Whether you are supplementing yourself or a client/patient, it is not uncommon to encounter difficulties in attempting to elevate blood vitamin D levels. I’ve seen people who spent the whole summer enjoying outdoor activities, only to find their vitamin D levels still below optimum in September. I’ve seen people who supplement D3 religiously, but each year at their physical fail to meet the mark for optimum blood levels. The tendency is to blame it on the quality of the vitamin D, or the quality of the supplement itself.
First, let’s set a few things straight about vitamin D, and then we can look at the factors that may influence achieving proper blood levels, as well as proper binding of vitamin D on the target receptors.
What is vitamin D? It turns out it’s not merely a vitamin, but is also considered a pro-hormone because vitamin D receptors are of a class called steroid hormone receptors. Vitamin D does help in absorption and utilization of nutrients like calcium, but also binds a multitude of receptors in our organs and tissues. We also have more than 1,000 genes that are regulated by hormonally active vitamin D (1,25(OH)2D3). This is what supplemented ergocalciferol or cholecalciferol will become in the body under proper conversion conditions in the kidneys and by certain receptors. While vitamin D is crucial for proper bone development and in maintaining density, and most supplementation historically was focused on this role, we now know that D indisputably plays a crucial role in the immune system and inflammatory processes, cell growth and proliferation, neuromuscular function, glucose metabolism and much more.
Ergocalciferol (D2) is fungally sourced, commercially produced by enhancing fungal production with UV light exposure. Cholecalciferol (D3) is typically made from harvesting a cholesterol from sheep’s wool that can be converted into stable cholecalciferol with intense UV light exposure and other extractions, mimicking the process our body goes through in converting sun exposure of cholesterol in the skin to cholecalciferol. There is also now cholecalciferol made from lichen, algae and genetic modification of microorganisms. The only significant difference between D2 and D3 seems to be in synthetic pathways and the consequences of production, and in the capacity of D3 to better increase the serum 25(OH)D produced by enzymes in the liver. This makes more availability of 1,25(OH)2D3 from the enzymatic conversion in the kidneys.
Why not make your own? While our bodies possess the capacity to make all the vitamin D we need without causing an overdose simply by exposing our skin to the sun’s light, or UV light in general, many people are still deficient. Clothing is the first inhibitor to making your own vitamin D. Sunscreen is the second. Both block UVB light enough to make production grind to a halt. Other factors include age, skin tone (more melanin in skin cells scatters the UV light necessary to convert 7-dehydrocholesterol to pre-vitamin D3, slowing conversion), obesity, inflammation, poor diet lacking in certain nutrients, parathyroid function, and liver or kidney disease. Elevated uric acid levels, a precursor to many chronic degenerative diseases, may inhibit production, absorption, conversion, and reception of vitamin D as well. Additionally, certain medications like statin-type pharmaceuticals will limit the production of vitamin D.
First and foremost, skin must be exposed, free of the cover of clothing or sunscreen, for at least 10 minutes a day under optimal intensity and angle of the sun. UVB rays are responsible for the conversion, and the amount of UVB rays in light lessens with the angle of the sun in northern and southern latitudes in winter. Secondarily, there must be sufficient sebum on the skin containing 7-dehydrocholesterol which is the crucial starting material for pre-vitamin D. Those people taking cholesterol lowering medications may not retain enough cholesterol in the skin for this conversion, especially given other factors, such as outdoor exposure and latitude. Pre-vitamin D is converted to cholecalciferol at body temperature. If you tend to be cooler than body temperature due to an endocrine issue, climate, malnourishment, dehydration or anything else, this may be another reason for poor conversion.
Now, let’s explore the challenges between skin production and conversion to hormonally active vitamin D. This requires conversion first in the liver, and second in the kidneys. It also requires that receptors in the liver, kidneys, and all other tissues be capable of binding. Thus, in cases of liver and/or kidney disease we will see poor conversion to the active form of D3, 1,25(OH)2D3. And in cases of obesity, elevated uric acid, elevated inflammatory markers, and a diet insufficient in polyphenols and other antioxidants, even the active forms may not be able to bind on the target receptors all over the body—immune cells, brain, parathyroid, prostate, breast, ovaries, uterus, periosteum, muscle fibers and so on. These health issues and dietary insufficiencies will affect both the person who is attempting to elevate their vitamin D naturally through sun exposure, and those who are doing so through supplementation. Further, the person utilizing supplements to elevate their serum vitamin D may encounter problems in absorption of the supplement from the intestine if they are experiencing any sort of inflammatory bowel disease, or have poor lipid digestion and assimilation.
Most people do not consume foods that contain natural D3 or sufficient D2. Very few cod liver oils retain natural vitamin D levels due to processing. Ideally, we want our clients and patients to make diet and lifestyle changes that will improve their production of pre-vitamin D organically from exposure to natural light. Exercising and sweating out of doors is an excellent way to produce this cholesterol in the skin and expose it to UVB light for natural conversion. The darker the skin is naturally, the more melanin, and the longer exposure is needed to produce the pre-vitamin D. Maintaining ideal body temperature through exercise, activity, proper nourishment and hydration, and monitoring of metabolic health with aid in the conversion to cholecalciferol.
Now, whether the cholecalciferol is coming from solar production or from a dietary supplement or food (liver) the rest of the pathways are identical. Here is where I, as a practitioner, am more concerned about what a person includes in their diet than what they exclude. I realize both can be crucial, but I have been more successful including healthy additions to a poor diet than I have removing the unhealthy staples. What can we add to the diet or to the supplemental regimen that will support better conversion and reception of active vitamin D?
Quercetin: Quercetin in coffee, tea, berries, capers, red wine, onion, kale, cacao, apples and in supplemental form of 500-1,000 mg daily can enhance vitamin D receptor binding. It also can lower Uric Acid which will improve outcomes on inflammation and obesity, further enhancing receptor activity.
Other Polyphenols: Many polyphenols including turmeric, EGCG, grape seed extract and berries have been shown to also enhance nuclear receptor binding of vitamin D. Including antioxidant rich foods and/or supplements in the diet is a successful strategy to combat the standard American diet and the ailments caused by it.
Inflammatory Response: Employing herbs and supplements to support an optimum immune response and tone down an excessive inflammatory response will improve vitamin D receptor activity in all tissues. In turn, it’s a positive feedback loop, with vitamin D supporting the function of immune cells themselves.
Liver Support: Through herbals, when appropriate, and through amino acid and vitamin support, we can improve liver health and function for the first stage of conversion of cholecalciferol.
Kidney Support: This is so often overlooked, and becomes a huge factor in vitamin D deficiency among other ailments in the elderly. Kidney function must be monitored and the organs, themselves, supported with proper hydration and electrolyte balance. Herbal medicine, especially TCM (traditional Chinese medicine) and ayurvedic medicine, may be some of the best ways to support optimal kidney function. In frank kidney disease, more intensive medical management may be necessary.
Mineral Status: One of the most common mineral insufficiencies is magnesium. It is also one of the easiest to remedy. Magnesium, like vitamin D, is crucial in so many processes in our bodies, it’s a wonder we function with insufficiency being so common. If you are struggling to elevate serum 25(OH)D, look at magnesium intake. Also, zinc supplemented together with vitamin D improves BDNF production, and this in turn affects energy, metabolism, mood and all chronic health outcomes.
Other Related Vitamins: Vitamin K2 has recently come into the limelight as a crucial companion to vitamin D sufficiency. These two work together in forming healthy bone, but there is more to it than that. K2 status seems to influence utilization of D in certain tissues.
Lipid Digestion and Metabolism: If you do not eat adequate fats with fat soluble vitamins like A, D, E and K, they will not be well absorbed. Also, if your gall bladder has been removed or pancreas is not producing enzymes sufficiently, you may not digest fats to solubilize the vitamins. So enzymes like lipase, and gall bladder support or replacement of bile can be helpful.
Even in the case of injectable 25(OH)D, these other interventions may be necessary. Having vitamin D in the bloodstream is one thing, but getting it to act upon receptors is another. If we can educate our clients and patients on these important cofactors for production, digestion, absorption and assimilation of vitamin D, we will likely see much better health outcomes overall. Vitamin D is a crucial nutrient and prohormone for all stages of life, for growth and healthy aging, for chronic disease prevention and acute immune function, and the reasons why people struggle to raise their serum levels and achieve better outcomes are being better demonstrated by research every day.
Amber Lynn Vitale practiced as a certified nutritionist, ayurvedic clinical consultant, advanced bodyworker and yoga therapist since 1996. Much of her nutrition practice was in collaboration with functional medicine doctors and other integrative practitioners. Since 2008, she has also produced written and video educational content for many publications, as well as for her own clients and an interested public audience. By 2012, she had realized that raw materials sourcing, labeling transparency, legitimate certifications and educational support were the criteria that would set quality natural products companies apart from others; and she made it her mission to educate the public on the importance of education before supplementation. Vitale continues to write, lecture, and produce online content on health and wellness topics important to the practitioner and the patient alike.