Using Vitamin D as a Supplement

Vitamin D is a very important vitamin. Its main role is to enable our body to absorb phosphorus and calcium. However, it does many other things as well. Most of the vitamin D that we need can be obtained through direct sun exposure. However, for a variety of reasons, including age, ethnic origin, job, geographical location, obesity and more, people are no longer getting the right amount of sun exposure. This is now so significant that it is believed some 60% of people in this country have a vitamin D deficiency and this is rising.

There are a number of good sources of vitamin D other than the sun. Various oily fish, for instance, contain the vitamin. Most of our dairy products, orange juices and cereals, have been fortified with vitamin D. However, these levels are all quite low. As a result, it is now recommended that people take a vitamin D supplement in order to avoid deficiency and the various health conditions associated with this.

What Is a Vitamin D Supplement Effective For?

Researchers have found that a vitamin D supplement can be effective for:

• Hypophosphatemia, which leads to low levels of phosphate
• Fanconi syndrome, which causes low phosphate levels
• Parathyroid problems, leading to low levels of calcium in the blood
• Osteomalacia, which is softening of the bones
• Psoriasis, although vitamin D should be used topically
• Renal osteodystrophy, a bone disorder in people with kidney failure
• Rickets
• Vitamin D deficiency

Because vitamin D is now known to be so important, researchers are always studying it and discovering new things. As a result, they have also declared that supplementation is likely to be effective for:

• Bone loss experienced by people who take corticosteroids
• Fall prevention
• Lowering blood pressure
• Decreasing body sway
• Osteoporosis

Researchers have also stated that supplements are possibly effective for the following conditions:

• Certain types of cancer
• Cavities
• Hyperparathyroidism, which causes bone loss
• Multiple sclerosis
• Respiratory infections
• Rheumatoid arthritis
• Tooth loss
• Weight loss

Through the research, scientists have also released a list of things that vitamin D may be ineffective for. These include:

• Breast cancer
• Muscle strength
• Bone loss in those who have had a kidney transplant
• Tuberculosis

Furthermore, while research continues, scientists have stated that there is currently insufficient evidence to suggest vitamin D supplements have any effect on the following:

• Asthma
• Heart disease
• Kidney disease
• Chronic obstructive pulmonary disease (COPD)
• Mental function
• Colorectal cancer
• Diabetes
• Heart failure
• High cholesterol
• High blood pressure
• Low birth weight
• Metabolic syndrome
• Overall mortality
• Myelodysplastic syndrome, a blood cell disease
• Gum disease
• Premenstrual syndrome
• Proximal myopathy, a muscle disease
• Seasonal depression
• Seborrheic keratosis (wart-like growths)
• Muscle pain caused by statins
• Vaginal atrophy
• Warts
• Bronchitis
• Breathing disorders

At the same time, however, many people with the above condition have said that they have noticed benefits from taking vitamin D. This is why further research are being done.

Safety and Side Effects

It is now recommended that people supplement their vitamin D intake each day. However, there is a lot of inconsistency about how much should be taken and by whom. Unfortunately, it is unlikely that there will be a straight answer about this soon. Nevertheless, a few details have been released in terms of safety.

Safety Details
Likely safe ·         When recommended IUs are taken orally.

·         When recommended IUs are injected into the muscle.


Taking too much will generally lead to vomiting, metallic taste, nausea, dry mouth, loss of appetite, headaches, sleepiness, fatigue and general weakness. Stopping supplementation usually makes these symptoms go away as well.

Possibly unsafe If more than 4,000 IUs are taken every day for an extended period.

Special Warnings about Vitamin D Supplementation

Taking too much vitamin D can cause an overdose, which is known as hypervitaminosis D. This is more likely in certain conditions. This is why some special warnings and precautions have also been released, as described in the table below.

Condition Warnings
Pregnant and nursing mothers Vitamin D is likely safe so long as 4,000 IUs aren’t exceeded. Vitamin D is possibly unsafe if higher doses are taken, potentially leading to serious harm to the infant.
Kidney disease Vitamin D may heighten levels of calcium, thereby hardening the arteries. At the same time, not supplementing can lead to renal osteodystrophy, a bone disease.
High serum calcium This could be made worse by taking supplements.
Atherosclerosis This could be made worse through supplementation, particularly if you also have kidney disease.
Sarcoidosis Vitamin D must be used with caution. It can lead to kidney stones.
Histoplasmosis Vitamin D must be used with caution. It can lead to kidney stones.
Hyperparathyroidism Vitamin D must be used cautiously.
Lymphoma Vitamin D must be used with caution. It can lead to kidney stones.
Tuberculosis Vitamin D must be used with caution. It can lead to kidney stones.

Interactions with Vitamin D

Another issue to be aware of when you choose to take a vitamin D supplement is that it can interact with other drugs. The list below shows moderate interactions. This means that you must be very cautious when using vitamin D:

• Aluminum
• Calcipotriene
• Digoxin
• Diltiazem
• Verapamil
• Water pills

Additionally, vitamin D is known to have minor interactions with the following:

• Cimetidine
• Heparin
• Low molecular weight heparins

Dosing of Vitamin D

There is still a lot of confusion about how much vitamin D someone should take. Because of this research, the accepted levels of the vitamin in IUs (international units) have been steadily increasing over the past one hundred years or so. What we do know, at present, is that if the vitamin is taken orally, the following IUs should be taken for certain specific conditions:

• Prevention of fractures and osteoporosis – 400 to 1,000. In the elderly, it may be better to take 1,000 to 2,000 per day.
• Prevention of multiple sclerosis – 400 IU per day
• Cancer prevention – 1,100 IU
• Muscle pain caused by statin drugs – 400 per day or 50,000 per week
• Flu prevention – 1,200 IU

It is hugely important that you don’t become your own doctor, however. You should never exceed the IU guidelines, unless a medical professional has advised you. Generally speaking, supplements only contain 400 IU. If you do want to take more, you should only do so if that has been recommended by your doctor.

An estimate has been released by the Institute of Medicine, which is the RDA (recommended daily allowance). They frequently update their RDA lists and the last time they did this for vitamin D was in 2010. They have said that:

• Those aged between 1 and 70 should take 600 IUs per day.
• Those over the age of 70 should take 800 IUs per day.
• Babies up to one year should take 400 IUs per day.
• Pregnant and nursing mothers should take 600 IUs per day.

However, other organizations have released different RDAs. The table below highlights this in greater detail.

Organization RDA in IUs Further details
American Academy of Pediatrics 400 In 2008, they recommended this for all infants and children. They also stated that parents shouldn’t use liquid vitamins. This is because one mistaken dropper-ful could deliver 10,000 IU. The FDA is now implementing new rules that ensure each dropper can only deliver 400 IUs.
National Osteoporosis Foundation ·         400 to 800 for adults under 50

·         800 to 1,000 for adults over 50

North American Menopause Society 700 to 800 This is their recommendation for women who could develop a vitamin D deficiency because they do not get sufficient sun exposure. This could be due to geographical location or lifestyle, for instance.
Osteoporosis Society of Canada ·         400 to 1,000 for people under 50

·         800 to 2,000 for people over 50

Canadian Cancer Society 1,000 for adults during fall and winter Adults should take 1,000 per day all year if they are at increased risk of deficiency. This could be those with dark skin, those who cover up, the elderly and people who spend most of their time indoors.

It is also agreed that people should take cholecalciferol, which is vitamin D3. This is more effective than ergocalciferol, which is vitamin D2.

Resources and References:

Benefits of Vitamin D Supplements Still Debated – Advantages of vitamin D supplements. (Harvard Health Publications)
Do You Really Need to Take Vitamin D Supplements? – Use of vitamin D supplements. (Cleveland Clinic, Health Essentials)
Vitamin D Supplements: Are Yours Helping or Hurting You? – Benefits of vitamin D supplements. (Precision Nutrition)
Vitamin D Safety – Safety issues on vitamin D supplements. (Mayo Clinic)
Vitamin D: Fact Sheet for Health Professionals – Information on vitamin D for health professionals. (