What dose of vitamin D does your body require? There isn't a straightforward answer—especially considering that everyone of us has different physiology, demands, and ways of taking it in.
Yes, there are a number of variables that can affect how you interact with vitamin D.
One of the most important is your age: As you grow older, you may need even more of the crucial micronutrient. Here are some factors that affect how critical age is and what you might want to modify about your vitamin D intake.
Understanding the effects of age on vitamin D levels
According to Ashley Jordan Ferira, Ph.D., RDN, vice president of scientific affairs at mindbodygreen, "as we age, our cutaneous production, or the skin synthesis, goes down naturally." We obtain vitamin D from sunlight through a process called skin synthesis: When sunlight strikes exposed skin, vitamin D3 is produced following a few conversion processes. As you age, this process simply slows, resulting in less vitamin D being produced by your skin, notes Ferira.
Another environmental issue at play is that as you age, you might spend less time outdoors or partake in outdoor activities, which reduces your exposure to the sun (and, thus, leads to less vitamin D3 production via your skin). Ferira claims that "Older age is a major vitamin D insufficiency risk factor to be careful of, for yourself and your loved ones" in addition to possible drug interactions.
Aside from limited direct sunlight, there is another way that aging may reduce our vitamin D levels: proper form. As Ferira explains, "The body's ability to convert vitamin D from its circulating 25(OH)D form to its doubly hydroxylated form, which is the active hormone form, is decreased as we age. Therefore, it is crucial to take enough D3 every day to prevent these age-related mechanisms."
What to do in response
While getting natural doses of Vitamin D is a perk to spending time in direct sunshine, it’s not the “solution” to your woes, As Ferira reminds us: "Of course, there's considerable risk to your skin with sun exposure over time. And there are so many variables that affect the sun. The amount of vitamin D you really get might vary depending on the season, time of day (sun angle), amount of time spent outside, clothes, skin tone, latitude or distance from the equator, pollution exposure, and the angle the sun is at when it hits your skin.”
Since getting enough vitamin D through food is improbable, most of us must turn to supplements. Note, though that even though your body naturally reduces cutaneous production as you age, if you're already giving your body enough vitamin D3 (5,000 IU plus per day) from a high-quality D3 supplement (or from a combination of food, sunshine, and supplement), then you're probably fine to begin with. The only way to be certain is to have your 25(OH)D levels checked.
However, for those who are unsure of how to restore their vitamin D levels, you will most likely need to take 5,000IU of vitamin D3 from a sustainable source. Studies have shown 5,000IU to be the most effective dose and vitamin D3 to be the form your body prefers most. Of course, always confirm your current levels with your doctor before beginning any new supplements.
In Summary
Your age is one of several key variables that can influence how you produce, ingest and react to vitamin D. Since each person is unique, you can be dealing with several issues at once, such as body composition affecting your vitamin D status. But if you take enough vitamin D through a high-quality D3 supplement, you may be able to balance out those individual differences.
