Vitamin D – Everything You Need to Know
Vitamins are nutrients that are essential in tiny amounts for virtually everything that our bodies do. We get vitamins from eating plants, animals or supplements – and in the case of Vitamin D, by being exposed to the sun. Vitamins are not building blocks for any body parts, and they don’t provide energy. But without vitamins, our bodies simply wouldn’t work.
What does Vitamin D do?
Vitamin D is probably best known for helping to prevent rickets, osteoporosis, and osteomalacia.
Did you just think, “Hmm, what about calcium?”
One of Vitamin D’s most important functions is to help us absorb calcium. Vitamin D also helps us to maintain the correct balance of calcium between blood and bone, called calcium homeostasis.
As we grow, calcium is deposited into bone by a process called mineralization, which strengthens our bones. Without enough Vitamin D to help us absorb calcium, the process of mineralization is disrupted. Soft young bones don’t become strong and hard. In children, this causes rickets, a disease characterized by soft bones and skeletal deformities.
I didn’t get rickets as a child. Does that mean that I have strong bones now?
Developing strong bones as a child is not a guarantee of having strong bones as an adult. This is because calcium is continually deposited into bone, where it stays until it is needed. When blood levels of calcium are low, tiny, unnoticeable amounts of bone are broken down, releasing the store of calcium. This normal cycle of breaking down and building up keeps bones strong, repairs minor injuries, and frees calcium for its other functions.
In an adult, if there is insufficient Vitamin D to help with calcium absorption, less calcium goes into existing bones and a disease similar to rickets, called osteomalacia, develops. The adult may have musculoskeletal pain, difficulty walking, and a gait that is compared to a duck waddle.
If calcium-containing bone is removed from the mature, developed bone faster than it can be replaced, the bone structure becomes less dense. The result is osteoporosis – brittle, weak bones, prone to fracturing.
I am generally healthy. Approximately how much Vitamin D do I need every day?
Ages 1-70 600 IU (“International Units”) or 15 mcg
Ages > 70 800 IU or 20 mcg
How much is too much?
People over age 9 should not get more than 4000 IU per day. Upper limits for younger children and infants are less. Yes, you can have too much of a good thing!
The above recommendations given for daily Vitamin D intake assume that people do not get much Vitamin D through sun exposure.
How do I get Vitamin D?
Fatty fish such as salmon, swordfish, tuna, and mackerel are some of the best sources. Fish oil, especially cod liver oil, is also an excellent source.
- Sunlight and Skin
Our skin is able to make Vitamin D when it is exposed to sunlight. In fact, we can make and store quite a lot of Vitamin D through sun exposure. However, leaving skin unprotected from the sun increases our risk of developing skin cancer. Therefore, it is not wise to expose skin to the sun for the purpose of making Vitamin D.
Always purchase supplements from a reputable manufacturer. If you take Vitamin D supplements, make sure that your total daily intake does not exceed 4000 IU.
How would I know if I have a Vitamin D deficiency?
One clue is a diagnosis of osteoporosis or osteomalacia. Unfortunately, most people are not aware that they have osteoporosis or osteomalacia until they develop pain, fractures, or leg or spinal deformities. In the elderly, these conditions often lead to rapid, irreversible physical and mental decline.
Vitamin D levels, referred to as serum 25-hydroxyvitamin D or 25(OH)D, can be measured during routine blood testing, or whenever your doctor feels it is necessary. If you are worried about your level, ask your doctor for the test.
What are the risk factors for a low Vitamin D level? Should I be worried?
Many variables can affect Vitamin D levels, including:
• Being elderly
Reasons that elderly people are at higher risk for low Vitamin D levels include: having skin that doesn’t effectively make Vitamin D from sunlight; spending less time outdoors; having diseases or medications that interfere with Vitamin D absorption; and not eating as well as they used to.
• Lack of outdoor sun exposure
People who dress modestly and don’t expose skin to the sun will not make much Vitamin D. Of course, people who spend little time outside won’t make much Vitamin D either! Having big windows doesn’t help, because Vitamin D synthesis requires exposure to UVB rays, which are blocked by most window glass. The role of sunscreen is unclear but using sunscreen might reduce Vitamin D synthesis. Use sunscreen anyway!
• Having dark skin
The pigment in darker skin reduces the skin’s ability to make Vitamin D from sunlight.
• Having a condition that impairs absorption of fat
Vitamin D is best absorbed when eaten with food containing fat. Certain diseases and conditions impair the ability to absorb fat, and consequently, to absorb Vitamin D. These conditions include cystic fibrosis, celiac disease, Crohn’s disease, some liver diseases, and some abdominal surgeries.
Having large amounts of fat affects the amount of Vitamin D that is released into the circulation for use.
• Breastfed infants
Typical infant-sized feedings of breast milk or breast milk plus formula do not provide enough Vitamin D for the development of strong bones. Until they are drinking enough milk or formula, infants and young children should be given supplemental Vitamin D, available in drops.
• Kidney disease
Kidneys play an important role in converting Vitamin D into its active (usable) form.
Is it true that Vitamin D cures psoriasis, prevents cancer, protects against dying from cardiovascular diseases, and improves cognitive function?
We know that Vitamin D is involved in reducing inflammation, regulating cell growth, and supporting our neuromuscular and immune systems. With that in mind, popular media has given people the impression that Vitamin D is almost a cure-all. However, scientists are not entirely clear on if and how we can use supplements to prevent or cure diseases linked to a Vitamin D deficiency.
In fact, the idea that higher Vitamin D intake (2000mg per day) can generally prevent the development of cancer and cardiovascular disease was recently disproven by a high-quality study. However, the study did show a link between adequate Vitamin D levels and reduced risk of death from cancer. That study is ongoing and will continue to look at other conditions for which Vitamin D supplementation may prove to be useful.
Even if you have only skimmed the rest of this article, do read this:
Vitamin D might – or might not – help with other medical conditions. It definitely helps us to develop and maintain strong bones. That alone is a great reason to make sure that we get at least the minimum recommended amount of Vitamin D.
How Halza can help
If you take supplements to meet the recommended amount of Vitamin D, the Halza mobile app lets you schedule medication reminders, so you’ll never miss a dose. The app also lets you keep track of the calcium levels in your body. Simply enter the necessary data to chart your bone health. You can also upload your x-rays and other medical documents to the app. Everything you need is with you, no matter where you are.