The Longevity Code, Daily FoundationWhat vitamins should you take in winter? Shorter days change one part of a vitamin routine more than any other. Why vitamin D is the vitamin most tied to the season, where it comes from, the difference between D2 and D3, and how to take it. Pause the background motion Codeage Education Winter vitamins In brief For most people the everyday base stays the same in winter: a varied diet and, for many, a daily multivitamin. The vitamin most tied to the season is vitamin D, because the skin makes it from the UVB in sunlight, and at many latitudes winter sunlight carries too little UVB for that to happen. Very few foods contain vitamin D naturally, which is why it is the vitamin most often discussed as the days get shorter. The rest is set by the label and by a qualified healthcare professional, who can measure vitamin D status with a blood test. Research described here was conducted independently and did not involve any specific Codeage product. I Does winter change which vitamins you need? Mostly, no. The vitamins and minerals the body uses do not change with the calendar. What changes is the day around them: fewer hours of daylight, more time indoors, more clothing when outside, and a different rhythm of meals. Most of those changes leave a vitamin routine untouched. One does not. Vitamin D is unusual among vitamins because the body can make it, and it makes it in the skin, from sunlight. That single fact ties one nutrient to the season in a way no other vitamin is tied. So a winter vitamin routine is less a new list than the same foundation with one question asked more carefully. Our guide to choosing the right multivitamin for every chapter of life covers the foundation. This guide covers the question. The Codeage film below starts from the same idea: a vitamins collection composed for different chapters of life. Winter is one of them. The film continues. Watch the full film: Vitamins for Every Chapter Replay the preview Mute the film Pause the film II Why is vitamin D called the winter vitamin? The skin contains a compound called 7-dehydrocholesterol. When ultraviolet B light, UVB, reaches bare skin, it converts that compound into previtamin D3, which the body then turns into vitamin D3. The process depends on UVB reaching the skin, and how much UVB reaches the ground depends on the angle of the sun. In winter the sun sits lower in the sky, its light travels through more of the atmosphere, and less UVB arrives. A 1988 study by Webb, Kline and Holick in the Journal of Clinical Endocrinology and Metabolism measured previtamin D3 formation in samples exposed to sunlight on cloudless days. In Boston, at 42 degrees north, it reported no previtamin D3 formation from November through February. In Edmonton, at 52 degrees north, that period ran from October through March. At 34 and 18 degrees north, formation took place even in midwinter. Latitude is not the only factor. The NIH Office of Dietary Supplements notes that clouds, smog, older age and darker skin all reduce the amount of vitamin D the skin makes, that sunscreen limits it, and that skin does not make vitamin D from sunlight through a window. Winter tends to bring more cloud, more clothing and more time behind glass. None of this says how much vitamin D any one person has. That is measured rather than read from a map, with a blood test for 25-hydroxyvitamin D. Research described here was conducted independently and did not involve any specific Codeage product. Sunlight, food and vitamin formulasWhere does vitamin D come from? There are only three routes: sunlight on the skin, a short list of foods, and vitamin formulas in two forms. Drawn from the NIH Office of Dietary Supplements vitamin D fact sheet. A description of sources, not intake advice. Source Form of vitamin D Good to know Sunlight on bare skin Vitamin D3, made in the skin Depends on UVB, which is limited in winter at higher latitudes. Not made through a window. Fatty fish and fish liver oils Vitamin D3 Trout, salmon, tuna and mackerel are among the few foods that contain vitamin D naturally. Mushrooms exposed to UV light Vitamin D2 Some mushrooms are exposed to UV light during growing, which produces vitamin D2. Fortified foods Vitamin D2 or D3, added Almost all milk sold in the US is fortified. Other fortified foods vary, so check the label. Vitamin formulas Vitamin D3 (cholecalciferol) or vitamin D2 (ergocalciferol) D3 is commonly sourced from lanolin or from lichen. D2 is made from yeast or fungi exposed to UV light. III Vitamin D2 or vitamin D3: what is the difference? Two forms of vitamin D appear in vitamin formulas. Vitamin D3, cholecalciferol, is the form the skin makes and the form found in fatty fish. Vitamin D2, ergocalciferol, is the form made by fungi and yeast exposed to UV light. Vitamin D3 for vitamin formulas is commonly sourced from lanolin, the natural wax in sheep's wool, or from lichen, which makes it suitable for a vegan formula. Several Codeage formulas use vitamin D3 from lichen, including Raw Vitamin D3+, Nanofood Liposomal Wonder-D and the Women's, Men's and Teen's Daily Multivitamin+. Some formulas carry both forms. Multivitamin D+ provides 4,000 IU of vitamin D per serving from D3 and D2 together. A D K Vitamins+, Vitamin D3 Gummies and Liquid Vitamins D3+K2 use D3. Which form, and how much, is a decision for a qualified healthcare professional. Our complete guide to vitamin D3 and our article on vitamin D2 go further into each. IV Why is vitamin D often paired with vitamin K2? Vitamins D and K are both fat-soluble, which is one reason formulators place them in the same capsule or drop. Vitamin K comes in two broad groups: vitamin K1, phylloquinone, found in leafy greens, and vitamin K2, the menaquinones, written MK-4, MK-7 and so on. In the body, vitamin K acts as a cofactor for an enzyme that activates several proteins, including proteins that bind calcium. The pairing with vitamin D is a formulation decision, and our guide to vitamins A, D and K sets out the biology. In the collection, A D K Vitamins+ pairs vitamin D3 with vitamin A and three forms of vitamin K: K1, MK-4 and MK-7. Liquid Vitamins D3+K2 carries D3 with MK-7 and MK-4. Nanofood Liposomal Wonder-D adds vitamin K2 as MK-7 and vitamin B12. Multivitamin D+ adds vitamin K2 as MK-7 alongside magnesium, zinc and boron. Vitamin K can interact with some medications, including blood thinners such as warfarin. Anyone taking medication should speak with a healthcare professional before adding a formula that contains vitamin K. Vitamin D formulas from the collection Capsules, a gummy and two liquids, from vitamin D3 on its own to D3 with vitamin K2. Previous formulas Next formulas Vitamin D3 and D2 Multivitamin D+ 4,000 IU of vitamin D from D3 and D2, with vitamin K2 as MK-7, magnesium, zinc and boron, in Codeage Helix liposomal delivery. Shop Now: Multivitamin D+ Vitamins A, D and K A D K Vitamins+ 5,000 IU of vitamin D3 with vitamin A and three forms of vitamin K: K1, MK-4 and MK-7. A 6-month supply. Shop Now: A D K Vitamins+ A chewable format Vitamin D3 Gummies 5,000 IU of vitamin D3 in a pectin-based, strawberry-flavored gummy. One gummy daily, preferably with a meal. Shop Now: Vitamin D3 Gummies A liquid drop Liquid Vitamins D3+K2 Vitamin D3 with vitamin K2 as MK-7 and MK-4, in MCT oil. One milliliter daily, followed by water. Shop Now: Liquid Vitamins D3+K2 Liquid, D3 from lichen Nanofood Wonder-D Vitamin D3 from lichen with vitamin K2 as MK-7 and vitamin B12, in a liposomal liquid taken with food. Shop Now: Nanofood Liposomal Wonder-D Whole food Raw Vitamin D3+ 5,000 IU of vitamin D3 from lichen with chlorella, a fruit and vegetable blend, probiotics and enzymes. Contains milk. Shop Now: Raw Vitamin D3+ Beyond vitamin D The whole foundation. Daily multivitamins, single vitamins and essential minerals, all in one place. View the full vitamins collection V How should you take vitamin D in winter? Start with the label, because it is the manufacturer's own answer and it comes before any general rule. Directions differ by format. Multivitamin D+, A D K Vitamins+ and Raw Vitamin D3+ may be taken with or without food. The Vitamin D3 Gummies label says preferably with a meal. Nanofood Liposomal Wonder-D is taken with food. Should vitamin D be taken with food? Vitamin D is fat-soluble, and the NIH Office of Dietary Supplements suggests taking it with a meal or snack that includes some fat. Where a label allows either, a meal is a simple fixed point in the day. Morning or night? None of these labels names an hour. A consistent daily time makes a routine easier to keep, and that matters more than the clock. Count every source. Vitamin D appears in multivitamins as well as in single vitamin D formulas, and the NIH sets a daily upper limit for vitamin D that counts intake from all sources together. Before combining products, add up the amounts on each label and check the total with a healthcare professional. Anyone who is pregnant or nursing, under 18, managing a medical condition or taking medication should speak with a physician first. VI Does the rest of a vitamin routine change in winter? Mostly not. A daily multivitamin is a year-round foundation, and the reasons to choose one, who it is formulated for, which nutrient forms it uses and how it is made, are the same in January as in July. Vitamin C comes up every winter, so it is worth being precise about it. Humans cannot make vitamin C, so it comes from food, mainly fruit and vegetables, every day of the year. Winter does not change that. What winter changes is less the list than the conditions: daylight, time indoors, the shape of meals. Vitamin D is where those conditions meet a nutrient. Everything else in the Codeage vitamins collection stays where it was. The vocabularySix terms worth knowing precisely. Most labels and articles about vitamin D in winter use these six terms. Vitamin D3 (cholecalciferol) The form of vitamin D the skin makes from sunlight and the form found in fatty fish. In formulas, D3 is commonly sourced from lanolin or lichen. Vitamin D2 (ergocalciferol) The form of vitamin D made by fungi and yeast exposed to UV light, found in UV-exposed mushrooms and some vitamin formulas. UVB Ultraviolet B, the part of sunlight that starts vitamin D production in the skin. Less of it reaches the ground in winter, and it does not pass through window glass. 7-dehydrocholesterol The compound in the skin that UVB converts into previtamin D3, the first step toward vitamin D3. 25-hydroxyvitamin D The form of vitamin D measured in a blood test to assess vitamin D status. Vitamin K2 (menaquinone) A group of vitamin K forms, written MK-4, MK-7 and so on, often paired with vitamin D3 in formulas because both are fat-soluble. QuestionsWinter vitamins, answered. What vitamins should you take in winter? For most people the everyday base stays the same in winter: a varied diet and, for many, a daily multivitamin. The vitamin most tied to the season is vitamin D, because the skin makes it from UVB sunlight, which is limited in winter at higher latitudes. A qualified healthcare professional can advise on individual needs and measure vitamin D status with a blood test. Why is vitamin D called the winter vitamin? Because the skin makes vitamin D3 from UVB light, and less UVB reaches the ground in winter. A 1988 study in the Journal of Clinical Endocrinology and Metabolism reported no previtamin D3 formation from November through February in Boston, at 42 degrees north. Research described was conducted independently and did not involve any specific Codeage product. Can you get vitamin D from the sun in winter? It depends on latitude. Closer to the equator, sunlight can start vitamin D3 production in the skin even in midwinter; at higher latitudes, winter sunlight carries too little UVB. Clouds, smog, older age, darker skin and sunscreen also reduce how much vitamin D the skin makes. Can you get vitamin D through a window? No. The NIH Office of Dietary Supplements notes that the skin does not make vitamin D from sunlight that comes through a window, because glass blocks UVB. What is the difference between vitamin D2 and D3? Vitamin D3, cholecalciferol, is the form the skin makes and the form found in fatty fish; for vitamin formulas it is commonly sourced from lanolin or lichen. Vitamin D2, ergocalciferol, is made by fungi and yeast exposed to UV light. Both forms are used in vitamin formulas. Which foods contain vitamin D? Very few foods contain it naturally. Fatty fish such as trout, salmon, tuna and mackerel, fish liver oils and mushrooms exposed to UV light are the main natural sources. Fortified foods, including almost all milk sold in the US, provide added vitamin D. Should vitamin D be taken with food? Vitamin D is fat-soluble, and the NIH Office of Dietary Supplements suggests taking it with a meal or snack that includes some fat. Follow the label: Codeage directions vary by format, from with or without food to with a meal. Is it better to take vitamin D in the morning or at night? The Codeage vitamin D labels do not name an hour. A consistent daily time, often with a meal, makes a routine easier to keep. Why is vitamin D taken with vitamin K2? Vitamins D and K are both fat-soluble, and vitamin K is a cofactor for an enzyme that activates several proteins, including proteins that bind calcium. Pairing them is a formulation decision. Vitamin K can interact with some medications, including blood thinners such as warfarin, so anyone taking medication should speak with a healthcare professional first. Can you take vitamin D every day? Codeage vitamin D labels set one daily serving. The NIH sets a daily upper limit for vitamin D that counts all sources, including multivitamins, so add up the amounts on each label before combining products and check the total with a healthcare professional. How do you check your vitamin D level? A blood test that measures 25-hydroxyvitamin D is the standard way to assess vitamin D status. It is arranged through a healthcare professional. Is vitamin D3 from lichen vegan? Yes. Lichen is a plant-like organism, and vitamin D3 sourced from lichen is a vegan alternative to vitamin D3 from lanolin. Whether a whole formula is vegan depends on its other ingredients, so check each label. Do you need a multivitamin in winter? A daily multivitamin is a year-round foundation rather than a seasonal one. Many multivitamins, including the Codeage Women's, Men's and Teen's Daily Multivitamin+, already contain vitamin D3, so count that amount before adding a single vitamin D formula. The days get shorter.The foundation stays the same. What winter changes about a vitamin routine, and what it leaves alone. VII Where do vitamins sit in The Longevity Code? Vitamin D and the daily multivitamins sit in Daily Foundation, the first pillar of The Longevity Code: the everyday base a longevity routine is built on. A pillar is a location within a framework. It describes a category, and it describes nothing about an outcome for any reader. The house position is the one set out above. The seasonal link between sunlight and vitamin D is well described. Everything else about a routine is a matter of following the label, keeping to it and asking a qualified healthcare professional the questions a page cannot answer. Nothing on this page is advice to begin, stop or change anything, and nothing on it replaces a conversation with a qualified healthcare professional. Continue readingFurther reading from the Codeage library. Education How to choose the right multivitamin for every chapter of life Education The complete guide to vitamin D3 Education A guide to vitamins A, D and K Previously What liposomal glutathione is, and how to take it This article is provided for educational and informational purposes only and has been reviewed against FDA and FTC guidelines to ensure it does not make any health, disease, or treatment claim. Studies cited describe how published research was conducted and what it measured, and are not statements about outcomes for any individual. Research described was conducted independently and did not involve any specific Codeage product. Certain visuals, persons, or scenes in the film may include AI-enhanced or AI-generated imagery. Nothing here is advice to begin, stop or change any routine, and decisions of this kind should be made with a qualified healthcare professional. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Codeage, The Longevity Code
