A vitamin D deficiency can make you tired, weak, and moody.
While millions of people struggle with a vitamin D deficiency, there’s good news - reversing it is simple. With a concerted effort to increase your dietary intake and supplement daily, it’s easy to get your levels back up to snuff. But if you’ve started supplementing and aren't seeing an immediate difference, you’re probably wondering: how long until vitamin D starts to work? The answer to that question isn’t as simple as x number of days or week, so this article dives into what you need to know. We’ll cover what vitamin D is and why you need it, its deficiency, the best time to supplement, how long it takes to increase levels, and the best places to find vitamin D.
What Is Vitamin D And Why Do You Need It?
Of the vitamin kingdom, vitamin D comes out somewhere near the top. It plays a role in dozens of critical physiological functions that maintain optimal health and well-being.
But although it is called a vitamin, vitamin D isn’t - it’s a fat-soluble prohormone steroid that exhibits endocrine, autocrine, and paracrine functions 1. The endocrine functions of vitamin D are primarily involved in calcium homeostasis. Vitamin D and calcium work in tandem to maintain calcium levels in the bloodstream via promoting calcium and phosphate absorption from the gut or mobilizing calcium from bone tissue 1.
However, when calcium levels are normal, vitamin D has little influence on calcium metabolism. The paracrine and autocrine functions, on the other hand, are dependent on genetic transcription unique to the specific cell type expressing vitamin D receptors 2.
Some potential effects include inhibiting cell proliferation, promoting cell differentiation, and apoptosis, all of which are involved in cancer, immunity, and many other organ systems.Simply put, vitamin D exerts its effects through the vitamin D receptors (VDR), which are found in nearly all cells in the body. Vitamin D has a widespread impact on many systems, including the immune, digestive, circulatory, muscular, and nervous systems1.Unlike most other vitamins that must be obtained through diet or food, your body can synthesize vitamin D via the skin 2.
Upon exposure to UVS rays from sunlight, 7-dehydrocholesterol, the precursor to vitamin D, in the skin is converted to pre-vitamin D3.
Pre-vitamin D3 is then converted to vitamin D3 through a nonenzymatic process in the plasma membrane and then transported to the bloodstream where it will exert its effects on various tissues. That said, while the sun is the best source of vitamin D, most people still don’t get enough. Vitamin D deficiency is a global pandemic, with an estimated one billion people sitting below recommended levels 3.
Vitamin D Deficiency
But how does vitamin D insufficient or deficiency happen with such ease of access?
For most people, lack of sun exposure is the primary cause of low vitamin D status. Any factor limiting the transmission of UVB rays to the skin will interfere with vitamin D synthesis and serum concentrations.Melanin is highly efficient in absorbing UVB radiation, and increased skin pigmentation (high melanin concentrations) will therefore reduce vitamin D3 synthesis 4.
As such, people with darker skin tend to produce less vitamin D. Similarly, frequent sunscreen wearing will also limit synthesis, as an SPF of just 15 will absorb 99% of UVB radiation. Geography, aging, and diet are also causes of low levels.If you think you’re low in vitamin D, watch out for these symptoms 5:
- Back pain
- Fatigue
- Frequent illness or infection
- Bone pain
- Mood changes
- Poor wound healing
- Bone loss
- Hair loss
- Weight gain
- Anxiety
If left untreated, chronically low vitamin D levels can lead to some heft consequences, such as:
- Loss of bone density
- Osteoporosis
- Increased fracture risk
If you want to avoid the nasty consequences of vitamin D deficiency, getting on top of your vitamin D intake is recommended.
Whether through increasing dietary intake, getting more sun exposure, or supplementation, it’s easy to bump up your levels.
What’s The Best Time To Take Vitamin D?
While it’s easy to lump vitamin D in with the rest of your morning or evening supplements for convenience, sometimes it’s worth considering when the best time to take your supplement is.
There’s a specific time when vitamin D supplementation is most effective. As a fat-soluble vitamin, vitamin D requires the presence of dietary fat for optimal absorption and utilization; this is why you’ll commonly see vitamin D emulsified in a fat source. A 2010 study published in the Journal of Bone Mineral Research found that participants saw the most significant increase in vitamin D serum concentrations when supplementation was taken with the largest meal of the day 6. In just 2-3 months, patients saw a massive 50% increase in levels.
A similar study found that people who took vitamin D alongside a high-fat meal increased levels by 32% after 12 hours compared to those who took it with a fat-free meal 7.
These studies suggest that having a fat source alongside a vitamin D supplement - unless emulsified in a fat - would maximize absorption and its effects. But there’s a fair bit of inconsistency where the ideal time to supplement goes. For some people, throwing their vitamin D supplementing in with their morning pill popping is the easiest way to remember - and that’s a great way to ensure it’s taken. But some research also suggests a link between vitamin D and sleep.
Some research shows a correlation between low serum vitamin D concentrations and sleep quality, but other research indicates that high blood levels can also interfere with sleep. Although there’s little available research, one study did find that increases in blood vitamin D levels in people with MS resulted in decreased melatonin levels - the hormone responsible for regulating your wake/sleep cycle 8.
Because sufficient levels of melatonin are required for sleep, low levels can cause frequent disruptions.
How Long Does Vitamin D Take To Work?
While it would be great to think that supplementing vitamin D can have immediate effects, it’s not that simple.
How long vitamin D will take to work depends on several factors - age, absorption status, underlying health conditions, and more.
But the primary factor involved in the time it takes for vitamin D to work is how severe the deficiency is; the greater the starting deficiency, the longer it will take for levels to return to normal. For most people, regular supplementation can increase serum concentrations to a normal range within about two to three months, but some people may see results faster.If you’re looking for a sign that vitamin D supplementation is working, circling back to your original symptoms can serve as an indication.
If you’re experiencing fatigue or bone pain, look for improvements in symptoms after a few weeks of starting supplementation.
Vitamin D Dosage
If you’re trying to increase your levels, mega-dosing can be tempting - but don’t.
Because vitamin D is a fat-soluble vitamin, it can accumulate in tissues and lead to toxicity. Instead, supplement with a moderate dosage for a longer duration to improve levels. The United States Institute of Medicine (IOM) RDI for vitamin D for people with limited sun exposure is 600 IU/day. In comparison, some other institutions recommend a higher intake with a maximum dose of 3200 IU/day 9.
Alternatively, doses around 2000 IU/day have effectively boosted vitamin D3 levels without risk of toxicity over a prolonged supplementation period 10.Alternatively, 20 minutes of direct sunlight daily can help to increase levels, but research finds that beyond that, it can start to degrade the vitamin in your skin 9.
As such, focus on short, frequent sun exposure with maximum skin exposed.
Where To Find Vitamin D
Whether you’re looking to increase vitamin D intake through diet or supplementation, there are plenty of easy ways.
Our favorite is the ultra-powerful due of Performance Lab NutriGenesis Multi combined with PL-Immune - they’re ultramodern formulas designed to maintain optimal health.
NutriGenesis Multi stacks 17+ of the most innovative nature-identical vitamin and minerals into one capsule to fill nutrient gaps in the diet and support healthy bioactivities.
PL-Immune, on the other hand, supplies the best immune-boosting nutrients to strengthen immune defenses for optimal immune performance.
They’re clean, effective, and entirely research-backed to boost levels of critical nutrients needed to sustain health.
Alternatively, dose up on your vitamin D-rich foods. While there aren’t many plant-based sources of vitamin D, some of the best options include for meat-eaters include:
- Cold-water oily fish (salmon, sardines, mackerel, herring)
- Egg yolks
- Organ meats
- Cod liver oil
- Fortified foods (cereals, plant milk, juices)
Keep in mind that if you’re struggling with low vitamin D levels, increasing your intake of vitamin D-rich foods probably isn’t enough, so ideally, combine dietary options and supplementation for the most beneficial effects.
References
- Mostafa WZ, Hegazy RA. Vitamin D and the skin: Focus on a complex relationship: A review. J Adv Res. 2015;6(6):793-804.
- Vanchinathan V, Lim HW. A dermatologist's perspective on vitamin D . Mayo Clin Proc. 2012;87(4):372-380.
- Hovsepian S, Amini M, Aminorroaya A, Amini P, Iraj B. Prevalence of vitamin D deficiency among adult population of Isfahan City, Iran. J Health Popul Nutr. 2011;29(2):149-155.
- Holick MF, Chen TC. Vitamin D deficiency: a worldwide problem with health consequences. Am J Clin Nutr. 2008;87(4):1080S-6S.
- Galesanu C, Mocanu V. Vitamin D Deficiency and the Clinical. Rev Med Chir Soc Med Nat Iasi. 2015;119(2):310-318.
- Mulligan GB, Licata A. Taking vitamin D with the largest meal improves absorption and results in higher serum levels of 25-hydroxyvitamin D. J Bone Miner Res. 2010;25(4):928-930.
- Dawson-Hughes B, Harris SS, Lichtenstein AH, Dolnikowski G, Palermo NJ, Rasmussen H. Dietary fat increases vitamin D-3 absorption. J Acad Nutr Diet. 2015;115(2):225-230.
- Golan D, Staun-Ram E, Glass-Marmor L, et al. The influence of vitamin D supplementation on melatonin status in patients with multiple sclerosis. Brain Behav Immun. 2013;32:180-185.
- Hartley M, Hoare S, Lithander FE, et al. Comparing the effects of sun exposure and vitamin D supplementation on vitamin D insufficiency, and immune and cardio-metabolic function: the Sun Exposure and Vitamin D Supplementation (SEDS) Study. BMC Public Health. 2015;15:115.
- Smith SM, Gardner KK, Locke J, Zwart SR. Vitamin D supplementation during Antarctic winter. Am J Clin Nutr. 2009;89(4):1092-1098.
