Vitamin D is a fat soluble prohormone, which means it is a forerunner to a hormone.  In humans, this vitamin is needed to keep blood calcium and phosphorus levels within normal ranges.  In addition, vitamin d facilitates calcium and phosphorus absorption.  This is helpful in ensuring appropriate growth in teeth and bones in humans.  Other important benefits of this vitamin include aiding insulin secretion, regulating blood pressure and enhancing immunity.  Vitamin D is unique in that it is absorbed with either ingestion or through the skin by sunlight exposure.  However, as vital as this vitamin is to humans, an overdose can lead to serious harmful, and sometimes fatal, consequences.

What Vitamin D Toxicity Means

Toxicity is the degree to which a substance is harmful and can cause damage.  If the substance is vitamin D, an excess amount causes a once helpful nutrient to become toxic, or poisonous.  The body naturally has a low vitamin D requirement on a daily basis.  Even 10 to 15 minutes of sunlight three times a week causes the body to produce sufficient of this vitamin so that an otherwise healthy person would not need supplemental vitamins.  However, since humans are unable to shut down its absorption process, high levels build up in the bloodstream.  When toxic levels are reached the body reacts negatively.

How Vitamin D Toxicity Occurs

This serious condition can be the result of taking an accidental overdose of the vitamin.  This has been known to happen frequently with people who take vitamin supplements or certain nutritional supplements with high a concentration of vitamin D.  Other causes of toxicity can be an error on the part of a doctor, pharmacist or even the patient taking vitamin supplements.  In rare cases the overdose is intentional, as in a suicide or homicide.

Symptoms of a Vitamin D Overdose

Too much of this substance in the bloodstream can manifest such symptoms as bone pain, weakness in the muscles, fatigue, and itchy skin.  Some people have experienced nervousness, dehydration and deafness.

Physical Damage Related to a Vitamin D Overdose

A patient suffering from vitamin D toxicity will have elevated blood calcium levels.  Loss of appetite is accompanied by vomiting and other symptoms.  Eventually, the body goes into kidney failure.  In pregnant women this toxicity can lead to the birth of a mentally or physically retarded infant.

Risk Factors

Patients with rickets may be more susceptible to this condition since they are usually prescribed supplements.  People with other vitamin D deficiency related conditions are also at risk for toxicity.  Vitamin supplements, or any other medication, should be kept away from young children, who may mistake colored pills for candy.

Prevention and Treatment

No specific antidote is available for vitamin D toxicity.  Some doctors have been known to cease vitamin therapy for the patient and to simply allow the excess to eliminate from the patient’s system over time.  Unfortunately, if kidney damage has occurred due to this condition it cannot be reversed.  Health screenings and counseling, including dietary counseling, have been helpful in the prevention of vitamin D overdose.

The importance of vitamin D to good health is well documented.  A sufficient amount is helpful in boosting the body’s immune system, regulating blood pressure and maintaining calcium balance.  Vitamin D is commonly known to be absorbed through the skin from sunlight or taken as supplements.  It can also be found in some foods like egg yolks, cream and butter.

In the United State, fluid milk, evaporated milk and most dried milk has been enriched with vitamin D.  Also, orange juice and cereal products are fortified with this vitamin.  The food source which has the highest concentration is fish liver oil.  Even so, recent studies suggest a huge increase of Americans who are deficient in this vitamin.  The studies further revealed that as many as three-quarters of teens and adults in this country are deficient.

Vitamin D deficiency has adverse affects on the entire body.  The symptoms of this deficiency include, but are not limited to:

• Depression
• Weight loss
• Diabetes
• Heart disease
• Muscle weakness

Another symptom that a shortage of vitamin D can cause is susceptibility to autoimmune diseases.  These conditions include rheumatoid arthritis, diabetes and multiple sclerosis patients.  Changes in vitamin D levels influence no less than 229 human genes, as discovered by researchers in Canada and the UK.  This same study indicated that worldwide one billion people are affected by this deficiency.

Osteomalacia is yet another vitamin D deficiency concern.  This extreme condition causes abnormal bone malformation and softening.  Phosphorus and calcium deficiencies can also result in this condition.  It is treated with vitamin D and calcium supplements.  Osteomalacia has been known to occur more commonly after the winter season, when exposure to sunlight has been restricted.

Strict vegetarians are one common group of people susceptible to this deficiency.  This is because, as a whole, they do not ingest dairy foods which are fortified with vitamin D.

Alcoholics, darker skinned people as well as liver or kidney disease patients are also at increased risk.  Another common risk group is people who have inadequate pancreatic function, such cystic fibrosis or pancreatitis.  In pregnant women, pelvic contractions cause by rickets can occur as well as perinatal death.

According to the National Institute of Health Office, the level of vitamin D added to food is specified by law.

Because the vitamin is extremely stable, foods which have been fortified with vitamin D will not deteriorate if warmed or kept for a long time.  Such products will usually indicate that it is stable to oxidation and heat on the packaging.  Eating these foods has been known to cause improvement in vitamin D levels in the body.

The prevention of this deficiency, in most cases, can be achieved through eating healthy food. In fact, dietary guidelines point out food should supply most nutrient needs as it contains compounds which are beneficial to health.  There are instances when supplements to the diet are necessary.  A doctor can assess which course of action is best according to patient need and medical history.

Discussions and research continue worldwide about the connection between vitamin D and certain types of cancers.  It has long been proven that deficiencies in this vitamin are detrimental in sustaining good health.  A large percentage of Americans have this deficiency due to living in northern areas.  Some are deficient due to not getting enough sun.  While not a guarantee, evidence is emerging that indicates vitamin D could possibly be used to prevent cancer.

Vitamin D has been reported to cut the risk of cancer by as much as 25% in some case studies.  One observational study concluded that breast and colon cancer could be avoided by sufficient amounts of vitamin D.  Although the connection between vitamin D and cancer has been big news recently, research on this topic has been ongoing from 70 years ago until the present time.

It was observed in the 1930’s that people who spent years in the sun developed internal, deadly types of cancers much less often than those who did not.  These people did develop squamous cell skin cancer, which is relatively benign.  However, it was noted that cancer of the breast, colon and prostate were uncommon among this group.  The conclusion was that the cell skin cancer caused immunity against the more deadly cancer.  Although it was later proven that this conclusion was unfounded, the observation that people with the skin cancer developed deadly cancer in much lower numbers still remained true.

In the late 1980’s it was discovered that exposure to the sun reduced the risk of colon cancer.  The epidemiologists who made this discovery also found that breast cancer was diagnosed less (by half) in women who were exposed to sunlight than those who were not.  Other researchers found the same to be true of prostate cancer.

The benefits of vitamin D with regard to women’s health have been overwhelmingly positive.  Cancers commonly found in women; namely breast, colon and ovarian cancer, have been linked to low vitamin D levels.  In fact, it has been proven that women having higher vitamin D blood and calcium levels had a decreased risk for developing breast cancer.  The combination of the vitamin, along with calcium, seemed to protect the body from developing cancerous cells.

Even with such overwhelming reports which give hope that vitamin D has become the “wonder drug” against cancer, many in the medical profession remain cautious.  Though there is no doubt that vitamin D is an essential element to good health, there is no clear indication that it is associated with reduced risks of some forms of cancer.  The National Cancer Institute (NCI), a research institute, does not recommend its supplemental use in the prevention of cancer.  It is conceded that some protection against colorectal and other cancers has been proven through the evidence.  However, this evidence has been inconsistent and, by some accounts reported to increase the risk for some forms of cancer.

Whether it is agreed that vitamin D can be used in the prevention of cancer or not, there is has been no argument reported against the benefits of maintaining healthy vitamin D levels.

Medical professionals continue to remain cautious when treating people suffering from major depression.  This includes which methods of therapy are best for their patients.  These professionals are aware of growing research that does suggest that vitamin D could be an effective form of treatment for these patients.  However, they have also seen evidence that this has not been a solution for many who receive this unfortunate diagnosis.

Walter E. Stumpf is one of the pioneers in vitamin D research.  He is a professor at the University of North Carolina who made the insightful prediction that vitamin D and bright light would play a huge role in psychiatry over a decade ago.  His research confirmed that Ultra Violet B (UVB) produces vitamin D.  And further study indicated that bright light without UVB resulted in improved mood in this and countless other studies.  But there is still no clear answer to the question of whether this vitamin has an effect on the resulting mood improvement.  This is relevant because sunlight, a known resource for vitamin D, can be also considered “bright light”.

Seasonal affective disorder relates to a substantial change of mood or depression due to minimal exposure to sunlight.  This type of depression occurs in relation to the seasons. It is most commonly manifested during winter months; especially in people living in the northern areas of the country.  The symptoms include decreased concentration, sleepiness during the daytime, little or no energy and withdrawal from social activities.  Treatment consists of medication and talk therapy.  Light therapy with the use of a lamp which mimics sunlight is helpful to some patients.  Again, this may be proof to some that sunlight, although simulated, has a direct positive affect on the symptoms of depression.

Other research which seems to prove the relationship between vitamin D and depression has revealed that anxiety and depression are more common in people with this deficiency.  In addition, there is also some proof that vitamin D is helpful to brain health and increases serotonin levels.  Serotonin is a neurotransmitter that has undisputedly been shown to increase feelings of well being in humans.  This could possibly be a link to the positive effect which vitamin D would have on depression.  Some doctors have prescribed high doses of vitamin D which helped to relieve symptoms, leading to the conclusion that there is a possible relationship between vitamin D and depression.

Even so, there have been numerous challenges to these observations.  There are indications that there is no association between the symptoms of depression and vitamin D concentration in the bloodstream.  For each study conducted to prove there is a connection, there are just as many that reach conclusions that are the exact opposite.

Admittedly, researchers do state that more studies are needed to form any real conclusions.  Continual observation, reports and review emerge almost daily; with just as many opposing conclusions.  Doctors have advised patients to be evaluated based on their individual circumstances to determine whether vitamin D therapy is advisable to provide relief to their depression.

One of the reasons it is important for the body to maintain sufficient vitamin D is that it keeps the immune system boosted.  In addition, it is vital to many organs and prevents certain autoimmune diseases.  Maintaining a healthy diet goes a long way toward keeping vitamin D at adequate levels. This is because vitamin D can be found naturally in some food that is usually eaten on a daily basis.  Other food products are fortified, or enriched with vitamin to produce the same benefits.  The following foods contain vitamin D in its natural state.

Omega-3 rich fish and fish oil are the leading providers.  Some fish, like mackerel, contain 90% of the required amount of vitamin D.  The Food and Drug Administration suggests that oily fish be eaten to supplement not only vitamin D, but essential fatty acids that are not produced in the body.  Sockeye salmon provides the same percentage as mackerel; especially wild salmon.  Herring, tuna and sardines are sources of vitamin D rich food. Other fish, such as catfish, feed on plankton, which naturally create vitamin D from sunlight absorption.  Shrimp and other crustaceans are naturally plenteous in vitamin D.

Mushrooms are also packed with this vitamin, largely because of their ability to absorb sunlight, another natural source of vitamin D.  Shiitake mushrooms also contain most of the vitamin B group.  When purchasing mushrooms, it is recommended that finding mushrooms that have been dried in the sun are of far greater benefit than those that have been dried artificially.

Eggs contain small amounts of vitamin D.  One egg provides around 10% of the recommended amount of vitamin D.  It is suggested that free range eggs offer more benefit.  Liver and beef are natural sources of small amounts of vitamin D.  Non refined pure cod liver oil from which vitamin D has not been removed is another excellent source.  Reading the label on cod liver oil products will determine if vitamin D has been retained.

While the list of food containing natural vitamin D is relatively small, food enriched with this vitamin are relatively available.  Most popular among these are milk and milk products.  Fortified pre packaged food such as cereal has become another well accepted source of vitamin D.  Margarine, cheese, yogurt and some juices are enriched to help keep levels within normal range.  More recently infant formula is being sold that has been fortified with vitamin D.  There is also a wide selection of baby food with vitamin D added.  Many soy milk products are fortified for people who cannot tolerate cow’s milk.  Parents often offer soy milk to children who are simply averse to cow’s milk in order to ensure vitamin D consumption.

There are countless health benefits to having sufficient vitamin D in the body.  This can be achieved by making sure natural sources of vitamin D are eaten on a daily basis through careful meal planning.  In addition, food commonly eaten by both adults and children have had vitamin D added, making it easier to avoid deficient levels that put health at risk.