Join Dr. James Odell for Season 2 of the Science of Self-Healing Podcast! He's the medical and executive director for BRMI, as well as a practicing naturopathic doctor for over 35 years, and he's here to share with you his extensive knowledge of medicine from a different perspective.
Nearly half of Americans don't get enough vitamin D, but does that mean you need a supplement?
In this episode, you'll learn how vitamin D keeps your immune system strong, your bones healthy, and your mood balanced - plus discover even more surprising benefits. We'll break down everything you need to know about the "sunshine vitamin," from how your body naturally produces it to how it works together with other nutrients to keep you healthy.
You'll discover who's most likely to need supplements and get clear guidance to make the right choice for your health. We'll cut through the confusion about supplementation, share what the latest research tells us, and provide practical strategies to optimize your vitamin D levels throughout the year. Whether you're feeling tired, fighting off winter colds, or just want to stay healthy, this episode will help you make sense of the vitamin D puzzle and take control of your wellbeing.
Transcript: Should You Take a Vitamin D Supplement?
Welcome to the Science of Self-Healing Podcast where we explore health and wellness from a different perspective. Produced by the Bioregulatory Medicine Institute, that's BRMI. We provide valuable insights on how to naturally support your body's ability to self regulate, adapt, regenerate, and self heal.
I'm Dr. James Odell, your host and the executive and medical director of BRMI with over 35 years experience as a naturopathic doctor. Please note that this podcast is for informational purposes only and not a substitute for personalized medical care.
Before we start today's podcast, I invite you to join us for BMI's extraordinary conference retreat. It's entitled Charting Your Course to Optimal Health. From May 10th through the 18th, 2025, this eight night cruise on Celebrity Cruises will take you through the stunning ABC islands that's Aruba, Bonaire and Curacao. Departing from Fort Lauderdale, our event welcomes anyone passionate about health and longevity. Whether you're a practitioner, inventor, vendor or simply just curious about healthier living, please join us. Enjoy a perfect mix of learning and relaxation while deepening your understanding of bioregulatory medicine. For more details, please visit this page.
In today’s podcast we’re diving into a critical health topic that affects nearly half of all American adults: vitamin D deficiency. If you've ever wondered whether those winter blues might be linked to low vitamin D, or if you should join the millions of people taking vitamin D supplements, you're not alone. About 42% of Americans aren't getting enough of this crucial nutrient, and the numbers tend to climb even higher during the darker winter months.
Today we're going to discuss everything you need to know about vitamin D - from how your body uses it to stay healthy, to the latest research on supplementation. We'll explore practical ways to optimize your vitamin D levels, whether that's through sunlight, diet, or supplements. And most importantly, we'll look at how this "sunshine vitamin" works together with other nutrients to keep your body functioning at its best.
By the end of our discussion, you'll understand exactly what your body needs and how to make informed decisions about vitamin D, especially during those sun-scarce winter months. Whether you're dealing with fatigue, concerned about your immune system, or simply want to optimize your health, this information could be a game-changer for your wellbeing.
Let’s start by explaining the importance of vitamin D. This nutrient plays a central role in keeping our bodies strong and healthy, starting with our bones and teeth. It helps us absorb calcium and maintain the right balance of minerals in our blood, which prevents bone-weakening conditions like rickets in children and soft bones in adults. It also keeps our muscles working properly, which is especially important for older adults since it helps prevent falls and broken bones.
In addition to protecting our bones, vitamin D is a key player in our immune system. It helps fight off infections and may reduce the risk of autoimmune conditions like multiple sclerosis. Some research even suggests it helps lessen the severity of illnesses like the flu and COVID-19. Your mental health can benefit from vitamin D too, as it appears to affect mood and may help with depression.
Scientists have found other potential benefits of vitamin D as well, though more research is still needed in some areas. It might help protect against certain types of cancer, including colon, breast, and prostate cancer. There's also evidence that it could boost heart health and help with weight management when paired with calcium. Some studies even suggest it can lower the risk of type 2 diabetes. And other studies suggest that it is good for the liver and other organs and plays a role in the regulation and expression of thousands of genes in your body.
So, let’s talk for a moment about how our bodies synthesize vitamin D…
Our bodies naturally produce vitamin D when sunlight hits our exposed skin, specifically when ultraviolet B (UVB) rays trigger vitamin D synthesis in the skin cells. When UVB rays hit the skin, they convert a form of cholesterol called 7-dehydrocholesterol into pre-vitamin D3, which then becomes vitamin D3. However, this process only works in areas where the sun's rays are direct and strong enough to penetrate the atmosphere. This is why latitude matters so much for vitamin D production – the farther you are from the equator, the more the sun's rays have to travel through the atmosphere, which filters out UVB radiation.
For instance, in locations above 37 degrees latitude (roughly the latitude of San Francisco), the sun's rays aren't strong enough for vitamin D production during most winter months. Time of day also matters significantly – UVB rays are strongest between 10 AM and 3 PM when the sun is highest in the sky. Even during these peak hours, factors like cloud cover, air pollution, sunscreen use, and glass windows (which block UVB rays) can prevent vitamin D production. Additionally, people with darker skin need more–perhaps even two to five times as much–sun exposure than those with lighter skin to produce the same amount of vitamin D, since melanin acts as a natural sunscreen.
It’s also important to know that Vitamin D levels can only be stored in your fat tissue and liver for about 2-3 months, although this is very variable from person to person. Several factors affect how well your body stores and maintains vitamin D levels: your initial vitamin D status, body fat percentage (since vitamin D is fat-soluble, people with more body fat can store more), sun exposure, skin tone, age (people ages 65 and over don't produce and store it as efficiently– typically only one-fourth as much as people in their 20s do), overall health (especially liver and kidney function), individual metabolism rates, and perhaps even your gut microbiome.
Without regular intake from sunlight, food, or supplements however, vitamin D levels will start to decline after this storage period. This is particularly noticeable during winter months when sun exposure is limited – even people who build up good stores during summer often see their levels drop significantly by winter's end.
Lack of sun exposure during winter wouldn't be a significant problem if our diet provided enough vitamin D. However, there aren't many foods rich in vitamin D, and you'd need to eat large quantities to meet the recommended daily allowance (RDA). But, let's discuss some food sources that can help boost your vitamin D intake.
Keep in mind that the current recommended daily amount of vitamin D is 400 international units (IU) for babies under 12 months, 600 IU for people ages 1 to 70 years, and 800 IU for people over 70 years.
One of the highest sources of vitamin D comes from fatty fish. Wild-caught salmon is the best, providing around 988 IU of vitamin D per 3.5-ounce serving, compared to farmed salmon's 240 IU. Other good options include sockeye salmon (570 IU per 3 ounces), rainbow trout (645 IU per 3 ounces), and mackerel. Canned fish like sardines offer about 193 IU per 3.5-ounce serving, and fresh Atlantic herring provides 214 IU per 3.5-ounce serving.
A whole egg contains about 34 IU of vitamin D while pasture-raised eggs contain three to four times that amount, or around 100 IU or more.
Certain mushrooms, especially when exposed to UV light, are also high in vitamin D. Crimini mushrooms can contain up to as much as 1,595 IU per 100 grams (but this can vary greatly), and UV-exposed portobello mushrooms provide about 795 IU per cup.
For those who don't eat fish or mushrooms, fortified foods are also a source. Fortified cow's milk typically has 115-124 IU per cup and a cup of fortified orange juice is about 100 IUs.
Just one teaspoon of cod liver oil also contains high levels of vitamin D with about 400 to 1,000 IU – that’s a significant source of vitamin D, especially for those with limited sun exposure.
However, high doses of cod liver oil can cause side effects like heartburn, stomach upset, nausea, and increased bleeding risk. Excessive vitamin A from cod liver oil can lead to toxicity, causing dizziness, nausea, joint pain, and even liver damage in severe cases.
When choosing cod liver oil, look for third-party-tested products for purity and quality. Certifications from the International Fish Oil Standards (IFOS) program can ensure high quality. Opt for sustainably sourced cod from clean, cold waters, and consider flavored versions like lemon or orange to mask the fishy taste.
As with any supplement, it's best to consult with a healthcare provider before starting cod liver oil, especially if you're pregnant, have a medical condition, or are taking other medications.
Before we move onto what the research says, I just want to talk about the paradox of both high and low vitamin D status causing problems, and the synergistic importance of other nutrients alongside vitamin D.
The vitamin D paradox is that both too little and too much of this nutrient can impact health negatively. While low vitamin D levels can lead to weak bones, impaired immune function, and increased disease risk, very high levels can also cause problems, particularly by increasing calcium absorption too much, leading to calcium deposits in soft tissues like blood vessels and organs.
Researchers are theorizing that problems may arise because vitamin D needs to be balanced with several key nutrients such as vitamins A and K, and minerals magnesium and calcium.
Here’s how they work synergistically. Vitamins A and K work alongside vitamin D to ensure proper calcium handling in the body. Vitamin K, particularly K2, helps direct calcium into bones and teeth where it's needed, while preventing it from depositing in soft tissues. Vitamin A works synergistically with vitamin D to regulate calcium metabolism and helps prevent vitamin D toxicity.
Magnesium and calcium add another crucial layer to this nutrient interaction. Magnesium is essential because it's required for vitamin D to be converted into its active form and to carry out its functions. Without adequate magnesium, vitamin D supplementation might not be effective and could even cause problems by increasing calcium absorption without proper magnesium balance. Meanwhile, vitamin D helps your body absorb calcium from your diet, but this process needs to be carefully regulated.
Think of it as a complex partnership: vitamin D helps absorb calcium, vitamin K2 acts like a traffic cop directing calcium to bones instead of soft tissues, vitamin A helps regulate the whole process, magnesium activates vitamin D and helps control calcium movement, and calcium itself is the mineral being carefully regulated by all these nutrients. This intricate interplay explains why focusing on vitamin D alone, without considering these other nutrients, might not provide optimal health benefits. It's why many health experts now recommend ensuring adequate intake of all these nutrients together, rather than supplementing with vitamin D in isolation.
In addition, lysine and vitamin D work together to enhance bone health, calcium absorption, and immune function. Lysine helps the body absorb calcium and produce collagen, which is vital for bone strength, while vitamin D facilitates calcium absorption from the intestines. Together, they ensure efficient use of calcium in the body. Additionally, both contribute to a robust immune system, with vitamin D modulating immune responses and lysine offering antiviral properties. Their combined effects promote overall tissue health and repair, making them a powerful duo for maintaining overall health.
Another area of focus on vitamin D optimization relates to individual variability. Not everyone will experience a significant drop in vitamin D levels during winter.
This is because genetic variations, beyond just skin tone differences, play a big role in how our bodies handle vitamin D, both from sunlight and supplements. These differences in our genes can affect every step of the vitamin D process in our bodies. Some people's skin might be really good at making vitamin D when exposed to sunlight, while others might not produce as much even with lots of sun exposure. Similarly, some people's bodies are better at converting vitamin D into its active form, while others might struggle with this process. Genetic differences may also affect how vitamin D is carried around in our blood and how well our cells respond to it.
These genetic variations explain why vitamin D levels can vary so much from person to person, even when they have similar sun exposure or take the same amount of supplements. Some people might need very little sun or supplements to maintain healthy vitamin D levels, while others might need much more. This is why a one-size-fits-all approach to vitamin D doesn't always work.
Now let’s get into the research studies for specific conditions. Let’s start with Vitamin D & Cardiovascular Health
In 2023, researchers reviewed 80 clinical trials on vitamin D and its impact on heart health and mortality. The findings, published in the Journal of Nutrients, showed that vitamin D supplements reduced overall mortality in some high-quality trials. However, there was no significant effect on cardiovascular mortality, heart attacks, strokes, heart failure, or other major cardiovascular events. Despite some promising results, more well-designed studies are needed to determine the optimal use of vitamin D for cardiovascular health.
Vitamin D & the Immune System
Studies on vitamin D and immune system diseases show mixed results. A large study found that people taking vitamin D had a slightly lower risk of autoimmune diseases, dropping from 12 to 9.5 per 1,000 people. However, vitamin D didn't clearly prevent any specific autoimmune disease. The connection between vitamin D and the immune system is complex, but it appears to help keep the immune system balanced and might protect against some immune-related diseases, especially in those with vitamin D deficiency.
Vitamin D & Mental Health
Vitamin D supports brain health and development, influences mood regulation, and helps maintain healthy sleep patterns. Some studies show that vitamin D supplements can improve depression, particularly in overweight and obese individuals, due to its role as a neurosteroid hormone. For epilepsy, research indicates that many individuals with the condition have low vitamin D levels, and supplementation can reduce seizure frequency. One study showed an average 40% reduction in seizures among participants taking vitamin D. However, the effects of vitamin D on bipolar disorder and schizophrenia are less clear, with inconsistent results from supplementation studies.
Vitamin D & Metabolic Health
Research suggests that vitamin D supplements may benefit people with type 2 diabetes by reducing inflammation and oxidative stress, potentially slowing the disease and lowering the risk of heart problems. In type 1 diabetes, animal studies indicate that vitamin D might delay disease onset and boost helpful immune cells.
The challenges of studying vitamin D’s effects on health
Despite vitamin D's many potential benefits, most randomized controlled studies haven't shown clear positive results when testing vitamin D supplements. There are several reasons for this:
It takes a long time to see effects on chronic diseases, so studies need to be very long.
The way vitamin D is given matters. Large, infrequent doses might be harmful, while daily doses of 1000-2000 IU might be better.
Instead of comparing groups based on how much vitamin D they take, it might be better to compare people who reach normal vitamin D levels with those who don't.
The right amount of vitamin D might be different for different health issues. For example, you might need more vitamin D for immune system benefits than for bone health.
As mentioned earlier, people respond differently to vitamin D supplements. Some people's bodies use vitamin D very well, while others don't respond as much to the same dose.
Lastly, since vitamin D works synergistically, more studies need to look at how it interacts with other nutrients.
This past year, the Endocrine Society issued guidelines for vitamin D supplementation. Here’s what they have to say…
The researchers determined several groups need more vitamin D than the Recommended Dietary Allowance suggests. These recommendations affect a few groups: children ages 1 through 18, people over the age of 75, pregnant women, and those with prediabetes. They aren’t suggesting a specific dose, but they are saying more than 600 IU or 15 mcg from fortified foods and/or supplements.
Interestingly enough they also advise against routine testing for 25-hydroxyvitamin D levels in all populations because of a lack of clarity about what vitamin D levels are optimal for various conditions.
They also suggest that other groups of people should not exceed the daily recommendation of 600 IU unless they have an underlying condition that suggests otherwise.
And lastly, they tend to suggest against routine vitamin D supplementation for the general population (ages 19 - 74 years of age).
Here’s what I’m thinking… I have 10 recommendations regarding vitamin D supplementation:
A core principle of bioregulatory medicine is that we are all unique and have unique health needs. Therefore, it’s important to consider your unique traits (DNA), lifestyle, diet, health status, and concerns regarding vitamin D supplementation. While vitamin D is crucial for overall health, blanket recommendations for winter supplementation are not supported by current evidence. For many people, a combination of sensible sun exposure, a balanced diet, and targeted supplementation when necessary may be the most appropriate approach to maintaining optimal vitamin D levels year-round.
Really make sure that you get enough sensible sunshine from March until September by getting out in the mid-day sun, aiming for 10-30 minutes of midday sun exposure several times per week. Remember that your body is really good at self-regulation (another bioregulatory principle) and that your body can store vitamin D as well. And eat well - making sure that you get enough magnesium, calcium, vitamin A and vitamin K. An added benefit to sunlight exposure is that simultaneously, sunlight exposure also leads to the synthesis of cholesterol sulfate, which plays a crucial and multifaceted role in various biological processes.
Despite what the Endocrine Society recommends, I think that it’s a good idea to test for vitamin D deficiency through a blood test called 25-hydroxy vitamin D (25-OH D). This is considered the most accurate measure of vitamin D status in your body. While current medical guidelines consider levels below 20 ng/mL as deficient, research suggests this threshold may be too low for optimal health. For most people, maintain vitamin D levels between 30 and 50 ng/mL through a combination of sensible sun exposure and vitamin D3 supplementation when necessary.To maintain healthy vitamin D levels, it's recommended to test twice a year and adjust your sun exposure or supplementation based on the results. After making changes, retest in three to four months to ensure you've reached your target level.
Consider the risks of taking too much vitamin D from supplements since it can harm your health and cause hypercalcemia. This condition occurs when your body absorbs more calcium from your food and releases more calcium from your bones into your bloodstream. Normally, vitamin D helps maintain the right calcium levels, but excess vitamin D disrupts this balance. Your kidneys usually filter out extra calcium, but they can't keep up when there's too much, leading to a buildup of calcium in your blood. This typically happens from taking too many supplements, not from sunlight or food sources of vitamin D. Therefore, it's crucial to follow recommended dosages and consult your doctor before taking high doses. Hypercalcemia can cause calcium to be deposited in arteries as well as cause symptoms like nausea, weakness, and confusion. In severe cases, excess vitamin D can damage your kidneys or weaken your bones. Recent research suggests that even moderately high doses of vitamin D, around 3200-4000 IU daily, can increase the risk of hypercalcemia in some people. This is lower than the previously considered safe upper limit of 10,000 IU per day. Toxicity symptoms usually appear when blood levels of vitamin D exceed 150 ng/mL (nanograms per milliliter), which is much higher than the normal range.
For individuals who get limited sun exposure, have darker skin, are of older age, or have certain medical conditions, vitamin D supplementation should be considered. The University of Georgia linked low vitamin D levels with a greater risk of seasonal affective disorder (SAD). A 2020 study suggested that vitamin D supplementation during winter might help maintain healthier patterns of psychophysiological responses to stress. A personalized treatment approach and a prescribed dosing range from 600-2000 IUs (20-50 µg) would be a reasonable approach.
If you do feel that you should supplement, choose D3 (cholecalciferol) because it's more effective (about 40% more) at raising blood levels of vitamin D compared to vitamin D2. When choosing a supplement, look for products that have been third-party tested for quality and purity.
For dosage, recommendations vary. The recommended dietary allowance (RDA) is 600-800 IU per day for adults. The National Institutes of Health (NIH) suggests 600 IU (15 mcg) per day for people aged 1-70. Many health professionals recommend higher doses per day for optimal health benefits. The Vitamin D and OmegA-3 Trial (VITAL) showed that taking 2,000 IU daily is safe for most adults, with no signs of toxicity. However, until we know more, make sure your intake from supplemental sources doesn't exceed 2,000 IU per day, the current upper limit set by the National Academy of Sciences.
When taking vitamin D, it's beneficial to pair it with other vitamins and minerals to enhance its absorption and effectiveness.
Consider a vitamin D3 supplement made from lichen. It’s vegan and it is effectively absorbed, raising blood levels of vitamin D similarly to conventional animal-based vitamin D3. The biggest downside is the cost.
If you have certain medical conditions such as kidney disease, kidney stones, or a condition such as sarcoidosis or histoplasmosis, check with your doctor before taking vitamin D supplements. Vitamin D3 might increase calcium levels and increase the risk of kidney stones or kidney damage, and people with sarcoidosis or histoplasmosis can experience an increase in the body's vitamin D production, leading to high levels and potential toxicity.
The science of vitamin D continues to evolve, and while researchers work to fully understand its role in our health, we can take a balanced approach to maintaining healthy vitamin D levels. Our bodies are naturally equipped to regulate vitamin D when given the right tools - primarily adequate sunlight exposure and nutrient-rich foods. While some people may need supplements, supplementation should be approached thoughtfully and ideally with professional guidance based on current scientific understanding.
Thank you for tuning in today. Be well.
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