While generally considered a nutrient, Vitamin D in dietary form also functions as a precursor and building block of a powerful steroid hormone in the body called calcitriol.

Vitamin D is the only nutrient that acts as a hormone and belongs to a fat-soluble nutrient group called sterols. Vitamin D works with other nutrients and hormones in your body to support healthy bone renewal — an ongoing process of mineralisation and demineralization.

Researchers are discovering that Vitamin D also promotes normal cell growth and differentiation throughout the body, working as a key factor in maintaining hormonal balance and a healthy immune system. Studies show that calcitriol actually becomes part of the physical composition of cells, assisting in the build-up and breakdown of healthy tissue. Vitamin D also helps regulate the processes that keep you healthy by monitoring your immune system.

The Sunshine Vitamin

The human body isn’t able to make Vitamin D on its own. It can be derived from food sources or as a result of exposure to ultraviolet B (UVB) light. The best natural source of Vitamin D is sunlight, as the sun’s rays activate a form of cholesterol and convert it to cholecalciferol. This compound travels to the kidneys and liver where it is further converted to two active forms of circulating Vitamin D. (This is the reason why you can have lower Vitamin D levels if you’re on cholesterol medication.)

As previously mentioned, sunlight is a great source of Vitamin D. Ideally, you should spend up to half an hour daily in the early morning or late afternoon sun (the safest sunlight hours). Remember that applying sunscreen prevents Vitamin D absorption and exposing larger skin surfaces will absorb more Vitamin D. Also keep in mind that Vitamin D is absorbed for up to 48 hours after sun exposure and washing with soap decreases absorption.

Vitamin D benefits

Vitamin D offers an amazing range of health benefits, foremost of which is protection against serotonin depletion. Serotonin is a compound that helps regulate your body temperature (among many other things). This means Vitamin D can reduce hot flushes and alleviate night sweats. Serotonin is also crucial for improved moods and motivation.

Vitamin D also helps your body absorb calcium, making it essential for building and maintaining strong bones and preventing osteoporosis. Along with oestrogen and progesterone, Vitamin D is essential for improving bone health especially as we approach midlife. Declining oestrogen levels during menopause can encourage Vitamin D deficiency and exacerbating symptoms such as loss of bone mass, so make sure your Vit D levels are optimal during this transition.

Vitamin D helps the body use insulin more efficiently and prevent diabetes, as well as lower blood pressure readings for people who have hypertension (high blood pressure). Vitamin D is also excellent for mental health as it has a positive effect on low mood and cognitive performance. Did you ever notice how going out in the sun can quickly elevate your mood and lift your spirit? Hence, the theory that winter can make you depressed!

Vitamin D can also improve a host of other symptoms associated with the following:

• glucose intolerance

• multiple sclerosis

• osteoarthritis

• heart disease

• obesity

• irritable bowel syndrome (IBS)

• muscle weakness

• celiac disease and other autoimmune diseases

• fibromyalgia and chronic fatigue syndrome

• chronic pain

• asthma and allergies

Vitamin D and hormones

Vitamin D in your body interacts with and has an effect on the secretion of hormones from the parathyroid glands. These butterfly-shaped glands located in the neck secrete the parathyroid hormone (PTH), a messenger molecule that helps to regulate calcium. PTH promotes the activation of vitamin D within your cells, which in turn leads to calcium regulation. A deficiency in Vitamin D can lead to the abnormal release of PTH because the parathyroid glands need to produce very large amounts of the hormone to compensate. Over time, this can lead to a hormonal imbalance due to high levels of circulating PTH.

Vitamin D deficiency can also have an effect on your pituitary gland, a small hormone in your brain that produces a range of other hormones. One crucial aspect of regulating pituitary function is control over pituitary cell growth. Abnormal pituitary growth can lead to the development of tumours, which in turn can disrupt normal pituitary function and cause a hormonal imbalance. In some cases, treatment with Vitamin D supplements can help to relieve the symptoms associated with rapid changes in hormone levels.

Foods rich in Vitamin D

• Mushrooms

• Halibut

• Sardines

• Salmon

• Mackerel

• Herring

• Oysters

• Caviar

• Trout

• Tuna

• Fortified breakfast cereals

• Milk products

• Fortified milk alternatives (e.g. rice milk and nut milk)

• Organ meats

• Bonemeal

• Fish-liver oils

• Eggs

Summary

Now you see how Vitamin D is important in maintaining optimum hormonal health. It’s always best to get a blood test from your GP to determine if you are deficient in Vitamin D.