Are Vitamin D Supplements Worthless (or Worse)?

Posted on July 2, 2024

Woman with brown hair smiling with eyes closed in a tropical setting facing the sun

Vitamin D (aka calciferol) is crucial for numerous bodily functions. Some research suggests large populations are likely suffering from chronically low vitamin D levels. Yet a recent clinical trial from the Annals of Internal Medicine concluded calcium carbonate and vitamin D supplements were a bit of a double-edged sword. In a group of over 36,000 postmenopausal women, they were linked with decreased cancer rates, but also a higher incidence of cardiovascular problems.

While the supplements made no difference to all-cause mortality, the effects were still significant enough to warrant increased scrutiny of the role certain supplements play in our health. This means looking closely at how a vitamin or nutrient affects our bodies and any compound variations.

Taking a Second Look at Vitamin D Supplements

The calcium/vitamin D supplement study was funded by the NIH's National Heart, Lung, and Blood Institute. Its findings also came shortly after a 2022 study concluding vitamin D3 supplementation "did not have a significant effect on total fractures" among 25,000+ men and women over the ages of 50 and 55, respectively.

Although it's clear bone health depends on vitamin D, it appears calcium/vitamin D supplements themselves did not improve bone strength. The NIH study's findings also gave cause to avoid most vitamin D and/or calcium supplements, which increased the risk of heart and cardiovascular disease.

Understanding Vitamin D

Vitamin D is a steroid-like hormone that supports numerous bodily systems. One of those functions is to help the intestines absorb calcium and mineralize into bones. The problem is that various types of vitamin D vary by source, potency, and effect.
By interacting with other substances, vitamin D (and calcium) can also have very complex effects on the body at a wide scale. It gets even more confusing since calcium requires vitamin D for proper gut absorption—but excess vitamin D can increase serum (circulating) levels of calcium to unhealthy levels.

Whether for dietary or lifestyle reasons, many people trying to avoid vitamin D deficiency have turned to vitamin D supplements. Yet just as it's important to increase vitamin D levels, it's important to do so in the most effective way.

Why Is Vitamin D Important to Our Health?

Vitamin D provides numerous health benefits and can be helpful for health enthusiasts seeking:


  • Elevated mood and hormone production
  • Stronger bones
  • Greater immunity
  • Cell and organ function
  • Blood sugar control
  • Cardiovascular health


Given most people will face these issues at some point in their lives, it's no exaggeration to say increasing the right type of vitamin D intake, and in the right way, is a near-universal health need.

Yet with so many types and sources of vitamin D, the question is, which one carries the highest benefits and minimal drawbacks?

What's the Difference Between Vitamin D and Vitamin D3?

Like many vitamins, "vitamin D" can refer to a complex of vitamins and substances that harmoniously affect the body. Vitamin D also comes from a variety of sources, and they each affect the biochemical pathways of the body differently.

There are two main forms of vitamin D:


  • Ergocalciferol, or D2—either synthetic or plant-derived (usually the former). People usually obtain ergocalciferol from fortified foods and supplements.
  • Cholecalciferol, or D3—the most truly natural form of vitamin D. Widely considered superior to D2, and only available through diet/wholefood sources and photochemical reactions via sunlight.


The difference in potency and effect between D2 and D3 is almost enough to consider them wholly separate. For one thing, D3 is more bioavailable and has a much greater effect on a certain kind of serum vitamin D, called 25(OH)D.

On the other hand, D2 is potentially safer at high doses, including when taken frequently over the long term. However, that's at least partly because you have to take more vitamin D2 to get adequate serum levels, as it's not as bioavailable or as potent as D3.

While it's not true in every conceivable way, these important differences have led many health researchers to conclude that D3 is far superior to D2 of most kinds.

What About Vitamin D1?

When German researcher Adolf Windaus discovered vitamin D in the 1920s, he recognized three unique types and categorized them as D1, D2, and D3. Later, other researchers realized "vitamin D1" was several metabolites and other more nuanced compounds closely related to D2 (such as lumisterol, calcidol, and calcitriol.

While "vitamin D1" doesn't technically exist, certain of these compounds have significant effects on how the body absorbs vitamin D2 and D3. For instance:


  • Lumisterol induces greater synthesis of D2 and yet reduces serum D3 levels
  • Calcidol is the primary circulating metabolite of D3, helping the body use it
  • Calcitriol, a hormone, helps transport calcium from the gut


Understand that these vitamin D-related compounds are neither considered nor promoted as nutrients, and researchers still aren't entirely sure of their total effects on the body.

How Is Vitamin D From Sunlight Different?

The total compounding effects of any exogenous (external) source of vitamin D can also widely vary—and nowhere is that truer than getting vitamin D from the sun. That's because when UVB stimulates Vitamin D production in the skin, it initiates a slate of photoreactive processes that carry a suite of other health effects not easily achieved by other means. These include:


  • Mitochondrial and ATP energy production
  • Cellular signaling
  • Cell genesis and proliferation (including stem cells)
  • Higher oxidation levels in the form of ROS
  • Various metabolic processes
  • Overall homeostasis
  • Melatonin production


Of course, excess UVB can also increase the development of skin cancer cells; though to what extent depends on latitude and a multitude of personal and environmental factors. Getting your vitamin D levels right requires caution no matter which method you choose.

Non-Wholefood Vitamin D Supplements vs Natural Sources

By comparison, vitamin D supplements generally only provide the benefits of vitamin D itself—and depending on which form it is, those benefits can be minimal and even harmful.

Certain other factors also play a role in the effects of vitamin D on the body, particularly:


  • The presence of other nutrients, especially calcium (and in the case of sunlight, cholesterol, and photoreactive compounds called chromophores)
  • Certain medications
  • Long-term intake and serum vitamin D levels
  • The type of vitamin D—i.e., D2 vs. D3 and wholefood vs. synthetic


Above all, wholefood sources of vitamin D (whether eaten as foods or shelf-stable wholefood supplements) generally carry far more benefits and fewer disadvantages than synthetic copies.

Negative Effects of Vitamin D Supplements

One major drawback of most vitamin D supplements is that serum levels don't always reflect uptake levels reliably. This makes it hard to know how much is too much, which can lead to several adverse effects:


  • Hypercalcemia, where the body counters excess vitamin D by dumping calcium into the blood
  • Hypercalciuria, or elevated levels of calcium in urine
  • Hyperphosphatemia is an electrolyte imbalance caused by elevated serum phosphate levels
  • Tissue and organ damage, including kidneys


Even the most ideal form of vitamin D has its limits, as natural sources can still have toxic effects if taken in excess. 

However, don't fear getting a reasonably high amount of high-quality vitamin D, within safe limits. Some research suggests that upwards of 10,000 IU is a safe daily limit, with no toxic effects in healthy individuals.

Debunking Myths Surrounding Vitamin D Supplements

We'll break down the main sources of confusion surrounding vitamin D, given its multifaceted effects on the body and the major differences between its different forms.

Myth #1: Everyone Needs to Take Supplements

Supplements are only one possible source of any nutrient. In the case of vitamin D, there's an even wider range of sources than usual, particularly:


  • Diet, including natural sources and fortified foods
  • Sunlight, given the right preconditions
  • Wholefood-based supplements
  • Artificial D2 supplements
As we've explored, each of these sources requires their analysis. When it comes to improving serum vitamin D levels, the best strategy is twofold:
  1. Increase natural dietary sources of D3 (and to a limited extent, healthy D2)
  2. Get more UVB sunlight, and in the right quantity depending on your latitude, the season, and personal factors


Myth #2: Supplements Are Always Safe

The Annals of Internal Medicine study shows not every supplement is fully safe. In many cases, the effects of supplements or any substance at all can have positive or negative effects on your health.

Perhaps the study's greatest lesson is that taking any compound should raise certain questions, including:


  • Which bodily system(s) will a given vitamin or nutrient affect, and how so?
  • How does a supplement interact with other compounds or drugs?
  • When and how should you take a certain supplement?


Myth #3: Vitamin D Supplements Can Replace Whole Food Sources

That's not true, and the effects of synthetic vitamin D supplements have been lackluster in several ways, showing little to no effect on bone health, and possibly damaging cardiovascular health in the process.

Myth #4: You Can Only Get Vitamin D From the Sun

In many ways, the sun is an ideal source of vitamin D, but diet still plays an important role. Only getting vitamin D from the sun can leave you vulnerable to either low serum D levels or an increased risk of burns and skin cancer.

Vitamin D Risks and Considerations

How to Safely Increase Your Vitamin D Levels

In certain cases, too much vitamin D can cause a release of calcium in the blood, which may calcify soft tissue. This is especially problematic in blood vessels, and why many health professionals advise caution when increasing calcium intake.
One simple fix is consuming vitamin D and/or calcium with vitamin K, as the latter helps usher calcium into the bones where it largely belongs (though it also functions as an electrolyte and helps cell signaling in several tissues, in the right amount).
These considerations are crucial if taking vitamin D with bone-strengthening supplements, which generally depend on a sophisticated balance of:


  • Boron
  • Magnesium
  • Vitamin D
  • Calcium
  • Vitamin K


Vitamin D/Medication Interactions

Vitamin D also interacts with certain medications and can have unintended effects. You and your healthcare provider might do well to time your vitamin D intake away from the following medications or drugs:


  • Thiazide diuretics, which (when taken with calcium and vitamin D supplements) can cause hypercalcemia
  • Atorvastatin (a cholesterol drug) may increase 25(OH)D serum levels—but conversely, vitamin D supplements decrease concentrations of atorvastatin


There's also a long list of drugs that inhibit the expression of a gene involved in converting both ergo- and cholecalciferol to serum form. When making any significant nutritional adjustment, it's important to consult a trusted healthcare professional, such as a qualified dietitian or your primary care provider.

Practical Tips to Optimize Vitamin D Intake

Who Would Benefit Most From Increasing Vitamin D Levels?

Just as vitamin D impacts countless bodily functions, it carries equivalent breadth in terms of the conditions it can aid, including for those with:


  • Osteoporosis and certain other bone conditions
  • Increased risk of illness or compromised immunity
  • Mental health and mood conditions, especially depression
  • Physical injuries
  • Cardiovascular conditions
  • Thyroid deficiencies


Note the recommended intake for vitamin D is higher for those over 70, and lower for pregnant and breastfeeding women. Additionally, those at higher latitudes (and almost everyone during winter) will typically want to increase their dietary intake of vitamin D.

Improving Vitamin D Levels Naturally

If you're trying to increase vitamin D levels, most people are better off abstaining from non-food-based vitamin D supplements and taking a natural, multifaceted approach that entails:


  • Making more excuses to get outdoors
  • Increasing natural dietary sources of vitamin D
  • Using clothes designed to let UV rays pass through


How Much Sun for Vitamin D?

So exactly how much vitamin D do you get from the sun? It depends on many factors—but studies have shown that at latitudes equivalent to Kansas City, getting sufficient vitamin D from sunlight requires anywhere from 8 to 15 minutes in the warmer months and upwards of two hours in the winter.

These figures vary based on skin tone, location, season, diet, and a multitude of other factors. Also note you can't synthesize vitamin D from sunlight through a window, as the glass filters out that all-important UVB spectrum.

Dietary Strategies for Increasing Vitamin D Levels

Increasing vitamin D levels from the sun is one of the most effective ways, but dietary sources are still important. Even the best diet may not provide enough vitamin D on its own, and food sources of vitamin D don't provide the cascade of other photochemical effects.


As important as whole-food sources of vitamin D are for overall health, relatively few foods carry a significant amount of vitamin D. On the plus side, that makes it easier to memorize the list of quality food sources of vitamin D, which pretty much amounts to:


  • Salmon, sardines, and mackerel
  • Cod liver oil
  • Beef liver
  • Egg yolks
  • Certain types of dairy
  • Mushrooms—and for most types of mushrooms, exposing the gills to sunlight can increase vitamin D levels by hundreds of times


There are also vitamin D-fortified foods, but you must be careful that they're fortified with food-based (not synthetic) sources. The latter may present much of the same negative effects of certain types or uses of vitamin D supplements.

Also, because vitamin D is fat-soluble, consuming vitamin D food sources with a high-fat meal can improve its absorption.

Support Your Vitamin D Needs With Laird Daily Greens!

Whether getting vitamin D from the sun or dietary sources, know the pros and cons of any given form.

Much of this research came out in the late 2010s and early 2020s, turning certain conventional dietary wisdom on its head. It should come as no surprise that the full effects of vitamin D on health remain a mystery, but researchers are much more interested in understanding the potential drawbacks of synthetic vitamin D supplements, and just why food-based forms are ideal.

Amidst these twists and turns, one thing is certain: the best strategy for most people is to increase your vitamin D from the sun and good dietary sources—such as Laird's specially formulated Daily Greens, possessing a well-balanced and comprehensive blend of high-quality wholefood vitamins.


Refreshing tall glass of vibrant Laird Superfood Daily Prebiotic Greens

Contact us with any questions, or learn more about the full-spectrum health benefits of Daily Greens, which include:


  • Vitamin D, calcium, and related constituent products in the right balance
  • Probiotics
  • Antioxidants
  • Anti-inflammatory compounds
  • A powerful mix of functional and adaptogenic mushrooms


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