By Shannon Rivera
So many of us avoid the sun at all costs including slathering on sunscreen every time we venture out. There is a time and place for sunscreen as the UVA and UVB rays from the sun can be damaging to the skin when exposed for long periods of time. However, daily exposure of our skin to the sun for limited times is the best way to get natural vitamin D according to the Vitamin D Council.
Vitamin D (which is not a vitamin at all but a prohormorne) is fat soluble which means it needs adequate dietary fat to breakdown and be absorbed. Vitamin D can be obtained through foods (both fortified and naturally containing), supplementation and made by our body from the sun. These various sources of vitamin D are biologically inactive (our body cannot use it in this form) until it is activated (a process called hydroxylation) in 2 ways; through the liver first. and second through the kidneys where it is changed to the active form of vitamin D — 1,25 dihydroxyvitamin D OR D3 (National Institutes of Health). So the intake of vitamin D is not enough to sustain adequate vitamin D levels; the function of the liver and kidneys are one of the determinants of how well vitamin D can actually be made and utilized. Additionally, a well functioning gut is essential to vitamin D absorption. The presence of vitamin D enables the absorption of calcium (from the intestines) and helps to maintain balance between calcium and phosphorus, which in turn helps make our strong bones. Insufficient vitamin D can lead to insufficient calcium absorption, leading to things like osteopenia, osteoporosis and osteomalacia (1).
Vitamin D receptors are located throughout the body and when vitamin D attaches to these receptors it has the potential to influence how genes express themselves(10). So vitamin D, or lack there of, has the ability to influence our health in various ways.
Forms of vitamin D
There are two forms of vitamin D, both can be converted for use by the body.
D3, converted by the skin from exposure to ultraviolet B rays (sun), and
D2, found in plants and fungi that have been exposed to UVB (2).
What Should My Vitamin D Level Be?
The Institutes of Medicine concludes that a serum vitamin D level of <25nmol/L is considered deficiency, <30nmol/L is at risk for becoming deficient and >50nmol/L is considered sufficient. Levels of >125nmol/L is associated with other adverse health risks.
Did You Know?
- Insufficient vitamin D levels have been strongly associated with diseases/illnesses such as cancer, rheumatoid arthritis, multiple sclerosis, autoimmune hypothyroid, cardiovascular disease, diabetes, poor immune function, problematic nerve function, infections and obesity (2,3,4,11).
- Before antibiotics came on the scene in the late 1920’s, vitamin D supplementation, cod liver oil and sunlight were used to treat tuberculosis (2, 7) What vitamin D does is boost the innate immune system- this is the immune system you are born with and it’s ability to identify foreign invaders of the body and to attack them; in other words the innate immune system is fast acting to protect us from infection shortly after we are exposed (3).
- Vitamin D also modulates (balances) the immune system by supporting an important part of immune function– regulatory T cells (T regs). Tregs when sufficient and functioning well, are important in the prevention of autoimmune diseases (4).
- Sufficient serum vitamin D levels may be associated with having good blood sugar control and improving insulin sensitivity (6).
- Some research has found vitamin D deficiency in type II muscle fibers (fast twitch muscles). Type II fibers are important in quick reactions like preventing a fall and quick bursts of movement, for instance. Some degree of muscle atrophy was also found in the type II muscle fibers that were deficient in vitamin D(5).
- Other fat soluble vitamins, A and K, also influence Vitamin D and its function. These three vitamins work together for absorption, protecting the heart, maintaining good bone health, as well as prevention of vitamin D toxicity.
On another note, vitamin D deficiency can be indicative of hypocalcemia, or low calcium. As previously mentioned, one of the jobs of vitamin D is to balance calcium and phosphorus and keep calcium levels in the blood at an appropriate level. When calcium is low (as sensed by the parathyroid gland), vitamin D is activated and attempts to increase calcium levels by
- 1) increasing absorption of calcium through the food you eat, and/or
- 2) taking calcium from the bones (not so good) (8,9).
How is Vitamin D Measured?
25(OH) D is the best form of measurement for serum vitamin D status and is measured in nmol/L (1). Considering vitamin D status is dependent on other factors, other labs like PTH and calcium may also need to be evaluated along with vitamin D levels (9).
Vitamin D Containing Foods
The best UN-fortified sources of vitamin D are fatty fish such as wild caught Salmon, Mackerel and Tuna, as well as fish liver oils (Cod liver oil). Small amounts of vitamin D are also available in egg yolks, beef liver and cheese. I definitely encourage when buying fish to purchase wild caught (vs. farm raised), and buying grass-fed sources of beef & cheese, and eggs that are organic and pasture raised.
A Few Things to Consider When Evaluating Your Vitamin D Status.
- Do you get frequent infections
- Do you have any autoimmune disease
- Are you eating vitamin D rich foods
- Are you getting sun daily without applying sunscreen
- Do you eat enough healthy fats
- Do you have gastrointestinal problems that interfere with digestion and absorption of nutrients (gallbladder issues, leaky gut, IBS)
- Do you take medications that decrease vitamin D (antacids, corticosteroids)
Although there is only one reference range for vitamin D given for an entire population of people, individuality, ethnicity, and current health state has to be considered before randomly supplementing with vitamin D. Consider this; vitamin D supplementation without medical supervision has the potential for you to develop vitamin D toxicity which comes with consequences including heart attack, low bone density, headache, nausea, vomiting, and kidney stones to name just a few.
Shannon Rivera is a registered nurse, ACE certified health coach and Functional nutrition educator. She is a health coach at URENÜ LLC, helping people to restore balance and health to their life (YouRenewYou.com)
More Food For Your Brain
1. Institutes of Medicine. https://ods.od.nih.gov/
2. The vitamin D–antimicrobial peptide pathway and its role in protection against infection. https://www.ncbi.nlm.nih.
3. Molecular Biology of the Cell. 4th edition. https://www.ncbi.nlm.nih.gov/
4. Regulatory T Cells. Journal of Investigative Dermatology. https://www.sciencedirect.
5. Vitamin D and Its Role in Skeletal Muscle. https://www.ncbi.nlm.nih.
6.Vitamin D Deficiency and Risk for Cardiovascular Disease. https://www.ncbi.nlm.nih.
7. A Brief History of the Antibiotic Era: Lessons Learned and Challenges for the Future. https://www.ncbi.nlm.nih.
8. An Ancestral Perspective on Vitamin D Status, Part 2: Why Low 25(OH)D Could Indicate a Deficiency of Calcium Instead of Vitamin D. https://chrismasterjohnphd.com
9. Parathyroid Glands: Vitamin D and calcium levels. http://endocrinediseases.
10. A ChIP-seq defined genome-wide map of vitamin D receptor binding: associations with disease and evolution. https://www.ncbi.
Easy Reads and Videos
- Vitamin D: More Is Not Better. https://chriskresser.com/
- The Role of Vitamin D Deficiency in Thyroid Disorders. https://
chriskresser.com/the-role-of- vitamin-d-deficiency-in- thyroid-disorders/
- Chris Masterjohn, PhD. https://chrismasterjohnphd.