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Vitamin D: Is it a Wonder Pill?
Vitamin D is an essential nutrient important for strong bones. In addition vitamin D can boost your immune system, support muscle function, keep your heart healthy, and aid in brain development. Vitamin D is produced by the body when your skin is exposed to sunlight. It's important to get enough of this vital nutrient so you don't wind up with a vitamin D deficiency.
Vitamin D Boosts Bone Health
Your body needs vitamin D to help absorb the calcium and phosphorus in your diet that makes for strong bones. Vitamin D deficiency can cause rickets in children and a condition called osteomalacia in adults. Symptoms may include weakness and bone pain.
Vitamin D and Multiple Sclerosis
Higher blood levels of vitamin D seem to be associated with a lower risk of developing multiple sclerosis (MS). A recent study shows vitamin D may slow the progression of the disease, though the connection between the vitamin and MS is not clear and it is unknown if low levels of vitamin D cause MS, or are a result of the disease. Supplementation with vitamin D may be beneficial for MS patients, but the dose is yet to be determined.
Vitamin D and Diabetes
Type 2 diabetes is a condition where the body does not use insulin properly, and blood sugar levels can rise above normal. Researchers are looking into whether vitamin D can help regulate blood sugar levels. In addition, vitamin D helps with the absorption of calcium, and calcium helps manage sugar in the blood. Studies have found people with low levels of vitamin D in the blood have a higher risk of developing type 2 diabetes later in life, but the link is not conclusive. More research is needed to determine if vitamin D supplementation can help people with type 2 diabetes.
Vitamin D and Weight Loss
Obesity is a risk factor for low vitamin D levels, because the more weight you carry, the more of the vitamin you require. Studies have also shown a deficiency of vitamin D may increase your risk of becoming obese later in life. One small study found women with low levels of vitamin D might be more prone to gain weight.
Low "D" and Depression
There may be an association between low levels of vitamin D and depression. Studies show mixed results, however, and further research is needed. Vitamin D itself may not ward off depression but in patients who are taking antidepressants, taking them along with vitamin D may help reduce symptoms of depression.
How Does Sun Give You Vitamin D?
The easiest way to get vitamin D is by exposing your skin to direct sunlight, specifically, ultraviolet B (UVB) rays. The more you expose your skin, the more vitamin D your body produces. You only need to spend about half as much time as it takes to turn pink and get sunburn. This means if you are fair-skinned and normally start to turn pink in 30 minutes, you only need 15 minutes of skin exposure to the sun to produce the vitamin D3 your body needs. The darker your skin, the more time you need in the sun to produce vitamin D. The amount of vitamin D you get from sun exposure depends on the time of day, your skin tone, where you live, and how much skin you expose.
Dining With Vitamin D
Generally, sun exposure is the best way to get the vitamin D your body needs. Most foods that contain vitamin D only contain small amounts and won't give you all your body needs. Foods that contain vitamin D include fatty fish such as salmon or mackerel, beef liver, egg yolk, milk or orange juice fortified with vitamin D, fortified cereals, and infant formulas.
Begin Your Day With Vitamin D
Many foods typically eaten for breakfast are fortified with vitamin D. Milk, cereal, orange juice, and breads often have added vitamin D. Egg yolks also contain the vitamin. Read labels to find out how much vitamin D is in the food you eat for breakfast.
Vitamin D Supplements
If you don't get enough sun exposure, food is unlikely to give you the amount of vitamin D your body needs. In this case, your doctor may recommend you take vitamin D supplements. There are two forms of vitamin D: D2 (ergocalciferol), found in food, and D3 (cholecalciferol), produced by your body from exposure to sunlight. Most over-the-counter vitamin D supplements contain vitamin D3, which is not usually vegetarian. If you have concerns about this, your doctor may prescribe vitamin D2 supplements.
Are You Vitamin D Deficient?
There are some risk factors for vitamin D deficiency. These include factors you can control such as:
Symptoms of "D" Deficiency
Symptoms of vitamin D deficiency may be very general. You might have aches and pains and fatigue. You may not have any symptoms at all. If your vitamin D deficiency is severe, you may suffer form bone pain and reduced mobility. In adults, severe vitamin D deficiency is called osteomalacia, and in children a severe deficiency can lead to rickets.
Testing Your Vitamin D Level
A simple blood test called the 25(OH)D test can measure levels of vitamin D in the blood. Levels of the vitamin are measured in nanograms per milliliter (ng/mL), and the Institute of Medicine currently recommends 20 ng/mL as an adequate level for bone and overall health. Many experts suggest that higher levels of vitamin D, 35 to 40 ng/ml, are suggested for preventive health. Levels higher than that do not appear to offer any additional benefits.
How Much Vitamin D Do You Need?
The U.S. recommended daily allowance (USRDA) for vitamin D is 600 IU (international units) per day for children age 1 year up to adults of 70 years. Infants under 1 year need 400 IU, while adults 71 and older require 800 IU. Vitamin D in excess of 4,000 IU can cause side effects such as anorexia, excessive urine output, heart arrhythmias, and kidney stones.
Daily "D" for Breast-feeding Babies
The amount of vitamin D in human breast milk is minimal. In addition, because infants should be kept from direct sunlight and use sunscreen, they generally do not get enough of this vitamin without supplementation. The American Academy of Pediatrics (AAP) recommends nursing infants should receive 400 IU of vitamin D supplementation per day.
Vitamin D for Older Children
Many children do not get the recommended amounts of vitamin D in their diet, putting them at risk for vitamin D deficiency and rickets. The AAP recommends infants 1 year and under get 400 IU per day of vitamin D, and 600 IU daily of vitamin D for children and teens. Talk to your child's pediatrician about vitamin D supplementation and the right amount for your child.
How Much Is Too Much Vitamin D?
There is such a thing as too much vitamin D. Vitamin D in excess of 4,000 IU can cause side effects such as anorexia, excessive urine output, heart arrhythmias, and kidney stones. Long-term toxicity can cause damage to the heart, blood vessels, and kidneys. Excess vitamin D is usually caused by taking too much in the form of supplements. It is not possible to get too much vitamin D from sun exposure – the body regulates the amount it produces.
Drugs That Interact With Vitamin D
Vitamin D supplements can interact with several types of medications. Steroids can interfere with vitamin D metabolism and affect calcium absorption. Weight loss drugs including orlistat (Xenical, and Alli) and the cholesterol-lowering drug cholestyramine (Questran, LoCholest, Prevalite) can reduce your body's absorption of vitamin D and other fat-soluble vitamins. Drugs to control epileptic seizures phenobarbital and phenytoin (Dilantin) can increase the metabolism of vitamin D and reduce calcium absorption. Statins and diuretics can increase vitamin D levels. Tell your doctor if you take any vitamin D supplements.
Vitamin D and Colon Cancer
Some studies have shown vitamin D may affect cancer risk. More research is needed to determine if low levels of vitamin D in the blood increase cancer risk, or if adequate supplementation of vitamin D can prevent cancer.
Vitamin D and Other Cancers
Research is ongoing on the possible connection between certain cancers and vitamin D. Some think it may help prevent colon, prostate, and breast cancers, but the evidence so far is lacking and it is unknown if vitamin D can prevent cancer, or increase risk. One study even found vitamin D levels might increase the risk of pancreatic cancer. Currently, the VITAL Study at the Brigham and Women's Hospital, an affiliate of Harvard University Medical School, is investigating whether taking vitamin D and omega-3 fatty acids reduces the risk for developing cancer, heart disease, and stroke.
Vitamin D and Heart Disease
Low levels of dietary vitamin D are associated with a greater risk for stroke and heart disease. On the flip side, high levels of vitamin D deficiency can cause toxicity and damage the heart, blood vessels, and kidneys. Talk to your doctor about the right amount of vitamin D for your heath needs.
A Factor in Dementia?
One risk factor for lower levels of vitamin D is age. As we age, our skin thins, and we can't produce as much vitamin D as we used to. Low levels of vitamin D have been associated with cognitive decline; however, more research is needed to determine the optimum levels of vitamin D needed to possibly prevent dementia.
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