Stress is a common part of daily life. When we feel stressed, our bodies produce stress hormones like cortisol to help us respond to perceived threats. Prolonged stress can take a toll on physical and mental health. Some research suggests that stress may also negatively impact vitamin D levels in the body. Vitamin D is important for bone health and proper immune function. This article reviews the evidence on whether stress lowers vitamin D levels.
What is vitamin D?
Vitamin D is a nutrient that helps the body absorb calcium and phosphorus. These minerals are essential for building and maintaining strong bones and teeth.[1] Vitamin D also supports immune system function, brain development, and cell growth.[2]
There are two main forms of vitamin D:
– Vitamin D2 (ergocalciferol): Found in plant sources like mushrooms.
– Vitamin D3 (cholecalciferol): Made in the skin when exposed to sunlight and found in animal sources like fatty fish and egg yolks.
Vitamin D3 is the more active form and is produced in the body when sunlight converts cholesterol in the skin into previtamin D3. The liver and kidneys then convert previtamin D3 into the active form of vitamin D3.[3]
Very few foods naturally contain vitamin D. Oily fish like salmon and mackerel are among the best food sources. Since it’s challenging to get enough vitamin D from diet alone, some foods like milk and cereal are fortified with vitamin D.[4]
Vitamin D is sometimes called the “sunshine vitamin” because sun exposure is the main natural source. Just 15–30 minutes per day of direct sunlight on the arms, legs, and back can satisfy vitamin D needs for lighter-skinned individuals. Those with darker skin need a little more sun exposure to produce adequate vitamin D.[5]
Vitamin D deficiency
Vitamin D deficiency is common worldwide but especially prevalent in regions far from the equator where sunlight is limited in the winter months. Deficiency is also widespread in countries where skin covering clothing is common.[6]
According to estimates, roughly 1 billion people worldwide have deficient blood levels of vitamin D.[7]
In addition to limited sun exposure, risk factors for deficiency include:[8]
– Having darker skin. Melanin reduces vitamin D production.
– Being older. Skin loses its ability to synthesize vitamin D with age.
– Obesity. Vitamin D gets deposited in body fat stores.
– Malabsorption disorders like celiac disease. This impairs vitamin D absorption from food.
– Kidney and liver disease. These conditions impair vitamin D activation.
Without sufficient vitamin D, bones can become thin and brittle. In children, vitamin D deficiency causes rickets, which results in skeletal deformities.[9]
In adults, severe deficiency leads to osteomalacia, or softening of the bones. Milder vitamin D deficiency can precipitate osteoporosis, a condition characterized by gradual bone loss.[10]
Low vitamin D levels are also associated with an increased risk of infections, autoimmune diseases, cardiovascular disease, psychiatric conditions, and cancer.[11]
How might stress impact vitamin D levels?
Research suggests that stress may lower vitamin D levels through several mechanisms:
1. Decreased sun exposure
Stress, anxiety, and depression can reduce outdoor activity and sun exposure. Limited sunlight means less vitamin D production in the skin.[12]
A study in 18,883 adults found that depressed individuals had a 12% higher risk of vitamin D deficiency compared to non-depressed people. The decreased outdoor activity associated with depression likely contributed to this deficiency.[13]
2. Disruption of vitamin D metabolism
Some studies indicate that stress hormones like cortisol may interfere with vitamin D activation and metabolism.
A study in healthy women found that a dose of cortisol decreased blood levels of activated vitamin D3 by 24% over 8 hours.[14]
Other research shows that cortisol slows vitamin D’s synthesis and binding to receptors on cells.[15]
By hampering molecular pathways, elevated cortisol levels may disrupt the body’s ability to maintain adequate vitamin D status.
3. Unhealthy lifestyle habits
Stress often coincides with other behaviors that can lower vitamin D levels, including:[16]
– Poor diet: People undergoing stress may eat fewer vitamin-D-rich foods like fish and eggs.
– Sedentary routines: Stress and low motivation levels can reduce exercise and outdoor activity.
– Increased weight: Stress drives overeating and weight gain in some individuals. Excess body fat sequesters vitamin D.
– Smoking: Cigarette smoke may alter vitamin D activation.
– Excess alcohol: Heavy drinking interferes with vitamin D absorption and activation.
Fixating on stressors often takes precedence over healthy lifestyle habits. As a result, stressed individuals may be at increased risk of vitamin D deficiency.
4. Impaired kidney and liver function
Chronic stress may eventually induce subtle changes in kidney and liver function. Since these organs activate and maintain vitamin D levels in the body, changes to their structure and performance could disturb vitamin D metabolism in the long run.[17]
However, more research is needed to confirm whether kidney and liver problems link stress to vitamin D deficiency.
5. Associated health conditions
Health issues associated with high stress may independently lower vitamin D levels. For example:
– Obesity: Excess fat binds and draws in vitamin D.[18]
– Inflammation: Impairs vitamin D activation and absorption.[19]
– Gut disorders: Can reduce dietary vitamin D absorption.[20]
– Chronic pain: Results in less outdoor activity.[21]
By contributing to inflammation, weight gain, inactivity, and illness, prolonged stress may multiply the risk of low vitamin D levels.
Does fixing vitamin D deficiency reduce stress?
While stress may lower vitamin D levels, there’s also evidence that vitamin D supplements may alleviate anxiety and depression.
In one double-blind study, healthy adults took a high dose vitamin D supplement or placebo weekly for 5 weeks. Vitamin D supplementation led to decreased symptoms of anxiety and depression compared to placebo.[22]
Another study in people with fibromyalgia found that high-dose vitamin D reduced symptoms of depression and anxiety by over 30%. However, lower vitamin D doses didn’t improve psychological distress.[23]
The anti-inflammatory and neuroprotective properties of vitamin D may underlie these mental health benefits.[24] Correcting deficiency may also prevent conditions associated with low vitamin D like chronic pain, obesity, and gut inflammation that can exacerbate mood issues.
Overall, clinical trials demonstrate that vitamin D supplements can lessen anxiety and depression in certain groups, particularly people with severe deficiencies.[25] Whether supplementation also reduces perceived stress still needs further research.
Can you get too much vitamin D?
The recommended daily intake for vitamin D is:
– 600 IU (15 mcg) for most adults up to age 70.
– 800 IU (20 mcg) for those over 70.
The safe upper limit for vitamin D is 4,000 IU (100 mcg) for adults. Kids over age 9 shouldn’t exceed 4,000 IU daily.[26]
Consuming too much vitamin D over long periods can cause excess calcium buildup in the blood. This leads to side effects like:[27]
– Nausea, vomiting, poor appetite
– Stomach pain, constipation
– Increased urination and thirst
– Kidney stones
– Bone loss
– Confusion, delirium
High vitamin D may also interact with certain heart medications. Unless correcting deficiency, most adults don’t need more than the recommended daily vitamin D intake from foods and supplements combined.
Excess sun exposure doesn’t cause vitamin D toxicity because the body regulates how much gets synthesized in the skin.[28]
Signs of vitamin D deficiency
The main symptom of severe vitamin D deficiency is bone pain caused by osteomalacia. Milder deficiency usually has no overt symptoms.[29]
Along with pain, signs of significant vitamin D deficiency can include:[30]
– Muscle weakness, spasms, or cramps
– Joint pain or stiffness
– Difficulty thinking and concentrating
– Headaches
– Depression, anxiety, irritability
– Fatigue, tiredness
– Frequent sickness and infections
– Slow wound healing
– Hair loss
– Bone loss, fractures
These non-specific symptoms also coincide with many other conditions. Blood levels below 30 ng/ml (75 nmol/l) confirm vitamin D deficiency.[31]
Doctors may order a 25-hydroxy vitamin D blood test if deficiency is suspected. Levels below 20 ng/ml (50 nmol/l) indicate deficiency.
Optimal vitamin D status is thought to be between 30-80 ng/ml (75-200 nmol/l). The highest absorption of calcium from the intestines occurs when blood vitamin D levels reach 80 ng/ml (200 nmol/l).[32]
Food sources of vitamin D
Very few foods naturally contain vitamin D. The best dietary sources include:[33]
Wild-caught fatty fish:
– Salmon: 600–1000 IU vitamin D in 3.5 ounces (100 grams)
– Mackerel: 360 IU in 3.5 ounces
– Sardines: 270 IU in 3.5 ounces
– Tuna: 228 IU in 3.5 ounces
– Herring: 288 IU in 3.5 ounces
Fish liver oils:
– Cod liver oil: 1,300 IU in 1 teaspoon
Whole eggs:
– 20 IU in 1 standard egg yolk
Mushrooms:
– White mushrooms: 11 IU in 3.5 ounces
– Portobello mushrooms: 19 IU in 3.5 ounces
– Morel mushrooms: 22 IU in 3.5 ounces
Fortified foods:
– Cow’s milk: 115–124 IU per cup
– Soy milk: 119 IU per cup
– Orange juice: 137 IU per cup
– Cereal: 40–50 IU per serving
– Yogurt: 20 IU per 6 ounces
Beef liver, cheese, and egg yolks contain modest amounts of vitamin D. But it’s very challenging to get enough vitamin D from food without abundant oily fish intake.
Sunlight accounts for 90% of vitamin D intake. Just 10-15 minutes of midday sun exposure to bare skin synthesizes about 10,000–20,000 IU vitamin D.[34] However, vitamin D production is drastically reduced during winter at latitudes above 37° north or below 37° south of the equator.[35]
How much vitamin D should you take for deficiency?
The dose of supplemental vitamin D needed to correct deficiency depends on the severity. Those with mild to moderate deficiency are typically advised to take 2,000–5,000 IU (50–125 mcg) of vitamin D per day for 8–12 weeks to restore adequate levels. Higher doses may be used under medical supervision.[36]
For maintenance after repletion, most adults require 1,000–2,000 IU (25–50 mcg) of vitamin D daily from food and supplements combined. Older adults, the obese, and those with limited sun exposure benefit from the higher maintenance dose.[37]
Unlike vitamin D, the active hormone calcitriol is available only by prescription. Doctors may prescribe calcitriol to treat deficiency in those with severe fat malabsorption or very low blood calcium levels.[38]
Typical treatment of vitamin D deficiency:[39]
– Mild deficiency (20-29 ng/ml): 2,000 IU vitamin D per day
– Moderate deficiency (10-19 ng/ml): 5,000 IU vitamin D per day
– Severe deficiency (Sun exposure guidelines
Below are sensible sun exposure guidelines to balance vitamin D needs with skin cancer risk:[40]
– Expose large areas of skin, such as the back, arms, legs, and chest. Avoid excess sun on the face.
– Aim for 10–30 minutes between 10 AM – 3 PM, when UVB rays are strongest. Avoid midday sun in tropical regions.
– Those with darker skin need at least 30 minutes exposure due to higher melanin levels.
– Know your latitude. Vitamin D production is very limited or absent in winter above 37° north or south of the equator.
– Don’t exceed 30 minutes even in winter. After that, vitamin D synthesis plateaus while skin cancer risk keeps rising.
– Use sunshine, not sunbeds. UV machines also raise skin cancer risk.
– Cover up or seek shade when skin starts to redden or burn.
– Use broad-spectrum sunscreen of at least SPF 30 on the face and exposed skin outside peak sunshine hours.
Should you take vitamin D with magnesium?
Research suggests there may be benefits to taking vitamin D and magnesium supplements together.
Magnesium assists in activating vitamin D. Studies show magnesium intake has a significant impact on vitamin D status — deficiency impairs the body’s ability to activate and utilize vitamin D.[41]
Low magnesium levels are another widespread problem, with an estimated 30-80% of American adults not meeting the RDA of 320-420 mg per day for men and women.[42]
In addition, magnesium and vitamin D work synergistically to support bone and heart health.[43]
For these reasons, magnesium supplementation may enhance the effects of vitamin D pills or sunshine. Most multivitamin formulas include some magnesium. Standalone magnesium supplements can also be taken with separate vitamin D.
Adults can safely supplement with 200-400 mg magnesium per day, in divided doses with food to prevent diarrhea.[44] Unless prescribed by a doctor, avoid mega-dosing magnesium for extended periods.
The bottom line
Stress may potentially lead to lower vitamin D levels by reducing sun exposure, disrupting metabolic pathways, depleting nutrient stores, and worsening lifestyle habits.[45]
However, not all studies agree that stress directly causes vitamin D deficiency. Well-designed clinical trials are still needed to determine whether stress interventions like exercise, mindfulness, and therapy can improve vitamin D status.[46]
Correcting an existing vitamin D deficiency appears to alleviate low mood and depression. But it’s unclear whether vitamin D supplements relieve perceived stress in healthy people.[47]
For optimal health, it’s ideal to manage stress levels through tactics like time management, relaxation techniques, support networks, and professional help. Balancing lifestyle factors like diet, exercise, sleep, and sun exposure is also key for both mood and stable vitamin D levels.[48]
If experiencing symptoms like persistent tiredness or bone pain, get vitamin D levels tested. Correcting any deficiencies shown on bloodwork may then provide an extra mood and health boost. But vitamin D pills aren’t a standalone fix for the effects of chronic stress.[49]