Vitamin D has been topical, as far as vitamins go. Since the start of the COVID pandemic at the end of 2019 interest in vitamin D has spiked amongst the general public. Vitamin D is a nutrient that, for those people whose primary education did touch on it in biology class, was discovered in connection with Rickett’s Disease and is essential for the absorption of calcium and phosphorous from the intestines and their incorporation into the bone matrix. Since the 1980s medical science has gradually learned more about the other, diverse biological roles that vitamin D plays, which includes regulating the immune system, even as the some of the biomechanics behind these seemingly unrelated roles are still being debated.

During the pandemic, several studies and researchers went so far as to make far-reaching claims about vitamin D as protective against COVID-19, and this has been followed with additional research into how vitamin D mediates humoral immunity. Various studies published in the last two decades have shown mild protective effects against autoimmune diseases from vitamin D supplementation, and many public health experts and nutritionists have sounded the alarm on widespread vitamin D deficiencies in many Western countries, particularly those at higher latitudes and among darker-skinned residents in said countries. The mushroom industry (especially the common Agaricus varieties) has shifted much of its marketing towards vitamin D as a result of these concerns and the increased public interest in immunity in the wake of the COVID19 pandemic.

What is vitamin D?
Vitamin D is not even a vitamin in the technical sense of the term, as humans and most mammals can theoretically synthesize sufficient quantities of the compound naturally through exposure to the sun. This is because in humans vitamin D is produced in the epidermis layer of the skin from the interaction of UVB light and 7-dehydrocholesterol. Alfred Fabian Hess, documenting the biosynthesis of vitamin D explained it simply: “Light equals vitamin D!” However, people living in high latitudes require more dietary intake of vitamin D due to the long winters and low UV radiation in those regions, which is also the key selective pressure for lighter skin tones.

Vitamin D is a fat-soluble secosteroid, and is more akin to a hormone than to other “vitamin” compounds. There are two forms of the vitamin utilized by humans: cholecalciferol and ergocalciferol, otherwise known as vitamin D3 and vitamin D2. Ergocalciferol is the form of vitamin D produced by some mushroom varieties when exposed to UV lighting, while cholecalciferol is the form of vitamin D produced by many animals through UV exposure. Ergocalciferol differs only by a double bond between the 23rd and 24th carbon molecule in the chain plus the presence of a methyl (CH3) group on carbon 24. Neither the vitamin D we consume or which is produced in our skin is the biologically active form of the vitamin, calcitriol, which is instead a metabolite formed as a result of a two-part hydroxylation process with the first stage occurring in the liver and the second stage in the kidneys. 

Vitamin D maintains calcium-phosphate homeostasis by aiding the absorption of these minerals in the intestines and helping to trigger the mineralization of collagen matrixes in bone. This is why the vitamin has an image as a bone-related nutrient among the general public. The widespread supplementation of vitamin D in diet following its discovery in the early decades of the 20th century has all but eliminated Ricketts disease, which once effected as much as 90% of children in higher latitude cities between the late 18th century and early 20th century. Vitamin D is considered a critical nutrient to reduce the risk of aging diseases such as osteomalacia (softening of the bones) as well. Obscured by the well-established biological functions of vitamin D related to bone health and maintenance, the other biological pathways of vitamin D that modulate immunity and cardiovascular health remained under-documented until the 1980s.

Vitamin D functions in the body by binding to steroid hormone nuclear receptors called vitamin D receptors (VDRs for short) and through these receptors regulates gene expression. There are thousands of binding sites that alter the expression of hundreds of genes, varying substantially between cell types. The biological function of vitamin D is therefore also different from other vitamins, which work as enzyme cofactors in metabolic processes and/or as antioxidants. Vitamin D has been shown to regulate inflammatory cytokine cycles by modulating the balance between proinflammatory and anti-inflammatory cytokines and thus adjusting the immune system’s response to infection. This is the proposed explanation for the observed relationships between vitamin D deficiencies (generally defined as blood serum levels 25(OH)D under 30 ng/mL) and increased risks of rheumatoid arthritis, diabetes mellitus, cancer, and also with more severe symptoms for those with irritable bowel syndrome, Lupus, Crohn’s disease and other autoimmune-related diseases.

Likewise, there appears to be a relationship between vitamin D and respiratory illnesses. Historically, tuberculosis patients were first treated with sunbathing sessions and doses of cod liver oil, both of which increase vitamin D blood serum levels. Vitamin D deficiency has been correlated to higher risk of tuberculosis infection, and to higher rates of severe respiratory illness, including COVID-19 (so-called cytokine storms triggering an over-active immune response are often the root cause behind severe cases of COVID-19). This should not, however, be construed as evidence that vitamin D itself is a therapeutic agent, nor that vitamin D supplementation can prevent serious respiratory illnesses. Evidence for such claims is inconclusive and difficult to study or model, given that there is debate as to whether blood serum levels of 25(OH)D are even an adequate measurement of vitamin D sufficiency.

Vitamin D is no less complicated than the topic of beta-glucans, possibly more so because of its multiple biological pathways in many different bodily systems. However, unlike with beta-glucans, my intention this time is not to explain vitamin D’s theorized biological functions in detail or relay the intricate debates about whether vitamin D supplementation works or not. I am limiting this review of vitamin D to giving a basic primer without getting too bogged in complicated details. However, if you are going to promote mushrooms with vitamin D, you should at least understand this much about what you are promoting.

"Red teaming" is a term for an activity originally done for Cold War era military training purposes, where one side role plays an opposing force with the explicit goal to win. That means a chance to more fully understand potential strategies and pitfalls ahead of you by playing against a simulated version of your opponent. This is a good exercise in critical thinking and planning that also applies to all levels of business, but especially for trying to decide how to market a product. In this case, what are some of the things that might make people skeptical about vitamin D claims and what advantages does the mushroom industry have? A good content marketing campaign balances two distinct goals: one, to reinforce the appeal to the believers, and two, to create new believers. I always approach marketing and branding topics with this quirky philosophy: start complex and then simplify. Why? I find that when you start simple and then complexify, things quickly become a mess, yet when you start complex and then keep on working, simplicity seems to come along naturally and consistently, yet if you need to complexify, you can take a step (or few) back to a previous stage at any time.

The most basic critical thinking process in science begins with acknowledging that correlation does not equal causation. Before using statistics, every single person should sign a legally binding contract that states they understand and will acknowledge that correlation does not equal causation. We humans are evolutionarily hard-wired for pattern recognition_emdash_pattern recognition isn’t a sign of intelligence; being able to filter the noise of unrelated patterns is. With medical research especially, it is almost impossible to control for all the potential variables, and this is why it is very important to brainstorm other potential relationships to a correlation and to be capital C Cautious with claims.

But a more complex potential answer involves population distribution: chronically low 25(OH)D blood serum levels could also be a symptom of the genetic and/or lifestyle predispositions for autoimmune disorders and related chronic diseases like rheumatoid arthritis or Lupus, rather than a cause or trigger of the diseases itself. People with lower serum levels 25(OH)D could represent a demographic skewed towards different disease vectors and frailty because of genetics and lifestyle. If that is the case, “healthy” blood serum levels of vitamin D would have notable relationships to mortality, respiratory illness hospitalizations, cancer outcomes, heart health and more, but vitamin D supplementation itself would offer modest or inconclusive benefits. The overall track record for vitamin D supplementation studies leaves this explanation very plausible.

In fact, stepping back again, all the correlations of vitamin D health benefits could just be correlations of sunlight exposure, which also regulates serotonin and other hormones.  Vitamin D and calcium supplementation haven’t even been shown to have a clear preventative effect on osteoporosis. The very act of participating in a health study can also cause people to alter their behavior_emdash_on the top of the placebo effect (if people strongly believe something is effective, the placebo often has a statistically significant positive effect) which is very real and very powerful.

The debate is more or less a rehash of the age-old tongue-in-cheek question: which came first, the chicken or the egg? Do some people have healthy vitamin D levels because they have a healthy, active lifestyle? Or can raising vitamin D levels through diet and supplementation itself make people even somewhat healthier even without an otherwise healthy or active lifestyle? Or are chronically low vitamin D levels just a marker of poor health or genetic disposition to autoimmune issues, not the cause of either? As previously mentioned, ice cream consumption has a strong correlation to shark attacks, but ice cream consumption doesn’t cause shark attacks. Instead, hot weather causes people to consume more ice cream and also go to the ocean_emdash_where shark attacks happen. Findings such as the fact that swimming pool drownings in the U.S. correlate with the number of films Nicholas Cage starred in in a given year are easy to find in data, but establishing causation itself is hard.

Another complicating factor is that vitamin D is a fat-soluble vitamin and high body fat percentages have been associated with low vitamin D blood serum levels even after supplementation. Some research has shown blood serum levels of vitamin D post-supplementation also decreased much faster in participants with high BMIs, meaning that supplementation had less of an impact depending on BMI. So is vitamin D deficiency a risk factor for diabetes mellitus, as shown in some studies, or is it simply co-existing with other risk factors that correlate to obesity and caused by underlying lifestyle decisions and habits, much like ice cream consumption and getting attacked by sharks are connected by hot weather? What’s more, vitamin D2, the form in mushrooms, has been found to drop off precipitously, with some studies showing vitamin D2 has as little as 1/3rd the potency of vitamin D3.

This is the crux of health marketing: consumers are likely to view it as a drop in the bucket; another buzzword in the mind-numbing roar of contemporary society. If you don’t approach health and lifestyle marketing from this perspective, you’re rarely growing your market outside of the small core of true believers. Every day the media reports a new food trend. Every day the media grabs onto one random scientific study or another and so that one day the voice from the microphone is screaming “Dark chocolate is packed with antioxidants and linked to lower risk of heart disease” and the next the scream is “Dark chocolate has high concentrations of lead and cadmium (based on ridiculously low U.S. safe intake levels for cadmium) and is literally toxic!” Consumers are going to be cynical, (as they should be) and that’s my point: I don’t think vitamin D claims alone will create a consistent and reliable health-based consumption impulse.

The challenge and the underlying thought-process of this 3-part series, is how to link different benefits together without being too overwhelming. The real talk is that mushrooms aren’t going to make a huge impact on blood serum levels of vitamin D (unless someone is eating 400~500 grams of maitake a day), and people who are really concerned about their intake of vitamins (including vitamin D) are probably just going to buy a pill. For those in the business of growing food, the gist of health marketing is always that if you go too hard people are just going to find a supplement that’s cheaper, no matter how questionable its quality controls or how murky its origins.

In my view there is only one way to approach this: plug a lot of very basic and simple issues. Freshness. Whole foods. Easy to prepare. Savory. Protein-rich. High in antioxidants. Great for gut health. Good source of vitamin D and B-vitamins. The superfood label is good, but everyone knows, for instance, that spinach and broccoli are superfoods too, but that alone doesn’t make people want to consume those vegetables if they don’t like them. Mushrooms_emdash_all varieties_emdash_have to become a fun brand. The image of mushrooms has to become that of a versatile superfood packed with umami flavor. Fun, new, and the sense of experimenting with new recipes and ever-changing combinations of different types of mushrooms is a potent marketing tool, especially for local growers connected directly to their regional markets and customer base. Many young consumers around the world, but especially in the United States, now crave novelty, change, playfulness, and flexibility, even down to the food they cook and buy.