Nutrients - Vitamin D

Vitamin D

Overview

Many of us are deficient in certain nutrients and our doctors do not test us as we age. Some of us do have sufficient quantities in our diets and then take supplements, which may give us an oversupply. Your doctor should test for all of these (that have testing available) before you run out and buy supplements. You may not need them as part of your diet because you are already obtaining sufficient intake from your diet.

I would be remiss if I did not give you a warning about not overcompensating and ingesting too much of some of these nutrients as there are some medical concerns with toxicity and conflicts with certain prescription medications. More is often not better and can be fatal with some supplements and herbal supplements.

Vitamin D is one large misnomer as it is a hormone, but this is now commonly accepted and will likely never be changed. It is the one that most people will have a difficult time in overdosing, but it has happened.

Tests

This is to inform you that the newer Vitamin D blood tests are over 40 percent unreliable and you need to make sure that the tests are not used. Please read this article in WebMD. Older testing procedures are the better bet.

Recommended Daily Allowance

The current RDA for vitamin D is being revised, and some experts suggest that adults should take at least 2000 IU of vitamin D daily. I personally use 3000 IU of Vitamin D3 daily and some that I know take as high as 10,000 IU.

Recommended dietary allowances currently for vitamin D are listed below. Seniors and people who don't get exposed too much sunlight may need to take supplements. Seniors may be at risk of developing vitamin D deficiency because, as we age, the body does not make as much vitamin D from sunlight, and it has a harder time converting vitamin D into a form it can use.

If you are concerned about your vitamin D levels, ask your doctor whether you should take a supplement, and how much.

Pediatric

1. Infants birth to 12 months: 400 IU (adequate intake)

2. Children 1 - 18 years: 600 IU (recommended dietary allowance)

Note: The American Academy of Pediatrics (AAP) recommends 400 IU of vitamin D daily for breastfed infants until they are weaned and drinking at least 1 liter of whole milk or formula fortified with vitamin D. The AAP also recommends that children and teens who drink less than 1 liter of milk a day take 400 IU of vitamin D.

Ask your doctor before giving a vitamin D supplement to a child.

Adult

1. 19 - 50 years: 600 IU (recommended dietary allowance)

2. 70 years and older: 800 IU (recommended dietary allowance)

3. Pregnant and breastfeeding females: 600 IU (recommended dietary allowance)

Food Sources

There are two dietary forms of vitamin D:

1. Cholecalciferol - D3

2. Ergocalciferol - D2

These are naturally found in foods and are added to milk. Not all yogurt and cheese are fortified with vitamin D. Food sources of vitamin D include:

1. Cod liver oil (best source). Cod liver oil often contains very high levels of vitamin A, which can be toxic over time. Ask your health care provider about this source of vitamin D.

2. Fatty fish such as salmon, mackerel, tuna, sardines, herring

3. Vitamin D-fortified milk and cereal

4. Eggs

Functions

Taking the proper amount of vitamin D may help prevent several serious health conditions. These conditions include:

1. Osteoporosis - Vitamin D helps your body absorb and use calcium, which you need for strong bones. Getting enough vitamin D throughout your life is important, since most bone is formed when you are young. For post-menopausal women who are at higher risk of osteoporosis, taking vitamin D along with calcium supplements can reduce the rate of bone loss, help prevent osteoporosis, and may reduce the risk of fractures.

2. Other Bone Disorders - Vitamin D protects against rickets and osteomalacia, softening of the bones in adults. Seniors who live in northern areas and people who do not get direct sunlight for at least 45 minutes per week should make sure they get enough vitamin D through fortified milk and dairy products. Or, they can take a vitamin D supplement or a multivitamin with vitamin D.

3. Prevention of Falls - People who have low levels of vitamin D are at greater risk of falling, and studies have found that taking a vitamin D supplement (700 - 1000 IU daily) may reduce that risk. In seniors, vitamin D may reduce falls by 22%.

4. Parathyroid Problems - The four parathyroid glands are located in the neck. They make parathyroid hormone (PTH), which helps the body store and use calcium and phosphorus. Vitamin D is often used to treat disorders of the parathyroid gland.

5. High Blood Pressure (Hypertension) - People with low levels of vitamin D seem to have a high risk of developing high blood pressure than those with higher levels of vitamin D. However, there's no proof that low levels of vitamin D cause high blood pressure in healthy people. Evidence about vitamin D and blood pressure has been mixed.

6. Cancer - There is some evidence that getting enough vitamin D may lower your risk of certain cancers, especially of the colon, breast, prostate, skin, and pancreas. This evidence is based mostly on studies of large groups of people, population studies, and doesn't prove a connection between taking vitamin D and lowering your cancer risk. Some research suggests that postmenopausal women who take calcium and vitamin D supplements may have a lower risk of developing cancer of any kind compared to those who don' t take these supplements.

7. Seasonal Affective Disorder (SAD) - SAD is a type of depression that happens during the winter months, when there's not much sunlight. It's often treated with photo (light) therapy. A few studies suggest that the mood of people with SAD improves when they take vitamin D. Talk to your doctor about whether vitamin D might help your treatment for SAD.

8. Diabetes - Studies find that people who have lower levels of vitamin D are more likely to develop type 2 diabetes than people who have higher levels of vitamin D. But there is no evidence that taking vitamin D can help prevent or treat type 2 diabetes. One study found that giving infants doses of 2,000 IU per day of vitamin D during the first year of life may help protect them from developing type 1 diabetes when they are older.

9. Heart Disease - Studies suggest that people with low levels of vitamin D have a greater risk of developing heart disease, including heart attack, stroke, and heart failure compared to people with higher levels of vitamin D. Low levels of vitamin D may increase the risk of calcium build-up in the arteries. Calcium build-up is part of the plaque that forms in arteries when you have atherosclerosis and can lead to a heart attack or stroke.

10. Multiple Sclerosis (MS) - Studies have found that women who take at least 400 IU of vitamin D daily lower their risk of developing MS. And higher levels of vitamin D in the blood seem to be associated with a lower risk of developing MS in white men and women, although the same may not be true of African American and Hispanic men and women. However, this does not mean that vitamin D supplements will help prevent or treat MS in people.

11. Obesity - Studies have found that people who have lower levels of vitamin D are more likely to be obese compared to people with higher levels of vitamin D. One high-quality study also found that postmenopausal women who took 400 IU vitamin D plus 1,000 mg calcium daily for 3 years were less likely to gain weight than those who took placebo, although the weight difference was small. Women who were not getting enough calcium to start with (less than 1,200 mg per day) saw the most benefit.

12. Overall Mortality - Studies suggest that people with lower levels of vitamin D have a higher risk of dying from any cause.

Precautions

Because of the potential for side effects and interactions with medications, you should take dietary supplements only under the supervision of a knowledgeable health care provider.

Taking too much vitamin D can cause several side effects. However, scientists don' t all agree on how much is too much. The National Institutes of Health has set the maximum tolerable upper limit at 1,000 IU daily for infants 0 - 6 months, 1,500 IU daily for infants 6 months to one year, 2,500 IU daily for children 1 - 3 years, 3,000 IU daily for children 4 - 8 years, and 4,000 IU daily for anyone over 9. Ask your doctor to determine the right dose for you or your child.

Side effects may include:

• Being very thirsty
• Metal taste in mouth
• Poor appetite
• Weight loss
• Bone pain
• Tiredness
• Sore eyes
• Itchy skin
• Vomiting
• Diarrhea
• Constipation
• A frequent need to urinate
• Muscle problems

You cannot get too much vitamin D from sunlight, and it would be very hard to get too much from food. Generally, too much vitamin D is a result of taking supplements in too high a dose.

People with the following conditions should be careful when considering taking vitamin D supplements:

 High blood calcium or phosphorus levels

 Heart problems

 Kidney disease

 Sarcoidosis

 Tuberculosis

Possible Interactions

If you are currently being treated with any of the following medications, you should not use vitamin D supplements without first talking to your health care provider.

Atorvastatin (Lipitor) -- Taking vitamin D may reduce the amount of Lipitor absorbed by the body, making it less effective. If you take Lipitor or any statin (drugs used to lower cholesterol), ask your doctor before taking vitamin D.

Calcipotriene (Dovonex) -- It's possible that taking vitamin D supplements and using calcipotriene, a medication applied to the skin for psoriasis, could cause calcium levels to get dangerously high in the blood.

Calcium channel blockers -- Vitamin D may interfere with these medications, used to treat high blood pressure and heart conditions. If you take any of these medications, do not take vitamin D without first asking your doctor. Calcium channel blockers include:

 Nifedipine (Procardia)

 Verapamil (Calan)

 Nicardipine (Cardene)

 DiltiaZem (Cardizem, Dilacor)

 Amlodipine (Norvasc)

Corticosteroids (prednisone) -- Taking corticosteroids long-term can cause bone loss, leading to osteoporosis. Supplements of calcium and vitamin D can help maintain bone strength. If you take corticosteroids for 6 months or more, ask your doctor about taking a calcium and vitamin D supplement.

Digoxin (Lanoxin) -- a medication used to treat irregular heart rhythms. Taking vitamin D if you take digoxin may cause levels of calcium to get dangerously high in the blood.

These drugs may raise the amount of vitamin D in the blood:

Estrogen -- Hormone replacement therapy with estrogen seems to raise vitamin D levels in the blood, which may have a positive effect on calcium and bone strength. In addition, taking vitamin D supplements along with estrogen replacement therapy (ERT) increases bone mass more than ERT alone. However, that may not be true if you also take progesterone.

Isoniazid (INH) -- a medication used to treat tuberculosis.

Thiazide -- A diuretic or water pill that helps your body get rid of too much fluid. It can increase vitamin D activity and lead to high calcium levels in the blood.

Vitamin D levels may be lowered by the following medications. If you take any of these medications, ask your doctor if you need more vitamin D:

Antacids -- Taking certain antacids for long periods of time may alter the levels, metabolism, and availability of vitamin D.

Anti-seizure medications -- these medications include:

 Phenobarbital

 Phenytoin (Dilantin)

 Primidone (Mysoline)

 Valproic acid (Depakote)

Bile acid sequestrants -- used to lower cholesterol. These medications include:

 Cholestyramine (Questran, Prevalite)

 Cholestipol (Colestid)

Rifampin -- used to treat tuberculosis

Mineral oil -- Mineral oil also interferes with absorption of vitamin D.

Orlistat (Alli) -- a medication used for weight loss that prevents your body for absorbing fat. Because of how it works, orlistat may also prevent the absorption of fat-soluble vitamins such as vitamin D. Doctors who prescribe orlistat tell their patients to take a multivitamin with fat-soluble vitamins.