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Vitamin D…Hormone or Vitamin?

Updated: Jan 31

By J.Maxine MacGwyre, Licensed Aesthetician, Nutrition Specialist 1/1/2024

Vitamin D is considered an essential vitamin because our overall wellness depends upon it. It is responsible for multiple functions in our body, such as promoting healthy bones and regulating our immune system. Unlike other vitamins, it also acts like a hormone, controlling and coordinating various activities in our body. Vitamin D can be obtained through food sources, supplements, and is generated by our body when we are exposed to invisible UV rays from the sun, which is why Vitamin D is nicknamed the “sunshine vitamin".

So what exactly does Vitamin D do to support our health?

Bone Health

Physical activity, dietary intake, and genetics all affect our bone mass. By the time we reach 40, our bone mass has begun to decline, which can eventually cause osteopenia, osteoporosis, and bone fractures.

The bone builder, super-hero mineral, Calcium, requires Vitamin D for absorption and maintaining appropriate Calcium levels in the blood. Low blood levels of Vitamin D cause Calcium to be released from the bones to help maintain blood levels, which in turn, can cause softening and brittleness of our bones.

Boosting immunity

Our immune system constantly defends our body from foreign microscopic invaders. Research shows that low levels of vitamin D are associated with an increased susceptibility

to infection as well as multiple types of autoimmune diseases including lupus, multiple sclerosis, and rheumatoid arthritis.

Cardiovascular health

Vitamin D deficiency is a known risk factor for cardiovascular disease. Combining Vitamin D and Calcium supplementation is thought to decrease the risk of heart failure by 25-37%. Additionally, adequate levels of Vitamin D may help regulate parathyroid hormone levels. This hormone regulates calcium in the blood. An increase in blood calcium is linked to hypertension, heart failure and stroke. Lastly, according to studies, Vitamin D supplementation may improve blood flow.

Brain Health

Research is establishing a link between age-related cognitive decline and Vitamin D deficiency since Vitamin D may have neuro-protective effects such as reducing protein buildup which has been shown to contribute to the development of Alzheimer’s disease.

Additionally, because Vitamin D is an antioxidant, adequate levels may help reduce or prevent oxidative damage to nervous tissue which also contributes to cognitive decline.

Finally, high dose supplementation of Vitamin D may improve visual memory.

How much vitamin D do you need?

The Food and Nutrition Board at the Institute of Medicine sets intake guidelines for both macro and micronutrients, known as the Recommended Dietary Allowance (RDA). The

RDA for Vitamin D establishes a daily intake sufficient to maintain bone health and normal calcium metabolism for most healthy people.

Also established is the Upper Intake Level (UL), which is the maximum daily amount that is unlikely to cause adverse effects. Vitamin D is a fat-soluble vitamin and is thus stored in fat cells as well as the liver. Excess amounts can build up to dangerous levels, causing high blood calcium, contributing to heart, blood vessel, and kidney damage. Vitamin D levels should be tested on a semi-annual or annual basis, particularly when using clinical level supplementation. Some medical practitioners recommend a Vitamin D, 25-Hydroxy blood value as high as 50-80 ng/mL.

Vitamin D deficiency

Vitamin D deficiency is more common than you may think, approximately 41% of the population. Deficiency brings with it serious health concerns, including diabetes, cancer, osteoporosis, and high blood pressure.

Populations at the greatest risk of deficiency include older adults, inhabitants of the northern regions of the world, breastfed infants whose mothers have low levels of vitamin D, individuals with ethnic skin tones, those with a Body Mass Index (BMI) ≥30 indicating obesity, and patients suffering from chronic conditions affecting fat absorption such as Celiac Disease and Ulcerative Colitis.

How do I get enough Vitamin D?

Sun exposure...walking the line

Spending 5-30 minutes outside twice a week provides enough UVB exposure to meet vitamin D needs. When the UVB rays contact our skin, cholesterol in our skin cells react to convert the UVB rays into Vitamin D. This reaction is impacted by the amount of skin exposed to sunlight, as well as the melanin level in our skin. Darker ethnic skin has more melanin (pigment), causing less UVB ray absorption. Additionally, the required sun exposure needs to be accomplished without sunscreen for maximum UVB delivery. I hear you say, "Maxine...WHHHHATTTT??" Yes, emphatically yes, sun exposure can increase the risk of skin cancer, so only spend short periods of time in the sun without protection before or after the peak of the day for Vitamin D benefits.

Dietary sources

Natural food sources for vitamin D include:

· Beef liver

· Cheese

· Egg yolk

· Fatty fish (mackerel, salmon, and tuna)

· Some mushrooms (chanterelle, maitake, and UV-treated portabella)

Foods fortified with vitamin D sure to read the label:

· Dairy products (milk and yogurt)

· Non-dairy milk (almond milk)

· Orange juice


Because vitamin D is a fat-soluble vitamin, pairing vitamin D-rich foods or supplements with high-fat foods, such as avocados or nuts, can significantly increase absorption.

Vitamin K2, is often paired with vitamin D3, the preferred formulation, in supplements. Vitamin K2 enhances bone calcification while minimizing the accumulation of calcium in the blood vessels by driving calcium from our blood into the bones.

Where do I purchase high quality D3 & K2 and Calcium supplements?

You can click on the Fullscript shopping link to find my best picks, Dr Mercola Vitamins D3 & K2 and Integrative Therapeutics OsteoPrime Forte Bone Formula.

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