by insulin resistance.
Menopause Symptoms: Vitamin D deficiency may exacerbate menopausal symptoms such as mood swings, osteoporosis, and increased cardiovascular risk.

Diet and Nutrition for Optimal Vitamin D and Hormonal Health

Dietary sources of Vitamin D

Vitamin D in Fatty Fish:

Salmon: Wild-caught salmon can contain about 988 IU (International Units) per 3.5 oz (100 grams) serving. Farmed salmon has around 250 IU per 3.5 oz.
Mackerel: Provides about 360 IU per 3.5 oz.
Tuna: Canned light tuna offers about 268 IU per 3.5 oz.
Cod Liver Oil: One tablespoon provides about 1,360 IU, making it one of the most potent food sources.

Vitamin D in Egg Yolks:

Eggs from chickens that have been fed Vitamin D-enriched feed can have higher levels, around 100 to 200 IU per yolk.

Vitamin D in Mushrooms:

UV-exposed mushrooms can provide varying amounts of Vitamin D2. Some varieties offer as much as 450 IU per 3.5 oz serving.

Vitamin D in Fortified Foods:

Milk: Both cow's milk and some plant-based milks are often fortified with about 100 to 120 IU per cup.

Nutrition strategies for hormonal balance

Balanced Diet: Emphasize a diet rich in fruits, vegetables, whole grains, and lean proteins to support overall hormonal health.
Calcium and Magnesium: Key for bone health and hormonal balance. Found in dairy products, leafy greens, legumes, nuts, and seeds.
Omega-3 Fatty Acids: Essential for reducing inflammation and supporting hormonal production. Sources include fatty fish, flaxseeds, chia seeds, and walnuts.
Avoid Processed Foods: High in sugars and unhealthy fats, these can disrupt hormonal balance and contribute to inflammation.

During the autumn and winter, you need to get vitamin D from your diet because the sun is not strong enough for the body to make vitamin D.

But since it's difficult for people to get enough vitamin D from food alone, everyone (including pregnant and breastfeeding women) should consider taking a daily supplement containing 10 micrograms of vitamin D during the autumn and winter. Between late March/early April to the end of September, most people can make all the vitamin D they need through sunlight on their skin and from a balanced diet.

Is Diet Alone Enough to Get the Recommended Amount of Vitamin D?

It is worth noting that depending on where you live (i.e. the UK) diet alone may not be sufficient to provide you with the recommended amount of Vitamin D your body needs. Things to consider:

Individual Needs: The Recommended Dietary Allowance (RDA) for Vitamin D is around 600 to 800 IU per day for most adults, but this can vary based on age, health status, and other factors.
Geographical Location: In countries like the UK, where sunlight exposure is limited, especially in the winter months, achieving adequate Vitamin D levels through diet and sunlight can be challenging.
Dietary Habits: For those who consume limited amounts of Vitamin D-rich foods (like vegans or vegetarians), reaching the RDA through diet alone can be difficult.
Supplementation: In such cases, Vitamin D supplements can be beneficial. They can ensure adequate intake without the need to consume large amounts of Vitamin D-rich foods, which might not be feasible or desirable for everyone.

Research on Vitamin D and Women’s Health

PCOS and Vitamin D Supplementation

Background: Conducted by Thomson RL and colleagues, this study focused on the role of Vitamin D in PCOS, a common hormonal disorder among women of reproductive age.
Findings: The research highlighted that Vitamin D deficiency is common in women with PCOS and may exacerbate symptoms such as insulin resistance, menstrual irregularities, and lower pregnancy success. It also discussed the potential benefits of Vitamin D supplementation in managing PCOS.
Direct Link: Vitamin D in the etiology and management of polycystic ovary syndrome

Vitamin D for alleviating PMS symptoms

Background: This study, led by Bertone-Johnson ER and colleagues, investigated the relationship between calcium and Vitamin D intake and the risk of developing Premenstrual Syndrome (PMS).
Findings: The study suggested that higher intakes of Vitamin D and calcium were associated with a lower risk of developing PMS, indicating a potential role for these nutrients in reducing PMS symptoms.
Direct Link: Calcium and Vitamin D intake and risk of incident premenstrual syndrome

Postmenopausal Women and Vitamin D

Background: This study focuses on the effects of Vitamin D supplementation in postmenopausal women. It examines the relationship between Vitamin D levels and various health aspects affected by menopause, such as bone density, mood changes, and overall well-being.
Findings: The study explored how Vitamin D supplementation might improve various health parameters in postmenopausal women, including bone health, metabolic syndrome risk, and other menopause-related symptoms.
Direct Link: Vitamin D supplementation after the menopause

Research on how Vitamin D can support women’s health is ongoing, currently exploring a range of topics including:

Fertility: the role of Vitamin D in improving the outcomes of fertility treatments, including IVF.
Autoimmune Diseases: Studies are investigating how Vitamin D supplementation might reduce the risk or severity of autoimmune diseases, which are more common in women.
Long-term Effects: Ongoing research aims to understand the long-term impacts of Vitamin D supplementation on hormonal health across different stages of a woman's life, including pregnancy, menopause, and aging.

In conclusion, Vitamin D plays a vital role in female hormonal health, influencing everything from menstrual regularity to menopause. Its deficiency can have significant health implications. Adequate intake through diet and supplementation, particularly in sunlight-deficient regions, is crucial for maintaining hormonal balance and overall well-being.

Additional Resources & References

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Holick, M.F. (2007). Vitamin D deficiency. New England Journal of Medicine, 357(3), 266-281.
Institute of Medicine (US) Committee to Review Dietary Reference Intakes for Vitamin D and Calcium. (2011). Dietary Reference Intakes for Calcium and Vitamin D. National Academies Press.
Bertone-Johnson, E. R., Hankinson, S. E., Bendich, A., Johnson, S. R., Willett, W. C., & Manson, J. E. (2005). Calcium and vitamin D intake and risk of incident premenstrual syndrome. Archives of Internal Medicine, 165(11), 1246-1252.
Bacanakgil BH, İlhan G, Ohanoğlu K. Effects of vitamin D supplementation on ovarian reserve markers in infertile women with diminished ovarian reserve. Medicine (Baltimore). 2022 Feb 11;101(6):e28796. doi: 10.1097/MD.0000000000028796. PMID: 35147111; PMCID: PMC8830860.
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Thys-Jacobs, S. (2005). Micronutrients and the premenstrual syndrome: The case for calcium. Journal of the American College of Nutrition, 24(2), 96-102.
Thys-Jacobs, S., Ceccarelli, S., Bierman, A., Weisman, H., Cohen, M. A., & Alvir, J. (1987). Calcium supplementation in premenstrual syndrome: a randomized crossover trial. Journal of General Internal Medicine, 2(3), 168-173.
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