Factors That Might Affect Your Vitamin D Levels
Your vitamin D levels reflect many factors. For example:
Where you live. If you live in the northern states , you are at higher risk for a vitamin D deficiency because your skin may not be able to produce any vitamin D from sun exposure during the winter months.
Your age. Your skin’s ability to produce vitamin D drops with age. If you’re over age 65, you generate only one-fourth as much vitamin D as you did in your 20s.
Your skin color. People with darker skin typically have lower levels of vitamin D than lighter-skinned individuals. African Americans have, on average, about half as much vitamin D in their blood compared with white Americans.
Your weight. If you have a body mass index above 30, you may have low blood levels of vitamin D. Vitamin D is stored in fat, so in people with obesity, less of the vitamin circulates in the blood, where it’s available for use by the body.
The foods you eat. Very few foods naturally contain vitamin D. The U.S. government started a vitamin D milk fortification program in the 1930s to combat rickets, a bone-weakening disease caused by vitamin D deficiency, which was a major public health problem at the time. Breakfast cereals and some types of orange juice may also be fortified, but this varies by brand. So, the amount of vitamin D you get from food depends on the food you eat and how much milk you drink.
Side Effects Of Too Much Vitamin D
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Vitamin D is extremely important for good health.
It plays several roles in keeping your bodys cells healthy and functioning the way they should.
Most people dont get enough vitamin D, so supplements are common.
However, its also possible although rare for this vitamin to build up and reach toxic levels in your body.
This article discusses 6 potential side effects of getting excessive amounts of this important vitamin.
Are Vitamin D Or D3 The Same
When we refer to vitamin D, we are talking about Vitamin D2. Vitamin D2 and D3 are both widely used vitamin D supplements but are not the same. Vitamin D2 is ergocalciferol and comes from plant-based sources. Vitamin D3 is cholecalciferol and comes from animal-based sources. Both supplements are processed in the body by the liver to 25-hydroxyvitamin D, though vitamin D3 is thought to provide higher levels of 25D. Some formulations of vitamin D2 are prescription only, while all formulations of vitamin D3 are over-the-counter.
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Vitamin D Benefits And Warnings
Although the research is still hazy, some people will benefit from taking vitamin D supplements, along with sufficient calcium intake, to promote their bone health. But they don’t require large amounts of vitamin D to get the benefit. “More is not necessarily better. In fact, more can be worse,” says Dr. Manson. For example, a 2010 study published in JAMA showed that intake of very high doses of vitamin D in older women was associated with more falls and fractures.
In addition, taking a supplement that contains too much vitamin D can be toxic in rare cases. It can lead to hypercalcemia, a condition in which too much calcium builds up in the blood, potentially forming deposits in the arteries or soft tissues. It may also predispose women to painful kidney stones.
If you’re taking vitamin D supplements, the take-home message is moderation. Taking too much can limit the benefits of the sunshine vitamin.
Selected food sources of vitamin D
The Risks Of Very Low Levels
Theres no question that additional vitamin D is helpful if someone is low or deficient, says F. Michael Gloth III, M.D., an associate professor in the division of geriatric medicine at Johns Hopkins Universitys medical school. But no trial has shown any benefit for giving vitamin D in any population thats already getting enough.
In 2018, long-awaited results from a study that looked at the effects of vitamin D and fish oil pills in more than 25,000 people ages 50 and older were published in The New England Journal of Medicine. Known as the VITAL trial, it found that taking 2,000 IU of vitamin D daily didnt cut cancer or cardiovascular risks compared with a placebo. But few of the people in the study had low blood levels of vitamin D.
Still, some research questions how helpful it is to raise low vitamin D levels. For example, doctors commonly recommend that older adults take vitamin D pills to help prevent falls and fractures. But a 2018 analysis of 81 studies, published in The Lancet Diabetes & Endocrinology, failed to support this, although only a few of the trials included people with really low levels.
Moreover, too much vitamin D may actually contribute to fractures. A 2019 study published in JAMA found that people who took 4,000 or 10,000 IU a day saw a reduction in bone density compared with those who took 400 IU.
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Calcium And Vitamin D: A Partnership
Calcium and vitamin D is the dynamic duo that works together to strengthen and protect your bones. For years, healthcare providers have recommended that postmenopausal women take calcium and vitamin D supplements to prevent osteoporosis, a bone-thinning disease that is a major cause of devastating fractures in old age.
Research linking calcium supplements to heart attack and stroke caused many to take vitamin D supplements alone for prevention.
Calcium supplements can increase calcification in the arteries and predispose people, especially women, to heart disease, he says. Thats why we always prefer dietary calcium. However, some people get adequate dietary calcium but are low in vitamin D.
Why Do Doctors Prescribe Vitamin D2 Instead Of D3
Your doctor may determine your vitamin D recommendation based on lab work. Among some health professionals, there may be a perception that vitamin D2 is more effective because it is available by prescription only, even though studies have shown this is not necessarily true. Vitamin D2 may also be a lower cost to the patient, especially when covered in part or full by their insurance.
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Why We Need Vitamin D
Vitamin D helps you absorb calcium and phosphorus from your diet and use these minerals to keep your bones, teeth and muscles strong. This helps prevent falls as you get older.
Vitamin D may have other roles in the bodys immune system and heart health too.A lack of vitamin D can cause bone problems such as rickets in children and muscle weakness and painful or tender bones in adults.
Who Is Most At Risk Of Deficiency
Some people are at higher risk of vitamin D deficiency than others. For people at risk of vitamin D deficiency the government advises taking a vitamin D supplement all year round.
Those at higher risk of low vitamin D levels include:
People with dark skin
People with dark skin have more melanin, which reduces the skins ability to make vitamin D. Studies show people with dark skin generally have lower vitamin D levels.
People who cover their skin
We can only make vitamin D if our skin is exposed to the sun. People who cover most of their skin in the sun are unable to make vitamin D.
The government recommends that breast-fed babies are given a daily supplement containing vitamin D . This is because its hard to get enough from breast milk alone.
Even once a baby is weaned, its hard to get enough vitamin D from food and we tend to keep babies out of the sun, so theyre unlikely to get enough from sun exposure.
Formula milk is fortified with vitamin D, so babies having more than 500ml a day of formula shouldnt take a supplement.
People who rarely go outside
People who are frail, housebound or who live in a care home might not get out as much and as such have limited exposure to sunshine.
This also applies to people who work long days inside in shops or offices with little exposure to the sun.
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What You Can Do Now
If youre concerned about vitamin D deficiency, ask your doctor to check your vitamin D level, says Dr. Deal. If the level is low and your provider starts you on supplements, you need repeat testing in eight to 12 weeks to make sure the level is not too high or too low.
If testing shows your vitamin D level is normal, you need repeat testing every two to three years unless you have major changes in your overall health.
Different diseases need different doses of vitamin D. If you have chronic kidney disease or parathyroid disease, ask your kidney specialist or endocrinologist about the type and dose of vitamin D you need.
If youre pregnant or breastfeeding, Dr. Deal recommends you keep taking vitamin D supplements as long as your doctor prescribes them. The supplement is linked to healthy development for you and your baby.
For bone health, be sure to stay active and remember to eat a calcium-rich diet. Consult with your doctor frequently to make sure youre taking the right steps to current bone health.
Should Everyone Get Their Vitamin D Levels Checked Generally No
Karl Insogna, MD, director of Yale Medicines Bone Center
Most people should be fine. Testing is important only for certain populations: for people who are institutionalized for patients with a gastrointestinal disorder or osteoporosis those who have had weight loss surgery those on anti-convulsant medications and children who are immobilized and not outside and active. If youre over 70, I recommend getting your levels checked at least one time.
People whose cultural or religious beliefs require them to be fully clothed, especially if theyre living in northern climates, and whose dietary habits include little or no dairy , may also be vitamin D-deficient and should be tested.
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Some People Are Overdoing It In Search Of Better Health
Vitamin D is having its day in the sun. In recent years, research has associated low blood levels of the vitamin with higher risks of everything from heart disease, diabetes, and cancer to mood disorders and . The findings have not gone unnoticed. and screening tests have surged in popularity.
“Vitamin D testing is one of the top Medicare lab tests performed in the United States in recent years,” says Dr. JoAnn E. Manson, the Michael and Lee Bell Professor of Women’s Health at Harvard Medical School. “This is really surprising for a test that is recommended for only a small subset of the population.”
Unfortunately, this vitamin D trend isn’t all blue skies. Some people are overdoing it with supplements. Researchers looking at national survey data gathered between 1999 and 2014 found a 2.8% uptick in the number of people taking potentially unsafe amounts of vitamin D that is, more than 4,000 international units per day, according to a research letter published in the June 20 issue of The Journal of the American Medical Association . And during the same time period there was nearly an 18% increase in the number of people taking 1,000 IU or more of vitamin D daily, which is also beyond the dose of 600 to 800 IU recommended for most people.
Diet Medications And Surgery
A May 2013 study in PLOS One reported that many herbs, spices and supplements can produce negative and harmful interactions in combination with anticoagulant and antiplatelet drugs. This study found that a variety of foods and supplements including celery, chamomile, evening primrose, fenugreek, garlic, ginger, ginkgo, horse chestnut, licorice, red clover, turmeric and willow can produce serious cardiovascular side effects when taken with medications.
You’ll notice that many of these are the same products that the American Society of Anesthesiologists and Stanford University School of Medicine’s Department of Otolaryngology also recommend avoiding. However, some of these products are harmful even on their own.
Garlic, onion and curcumin, a polyphenol found in turmeric, have strong anticoagulant and antiplatelet activity. A June 2013 study in the International Journal of Woman’s Health reported that large amounts of garlic have resulted in excessive bleeding during different surgical procedures. When garlic is combined with blood thinning medications, more serious side effects, like a cerebral hemorrhage, are possible.
The same study reported that consumption of gingko produced severe bleeding following procedures like liver transplants, gallbladder removal and hip surgery. Gingko produces this issue on its own, rather than in combination with any medication.
- Baical skullcap root
- Fish oil
Large Doses Can Be Harmful Even Without Symptoms Of Toxicity
Large doses of vitamin D can be harmful, even though there may not be immediate symptoms of toxicity.
Vitamin D is very unlikely to cause severe symptoms of toxicity right away, and symptoms may take months or years to show up.
This is one reason why vitamin D toxicity is so difficult to detect.
There have been reports of people taking very large doses of vitamin D for months without symptoms, yet blood tests revealed severe hypercalcemia and symptoms of kidney failure .
The harmful effects of vitamin D are very complex. High doses of vitamin D can cause hypercalcemia without toxicity symptoms, but can also cause toxicity symptoms without hypercalcemia .
To be safe, you should not exceed the 4,000 IU upper limit without consulting with a doctor or dietitian.
Vitamin D toxicity usually develops over time, and the harmful effects are very complex. Large doses may cause damage, despite a lack of noticeable symptoms.
Potential Benefits Of Vitamin D Supplementation
The Vitamin D Council state that the two main ways to get sufficient amounts of vitamin D in the body are to expose bare skin to sunlight and take vitamin D supplements.
But Brant Cebulla, development director of the Vitamin D Council, told Medical News Today that for many people, frequent exposure to sunlight is not possible:
With our indoor lifestyles, we dont expose skin to the sun as much as we used to and are not fulfilling our vitamin D requirements. Supplements are one way to make up for this lifestyle.
Vitamin D supplementation has been linked to numerous health benefits.
More recent research has suggested that high levels of vitamin D may prevent cognitive impairment in patients with Parkinsons disease, while another study found that high vitamin D intake during pregnancy may increase the muscle strength of offspring.
Last year, a study published in The Lancet Diabetes & Endocrinology that analyzed 290 prospective observational studies and 172 randomized trials of vitamin D supplements, found no evidence that vitamin D supplementation yields any health benefits.
Furthermore, the study researchers suggested that low vitamin D levels are a consequence of ill health, not a cause.
A more recent study, also published in The Lancet Diabetes & Endocrinologyquestioned the health benefits of vitamin D supplementation.
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Advice For Infants And Young Children
The Department of Health and Social Care recommends that babies from birth to 1 year of age should have a daily supplement containing 8.5 to 10 micrograms of vitamin D throughout the year if they are:
- formula-fed and are having less than 500ml of infant formula a day, as infant formula is already fortified with vitamin D
Children aged 1 to 4 years old should be given a daily supplement containing 10 micrograms of vitamin D throughout the year.
You can buy vitamin D supplements or vitamin drops containing vitamin D at most pharmacies and supermarkets.
Women and children who qualify for the Healthy Start scheme can get free supplements containing vitamin D.
See the Healthy Start website for more information.
Who Should Avoid Vitamin D
How much vitamin D is too much if you take other daily medications? Because vitamin D can interact with some medications, vitamin D supplements should not be taken by anyone who takes these prescription drugs:
- Epilepsy drugs, such as phenobarbital and phenytoin
- The weight loss medication called Orlistat
People who have any of the health conditions listed below should not supplement with vitamin D without being monitored by a doctor:
- Williams syndrome
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How Much Vitamin D Is Too Much The Surprising Truth
Vitamin D toxicity is extremely rare, but does occur with extreme doses.
It usually develops over time, since extra vitamin D can build up in the body.
Nearly all vitamin D overdoses result from taking high amounts of vitamin D supplements.
It is almost impossible to get too much vitamin D from sunlight or food.
This is a detailed article about vitamin D toxicity and how much of it is considered to be too much.
Vitamin D Testing And Supplements Can Be Controversial
Routine testing for vitamin D can be controversial among medical professionals.
The National Endocrine Society and the Institute of Medicine , for example, recommend vitamin D testing be limited to specific patients . Rosen and Madan also say not everyone needs vitamin D supplements, only those who have a confirmed deficiency and experience symptoms, according to Madan.
One of the criticisms of routine vitamin D testing is that it can be time-consuming and costly for insurance companies. Out-of-pocket costs for vitamin D tests could range from $40 to $225,according to Kaiser Health News. And typically, most vitamin D tests are covered by health insurance.
Another issue is that widespread vitamin D testing can result in unnecessary treatment of patients with supplements. “It leads to lots of people taking very high doses of vitamin D,” Rosen says.
There are concerns around consuming too much vitamin D according to the NIH, excess vitamin D can cause nausea, poor appetite, constipation and weight loss. Severe vitamin D toxicity can cause confusion, disorientation and problems with heart rhythm.
Additionally, there is not a lot of scientific evidence that taking vitamin D, if you do not have a deficiency, does anything helpful. It’s safe to take in small doses, Rosen says , but “whether it’s effective is really the question.”
The NIH Office of Dietary Supplements does not recommend whether or not to take supplements, but says the daily upper limit for adults is 4,000 IUs.
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