Natural Health

Why a Personalised Method Is Finest

February 12, 2026
Admin


On this episode we talk about:

  • Why normal vitamin D suggestions don’t work for most individuals
  • The impression of weight problems, getting old, intestine well being, liver operate, and kidney well being
  • Optimum vitamin D blood ranges—and why extra just isn’t at all times higher
  • The U-shaped threat curve of vitamin D deficiency and extra
  • Why testing and seasonal retesting are important
  • Magnesium’s newly found position as a “vitamin D thermostat”
  • Solar publicity advantages past vitamin D manufacturing
  • Learn how to personalize supplementation based mostly on labs and way of life
  • Sensible steerage on dosing, cofactors, and seasonal changes

Present notes:

Hey all people, Chris Kresser right here. Welcome to a different episode of Revolution Well being Radio. Researchers at Vanderbilt simply revealed a captivating examine that would change how we take into consideration vitamin D supplementation. They discovered that magnesium doesn’t simply increase vitamin D ranges throughout the board, it acts like a thermostat, elevating vitamin D ranges in people who find themselves poor whereas decreasing them in these whose ranges are already excessive.

That is the primary medical proof suggesting that magnesium helps optimize vitamin D ranges moderately than merely rising them. This discovering is important as a result of vitamin D supplementation has turn out to be more and more frequent. Tens of millions of individuals are taking vitamin D dietary supplements, typically in doses of 2000, 5000, and even 10,000 IU per day. Many are doing this with out ever testing their ranges or contemplating the elements that have an effect on how their physique produces, absorbs, and makes use of vitamin D. The mainstream method to vitamin D is actually one dimension suits all. Take 400 IU when you’re following official tips, or possibly 2000 to 5000 IU when you’re following in style well being recommendation. However right here’s the issue with that method. Your vitamin D wants are usually not the identical as your neighbor’s wants or your partner’s or what you learn in {a magazine} article. They rely in your ethnicity, physique weight, well being standing, the place you reside, how a lot time you spend outdoors, and the standing of different vitamins in your physique, like magnesium, vitamin K2, and vitamin A.

I get why that is complicated. There’s conflicting recommendation in every single place. Some sources say 400 IU is a lot. Others say you want 5000 or 10,000 IU. Some declare vitamin D is a miracle nutrient that stops every little thing from most cancers to coronary heart illness. Others warn about toxicity. The reality is extra nuanced than any of those excessive positions. By the tip of this episode, you’ll perceive why a personalised method to vitamin D is smart, what your optimum vary may be based mostly on particular person elements, why testing and retesting is essential, which cofactors you have to take note of, and the way to use solar publicity and supplementation strategically. Let’s dive in.

Why One Dimension Doesn’t Match All

Let’s begin with why the one dimension suits all method doesn’t work. The usual advice you’ll see from most mainstream sources is 400 to 800 IU per day for adults. That comes from the Institute of Medication, which set these ranges based mostly on skeletal well being outcomes, particularly stopping rickets and osteomalacia. For some individuals, 400 IU may be satisfactory. For others, and I might say most individuals, it’s nowhere close to sufficient. A big examine revealed within the journal Scientific Diet in 2024 checked out vitamin D ranges in practically 440,000 individuals from totally different ethnic backgrounds within the UK. They discovered large variation. Median vitamin D ranges had been about 25 nanomoles per liter in Asian individuals, 31 in Black individuals, and 48 in White individuals. If you convert these to the models extra generally used within the US, that’s roughly 10 nanograms per milliliter for Asian individuals, 12 for Black individuals, and 19 for White individuals. Practically 50 % of Asian individuals and 35 % of Black individuals had frank vitamin D deficiency in comparison with 12 % of White individuals. These variations persevered even when researchers accounted for solar publicity, supplementation, eating regimen, and different way of life elements.

Pores and skin pigmentation issues enormously. Melanin blocks ultraviolet B radiation, the wavelength that triggers vitamin D manufacturing in your pores and skin. When you have darker pores and skin, you want considerably extra solar publicity to provide the identical quantity of vitamin D as somebody with lighter pores and skin. However ethnicity is only one variable. Physique weight is one other big issue. The identical UK Biobank examine discovered that the affiliation between physique mass index and vitamin D ranges was constant throughout all ethnic teams. Increased BMI meant decrease vitamin D ranges. And right here’s the kicker – the unfavourable impact of weight problems on vitamin D standing was truly stronger in individuals who had been taking dietary supplements. Individuals with weight problems convert much less daylight to vitamin D of their pores and skin, they usually take in much less vitamin D from dietary supplements and eating regimen. The mechanism isn’t totally clear, however it most likely includes sequestration of vitamin D in physique fats compartments the place it’s much less bioavailable. Age additionally issues. As we become old, our pores and skin’s capability to provide vitamin D declines. A 70-year-old particular person produces about 25 % much less vitamin D from the identical solar publicity in comparison with a 20-year-old. The UK examine discovered that the weakening affiliation between solar publicity and vitamin D ranges began at comparatively youthful ages, not simply within the aged.

Well being standing is one other important variable that usually will get ignored. When you have inflammatory bowel illness like Crohn’s or ulcerative colitis, you’re doubtless not absorbing vitamin D as successfully from meals or dietary supplements. The irritation damages the intestinal lining, which impairs fats absorption, and vitamin D is a fats soluble vitamin. Sufferers with IBD typically have decrease vitamin D ranges than the overall inhabitants, they usually might have larger doses to succeed in satisfactory standing. Liver illness and kidney illness also can have an effect on vitamin D metabolism. Vitamin D will get transformed to 25-hydroxyvitamin D within the liver, which is what we measure once we check vitamin D standing. If liver operate is compromised, that conversion won’t occur effectively. The ultimate activation step occurs within the kidneys, the place 25-hydroxyvitamin D will get transformed to the energetic kind, 1,25-dihydroxyvitamin D. Continual kidney illness can disrupt this course of. If you add up all these variables, ethnicity, physique weight, well being standing, solar publicity, eating regimen, complement use, it turns into clear that telling everybody to take the identical dose of vitamin D is senseless. What works for a 30-year-old White lady at a wholesome weight residing in Arizona just isn’t going to work for a 65-year-old Black man with weight problems and Crohn’s illness residing in Seattle.

Optimum Vitamin D Vary

All proper, let’s speak about optimum vitamin D vary. The frequent reference vary you’ll see on lab checks within the US is 30 to 74 nanograms per milliliter for serum 25-hydroxyvitamin D. Some advocacy teams just like the Vitamin D Council suggest a better goal of 40 to 80, with a perfect of round 50. If you have a look at the analysis, there’s little to no proof exhibiting profit to ranges above 70, and rising proof suggesting that very excessive ranges could trigger hurt. Vitamin D follows what’s known as a U-shaped curve for well being outcomes. Each low ranges and really excessive ranges are related to elevated threat. Penalties of vitamin D toxicity embody cardiovascular occasions, kidney stones, hypercalcemia, nausea, vomiting, bone loss, and in extreme circumstances, organ harm. Most circumstances of toxicity come from over supplementation, not solar publicity, though there’s a minimum of one examine on Israeli lifeguards suggesting that toxicity from solar publicity alone is feasible in excessive circumstances. Based mostly on my evaluation of the literature and my medical expertise, I feel the useful vary for most individuals is round 40 to 60 nanograms per milliliter. For individuals with non-white ancestry, the optimum vary could also be considerably decrease. Black individuals, for instance, usually have decrease vitamin D ranges than white individuals, but additionally they have larger bone mineral density. There’s proof suggesting that folks with non-white ancestry could also be tailored to decrease optimum vitamin D ranges. For individuals with autoimmune illness, the optimum vary would possibly lengthen as much as 70 nanograms per milliliter to maximise the immune regulating advantages of vitamin D. Once more, I haven’t seen medical advantages or analysis supporting further advantages above 70, and the chance of vitamin D toxicity begins to extend at these larger ranges. This must be individualized based mostly on testing and medical response.

In uncommon circumstances the place somebody is having hassle getting their vitamin D ranges above 35 nanograms per milliliter regardless of supplementation, I’d check parathyroid hormone to see in the event that they’re chronically poor or simply have a decrease optimum vitamin D degree. However for most individuals, this degree of complexity isn’t needed. The essential framework of testing your 25-hydroxyvitamin D degree, and adjusting based mostly in your particular person elements is ample. The significance of testing and retesting can’t be overstated. Take a look at, don’t guess, as we are saying in useful medication. This phrase applies to so many issues in useful medication, and it undoubtedly applies to vitamin D. Your vitamin D degree just isn’t static. It modifications all year long based mostly on solar publicity, it modifications once you modify your complement dose, and it modifications based mostly on all the person elements we’ve been discussing. Seasonal variation of vitamin D ranges is important. A examine vitamin D testing patterns discovered that ranges observe a sinusoidal sample that intently tracks hours of daylight. Winter ranges are considerably decrease than summer season ranges for most individuals who aren’t supplementing closely. For those who check in late summer season, when your ranges are naturally at their peak from solar publicity, and also you look satisfactory, that doesn’t imply you’ll keep satisfactory via the winter, when UV radiation is inadequate for vitamin D manufacturing. Conversely, when you check in late winter or early spring when your ranges are naturally at their lowest and your physician prescribes a complement based mostly on that single check, you would possibly find yourself with ranges which are too excessive by late summer season, when solar publicity is including to your vitamin D manufacturing. This is the reason I like to recommend testing a minimum of twice a 12 months, as soon as in late winter or early spring and as soon as in late summer season or early fall. That offers you a way of your 12 months spherical standing and means that you can regulate your complement dose seasonally if wanted. You must also retest three to 4 months after altering your complement dose. Vitamin D has a half-life of about two to a few weeks, so it takes a number of months for ranges to stabilize after you alter your consumption. Don’t check two weeks after beginning a complement, and assume you recognize the place you’ll find yourself. Give it time to succeed in a gradual state.

Vitamin D is likely one of the most misunderstood—and misused—dietary supplements in fashionable well being. On this episode, we break down why standardized dosing suggestions typically fail and the way a personalised method results in higher outcomes and fewer dangers. #vitaminD #ChrisKresser

How Nutrient Co-Elements Form Particular person Wants

Now let’s speak about co-factors, as a result of that is the place issues get actually attention-grabbing. The Vanderbilt examine I discussed at first discovered that magnesium primarily regulates vitamin D ranges. When magnesium was given to individuals with low vitamin D, it elevated their ranges. When it was given to individuals with excessive vitamin D, it decreased their ranges. This regulatory impact is necessary. The researchers famous that magnesium deficiency shuts down the vitamin D synthesis and metabolism pathway. So when you don’t have satisfactory magnesium, your physique can’t convert vitamin D into its energetic types effectively. This might clarify why some individuals who take excessive doses of vitamin D and their ranges barely budge, whereas others take reasonable doses and their ranges skyrocket. Magnesium standing would be the lacking variable. The examine authors identified that as much as 80 % of People don’t eat sufficient magnesium to satisfy the beneficial dietary allowance, and that’s based mostly on the outdated RDA. Newer research which have adjusted the magnesium RDA upwards recommend that over 90, possibly 95, % of People are usually not consuming sufficient magnesium. That’s a staggering quantity. Magnesium deficiency is an under-recognized public well being downside, and it could be quietly undermining vitamin D standing in an enormous portion of the inhabitants. Meals wealthy in magnesium embody darkish leafy greens, beans, complete grains, darkish chocolate, fatty fish like salmon, nuts, and avocados. However even with a great eating regimen, it’s very tough to get satisfactory magnesium from meals alone due to soil depletion. This is likely one of the few vitamins the place I feel supplementation over the long run is smart for most individuals. I usually suggest 400 to 600 milligrams of magnesium glycinate per day.

Vitamin K2 is one other important cofactor that works synergistically with vitamin D. Vitamin D promotes the manufacturing of sure proteins, together with osteocalcin and matrix Gla protein. These are vitamin Okay-dependent proteins, that means they require vitamin Okay to turn out to be activated via a course of known as carboxylation. When these proteins are correctly carboxylated, they assist direct calcium into your bones and enamel the place you need it, and hold it out of sentimental tissues like your arteries the place you undoubtedly don’t need it. Analysis revealed within the Worldwide Journal of Endocrinology discovered that vitamin D and Okay mutually improve one another. Animal research confirmed that giving each nutritional vitamins collectively elevated bone formation markers in a time-dependent method, whereas giving them individually didn’t produce the identical impact. Scientific trials in postmenopausal ladies discovered that mixed vitamin D and K2 supplementation enhance bone mineral density greater than both vitamin alone.

There’s additionally rising proof for cardiovascular advantages. A examine within the journal Hypertension discovered that low vitamin D and low vitamin Okay standing collectively had been synergistically related to larger blood strain and elevated hypertension threat. When vitamin Okay-dependent proteins like matrix Gla protein stay undercarboxylated due to insufficient vitamin Okay, they will’t inhibit vascular calcification successfully. Vitamin D will increase the expression of those proteins, however with out satisfactory vitamin Okay to activate them, chances are you’ll be setting the stage for arterial calcification. Vitamin K2 exists in a number of types. You’ll typically hear that MK-7 is superior as a result of it has an extended half-life in plasma, however that argument misses one thing necessary. MK-4 doesn’t do its work in plasma. It really works inside cells. Plasma half-life tells you nothing about whole-body half-life or tissue distribution. Actually, analysis means that MK-4 and MK-7 distribute to totally different tissues based mostly on how they’re packaged in lipoproteins. MK-4 tends to be preferentially delivered to tissues like the guts, mind, kidneys, and skeletal muscle, whereas MK-7 goes extra to liver and bone. The Rotterdam Examine, which is observational however fairly giant, discovered that dietary vitamin K2, a lot of which is MK-4, was related to decreased threat of coronary calcification and coronary heart illness, whereas vitamin K1 was not. Comparable findings emerge for prostate most cancers threat. These are dietary doses we’re speaking about, not megadoses. The concept MK-4 has no relevance at low doses doesn’t maintain up once you have a look at the totality of the proof.

Vitamin A is the third key co-factor. Analysis going again to the Thirties has recommended that vitamin A and vitamin D have an antagonistic relationship at very excessive doses, however at physiologic doses they work collectively. A 2007 paper in Medical Hypotheses proposed that vitamin D toxicity may go by inducing a useful vitamin Okay deficiency, and that vitamin A protects in opposition to this by supporting vitamin Okay-dependent processes. What this implies virtually is that when you’re taking excessive doses of vitamin D, you wish to be sure to’re getting satisfactory vitamin A and K2 to guard in opposition to potential toxicity. This isn’t about megadosing these nutritional vitamins. It’s about sustaining steadiness. Good sources of vitamin A embody liver, egg yolks, butter, and dairy merchandise from pastured animals. The shape issues. You need retinol or retinyl palmitate from animal sources, not simply beta-carotene from crops, as a result of conversion of beta-carotene to energetic vitamin A is extremely variable and infrequently inefficient.

One factor that’s turn out to be clear from the analysis is these vitamins don’t work in isolation. They work as a system. When one is out of steadiness, it impacts the others. The Vanderbilt magnesium examine is an ideal instance of this. Magnesium standing influences vitamin D standing. Vitamin D standing influences calcium metabolism. Vitamin Okay standing influences whether or not that calcium goes into bone or gentle tissue. It’s interconnected.

Continual Well being Situation Considerations

This brings us to an necessary level about how well being situations have an effect on your vitamin D wants. We touched on inflammatory bowel illness earlier, however the impression of GI situations on vitamin D absorption deserves extra consideration. Celiac illness, quick bowel syndrome, power pancreatitis, cystic fibrosis, and small intestinal bacterial overgrowth, or SIBO, impair fats absorption, which implies they impair absorption of fat-soluble nutritional vitamins, together with vitamin D. SIBO has turn out to be fairly frequent, and it interferes with vitamin D and mineral absorption in ways in which typically go unrecognized. Even past absorption points, energetic irritation itself can have an effect on vitamin D standing. Some analysis means that 25-hydroxyvitamin D could act as a unfavourable acute part reactant, that means ranges drop throughout energetic irritation. This might clarify why individuals with energetic Crohn’s illness or ulcerative colitis typically have decrease vitamin D ranges than individuals in remission, even when dietary consumption is comparable. Weight problems, which we already mentioned, is one other situation that will increase vitamin D necessities. Research recommend that folks with weight problems might have two to a few instances greater than an ordinary dose to attain the identical vitamin D ranges as somebody at a wholesome weight. A paper within the Journal of Diet Science has argued for weight based mostly vitamin D dosing methods particularly due to this differential response.

What I would like you to remove from this part is, in case you have any power well being situation, notably one which impacts your intestine, liver, kidneys, metabolism, or irritation, you have to be particularly considerate about vitamin D. The usual suggestions weren’t developed with these situations in thoughts. It’s essential to check, chances are you’ll want larger doses than the typical particular person, and you have to monitor your response over time.

Like what you’re studying? Get my free e-newsletter, recipes, eBooks, product suggestions, and extra!

Advantages of Solar Publicity

Let’s shift gears and speak about solar publicity, as a result of vitamin D is basically simply the tip of the iceberg in the case of the advantages of daylight. When your pores and skin is uncovered to UVB radiation, you produce a number of necessary compounds past simply vitamin D. These embody beta-endorphin, a pure opiate that promotes leisure and ache tolerance. Calcitonin gene-related peptide, which dilates blood vessels and protects in opposition to hypertension and vascular irritation. Substance P, which regulates immune operate. And melanocyte-stimulating hormone, which impacts urge for food and metabolism. UVA radiation, which is a special wavelength from UVB, triggers the discharge of nitric oxide from storage in your pores and skin. Nitric oxide is a potent vasodilator that reduces blood strain. A 20-year examine following practically 30,000 individuals discovered that those that prevented solar publicity had been twice as more likely to die from all causes in comparison with those that bought common solar publicity. That mortality profit can’t be defined by vitamin D alone. One thing else is occurring with daylight that’s profoundly helpful. Daylight additionally entrains your circadian rhythm. Vivid mild publicity through the day indicators your suprachiasmatic nucleus within the hypothalamus, which regulates melatonin manufacturing out of your pineal gland. Disrupted circadian rhythms are related to temper problems, cognitive deficits, and metabolic syndrome. Getting morning daylight is likely one of the most necessary issues you are able to do to your sleep high quality and metabolic well being.

So once we speak about vitamin D optimization, we have to assume past simply the vitamin D quantity. Solar publicity gives advantages that dietary supplements can’t replicate. That doesn’t imply dietary supplements don’t have a spot. They do, particularly throughout winter months or for individuals who can’t get satisfactory solar publicity. However daylight needs to be your major supply when attainable. My advice for solar publicity is easy. Spend about half as a lot time in direct daylight because it takes your pores and skin to show pink. This robotically accounts for variation in pores and skin tone, latitude, time of 12 months, and photo voltaic angle. Somebody with particularly reasonable pores and skin in summer season would possibly begin to pink in 20 minutes, so they need to get solely about 10 minutes of solar publicity with out safety. Somebody with darker pores and skin won’t pink for an hour, so they might safely get half-hour. This guideline is sensible as a result of it’s self-regulating. You don’t must calculate UV index or seek the advice of charts. Your pores and skin tells you. And importantly, you wish to do that with out sunscreen, a minimum of initially. Sunscreen blocks not solely vitamin D manufacturing, but in addition all the opposite helpful photoproducts your pores and skin produces in response to UVB. You possibly can apply sunscreen after you’ve gotten your baseline publicity, or you’ll be able to cowl up with a shirt when you’re going to be out longer. Expose as a lot pores and skin as is cheap and socially acceptable. The extra floor space you expose, the extra vitamin D you’ll produce. Legs and arms are good, however when you can safely expose your torso, that’s even higher. The aim is to get common, reasonable solar publicity, to not burn. Sunburns are damaging and needs to be prevented if attainable.

Throughout winter months at latitudes above about 35 levels north or south, the solar angle is simply too low for significant vitamin D manufacturing, even on clear days. In Boston, for instance, no previtamin D is produced in pores and skin from November via February, even on cloudless days. For those who stay in these latitudes, you’ll must rely extra on supplementation or dietary sources throughout winter, which is why testing in late winter is smart to see the place you truly land.

Personalizing Your Supplementation

On the subject of supplementation, the dose you want will depend on all of the elements we’ve mentioned – your present vitamin D degree, ethnicity, physique weight, well being standing, age, solar publicity patterns, and your consumption of co-factors. This is the reason I can’t provide you with a common quantity. What I may give you is a framework. In case your vitamin D degree is beneath 20 nanograms per milliliter, you doubtless want some mixture of solar publicity, dietary sources like fatty fish or cod liver oil, and a vitamin D3 complement. The dose may be wherever from 2000 to 10,000 IU per day, relying in your particular person elements, with larger doses for individuals with weight problems or malabsorption points. The bottom line is to retest in three to 4 months, and regulate accordingly. In case your degree is between 20 and 40 nanograms per milliliter, I like to recommend supplementing with 2000 to 5000 IU per day, relying in your particular person elements, till your degree is within the 40 to 60 vary. Individuals with weight problems and different well being situations might have 10,000 IU per day or much more. There’s just about no threat in taking vitamin D dietary supplements to convey your ranges into this vary, and there’s big potential profit. In case your degree is between 40 and 60, proceed what you’re doing. That’s a strong useful vary for most individuals. In case your degree is above 60, contemplate decreasing your complement dose and be sure to’re getting satisfactory vitamin K2, [vitamin] A, and magnesium to guard in opposition to potential toxicity.

The type of vitamin D issues too. Vitamin D3, or cholecalciferol, is simpler at elevating 25-hydroxyvitamin D ranges than vitamin D2, or ergocalciferol. Some prescription vitamin D formulations use vitamin D2, and cod liver oil additionally tends to comprise vitamin D2. However D3 is the shape you typically need. It’s additionally the shape your pores and skin produces naturally from solar publicity. This is likely one of the causes I developed Bio-Avail D3/K2 for Adapt Naturals. I needed a clear vitamin D3 complement that included vitamin K2 and allowed for exact dose titration. It’s a liquid components the place one drop delivers 1000 IU of vitamin D3 and 120 micrograms of vitamin K2. I selected MK-4 due to its preferential distribution to coronary heart, mind, and kidneys, and skeletal muscle – tissues the place vitamin Okay-dependent processes are important. The one different ingredient is MCT oil, which serves as a service and enhances absorption. The liquid format makes it straightforward to personalize your dose. For those who want 2000 IU, you simply take two drops. For those who want 5000 you are taking 5 drops. If testing exhibits you have to regulate up or down, you are able to do that exactly with out having to change between totally different capsule strengths. And since it consists of vitamin K2, you’re getting that synergistic profit for bone and cardiovascular well being with out having to take a separate complement. I formulated this as a result of I noticed the necessity clinically. Too many sufferers had been both taking vitamin D with out K2, which involved me from a calcium metabolism standpoint, or they had been taking capsules in mounted doses that didn’t permit them to fine-tune based mostly on their check outcomes. Having a liquid format with K2 included solved each issues.

All proper, let’s evaluate what we’ve lined. Vitamin D optimization requires a personalised method. Your optimum degree will depend on your ethnicity, physique weight, age, well being standing, and co-factor standing. For most individuals, purpose for 40 to 60 nanograms per milliliter, with ranges as much as 70 for these with autoimmune situations. Take a look at your ranges, don’t guess. Retest seasonally and after altering your dose. Take note of co-factors like magnesium, vitamin K2, and vitamin A that work along with vitamin D. Prioritize solar publicity when attainable and complement strategically based mostly in your particular person wants. The mainstream method relies on inhabitants averages, designed to forestall deficiency illness. It’s not designed to optimize your well being based mostly in your particular person biology. The one dimension suits all method doesn’t work, and also you now have the instruments to personalize your vitamin D technique.

Thanks for listening, everybody. You will discover present notes and hyperlinks to all of the research I discussed at ChrisKresser.com. When you have questions on vitamin D or some other matter you’d like me to cowl, head over to ChrisKresser.com/podcastquestion and submit your query there. I learn all of them, and I exploit them to information what matters I cowl on the present. I’ll speak to you subsequent time.



Leave a Reply

Your email address will not be published. Required fields are marked *