Vitamin D is a popular nutrient these days, as research has linked it to a variety of health benefits. Vitamin D may reduce the risk of cancer, heart disease, stroke, diabetes, autoimmune diseases, and other diseases in addition to its well-established role in bone health, according to research.
Vitamin D is unique in that it is both a vitamin and a hormone that your body can produce in response to sunlight. Despite the ability to obtain Vitamin D from food and the sun, it is estimated that 40-75 percent of the population is deficient.
Why? Vitamin D is scarce in our diets, and the sun is not a reliable source for everyone.
Season, time of day, latitude, air pollution, cloud cover, sunscreen, body parts exposed, color, and age are all factors that influence the skin's ability to produce Vitamin D. Dermatologists recommend using sunscreen and getting Vitamin D from food and supplements rather than risking exposure to the sun's harmful rays.
Spending time outside and in the sun is beneficial for a variety of reasons, including fresh air, reduced stress, and all of the benefits that come with going for walks or runs. And do you know what else it can help with? Defending against vitamin D deficiency!
When you step outside on a beautiful sunny day, you might hear someone talk about soaking up Vitamin D, and many of us understand that the sun is linked to Vitamin D in some way. However, not everyone is aware of what vitamin D is. Yes, nursing mothers typically learn about Vitamin D from their pediatricians in the context of their breastfed babies needing a Vitamin D drop for a certain period of time after birth due to Vitamin D deficiency. However, this deficiency has an effect.
Furthermore, what are the symptoms of Vitamin D deficiency? How do you get more of it? There are simply too many questions! But don't worry—what here's you need to know.
What is Vitamin D?
Some people are already aware that vitamin D aids in the maintenance of strong teeth and bones. However, it is also essential for proper immune function, assisting your body in developing resistance to certain illnesses. According to Jessica Nouhavandi, the lead pharmacist, co-founder, and co-CEO of the accredited online pharmacy Honeybee Health, Vitamin D plays a role in our immune system, which is our body's natural line of defense against infections.
Vitamin D can help boost the activity of our immune cells, which protect our bodies from pathogens that can cause infection. Higher levels of Vitamin D have previously been found to potentially reduce the risk of cold and flu, and thus the risk of contracting viral respiratory infections in humans.
We determined that Vitamin D supplementation reduces other types of viral respiratory infection by 70% in people who are Vitamin D deficient.
Vitamin D is inexpensive, generally very safe to take, and can be widely scaled. That's great news because it means that everyone should be able to increase their intake of this essential vitamin.
Roles of Vitamin D
Few foods naturally contain vitamin D. Almost all cow's milk in the United States has been voluntarily fortified with 100 IU of Vitamin D per cup since 1930. Other foods, such as yogurt, cereal, and orange juice, are being fortified to help consumers fill nutrient gaps in their diets.
Vitamin D should ideally be added to a calcium-containing food or beverage. Vitamin D is required for maximum calcium absorption from the intestine, which aids in the development of strong bones and teeth.
Vitamin D acts as a hormone in our bodies, regulating many processes that keep us healthy. One of the primary functions of Vitamin D is to help balance the levels of calcium and phosphorus in our bodies, which are required to form our bones and teeth, to help our muscles contract, to help nerves carry messages between the brain and the body, and to keep our cells functioning properly. Vitamin D is also necessary for our immune system to function properly.
Vitamin D, when combined with calcium, can help prevent osteoporosis in older adults. Without enough Vitamin D, bones can become brittle and prone to fracture. It is estimated that more than 40 million adults in the United States have or are at risk of
Vitamin D deficiency is associated with low bone mass and osteoporosis, which is estimated to affect 10 million adults over the age of 50 in the United States. Even in Atlanta, where the sun shines all year, particularly the elderly and people with dark skin, have low levels of Vitamin D because the sun is not a reliable source.
How much Vitamin D is required?
The Institute of Medicine's recommendations on how much Vitamin D and calcium people should get were solely focused on bone health.
Adults up to the age of 69 should take 600 IU/day, and adults over the age of 70 should take 800 IU/day. Older adults require more Vitamin D because their skin produces less Vitamin D as they age, they spend less time outside, and they do not get enough Vitamin D.
The committee did not take into account new research on any other conditions. Patsy Brannon, PhD, RD, a Cornell University professor of nutritional sciences and IOM committee member, discussed this at the American Dietetic Association's annual meeting in San Diego in 2011. "The committee of 14 scientists reviewed over 1,000 publications and determined that the evidence was inconclusive and inconsistent to include any other health benefits in the new recommendations," Brannon explained. "The committee is not dismissing the role of Vitamin D in other areas; however, more clinical trials, consistent evidence, and evidence supporting causality are required."
So, how much Vitamin D do most people require? According to Meltzer, this is where things can get a little complicated.
We don't know what the optimal levels of Vitamin D for immune function are. And, because few foods naturally contain Vitamin D, it can be difficult to stay on track. In general, a few minutes of natural sunlight per day can be enough to boost Vitamin D levels to healthy levels. However, if you don't get out much or live in the far north, a daily supplement can suffice. Of course, a Vitamin D supplement is fine to take even if you get outside every day; just consult your doctor and always follow their recommendations, as well as the dosage guidelines on the bottle.
According to Nouhavandi, the recommended daily dose of Vitamin D varies depending on age. "The current recommended dose of Vitamin D supplement is 600 IU for adolescents and adults, and 800 IU in people over the age of 70," according to WebMD. "However, many endocrinologists recommend a higher intake of 800-2,000 IU daily, with a daily maximum of 4,000 IU."
When it comes to increasing your intake of Vitamin D-rich foods, there aren't many options, but if you follow one of the many low-carb diets available, you're in luck. Sardines, salmon, and mackerel, as well as liver, red meat, and eggs, are the best sources of Vitamin D. If you're a vegan or vegetarian, fortified cereals and grains are your best source of Vitamin D.
Vitamin D deficiency symptoms
While it would be ideal if there was a magic list of symptoms that could quickly determine whether or not you were deficient in Vitamin D, this is rarely the case.
The most important thing to remember is that there isn't always a sign. An annual physical with blood work is a great way to get an overall picture of your health as well as your Vitamin D levels.
While vitamin D deficiency is often asymptomatic, there are some symptoms that may indicate low levels of vitamin D. These are some examples:
- Fatigue
- Mood changes
- Muscle cramps
- Weakness
- Bone and joint pain
Best sources of Vitamin D
The sun is a great source of Vitamin D, but it's difficult to quantify how much Vitamin D you get from being outside, and the risk of skin cancer may outweigh the benefits. Keli Hawthorne, a dietitian at Baylor College of Medicine, recommends starting with food. While supplements can fill in the gaps, it is always preferable to try to meet your nutritional needs with foods that contain fiber, phytonutrients, and so much more.
Without eating fortified foods or taking a supplement, it may be difficult to get enough Vitamin D without eating fatty fish or fish liver oils. Fortified dairy products, as well as some yogurts and cereals, are the primary dietary sources of Vitamin D. Small amounts can be found in mushrooms, eggs, cheese, and beef liver.
Reading food labels
Daily Values (DV) are displayed on nutrition fact panels to assist consumers in comparing nutrients in products and selecting a healthy diet. The FDA has set the DV for Vitamin D at 400 IU, which is less than the recommended 600 IU.
"Do the math: When one serving says it meets 100 percent DV, you still need an additional 200 IU to satisfy your requirement.
Amount of Vitamin D in sample food sources:
- 1 Tbsp cod liver oil: 1,360 IU
- 3 oz. salmon: 800 IU
- 3 oz. irradiated mushrooms: 400 IU
- 8 oz. fortified orange juice: 100 IU
- 8 oz. fortified milk: 100 IU
How much is too much?
Vitamin D is an essential fatty acid. Fat-soluble vitamins can accumulate in the body and are not excreted as easily as water-soluble vitamins. The IOM committee established 4,000 IU as the "tolerable upper limit," or the maximum amount that can be consumed safely on a daily basis.
Robert Heaney, MD, a vitamin D researcher and Creighton University professor, agrees with the new level but wishes it were higher.
"I am delighted that the upper limit for Vitamin D has been doubled to 4,000 IUs per day," Heaney tells WebMD. "However, this is a conservative level, given the body of scientific evidence indicating it should be 10,000 IU." "However, few people require more than 4,000 IUs, which will meet the needs of the majority of healthy people, give physicians confidence to recommend supplementation, and allow researchers to study higher Vitamin D levels."
The Endocrine Society Practice Guidelines, published in July 2011, recommended an upper limit of 10,000 IU/day for the evaluation, treatment, and prevention of Vitamin D.
Overdosing on supplements above 4,000 IU/day has the potential to cause harm, but there is no fear of overdosing from the sun because your skin acts as a regulatory system, only allowing production of the amount of Vitamin D you need.
Acceptable Vitamin D blood levels
A simple blood test can be performed by your doctor to determine your Vitamin D blood level.
The definition of the acceptable blood level of Vitamin D, clinically measured as 25-hydroxyVitamin D [25(OH)D], may be part of the confusion about whether or not you are getting enough Vitamin D.
Although using Vitamin D blood levels to estimate adequacy accounts for dietary intake and sunlight, experts disagree on what that level should be.
The IOM committee used a 25(OH)D blood level of at least 20 nanograms/ml to set the recommendations for Vitamin D because this level demonstrated adequacy for a wide variety of bone health indicators.
Many laboratories and experts (including Baetti) recommend a minimum Vitamin D blood level of 30 nanograms/ml as an acceptable level, as do the Endocrine Society Practice Guidelines.