Welcome to a new series on the blog: Nutrient Spotlight. Each week (Every Friday) I will share a quick reel on our instagram feed about one nutrient and it will be coupled with a detailed blogpost like this one! As we approach THHN's 5th year, I would really like to ramp up the educational aspect of the blog to really make it a one stop shop for heatlh and nutrition education in a simplified form that everyone can understand. I find that this isn't usually the case as nutrition information is usually filled with jargon and complex scientific information that isn't accessible to individuals who don't study nutrition science. I would like to bridge this gap. We will start with this series.
Vitamin D
The micronutrient, vitamin D (also known as calciferol or the sunshine vitamin) is a fat soluble vitamin which means it is better absorbed when there is fat present in the intestines. We can get vitamin D from food and we can make it in our skin when exposed to UV rays from the sun. There are two forms of vitamin D: Cholecalciferol which we get from animal sources such as eggs, milk, salmon, yogurt, tuna, canned fish etc; and ergocalciferol which we get from plant sources such as mushrooms, soy milk, tofu etc. Some plant milks as well as orange juice are fortified with vitamin D (usually indicated in the label). The vitamin D that we get from sun exposure is referred to as 25(OH)D- 25 hydroxy vitamin D. The vitamin D that we get from food and endogenous(in the skin) production needs to go through two reactions that modify it's chemical structure to activate it. The first reaction occurs in the liver to make 'calcidiol' and the second reaction occurs in the kidneys to make 'calcitrtiol'. Activated vitamin D is called calcitriol and will go on to exert its effects on the body and confer benefits. Vitamin D aids in the absorption of calcium and phosphorus. Calcium and phosphorus are both involved in bone mineralization and thus these three nutrients together are important for maintaining bone health. Vitamin is also involved in regulating the immune system and modulating inflammation. Vitamin D receptors(protein that allow cells to take in vitamin D) are present in a number of organs which means the vitamin might have additional roles- research is ongoing to explore this.
Recommended Dietary Allowance for Vitamin D
The recommended dietary allowance (this details the recommended intake of a nutrient that one should aim for daily to maintain health) for vitamin D varies by age. Under 12y/o - 400IU (10micrograms/mcg)
1-70y/o - 600IU (15mcg)
Over 70y/o - 800IU (20mcg)
Vitamin D Status, Intake and Deficiency
Serum vitamin D is typically what is used to assess vitamin D status (sufficiency/deficiency). Unfortunately, most people in the US are not getting sufficient vitamin D from the diet and are at risk of deficiency. As a result most will require supplementation and sunlight exposure. As mentioned in today's reel, don't take this information to mean that your vitamin D levels are low. Before taking supplements of any kind, confirm via blood test with your doctor that your status for that specific nutrient is low before you go and take supplements. Taking supplements when you aren't actually deficient in that nutrient could lead to nutrient toxicity (usually the case for nutrients in the supplement form) which can adversely affect your health.
A deficiency of vitamin D can result from limited sun exposure, eating a vegan diet that lacks vitamin D fortified foods, or if your kidneys have trouble converting vitamin D to its active form. Additionally, People who are lactose intolerant are also at risk of deficiency because their diet might be low in vitamin D. Some factors that hinder sufficient vitamin D synthesis from sun exposure include wearing long sleeve clothing or a lot of layers, not spending enough time outdoors, having melanin in the skin or living in a geographic location that doesn't get enough sunlight (long winters-northern hemisphere, above the equator). Melanin in the skin acts as a protective barrier from the sun and so individuals who have melanin(pigment in the skin) will need a longer exposure time in the sun in order to get enough vitamin D from the sun. Additionally, wearing sunscreen can also limit vitamin D synthesis in the skin because it essentially blocks UV ray penetration in the skin. With this in mind it is important to remember that UV radiation is a carcinogen and so please wear your sunscreen (even if you have melanin!).
Vitamin D deficiency can lead to increased risk of bone fractures and is also linked to depression as well. In the elderly population, vitamin D status is particularly of concern because the skin's ability to synthesize vitamin D from the sun declines with age and they tend to spend more time indoors. This group is at high risk for bone fractures and osteoporosis as a result. Low vitamin D intake in infants results in development of a bone deformity ('soft bones') condition known a rickets.
If you have any questions feel free to leave a comment under this blogpost or contact us on IG @theholistichealthnut.
See you next Friday for another nutrient spotlight.
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