Lesson 21b: Vitamin D

What is vitamin D?

Vitamin D, also known as cholecalciferol, is the form of natural vitamin D that is produced when your skin is exposed to sunlight. This essential nutrient’s most important function is its promotion of proper bone density, but vitamin D is also involved in cell growth, immune function, and inflammation reduction.

Is vitamin D water-soluble or fat-soluble?

Vitamin D is fat-soluble. Therefore, your body takes a while to dissolve and absorb this nutrient, and instead of immediately flushing out, vitamin D builds up in your tissues.

Where can vitamin D be found naturally? 

Vitamin D is most prevalent in fatty fish and fish liver oils. This nutrient is also available in small concentrations in dairy products, and some species of mushrooms also contain vitamin D. In general, however, animal products and artificially fortified foods and drinks are the only reliable food-based sources of this essential nutrient.

5 foods/drinks containing vitamin D

1. Cod liver oil 340% DV per 1 tablespoon or 15ml

2. Fortified milk 30% DV per 1 cup

3. Margarine 15% DV per 1 tablespoon

4. Tuna 39% DV per 85g

5. Cheddar cheese 4% DV per 1 cup 

What is the recommended daily intake for vitamin D?

The Office of Dietary Supplements (ODS) has set the recommended daily amount (RDA) of vitamin D at 15mcg for adult men and women. For adults over the age of 70, taking 20mcg of vitamin D per day is recommended.

What to consume to get a full daily dose of vitamin D?

Cod liver - approximately 1/3 tablespoon or 5ml

Fortified milk - approximately 3½ cups

Margarine - approximately 7 tablespoons

Tuna - approximately 225g

Cheddar cheese - approximately 25 cups

Can you absorb enough of vitamin D from food?

With a daily cod liver oil supplement, it’s easy to get enough vitamin D every day. Otherwise, you’ll need to go out of your way to eat seafood to get enough of this substance, and it’s possible that foods fortified with vitamin D may be inferior sources of this nutrient.

Why is vitamin D necessary for your body?

Adequate vitamin D intake is absolutely essential for maintaining healthy bone density. Without vitamin D, your body is unable to absorb dietary calcium, which results in a reduction in bone density and increased likelihood of sustaining fractures. Vitamin D is also involved in gene expression, and it helps your immune system function properly.

Functions of vitamin D

Blood calcium maintenance: Calcium is an important component of your blood, and your body can’t absorb this mineral without vitamin D.

Bone mineralization: Your body needs lots of vitamin D to promote proper bone mineralization, which is the process of adding calcium to your bone tissues.

Immune functions: People who get enough vitamin D in their diets are less likely to catch the flu and other common contagious conditions.

Anti-allergy functions: Children who consume enough vitamin D are less at risk of developing allergic conditions like eczema, asthma, and dermatitis.

Symptoms of vitamin D deficiency

Hypocalcemic Tetany

This condition occurs when you don’t have enough calcium in your blood. While hypocalcemic tetany only occurs in cases of severe vitamin D deficiency, this condition results in frequent and uncomfortable muscle spasms.

Bone Fracture

Since vitamin D is critical for transferring dietary calcium to your bones, being deficient in this nutrient increases your likelihood of sustaining bone fractures.

Frequent Illness

Vitamin D deficiency inhibits the effectiveness of your immune system, which can result in frequent illness and difficulty healing from infections.

How long do you need to take vitamin D to start experiencing its benefits if you’re deficient?

Your body takes a long time to absorb and process vitamin D, so the beneficial effects of supplementing with this nutrient when you’re deficient can take a while to become apparent. Before vitamin D supplementation can take effect, this substance must be processes by various bodily tissues.

How long does it take for your body to digest/absorb vitamin D?

The absorption rate of vitamin D varies from person to person. Under ideal circumstances, it’s possible to absorb around 100% of the vitamin D you consume, but certain absorption issues, called “malabsorption complications,” can reduce your ability to absorb vitamin D. As a general rule, vitamin D absorption is increased by the presence of fats in your diet.

How long does vitamin D stay in your body after you take it?

The vitamin D you consume may stay in your body for days, weeks, or even months as your body stores it for future use.

Is vitamin D an antioxidant?

The current status of vitamin D antioxidant status is highly controversial. Scientists aren’t entirely sure whether this substance exerts antioxidant activities, but many studies indicate that vitamin D reduces oxidative stress.

Can you overdose on vitamin D? What are the effects?

Since vitamin D is a fat-soluble nutrient, it’s relatively easy to overdose on this vitamin. Signs of moderate vitamin D overdose include anorexia, heart arrhythmia, and weight loss. However, this nutrient’s most dangerous overdose symptom is excessive levels of blood calcium, which can cause calcification in your veins, arteries, and heart.

Cardiovascular calcification dramatically increases your risk of stroke, heart attack, and other cardiovascular conditions. You can avoid these conditions by making a point not to exceed your RDA of vitamin D.

Does vitamin D dissolve, flush out, or build up in the body?

Vitamin D flushes out of your body eventually. However, it builds up in fatty tissues before it is used.

Can you take vitamin D during a diet?

Taking vitamin D doesn’t interfere with dietary restrictions, in fact, consuming plenty of this vitamin improves overall nutrient absorption.

Are there synthetic forms of vitamin D?

There are quite a few different synthetic forms of vitamin D. Some examples include maxacalcitol, calcipotriol, and dihydrotachysterol.

Why might synthetic forms of vitamin D be better?

Some synthetic forms of vitamin D lack certain detrimental aspects of natural vitamin D. For instance, they might have wider therapeutic windows, lack certain types of carbon, or require less processing by your organs.

Absorption rate of synthetic vitamin D

One type of synthetic vitamin D, dihydrotachysterol, appears to have a better absorption rate since it’s processed directly in the liver without having to go through the kidneys.

Why might natural forms of vitamin D be better?

Due to the different way that your body processes synthetic vitamin D, it might be easier to overdose on synthetic forms of this nutrient.

How to take vitamin D

You can take vitamin D in food, in the form of a liquid cod liver oil supplement, or in a daily multivitamin.

Why everyone should be taking WeAreFeel supplements

There’s been a lot of controversy surrounding vitamin D in recent years. While some skeptics have begun to think that supplementing with vitamin D isn’t necessary, it’s a solid fact that your body needs plenty of vitamin D to maintain proper bone density, blood calcium, and immune resistance.

For many people, getting enough vitamin D from food every day simply isn’t possible. Here at WeAreFeel, we understand that dietary restrictions and busy lifestyles can inadvertently lead to bad nutrition, which is why we include your full RDA of natural vitamin D in every capsule of our revolutionary multivitamin. Instead of messing with synthetic vitamin D, messy cod oil, or violating your dietary restrictions, keep up with your daily vitamin D intake with Feel!